Cisco IOS IPv6 Command Reference
ip mroute-cache through ipv6 general-prefix
Downloads: This chapterpdf (PDF - 767.0KB) The complete bookPDF (PDF - 9.3MB) | Feedback

ip mroute-cache

Table Of Contents

ip mroute-cache

ip name-server

ip route-cache

ip router isis

ip source-address (telephony-service)

ip unnumbered

ipv6 access-class

ipv6 access-list

ipv6 access-list log-update threshold

ipv6 address

ipv6 address anycast

ipv6 address autoconfig

ipv6 address dhcp

ipv6 address dhcp client request

ipv6 address eui-64

ipv6 address link-local

ipv6 atm-vc

ipv6 authentication key-chain eigrp

ipv6 authentication mode eigrp

ipv6 bandwidth-percent eigrp

ipv6 cef

ipv6 cef accounting

ipv6 cef distributed

ipv6 cef load-sharing algorithm

ipv6 cef optimize neighbor resolution

ipv6 cga modifier rsakeypair

ipv6 cga rsakeypair

ipv6 crypto map

ipv6 dhcp binding track ppp

ipv6 dhcp client information refresh minimum

ipv6 dhcp client pd

ipv6 dhcp database

ipv6 dhcp debug redundancy

ipv6 dhcp framed password

ipv6 dhcp ping packets

ipv6 dhcp pool

ipv6 dhcp relay destination

ipv6 dhcp-relay option vpn

ipv6 dhcp relay source-interface

ipv6 dhcp-relay show bindings

ipv6 dhcp-relay source-interface

ipv6 dhcp-relay bulk-lease

ipv6 dhcp-relay option vpn

ipv6 dhcp server

ipv6 dhcp server vrf enable

ipv6 eigrp

ipv6 enable

ipv6 flow

ipv6 flow mask

ipv6 flow mask option-headers

ipv6 flow-aggregation cache

ipv6 flow-cache entries

ipv6 flow-cache timeout

ipv6 flow-export destination

ipv6 flow-export source

ipv6 flow-export template

ipv6 flow-export template options

ipv6 flow-export version 9

ipv6 flowset

ipv6 general-prefix


ip mroute-cache


Note Effective with Cisco IOS Release 15.0(1)M and Cisco IOS Release 12.2(33)SRE, the ip mroute-cache command is not available in Cisco IOS software.


To configure IP multicast fast switching or multicast distributed switching (MDS), use the ip mroute-cache command in interface configuration mode. To disable either of these features, use the no form of this command.

ip mroute-cache [distributed]

no ip mroute-cache [distributed]

Syntax Description

distributed

(Optional) Enables MDS on the interface. In the case of Cisco 7500 series routers, this keyword is optional; if it is omitted, fast switching occurs. On the Cisco 12000 series, this keyword is required because the Cisco 12000 series does only distributed switching.


Command Default

On the Cisco 7500 series, IP multicast fast switching is enabled; MDS is disabled.
On the Cisco 12000 series, MDS is disabled.

Command Modes

Interface configuration

Command History

Release
Modification

10.0

This command was introduced.

11.2(11)GS

The distributed keyword was added.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

12.2SX

This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.

12.0(33)S

Support for IPv6 was added. This command was implemented on the Cisco 12000 series routers.

15.0(1)M

This command was removed.

12.2(33)SRE

This command was removed.


Usage Guidelines

On the Cisco 7500 Series

If multicast fast switching is disabled on an incoming interface for a multicast routing table entry, the packet will be sent at the process level for all interfaces in the outgoing interface list.

If multicast fast switching is disabled on an outgoing interface for a multicast routing table entry, the packet is process-level switched for that interface, but may be fast switched for other interfaces in the outgoing interface list.

When multicast fast switching is enabled (like unicast routing), debug messages are not logged. If you want to log debug messages, disable fast switching.

If MDS is not enabled on an incoming interface that is capable of MDS, incoming multicast packets will not be distributed switched; they will be fast switched at the Route Processor (RP). Also, if the incoming interface is not capable of MDS, packets will get fast switched or process switched at the RP.

If MDS is enabled on the incoming interface, but at least one of the outgoing interfaces cannot fast switch, packets will be process switched. We recommend that you disable fast switching on any interface when MDS is enabled.

On the Cisco 12000 Series

On the Cisco 12000 series router, all interfaces should be configured for MDS because that is the only switching mode.

Examples

The following example shows how to enable IP multicast fast switching on the interface:

ip mroute-cache

The following example shows how to disable IP multicast fast switching on the interface:

no ip mroute-cache

The following example shows how to enable MDS on the interface:

ip mroute-cache distributed

The following example shows how to disable MDS and IP multicast fast switching on the interface:

no ip mroute-cache distributed


ip name-server

To specify the address of one or more name servers to use for name and address resolution, use the ip name-server command in global configuration mode. To remove the addresses specified, use the no form of this command.

ip name-server [vrf vrf-name] server-address1 [server-address2...server-address6]

no ip name-server [vrf vrf-name] server-address1 [server-address2...server-address6]

Syntax Description

vrf vrf-name

(Optional) Defines a Virtual Private Network (VPN) routing and forwarding instance (VRF) table. The vrf-name argument specifies a name for the VRF table.

server-address1

IPv4 or IPv6 addresses of a name server.

server-address2...server-address6

(Optional) IP addresses of additional name servers (a maximum of six name servers).


Command Default

No name server addresses are specified.

Command Modes

Global configuration

Command History

Release
Modification

10.0

This command was introduced.

12.2(2)T

Support for IPv6 addresses was added.

12.0(21)ST

Support for IPv6 addresses was added.

12.0(22)S

Support for IPv6 addresses was added.

12.2(14)S

Support for IPv6 addresses was added.

12.2(28)SB

This command was integrated into Cisco IOS Release 12.2(28)SB.

12.2(25)SG

This command was integrated into Cisco IOS Release 12.2(25)SG.

12.4(4)T

The vrf keyword and vrf-name argument were added.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

12.2(33)SXH

This command was integrated into Cisco IOS Release 12.2(33)SXH.

Cisco IOS XE Release 2.1

This command was introduced on Cisco ASR 1000 Series Routers.


Examples

The following example shows how to specify IPv4 hosts 172.16.1.111 and 172.16.1.2 as the name servers:

ip name-server 172.16.1.111 172.16.1.2

This command will be reflected in the configuration file as follows:

ip name-server 172.16.1.111
ip name-server 172.16.1.2

The following example shows how to specify IPv4 hosts 172.16.1.111 and 172.16.1.2 as the name servers for vpn1:

Router(config)# ip name-server vrf vpn1 172.16.1.111 172.16.1.2


The following example shows how to specify IPv6 hosts 3FFE:C00::250:8BFF:FEE8:F800 and 2001:0DB8::3 as the name servers:

ip name-server 3FFE:C00::250:8BFF:FEE8:F800 2001:0DB8::3 

This command will be reflected in the configuration file as follows:

ip name-server 3FFE:C00::250:8BFF:FEE8:F800 
ip name-server 2001:0DB8::3

Related Commands

Command
Description

ip domain-lookup

Enables the IP DNS-based hostname-to-address translation.

ip domain-name

Defines a default domain name to complete unqualified hostnames (names without a dotted decimal domain name).


ip route-cache

To control the use of switching methods for forwarding IP packets, use the ip route-cache command in interface configuration mode. To disable any of these switching methods, use the no form of this command.

ip route-cache [cef | distributed | flow | policy | same-interface]

no ip route-cache [cef | distributed | flow | policy | same-interface]

Syntax Description

cef

(Optional) Enables Cisco Express Forwarding operation on an interface.

distributed

(Optional) Enables distributed switching on the interface. (This keyword is not supported on the Cisco 7600 routers.) Distributed switching is disabled by default.

flow

(Optional) Enables NetFlow accounting for packets that are received by the interface. The default is disabled.

policy

(Optional) Enables fast-switching for packets that are forwarded using policy-based routing (PBR). Fast Switching for PBR (FSPBR) is disabled by default.

same-interface

(Optional) Enables fast-switching of packets onto the same interface on which they arrived.


Command Default

The switching method is not controlled.

Command Modes

Interface configuration (config-if)

Command History

Release
Modification

10.0

This command was introduced.

11.1

The flow keyword was added.

11.2GS

The cef and distributed keywords were added.

11.1CC

cef keyword support was added for multiple platforms.

12.0

The policy keyword was added.

12.2(25)S

This command was integrated into Cisco IOS Release 12.2(25)S. The ip route-cache flow command is automatically remapped to the ip flow ingress command.

12.2(28)SB

This command was integrated into Cisco IOS Release 12.2(28)SB. This command is not supported on the Cisco 10000 series router.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

12.4(20)T

This command was integrated into Cisco IOS Release 12.4(20)T.

12.2(33)SXI

This command was integrated into Cisco IOS Release 12.2(33)SXI.


Usage Guidelines

IP Route Cache


Note The Cisco 10000 series routers do not support the ip route-cache command.


Using the route cache is often called fast switching. The route cache allows outgoing packets to be load-balanced on a per-destination basis rather than on a per-packet basis. The ip route-cache command with no additional keywords enables fast switching.

Entering the ip route-cache command has no effect on a subinterface. Subinterfaces accept the no form of the command; however, this disables Cisco Express Forwarding or distributed Cisco Express Forwarding on the physical interface and all subinterfaces associated with the physical interface

The default behavior for Fast Switching varies by interface and media.


Note IPv4 fast switching is removed with the implementation of the Cisco Express Forwarding infrastructure enhancements for Cisco IOS 12.2(25)S-based releases and Cisco IOS Release 12.4(20)T. For these and later Cisco IOS releases, switching path are Cisco Express Forwarding switched or process switched.


IP Route Cache Same Interface

You can enable IP fast switching when the input and output interfaces are the same interface, using the ip route-cache same-interface command. This configuration normally is not recommended, although it is useful when you have partially meshed media, such as Frame Relay or you are running Web Cache Communication Protocol (WCCP) redirection. You could use this feature on other interfaces, although it is not recommended because it would interfere with redirection of packets to the optimal path.

IP Route Cache Flow

The flow caching option can be used in conjunction with Cisco Express Forwarding switching to enable NetFlow, which allows statistics to be gathered with a finer granularity. The statistics include IP subprotocols, well-known ports, total flows, average number of packets per flow, and average flow lifetime.


Note The ip route-cache flow command has the same functionality as the ip flow ingress command, which is the preferred command for enabling NetFlow. If either the ip route-cache flow command or the
ip flow ingress command is configured, both commands will appear in the output of the
show running-config command.


IP Route Cache Distributed

The distributed option is supported on Cisco routers with line cards and Versatile Interface Processors (VIPs) that support Cisco Express Forwarding switching.

On Cisco routers with Route/Switch Processor (RSP) and VIP controllers, the VIP hardware can be configured to switch packets received by the VIP with no per-packet intervention on the part of the RSP. When VIP distributed switching is enabled, the input VIP interface tries to switch IP packets instead of forwarding them to the RSP for switching. Distributed switching helps decrease the demand on the RSP.

If the ip route-cache distributed, ip cef distributed, and ip route-cache flow commands are configured, the VIP performs distributed Cisco Express Forwarding switching and collects a finer granularity of flow statistics.

IP Route-Cache Cisco Express Forwarding

In some instances, you might want to disable Cisco Express Forwarding or distributed Cisco Express Forwarding on a particular interface because that interface is configured with a feature that
Cisco Express Forwarding or distributed Cisco Express Forwarding does not support. Because all interfaces that support Cisco Express Forwarding or distributed Cisco Express Forwarding are enabled by default when you enable Cisco Express Forwarding or distributed Cisco Express Forwarding operation globally, you must use the no form of the ip route-cache distributed command in the interface configuration mode to turn Cisco Express Forwarding or distributed Cisco Express Forwarding operation off a particular interface.

Disabling Cisco Express Forwarding or distributed Cisco Express Forwarding on an interface disables Cisco Express Forwarding or distributed Cisco Express Forwarding switching for packets forwarded to the interface, but does not affect packets forwarded out of the interface.

Additionally, when you disable distributed Cisco Express Forwarding on the RSP, Cisco IOS software switches packets using the next-fastest switch path (Cisco Express Forwarding).

Enabling Cisco Express Forwarding globally disables distributed Cisco Express Forwarding on all interfaces. Disabling Cisco Express Forwarding or distributed Cisco Express Forwarding globally enables process switching on all interfaces.


Note On the Cisco 12000 series Internet router, you must not disable distributed Cisco Express Forwarding on an interface.


IP Route Cache Policy

If Cisco Express Forwarding is already enabled, the ip route-cache route command is not required because PBR packets are Cisco Express Forwarding-switched by default.

Before you can enable fast-switched PBR, you must first configure PBR.

FSPBR supports all of PBR's match commands and most of PBR's set commands, with the following restrictions:

The set ip default next-hop and set default interface commands are not supported.

The set interface command is supported only over point-to-point links, unless a route cache entry exists using the same interface specified in the set interface command in the route map.
Also, at the process level, the routing table is consulted to determine if the interface is on a reasonable path to the destination. During fast switching, the software does not make this check. Instead, if the packet matches, the software blindly forwards the packet to the specified interface.


Note Not all switching methods are available on all platforms. Refer to the Cisco Product Catalog for information about features available on the platform you are using.


Examples

Configuring Fast Switching and Disabling Cisco Express Forwarding Switching

The following example shows how to enable fast switching and disable Cisco Express Forwarding switching:

Router(config)# interface ethernet 0/0/0
Router(config-if)# ip route-cache

The following example shows that fast switching is enabled:

Router# show ip interface fastEthernet 0/0/0   

FastEthernet0/0/0 is up, line protocol is up
  Internet address is 10.1.1.254/24
  Broadcast address is 255.255.255.224
  Address determined by non-volatile memory
  MTU is 1500 bytes
  Helper address is not set
  Directed broadcast forwarding is disabled
  Multicast reserved groups joined: 224.0.0.10
  Outgoing access list is not set
  Inbound  access list is not set
  Proxy ARP is enabled
  Security level is default
  Split horizon is enabled
  ICMP redirects are always sent
  ICMP unreachables are always sent
  ICMP mask replies are never sent
  IP fast switching is enabled
  IP fast switching on the same interface is disabled
  IP Flow switching is disabled
  IP Distributed switching is disabled
  IP Feature Fast switching turbo vector
  IP Null turbo vector
  IP multicast fast switching is enabled

The following example shows that Cisco Express Forwarding switching is disabled:

Router# show cef interface fastEthernet 0/0/0

FastEthernet0/0/0 is up (if_number 3)
  Corresponding hwidb fast_if_number 3
  Corresponding hwidb firstsw->if_number 3
  Internet address is 10.1.1.254/24
  ICMP redirects are always sent
  Per packet load-sharing is disabled
  IP unicast RPF check is disabled
  Inbound access list is not set
  Outbound access list is not set
  IP policy routing is disabled
  Hardware idb is FastEthernet0/0/0
  Fast switching type 1, interface type 18
  IP CEF switching disabled
  IP Feature Fast switching turbo vector
  IP Null turbo vector
  Input fast flags 0x0, Output fast flags 0x0
  ifindex 1(1)
  Slot 0 Slot unit 0 VC -1
  Transmit limit accumulator 0x48001A02 (0x48001A02)
  IP MTU 1500

The following example shows the configuration information for FastEthernet interface 0/0/0:

Router# show running-config
.
.
!
interface FastEthernet0/0/0
 ip address 10.1.1.254 255.255.255.0
 no ip route-cache cef
 no ip route-cache distributed
!

The following example shows how to enable Cisco Express Forwarding (and to disable distributed
Cisco Express Forwarding if it is enabled):

Router(config-if)# ip route-cache cef

The following example shows how to enable VIP distributed Cisco Express Forwarding and per-flow accounting on an interface (regardless of the previous switching type enabled on the interface):

Router(config)# interface e0
Router(config-if)# ip address 10.252.245.2 255.255.255.0
Router(config-if)# ip route-cache distributed
Router(config-if)# ip route-cache flow

The following example shows how to enable Cisco Express Forwarding on the router globally (which also disables distributed Cisco Express Forwarding on any interfaces that are running distributed
Cisco Express Forwarding), and disable Cisco Express Forwarding (which enables process switching) on Ethernet interface 0:

Router(config)# ip cef 
Router(config)# interface e0
Router(config-if)# no ip route-cache cef

The following example shows how to enable distributed Cisco Express Forwarding operation on the router (globally), and disable Cisco Express Forwarding operation on Ethernet interface 0:

Router(config)# ip cef distributed 
Router(config)# interface e0
Router(config-if)# no ip route-cache cef

The following example shows how to reenable distributed Cisco Express Forwarding operation on Ethernet interface 0:

Router(config)# ip cef distributed 
Router(config)# interface e0
Router(config-if)# ip route-cache distributed

Configuring Fast Switching for Traffic That Is Received and Transmitted over the Same Interface

The following example shows how to enable fast switching and disable Cisco Express Forwarding switching:

Router(config)# interface ethernet 0/0/0
Router(config-if)# ip route-cache same-interface

The following example shows that fast switching on the same interface is enabled for interface fastethernet 0/0/0:

Router# show ip interface fastEthernet 0/0/0  

FastEthernet0/0/0 is up, line protocol is up
  Internet address is 10.1.1.254/24
  Broadcast address is 255.255.255.224
  Address determined by non-volatile memory
  MTU is 1500 bytes
  Helper address is not set
  Directed broadcast forwarding is disabled
  Multicast reserved groups joined: 224.0.0.10
  Outgoing access list is not set
  Inbound  access list is not set
  Proxy ARP is enabled
  Security level is default
  Split horizon is enabled
  ICMP redirects are always sent
  ICMP unreachables are always sent
  ICMP mask replies are never sent
  IP fast switching is enabled
  IP fast switching on the same interface is enabled
  IP Flow switching is disabled
  IP Distributed switching is disabled
  IP Feature Fast switching turbo vector
  IP Null turbo vector
  IP multicast fast switching is enabled
  IP multicast distributed fast switching is disabled
  IP route-cache flags are Fast
  Router Discovery is disabled
  IP output packet accounting is disabled
  IP access violation accounting is disabled
  TCP/IP header compression is disabled
  RTP/IP header compression is disabled
  Probe proxy name replies are disabled
  Policy routing is disabled
  Network address translation is disabled
  WCCP Redirect outbound is disabled
  WCCP Redirect inbound is disabled
  WCCP Redirect exclude is disabled
  BGP Policy Mapping is disabled
  IP multicast multilayer switching is disabled

The following example shows the configuration information for FastEthernet interface 0/0/0:

Router# show running-config
.
.
!
interface FastEthernet0/0/0
 ip address 10.1.1.254 255.255.255.0
 ip route-cache same-interface
 no ip route-cache cef
 no ip route-cache distributed
!

Enabling NetFlow Accounting

The following example shows how to enable NetFlow switching:

Router(config)# interface ethernet 0/0/0
Router(config-if)# ip route-cache flow

The following example shows that NetFlow accounting is enabled for FastEthernet interface 0/0/0:

Router# show ip interface fastEthernet 0/0/0 

FastEthernet0/0/0 is up, line protocol is up
  Internet address is 10.1.1.254/24
  Broadcast address is 255.255.255.224
  Address determined by non-volatile memory
  MTU is 1500 bytes
  Helper address is not set
  Directed broadcast forwarding is disabled
  Multicast reserved groups joined: 224.0.0.10
  Outgoing access list is not set
  Inbound  access list is not set
  Proxy ARP is enabled
  Security level is default
  Split horizon is enabled
  ICMP redirects are always sent
  ICMP unreachables are always sent
  ICMP mask replies are never sent
  IP fast switching is enabled
  IP fast switching on the same interface is disabled
  IP Flow switching is enabled
  IP Distributed switching is disabled
  IP Flow switching turbo vector
  IP Null turbo vector
  IP multicast fast switching is enabled
  IP multicast distributed fast switching is disabled
  IP route-cache flags are Fast, Flow
  Router Discovery is disabled
  IP output packet accounting is disabled
  IP access violation accounting is disabled
  TCP/IP header compression is disabled
  RTP/IP header compression is disabled
  Probe proxy name replies are disabled
  Policy routing is disabled
  Network address translation is disabled
  WCCP Redirect outbound is disabled
  WCCP Redirect inbound is disabled
  WCCP Redirect exclude is disabled
  BGP Policy Mapping is disabled
  IP multicast multilayer switching is disabled

Configuring Distributed Switching

The following example shows how to enable distributed switching:

Router(config)# ip cef distributed
Router(config)# interface ethernet 0/0/0
Router(config-if)# ip route-cache distributed

The following example shows that distributed Cisco Express Forwarding switching is for FastEthernet interface 0/0/0:

Router# show cef interface fastEthernet 0/0/0

FastEthernet0/0/0 is up (if_number 3)
  Corresponding hwidb fast_if_number 3
  Corresponding hwidb firstsw->if_number 3
  Internet address is 10.1.1.254/24
  ICMP redirects are always sent
  Per packet load-sharing is disabled
  IP unicast RPF check is disabled
  Inbound access list is not set
  Outbound access list is not set
  IP policy routing is disabled
  Hardware idb is FastEthernet0/0/0
  Fast switching type 1, interface type 18
  IP Distributed CEF switching enabled
  IP Feature Fast switching turbo vector
  IP Feature CEF switching turbo vector
  Input fast flags 0x0, Output fast flags 0x0
  ifindex 1(1)
  Slot 0 Slot unit 0 VC -1
  Transmit limit accumulator 0x48001A02 (0x48001A02)
  IP MTU 1500

Configuring Fast Switching for PBR

The following example shows how to configure a simple policy-based routing scheme and to enable FSPBR:

Router(config)# access-list 1 permit 10.1.1.0 0.0.0.255
Router(config)# route-map mypbrtag permit 10
Router(config-route-map)# match ip address 1
Router(config-route-map)# set ip next-hop 10.1.1.195
Router(config-route-map)# exit
Router(config)# interface fastethernet 0/0/0
Router(config-if)# ip route-cache policy
Router(config-if)# ip policy route-map mypbrtag

The following example shows that FSPBR is enabled for FastEthernet interface 0/0/0:

Router# show ip interface fastEthernet 0/0/0

FastEthernet0/0/0 is up, line protocol is up
  Internet address is 10.1.1.254/24
  Broadcast address is 255.255.255.255
  Address determined by non-volatile memory
  MTU is 1500 bytes
  Helper address is not set
  Directed broadcast forwarding is disabled
  Multicast reserved groups joined: 224.0.0.10
  Outgoing access list is not set
  Inbound  access list is not set
  Proxy ARP is enabled
  Security level is default
  Split horizon is enabled
  ICMP redirects are always sent
  ICMP unreachables are always sent
  ICMP mask replies are never sent
  IP fast switching is enabled
  IP fast switching on the same interface is disabled
  IP Flow switching is disabled
  IP CEF switching is enabled
  IP Distributed switching is enabled
  IP Feature Fast switching turbo vector
  IP Feature CEF switching turbo vector
  IP multicast fast switching is enabled
  IP multicast distributed fast switching is disabled
  IP route-cache flags are Fast, Distributed, Policy, CEF
  Router Discovery is disabled
  IP output packet accounting is disabled
  IP access violation accounting is disabled
  TCP/IP header compression is disabled
  RTP/IP header compression is disabled
  Probe proxy name replies are disabled
  Policy routing is enabled, using route map my_pbr_tag
  Network address translation is disabled
  WCCP Redirect outbound is disabled
  WCCP Redirect inbound is disabled
  WCCP Redirect exclude is disabled
  BGP Policy Mapping is disabled
  IP multicast multilayer switching is disabled

Related Commands

Command
Description

exit

Leaves aggregation cache mode.

ip cef

Enables Cisco Express Forwarding on the RP card.

ip cef distributed

Enables distributed Cisco Express Forwarding operation.

ip flow ingress

Configures NetFlow on a subinterface.

set default interface

Configures a default interface for PBR.

set interface

Configures a specified interface for PBR.

set ip default next-hop

Configures a default IP next hop for PBR.

show cef interface

Displays detailed Cisco Express Forwarding information for interfaces.

show ip interface

Displays the usability status of interfaces configured for IP.

show mpoa client

Displays the routing table cache used to fast switch IP traffic.


ip router isis

To configure an Intermediate System-to-Intermediate System (IS-IS) routing process for IP on an interface and to attach an area designator to the routing process, use the ip router isis command in interface configuration mode. To disable IS-IS for IP, use the no form of the command.

ip router isis area-tag

no ip router isis area-tag

Syntax Description

area-tag

Meaningful name for a routing process. If it is not specified, a null tag is assumed and the process is referenced with a null tag. This name must be unique among all IP or Connectionless Network Service (CLNS) router processes for a given router.

Required for multiarea IS-IS configuration. Optional for conventional IS-IS configuration.

Note Each area in a multiarea configuration should have a nonnull area tag to facilitate identification of the area.


Defaults

No routing processes are specified.

Command Modes

Interface configuration (config-if)

Command History

Release
Modification

10.0

This command was introduced.

12.0(5)T

Multiarea functionality was added, changing the way the tag argument (now area-tag) is used.

12.2(28)SB

This command was integrated into Cisco IOS Release 12.2(28)SB.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

12.2(33)SRB

Support for IPv6 was added.

12.2(33)SB

Support for IPv6 was added.

12.2(33)SXI

This command was integrated into Cisco IOS Release 12.2(33)SXI.

15.1(2)S

This command was integrated into Cisco IOS Release 15.1(2)S.


Usage Guidelines

Before the IS-IS routing process is useful, a network entity title (NET) must be assigned with the net command and some interfaces must have IS-IS enabled.

If you have IS-IS running and at least one International Organization for Standardization Interior Gateway Routing Protocol (ISO-IGRP) process, the IS-IS process and the ISO-IGRP process cannot both be configured without an area tag. The null tag can be used by only one process. If you run ISO-IGRP and IS-IS, a null tag can be used for IS-IS, but not for ISO-IGRP at the same time. However, each area in an IS-IS multiarea configuration should have a nonnull area tag to facilitate identification of the area.

You can configure only one process to perform Level 2 (interarea) routing. If Level 2 routing is configured on any process, all additional processes are automatically configured as Level 1. You can configure this process to perform intra-area (Level 1) routing at the same time. You can configure up to 29 additional processes as Level 1-only processes. Use the is-type command to remove Level 2 routing from a router instance. You can then use the is-type command to enable Level 2 routing on some other IS-IS router instance.

An interface cannot be part of more than one area, except in the case where the associated routing process is performing both Level 1 and Level 2 routing. On media such as WAN media where subinterfaces are supported, different subinterfaces could be configured for different areas.

Examples

The following example specifies IS-IS as an IP routing protocol for a process named Finance, and specifies that the Finance process will be routed on Ethernet interface 0 and serial interface 0:

router isis Finance
 net 49.0001.aaaa.aaaa.aaaa.00
interface Ethernet 0
 ip router isis Finance
interface serial 0
 ip router isis Finance

The following example shows an IS-IS configuration with two Level 1 areas and one Level 1-2 area:

ip routing

.
.
.

interface Tunnel529
 ip address 10.0.0.5 255.255.255.0
 ip router isis BB

interface Ethernet1
 ip address 10.1.1.5 255.255.255.0
 ip router isis A3253-01
!
interface Ethernet2
 ip address 10.2.2.5 255.255.255.0
 ip router isis A3253-02


.
.
.

! Defaults to "is-type level-1-2"
router isis BB
 net 49.2222.0000.0000.0005.00
!
router isis A3253-01
 net 49.0553.0001.0000.0000.0005.00
 is-type level-1
!
router isis A3253-02
 net 49.0553.0002.0000.0000.0005.00
 is-type level-1

Related Commands

Command
Description

is-type

Configures the routing level for an IS-IS routing process.

net

Configures an IS-IS NET for a CLNS routing process.

router isis

Enables the IS-IS routing protocol.


ip source-address (telephony-service)

To identify the IP address and port through which IP phones communicate with a Cisco Unified CME router, use the ip source-address command in telephony-service or group configuration mode. To disable the router from receiving messages from Cisco Unified IP phones, use the no form of this command.

ip source-address {ipv4_address | ipv6_address} [port port] [secondary {ipv4 address | ipv6 address} [rehome seconds]] [any-match | strict-match]

no ip source-address

Syntax Description

ipv4_address

IPv4 address of the router, typically one of the addresses of the Ethernet port of the router.

ipv6_address

In Cisco Unified CME 8.0 and later versions: IPv6 address of the router, typically one of the addresses of the Ethernet port of the router.

port port

(Optional) TCP/IP port number to use for Skinny Client Control Protocol (SCCP). Default is 2000. For IPv4 only: Range is from 2000 to 9999.

Note For IPv6, do not configure the port number to change from the default value (2000).

secondary

(Optional) Second Cisco Unified CME router with which phones can register if the primary Cisco Unified CME router fails.

Note For dual-stack (IPv4 and IPv6) mode: Only an IPv4 address can be configured for a secondary router.

rehome seconds

(Optional) Used only by Cisco Unified IP phones that have registered with a Cisco Unified Survivable Remote Site Telephony (SRST) router. This keyword defines a delay that is used by phones to verify the stability of their primary SCCP controller (Cisco Unified Communications Manager or Cisco Unified CME) before the phones reregister with it. This parameter is ignored by phones unless they are registered to a secondary Cisco Unified SRST router. The range is from 0 to 65535 seconds. The default is 120 seconds.

The use of this parameter is a phone behavior and is subject to change, based on the phone type and phone firmware version.

strict-match

(Optional) Requires strict IP address checking for registration.


Command Default

The IP address for communicating with phones is not defined.

Command Modes

Telephony-service configuration (config-telephony)
Group configuration (conf-tele-group)

Command History

Cisco IOS Release
Cisco Product
Modification

12.1(5)YD

Cisco ITS 1.0

This command was introduced.

12.2(8)T

Cisco ITS 2.0

This command was integrated into Cisco IOS Release 12.2(8)T.

12.4(4)XC

Cisco Unified CME 4.0

The secondary ip-address and rehome seconds keyword-argument pairs were added.

12.4(9)T

Cisco Unified CME 4.0

The secondary ip-address and rehome seconds keyword-argument pairs were added.

12.4(22)T

Cisco Unified CME 7.0(1)

This command was added to VRF group mode.

15.0(1)XA

Cisco Unified CME 8.0

This command was modified. Support for IPv6 was added and the ipv4-address and ipv6-address arguments replaced the generic ip-address argument.

15.1(1)T

Cisco Unified CME 8.0

This command was integrated into Cisco IOS Release 15.1(1)T.


Usage Guidelines

This command enables a router to receive messages from Cisco Unified IP phones through the specified IP address and port.

The Cisco Unified CME router cannot communicate with Cisco Unified CME phones if the IP address of the port to which they are attached is not configured. In Cisco Unified CME 8.0 and later versions, the Cisco Unified CME router can receive messages from IPv6-enabled or IPv4-enabled IP phones or from phones in dual-stack (both IPv6 and IPv4) mode.

In Cisco Unified CME 8.0 and later versions: If the IP phones connected to Cisco Unified CME were configured for dual-stack mode by using dual-stack keyword with the protocol mode command, configure this command with the IPv6 address.

In Cisco Unified CME 8.0 and later versions: If the IP phones to be connected to the port to be configured are IPv4-enabled only or IPv6-enabled only, configure this command with the corresponding IPv4 or IPv6 address.

For IPv6: Do not configure the port port keyword argument combination in this command to change the value from the default (2000). If you change the port number, IPv6 CEF packet switching engine will not be able to handle the IPv6 SCCP phones and various packet handling problems may occur when more than a dozen (approximately) calls in IPv6 are going on.

Use the strict-match keyword to instruct the router to reject IP phone registration attempts if the IP server address used by the phone does not match the source address.

Prior to Cisco IOS Telephony Services (Cisco ITS) V2.1, this command helped the router to autogenerate the SEPDEFAULT.cnf file, which was stored in the flash memory of the router. The SEPDEFAULT.cnf file contains the IP address of one of the Ethernet ports of the router to which the phone should register.

In ITS V2.1 and in Cisco CME 3.0 and later versions, the configuration files were moved to system:/its/. The file named Flash:SEPDEFAULT.cnf that was used with previous Cisco ITS versions is obsolete, but is retained as system:/its/SEPDEFAULT.cnf to support upgrades from older phone firmware.

For systems using Cisco ITS V2.1 or later versions, the IP phones receive their initial configuration information and phone firmware from the TFTP server associated with the router. In most cases, the phones obtain the IP address of their TFTP server using the option 150 command and Dynamic Host Configuration Protocol (DHCP). For Cisco ITS or Cisco CME operation, the TFTP server address obtained by the Cisco Unified IP phones should point to the router IP address. The Cisco IP phones attempt to transfer a configuration file called XmlDefault.cnf.xml. This file is automatically generated by the router through the ip source-address command and is placed in router memory. The XmlDefault.cnf.xml file contains the IP address that the phones use to register for service, using the SCCP. This IP address should correspond to a valid Cisco CME router IP address (and may be the same as the router TFTP server address).

Similarly, when an analog telephone adapter (ATA) such as the ATA-186 is attached to the Cisco Unified CME router, the ATA receives very basic configuration information and firmware from the TFTP server XmlDefault.cnf.xml file. The XmlDefault.cnf.xml file is automatically generated by the Cisco Unified CME router with the ip source-address command and is placed in the router's flash memory.

By specifying a second Cisco Unified CME router in the ip source-address command, you improve the failover time for phones.

Examples

The following example sets the IP source address and port:

Router(config)# telephony-service
Router(config-telephony)# ip source-address 10.6.21.4 port 2000 strict-match

The following example establishes the router at 10.5.2.78 as a secondary router:

Router(config)# telephony-service
Router(config-telephony)# ip source-address 10.0.0.1 port 2000 secondary 10.5.2.78

Cisco Unified CME 8.0 and later versions

The following example shows how to configure this command with an IPv6 address. Do not change the port number from the default value (2000) when you configure an IPv6 address.

Router(config)# telephony-service
Router(config-telephony)# protocol mode ipv6
Router(config-telephony)# ip source-address 2001:10:10:10::3 
 

The following example shows how to configure an IP address for dual-stack mode. When the IP phones are configured for dual-stack mode, the IP address of the router port to which the IP phones are connected must be an IPv6 address. For dual-stack mode, the address of the secondary router must be an IPv4 address.

Router(config)# telephony-service
Router(config-telephony)# protocol mode dual-stack
Router(config-telephony)# ip source address 2001:10:10:10::3 secondary 10.5.2.78
Router(config-telephony)# 
 

Related Commands

Command
Description

option

Configures DHCP server options.

protocol mode

Configures a preferred IP-address mode for SCCP IP phones in Cisco Unified CME.


ip unnumbered

To enable IP processing on an interface without assigning an explicit IP address to the interface, use the ip unnumbered command in interface configuration mode or subinterface configuration mode. To disable the IP processing on the interface, use the no form of this command.

ip unnumbered type number

no ip unnumbered type number

Syntax Description

type

Interface on which the router has assigned an IP address. The interface cannot be unnumbered interface. For more information, use the question mark (?) online help function.

number

Interface or subinterface number. For more information about the numbering syntax for your networking device, use the question mark (?) online help function.


Command Default

IP processing on the unnumbered interface is disabled.

Command Modes

Interface configuration (config-if)
Subinterface configuration (config-subif)

Command History

Release
Modification

10.0

This command was introduced.

12.3(4)T

This command was modified to configure IP unnumbered support on Ethernet VLAN subinterfaces and subinterface ranges.

12.2(18)SXE

This command was integrated into Cisco IOS Release 12.2(18)SXE. This command became available on the Supervisor Engine 720.

12.2(18)SXF

This command was modified to support Ethernet physical interfaces and switched virtual interfaces (SVIs).

12.2(28)SB

This command was integrated into Cisco IOS Release 12.2(28)SB.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

Cisco IOS XE Release 2.5

This command was implemented on Cisco ASR 1000 series routers.


Usage Guidelines

When an unnumbered interface generates a packet (for example, for a routing update), it uses the address of the specified interface as the source address of the IP packet. It also uses the address of the specified interface in determining which routing processes are sending updates over the unnumbered interface. Restrictions are as follows:

This command is not supported on Cisco 7600 series routers that are configured with a Supervisor Engine 32.

Serial interfaces using High-Level Data Link Control (HDLC), PPP, Link Access Procedure Balanced (LAPB), Frame Relay encapsulations, and Serial Line Internet Protocol (SLIP), and tunnel interfaces can be unnumbered. It is not possible to use this interface configuration command with X.25 or Switched Multimegabit Data Service (SMDS) interfaces.

You cannot use the ping EXEC command to determine whether the interface is up because the interface has no address. Simple Network Management Protocol (SNMP) can be used to remotely monitor interface status.

It is not possible to netboot a Cisco IOS image over a serial interface that is assigned an IP address with the ip unnumbered command.

You cannot support IP security options on an unnumbered interface.

The interface you specify by the type and `number arguments must be enabled (listed as "up" in the show interfaces command display).

If you are configuring Intermediate System-to-Intermediate System (IS-IS) across a serial line, you should configure the serial interfaces as unnumbered. This configuration allows you to comply with RFC 1195, which states that IP addresses are not required on each interface.


Note Using an unnumbered serial line between different major networks (or majornets) requires special care. If at each end of the link there are different majornets assigned to the interfaces you specified as unnumbered, any routing protocol running across the serial line must not advertise subnet information.


Examples

In the following example, the first serial interface is given the address of Ethernet 0:

interface ethernet 0
 ip address 10.108.6.6 255.255.255.0
!
interface serial 0
 ip unnumbered ethernet 0

In the following example, Ethernet VLAN subinterface 3/0.2 is configured as an IP unnumbered subinterface:

interface ethernet 3/0.2
 encapsulation dot1q 200
 ip unnumbered ethernet 3/1

In the following example, Fast Ethernet subinterfaces in the range from 5/1.1 to 5/1.4 are configured as IP unnumbered subinterfaces:

interface range fastethernet5/1.1 - fastethernet5/1.4
 ip unnumbered ethernet 3/1

ipv6 access-class

To filter incoming and outgoing connections to and from the router based on an IPv6 access list, use the ipv6 access-class command in line configuration mode. To disable the filtering of incoming and outgoing connections to the router, use the no form of this command.

ipv6 access-class ipv6-access-list-name {in | out}

no ipv6 access-class

Syntax Description

ipv6-access-list-name

Name of an IPv6 access list. Names cannot contain a space or quotation mark, or begin with a numeric.

in

Filters incoming IPv6 connections.

out

Filters outgoing IPv6 connections.


Command Default

The filtering of incoming and outgoing connections to and from the router is not enabled.

Command Modes

Line configuration

Command History

Release
Modification

12.2(2)T

This command was introduced.

12.0(21)ST

This command was integrated into Cisco IOS Release 12.0(21)ST.

12.0(22)S

This command was integrated into Cisco IOS Release 12.0(22)S.

12.2(14)S

This command was integrated into Cisco IOS Release 12.2(14)S.

12.2(28)SB

This command was integrated into Cisco IOS Release 12.2(28)SB.

12.2(25)SG

This command was integrated into Cisco IOS Release 12.2(25)SG.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

12.2(33)SXH

This command was integrated into Cisco IOS Release 12.2(33)SXH.

Cisco IOS XE Release 2.1

This command was introduced on Cisco ASR 1000 Series Routers.


Usage Guidelines

The ipv6 access-class command is similar to the access-class command, except that it is IPv6-specific.

Identical restrictions should be set on all the virtual terminal lines because a user can connect to any of them.

The incoming connection source address is used to match against the access list source prefix. The router address on the received interface is used to match against the access list destination prefix.

IPv6 access control list (ACL) matches are made using TCP; an ACL permit match using IPv6 or TCP is required to allow access to a router.

Examples

The following example filters incoming connections on virtual terminal lines 0 to 4 of the router based on the IPv6 access list named cisco:

ipv6 access-list cisco
 permit ipv6 host 2001:0DB8:0:4::2/128 any

line vty 0 4
 ipv6 access-class cisco in

Related Commands

Command
Description

ipv6 access-list

Defines an IPv6 access list and sets deny or permit conditions for the defined access list.

ipv6 traffic-filter

Filters incoming or outgoing IPv6 traffic on an interface.

show ipv6 access-list

Displays the contents of all current IPv6 access lists.


ipv6 access-list

To define an IPv6 access list and to place the router in IPv6 access list configuration mode, use the ipv6 access-list command in global configuration mode. To remove the access list, use the no form of this command.

ipv6 access-list access-list-name

no ipv6 access-list access-list-name

Syntax Description

access-list-name

Name of the IPv6 access list. Names cannot contain a space or quotation mark, or begin with a numeric.


Command Default

No IPv6 access list is defined.

Command Modes

Global configuration

Command History

Release
Modification

12.2(2)T

This command was introduced.

12.0(21)ST

This command was integrated into Cisco IOS Release 12.0(21)ST.

12.0(22)S

This command was integrated into Cisco IOS Release 12.0(22)S.

12.0(23)S

Support for IPv6 address configuration mode and extended access list functionality (the filtering of traffic based on IPv6 option headers and optional, upper-layer protocol type information) was added. Additionally, the following keywords and arguments were moved from global configuration mode to IPv6 access list configuration mode: permit,
deny, source-ipv6-prefix/prefix-length, any, destination-ipv6-prefix/
prefix-length, priority. See the "Usage Guidelines" section for more details.

12.2(13)T

Support for IPv6 address configuration mode and extended access list functionality (the filtering of traffic based on IPv6 option headers and optional, upper-layer protocol type information) was added. Additionally, the following keywords and arguments were moved from global configuration mode to IPv6 access list configuration mode: permit,
deny, source-ipv6-prefix/prefix-length, any, destination-ipv6-prefix/
prefix-length, priority. See the "Usage Guidelines" section for more details.

12.2(14)S

This command was integrated into Cisco IOS Release 12.2(14)S.

12.2(28)SB

This command was integrated into Cisco IOS Release 12.2(28)SB.

12.2(25)SG

This command was integrated into Cisco IOS Release 12.2(25)SG.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

12.2(33)SXH

Duplicate remark statements can no longer be configured from the IPv6 access control list.

Cisco IOS XE Release 2.1

This command was introduced on Cisco ASR 1000 series routers.


Usage Guidelines

The ipv6 access-list command is similar to the ip access-list command, except that it is IPv6-specific.

In Cisco IOS Release 12.2(2)T or later releases, 12.0(21)ST, and 12.0(22)S, standard IPv6 access control list (ACL) functionality is used for basic traffic filtering functions—traffic filtering is based on source and destination addresses, inbound and outbound to a specific interface, and with an implicit deny statement at the end of each access list (functionality similar to standard ACLs in IPv4). IPv6 ACLs are defined and their deny and permit conditions are set by using the ipv6 access-list command with the deny and permit keywords in global configuration mode.

In Cisco IOS Release 12.0(23)S or later releases, the standard IPv6 ACL functionality is extended to support—in addition to traffic filtering based on source and destination addresses—filtering of traffic based on IPv6 option headers and optional, upper-layer protocol type information for finer granularity of control (functionality similar to extended ACLs in IPv4). IPv6 ACLs are defined by using the ipv6 access-list command in global configuration mode and their permit and deny conditions are set by using the deny and permit commands in IPv6 access list configuration mode. Configuring the ipv6 access-list command places the router in IPv6 access list configuration mode—the router prompt changes to Router(config-ipv6-acl)#. From IPv6 access list configuration mode, permit and deny conditions can be set for the defined IPv6 ACL.


Note IPv6 ACLs are defined by a unique name (IPv6 does not support numbered ACLs). An IPv4 ACL and an IPv6 ACL cannot share the same name.


In Cisco IOS Release 12.0(23)S or later releases, and 12.2(11)S or later releases, for backward compatibility, the ipv6 access-list command with the deny and permit keywords in global configuration mode is still supported; however, an IPv6 ACL defined with deny and permit conditions in global configuration mode is translated to IPv6 access list configuration mode.

Refer to the deny (IPv6) and permit (IPv6) commands for more information on filtering IPv6 traffic based on IPv6 option headers and optional, upper-layer protocol type information. See the "Examples" section for an example of a translated IPv6 ACL configuration.


Note In Cisco IOS Release 12.0(23)S or later releases, every IPv6 ACL has implicit permit icmp any any nd-na, permit icmp any any nd-ns, and deny ipv6 any any statements as its last match conditions. (The former two match conditions allow for ICMPv6 neighbor discovery.) An IPv6 ACL must contain at least one entry for the implicit deny ipv6 any any statement to take effect.

The IPv6 neighbor discovery process makes use of the IPv6 network layer service; therefore, by default, IPv6 ACLs implicitly allow IPv6 neighbor discovery packets to be sent and received on an interface. In IPv4, the Address Resolution Protocol (ARP), which is equivalent to the IPv6 neighbor discovery process, makes use of a separate data link layer protocol; therefore, by default, IPv4 ACLs implicitly allow ARP packets to be sent and received on an interface.



Note IPv6 prefix lists, not access lists, should be used for filtering routing protocol prefixes.


Use the ipv6 traffic-filter interface configuration command with the access-list-name argument to apply an IPv6 ACL to an IPv6 interface. Use the ipv6 access-class line configuration command with the access-list-name argument to apply an IPv6 ACL to incoming and outgoing IPv6 virtual terminal connections to and from the router.


Note An IPv6 ACL applied to an interface with the ipv6 traffic-filter command filters traffic that is forwarded, not originated, by the router.



Note When using this command to modify an ACL that is already associated with a bootstrap router (BSR) candidate rendezvous point (RP) (see the ipv6 pim bsr candidate rp command) or a static RP (see the ipv6 pim rp-address command), any added address ranges that overlap the PIM SSM group address range (FF3x::/96) are ignored. A warning message is generated and the overlapping address ranges are added to the ACL, but they have no effect on the operation of the configured BSR candidate RP or static RP commands.


In Cisco IOS Release 12.2(33)SXH and subsequent Cisco IOS SX releases, duplicate remark statements can no longer be configured from the IPv6 access control list. Because each remark statement is a separate entity, each one is required to be unique.

Examples

The following example is from a router running Cisco IOS Release 12.0(23)S or later releases. The example configures the IPv6 ACL list named list1 and places the router in IPv6 access list configuration mode.

Router(config)# ipv6 access-list list1
Router(config-ipv6-acl)#

The following example is from a router running Cisco IOS Release 12.2(2)T or later releases, 12.0(21)ST, or 12.0(22)S. The example configures the IPv6 ACL named list2 and applies the ACL to outbound traffic on Ethernet interface 0. Specifically, the first ACL entry keeps all packets from the network FEC0:0:0:2::/64 (packets that have the site-local prefix FEC0:0:0:2 as the first 64 bits of their source IPv6 address) from exiting out of Ethernet interface 0. The second entry in the ACL permits all other traffic to exit out of Ethernet interface 0. The second entry is necessary because an implicit deny all condition is at the end of each IPv6 ACL.

Router(config)# ipv6 access-list list2 deny FEC0:0:0:2::/64 any
Router(config)# ipv6 access-list list2 permit any any

Router(config)# interface ethernet 0
Router(config-if)# ipv6 traffic-filter list2 out

If the same configuration was entered on a router running Cisco IOS Release 12.0(23)S or later releases, the configuration would be translated into IPv6 access list configuration mode as follows:

ipv6 access-list list2 
  deny FEC0:0:0:2::/64 any
  permit ipv6 any any

interface ethernet 0
 ipv6 traffic-filter list2 out

Note IPv6 is automatically configured as the protocol type in permit any any and deny any any statements that are translated from global configuration mode to IPv6 access list configuration mode.



Note IPv6 ACLs defined on a router running Cisco IOS Release 12.2(2)T or later releases, 12.0(21)ST, or 12.0(22)S that rely on the implicit deny condition or specify a deny any any statement to filter traffic should contain permit statements for link-local and multicast addresses to avoid the filtering of protocol packets (for example, packets associated with the neighbor discovery protocol). Additionally, IPv6 ACLs that use deny statements to filter traffic should use a permit any any statement as the last statement in the list.



Note An IPv6 router will not forward to another network an IPv6 packet that has a link-local address as either its source or destination address (and the source interface for the packet is different from the destination interface for the packet).


Related Commands

Command
Description

deny (IPv6)

Sets deny conditions for an IPv6 access list.

ipv6 access-class

Filters incoming and outgoing connections to and from the router based on an IPv6 access list.

ipv6 pim bsr candidate rp

Configures the candidate RP to send PIM RP advertisements to the BSR.

ipv6 pim rp-address

Configure the address of a PIM RP for a particular group range.

ipv6 traffic-filter

Filters incoming or outgoing IPv6 traffic on an interface.

permit (IPv6)

Sets permit conditions for an IPv6 access list.

show ipv6 access-list

Displays the contents of all current IPv6 access lists.


ipv6 access-list log-update threshold

To specify the number of updates that are logged for IPv6 access lists, use the ipv6 access-list log-update threshold command in global configuration mode. To return the number of logged updates to the default setting, use the no form of this command.

ipv6 access-list log-update threshold value

no ipv6 access-list log-update threshold

Syntax Description

value

Specifies the number of updates that are logged for every IPv6 access list configured on the router. The acceptable range is from 0 to 2147483647.


Command Default

The default is 2147483647 updates.

Command Modes

Global configuration

Command History

Release
Modification

12.0(23)S

This command was introduced.

12.2(13)T

This command was integrated into Cisco IOS Release 12.2(13)T.

12.2(14)S

This command was integrated into Cisco IOS Release 12.2(14)S.

12.2(28)SB

This command was integrated into Cisco IOS Release 12.2(28)SB.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

12.2(33)SXH

This command was integrated into Cisco IOS Release 12.2(33)SXH.


Usage Guidelines

The ipv6 access-list log-update threshold command is similar to the ip access-list log-update threshold command, except that it is IPv6-specific.

IPv6 ACL updates are logged at five minute intervals, following the first logged update. Configuring a lower number of updates (a number lower than the default) is useful when more frequent update logging is desired.

Examples

The following example configures a log threshold of ten updates for every IPv6 access list configured on the router.

ipv6 access-list log-update threshold 10

Related Commands

Command
Description

ipv6 access-list

Defines an IPv6 access list and enters IPv6 access list configuration mode.

show ipv6 access-list

Displays the contents of all current IPv6 access lists.


ipv6 address

To configure an IPv6 address based on an IPv6 general prefix and enable IPv6 processing on an interface, use the ipv6 address command in interface configuration mode. To remove the address from the interface, use the no form of this command.

ipv6 address {ipv6-address/prefix-length | prefix-name sub-bits/prefix-length}

no ipv6 address {ipv6-address/prefix-length | prefix-name sub-bits/prefix-length}

Syntax Description

ipv6-address

The IPv6 address to be used.

/prefix-length

The length of the IPv6 prefix. A decimal value that indicates how many of the high-order contiguous bits of the address comprise the prefix (the network portion of the address). A slash mark must precede the decimal value.

prefix-name

A general prefix, which specifies the leading bits of the network to be configured on the interface.

sub-bits

The subprefix bits and host bits of the address to be concatenated with the prefixes provided by the general prefix specified with the prefix-name argument.

The sub-bits argument must be in the form documented in RFC 2373 where the address is specified in hexadecimal using 16-bit values between colons.


Command Default

No IPv6 addresses are defined for any interface.

Command Modes

Interface configuration

Command History

Release
Modification

12.2(2)T

This command was introduced.

12.2(28)SB

This command was integrated into Cisco IOS Release 12.2(28)SB.

12.2(25)SG

This command was integrated into Cisco IOS Release 12.2(25)SG.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

12.2(33)SXH

This command was integrated into Cisco IOS Release 12.2(33)SXH.

Cisco IOS XE Release 2.1

This command was introduced on Cisco ASR 1000 Series Routers.


Usage Guidelines

The ipv6 address command allows multiple IPv6 addresses to be configured on an interface in various different ways, with varying options. The most common way is to specify the IPv6 address with the prefix length.

Addresses may also be defined using the general prefix mechanism, which separates the aggregated IPv6 prefix bits from the subprefix and host bits. In this case, the leading bits of the address are defined in a general prefix, which is globally configured or learned (for example, through use of Dynamic Host Configuration Protocol-Prefix Delegation (DHCP-PD)), and then applied using the prefix-name argument. The subprefix bits and host bits are defined using the sub-bits argument.

Using the no ipv6 address autoconfig command without arguments removes all IPv6 addresses from an interface.

IPv6 link-local addresses must be configured and IPv6 processing must be enabled on an interface by using the ipv6 address link-local command.

Examples

The following example shows how to enable IPv6 processing on the interface and configure an address based on the general prefix called my-prefix and the directly specified bits:

Router(config-if) ipv6 address my-prefix 0:0:0:7272::72/64

Assuming the general prefix named my-prefix has the value of 2001:DB8:2222::/48, then the interface would be configured with the global address 2001:DB8:2222:7272::72/64.

Related Commands

Command
Description

ipv6 address anycast

Configures an IPv6 anycast address and enables IPv6 processing on an interface.

ipv6 address eui-64

Configures an IPv6 address and enables IPv6 processing on an interface using an EUI-64 interface ID in the low-order 64 bits of the address.

ipv6 address link-local

Configures an IPv6 link-local address for an interface and enables IPv6 processing on the interface.

ipv6 unnumbered

Enables IPv6 processing on an interface without assigning an explicit IPv6 address to the interface.

no ipv6 address autoconfig

Removes all IPv6 addresses from an interface.

show ipv6 interface

Displays the usability status of interfaces configured for IPv6.


ipv6 address anycast

To configure an IPv6 anycast address and enable IPv6 processing on an interface, use the ipv6 address anycast command in interface configuration mode. To remove the address from the interface, use the no form of this command.

ipv6 address ipv6-prefix/prefix-length anycast

no ipv6 address [ipv6-prefix/prefix-length anycast]

Syntax Description

ipv6-prefix

The IPv6 network assigned to the interface.

This argument must be in the form documented in RFC 2373 where the address is specified in hexadecimal using 16-bit values between colons.

/prefix-length

The length of the IPv6 prefix. A decimal value that indicates how many of the high-order contiguous bits of the address comprise the prefix (the network portion of the address). A slash mark must precede the decimal value.


Command Default

No IPv6 addresses are defined for any interface.

Command Modes

Interface configuration

Command History

Release
Modification

12.3(4)T

This command was introduced.

12.2(25)S

This command was integrated into Cisco IOS Release 12.2(25)S.

12.2(28)SB

This command was integrated into Cisco IOS Release 12.2(28)SB.

12.2(25)SG

This command was integrated into Cisco IOS Release 12.2(25)SG.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

12.2(33)SXH

This command was integrated into Cisco IOS Release 12.2(33)SXH.


Usage Guidelines

Using the no ipv6 address command without arguments removes all manually configured IPv6 addresses from an interface.

Examples

The following example shows how to enable IPv6 processing on the interface, assign the prefix 2001:0DB8:1:1::/64 to the interface, and configure the IPv6 anycast address 2001:0DB8:1:1:FFFF:FFFF:FFFF:FFFE:

ipv6 address 2001:0DB8:1:1:FFFF:FFFF:FFFF:FFFE/64 anycast

Related Commands

Command
Description

ipv6 address eui-64

Configures an IPv6 address and enables IPv6 processing on an interface using an EUI-64 interface ID in the low-order 64 bits of the address.

ipv6 address link-local

Configures an IPv6 link-local address for an interface and enables IPv6 processing on the interface.

ipv6 unnumbered

Enables IPv6 processing on an interface without assigning an explicit IPv6 address to the interface.

show ipv6 interface

Displays the usability status of interfaces configured for IPv6.


ipv6 address autoconfig

To enable automatic configuration of IPv6 addresses using stateless autoconfiguration on an interface and enable IPv6 processing on the interface, use the ipv6 address autoconfig command in interface configuration mode. To remove the address from the interface, use the no form of this command.

ipv6 address autoconfig [default]

no ipv6 address autoconfig

Syntax Description

default

(Optional) If a default router is selected on this interface, the default keyword causes a default route to be installed using that default router.

The default keyword can be specified only on one interface.


Command Default

No IPv6 address is defined for the interface.

Command Modes

Interface configuration

Command History

Release
Modification

12.2(13)T

This command was introduced.

12.2(33)SRE

This command was modified. It was integrated into Cisco IOS Release 12.2(33)SRE.

Cisco IOS XE Release 2.5

This command was updated. It was integrated into Cisco IOS XE Release 2.5.

12.2(33)XNE

This command was modified. It was integrated into Cisco IOS Release 12.2(33)XNE.


Usage Guidelines

The ipv6 address autoconfig command causes the device to perform IPv6 stateless address auto-configuration to discover prefixes on the link and then to add the EUI-64 based addresses to the interface. Addresses are configured depending on the prefixes received in Router Advertisement messages.

Using the no ipv6 address autoconfig command without arguments removes all IPv6 addresses from an interface.

Examples

The following example assigns the IPv6 address automatically:

Router(config)# interface ethernet 0
Router(config-if)# ipv6 address autoconfig 

Related Commands

Command
Description

ipv6 address eui-64

Configures an IPv6 address and enables IPv6 processing on an interface using an EUI-64 interface ID in the low-order 64 bits of the address.

ipv6 address link-local

Configures an IPv6 link-local address for an interface and enables IPv6 processing on the interface.

ipv6 unnumbered

Enables IPv6 processing on an interface without assigning an explicit IPv6 address to the interface.

show ipv6 interface

Displays the usability status of interfaces configured for IPv6.


ipv6 address dhcp

To acquire an IPv6 address on an interface from the Dynamic Host Configuration Protocol for IPv6 (DHCPv6) server, use the ipv6 address dhcp command in the interface configuration mode. To remove the address from the interface, use the no form of this command.

ipv6 address dhcp [rapid-commit]

no ipv6 address dhcp

Syntax Description

rapid-commit

(Optional) Allows the two-message exchange method for address assignment.


Command Default

No IPv6 addresses are acquired from the DHCPv6 server.

Command Modes

Interface configuration (config-if)

Command History

Release
Modification

12.4(24)T

This command was introduced.

12.2(33)SRE

This command was modified. It was integrated into Cisco IOS Release 12.2(33)SRE.


Usage Guidelines

The ipv6 address dhcp interface configuration command allows any interface to dynamically learn its IPv6 address by using DHCP.

The rapid-commit keyword enables the use of the two-message exchange for address allocation and other configuration. If it is enabled, the client includes the rapid-commit option in a solicit message.

Examples

The following example shows how to acquire an IPv6 address and enable the rapid-commit option:

Router(config)# interface fastethernet 0/0
Router(config-if)# ipv6 address dhcp rapid-commit

You can verify your settings by using the show ipv6 dhcp interface command in privileged EXEC mode.

Related Commands

Command
Description

show ipv6 dhcp interface

Displays DHCPv6 interface information.


ipv6 address dhcp client request

To configure an IPv6 client to request a vendor-specific option from a Dynamic Host Configuration Protocol for IPv6 (DHCPv6) server, use the ipv6 address dhcp client request command in interface configuration mode. To remove the request, use the no form of this command.

ipv6 address dhcp client request vendor

no ipv6 address dhcp client request vendor

Syntax Description

vendor

Requests the vendor-specific options.


Command Default

IPv6 clients are not configured to request an option from DHCP.

Command Modes

Interface configuration (config-if)

Command History

Release
Modification

12.4(24)T

This command was introduced.

12.2(33)SRE

This command was modified. It was integrated into Cisco IOS Release 12.2(33)SRE.


Usage Guidelines

Use the ipv6 address dhcp client request vendor command to request a vendor-specific option. When this command is enabled, the IPv6 client can request a vendor-specific option only when an IPv6 address is acquired from DHCP. If you enter the command after the interface has acquired an IPv6 address, the IPv6 client cannot request a vendor-specific option until the next time the client acquires an IPv6 address from DHCP.

Examples

The following example shows how to configure an interface to request vendor-specific options:

Router(config)# interface fastethernet 0/0
Router(config-if)# ipv6 address dhcp client request vendor

Related Commands

Command
Description

ipv6 address dhcp

Acquires an IPv6 address on an interface from the DHCPv6 server.


ipv6 address eui-64

To configure an IPv6 address for an interface and enables IPv6 processing on the interface using an EUI-64 interface ID in the low order 64 bits of the address, use the ipv6 address eui-64 command in interface configuration mode. To remove the address from the interface, use the no form of this command.

ipv6 address ipv6-prefix/prefix-length eui-64

no ipv6 address [ipv6-prefix/prefix-length eui-64]

Syntax Description

ipv6-prefix

The IPv6 network assigned to the interface.

This argument must be in the form documented in RFC 2373 where the address is specified in hexadecimal using 16-bit values between colons.

/prefix-length

The length of the IPv6 prefix. A decimal value that indicates how many of the high-order contiguous bits of the address comprise the prefix (the network portion of the address). A slash mark must precede the decimal value.


Command Default

No IPv6 address is defined for the interface.

Command Modes

Interface configuration

Command History

Release
Modification

12.2(2)T

This command was introduced.

12.0(21)ST

This command was integrated into Cisco IOS Release 12.0(21)ST.

12.0(22)S

This command was integrated into Cisco IOS Release 12.0(22)S.

12.2(14)S

This command was integrated into Cisco IOS Release 12.2(14)S.

12.2(28)SB

This command was integrated into Cisco IOS Release 12.2(28)SB.

12.2(25)SG

This command was integrated into Cisco IOS Release 12.2(25)SG.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

12.2(33)SXH

This command was integrated into Cisco IOS Release 12.2(33)SXH.

Cisco IOS XE Release 2.1

This command was introduced on Cisco ASR 1000 Series Routers.


Usage Guidelines

If the value specified for the /prefix-length argument is greater than 64 bits, the prefix bits have precedence over the interface ID.

Using the no ipv6 address command without arguments removes all manually configured IPv6 addresses from an interface.

If the Cisco IOS software detects another host using one of its IPv6 addresses, it will display an error message on the console.

Examples

The following example assigns IPv6 address 2001:0DB8:0:1::/64 to Ethernet interface 0 and specifies an EUI-64 interface ID in the low order 64 bits of the address:

Router(config)# interface ethernet 0
Router(config-if)# ipv6 address 2001:0DB8:0:1::/64 eui-64

Related Commands

Command
Description

ipv6 address link-local

Configures an IPv6 link-local address for an interface and enables IPv6 processing on the interface.

ipv6 unnumbered

Enables IPv6 processing on an interface without assigning an explicit IPv6 address to the interface.

show ipv6 interface

Displays the usability status of interfaces configured for IPv6.


ipv6 address link-local

To configure an IPv6 link-local address for an interface and enable IPv6 processing on the interface, use the ipv6 address link-local command in interface configuration mode. To remove the address from the interface, use the no form of this command.

ipv6 address ipv6-address/prefix-length link-local [cga]

no ipv6 address [ipv6-address/prefix-length link-local]

Syntax Description

ipv6-address

The IPv6 address assigned to the interface.

This argument must be in the form documented in RFC 2373 where the address is specified in hexadecimal using 16-bit values between colons.

/prefix-length

The length of the IPv6 prefix. A decimal value that indicates how many of the high-order contiguous bits of the address comprise the prefix (the network portion of the address). A slash mark must precede the decimal value.

link-local

Specifies a link-local address. The ipv6-address specified with this command overrides the link-local address that is automatically generated for the interface.

cga

(Optional) Specifies the CGA interface identifier.


Command Default

No IPv6 address is defined for the interface.

Command Modes

Interface configuration

Command History

Release
Modification

12.2(2)T

This command was introduced.

12.0(21)ST

This command was integrated into Cisco IOS Release 12.0(21)ST.

12.0(22)S

This command was integrated into Cisco IOS Release 12.0(22)S.

12.2(14)S

This command was integrated into Cisco IOS Release 12.2(14)S.

12.2(28)SB

This command was integrated into Cisco IOS Release 12.2(28)SB.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

12.2(33)SXH

This command was integrated into Cisco IOS Release 12.2(33)SXH.

Cisco IOS XE Release 2.1

This command was introduced on Cisco ASR 1000 Series Routers.

12.4(24)T

The cga keyword was added


Usage Guidelines

Using the no ipv6 address command without arguments removes all manually configured IPv6 addresses from an interface.

If the Cisco IOS software detects another host using one of its IPv6 addresses, it will display an error message on the console.

The system automatically generates a link-local address for an interface when IPv6 processing is enabled on the interface, typically when an IPv6 address is configured on the interface. To manually specify a link-local address to be used by an interface, use the ipv6 address link-local command.

A double colon may be used as part of the ipv6-address argument when consecutive 16-bit values are denoted as zero. You can configure multiple IPv6 addresses per interfaces, but only one link-local address.

Examples

The following example assigns FE80::260:3EFF:FE11:6770 as the link-local address for Ethernet interface 0:

interface ethernet 0
 ipv6 address FE80::260:3EFF:FE11:6770 link-local

Related Commands

Command
Description

ipv6 address eui-64

Configures an IPv6 address and enables IPv6 processing on an interface using an EUI-64 interface ID in the low-order 64 bits of the address.

ipv6 unnumbered

Enables IPv6 processing on an interface without assigning an explicit IPv6 address to the interface.

show ipv6 interface

Displays the usability status of interfaces configured for IPv6.


ipv6 atm-vc

To configure a mapping between a virtual circuit (VC) and the IPv6 address of a system at the far end of that circuit, use the ipv6 atm-vc command in map-list configuration mode. To remove the mapping, use the no form of this command.

ipv6 ipv6-address atm-vc vcd [broadcast]

no ipv6 ipv6-address atm-vc vcd [broadcast]

Syntax Description

ipv6-address

The IPv6 address of a system at the far end of the specified virtual circuit.

This argument must be in the form documented in RFC 2373 where the address is specified in hexadecimal using 16-bit values between colons.

vcd

The virtual circuit descriptor for the virtual circuit mapped to the specified IPv6 address.

broadcast

(Optional) Specifies that this map entry is used when sending IPv6 multicast packets to the interface (for example, network routing protocol updates).


Command Default

No default behavior or values.

Command Modes

Map-list configuration

Command History

Release
Modification

12.2(2)T

This command was introduced.

12.0(21)ST

This command was integrated into Cisco IOS Release 12.0(21)ST.

12.0(22)S

This command was integrated into Cisco IOS Release 12.0(22)S.

12.2(14)S

This command was integrated into Cisco IOS Release 12.2(14)S.

12.2(28)SB

This command was integrated into Cisco IOS Release 12.2(28)SB.

12.2(25)SG

This command was integrated into Cisco IOS Release 12.2(25)SG.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

12.2(33)SXH

This command was integrated into Cisco IOS Release 12.2(33)SXH.


Usage Guidelines

ATM permanent virtual circuits (PVCs) can be configured in the following modes:

Nonbroadcast multiaccess (NBMA) mode—A neighbor is mapped to a PVC. ATM point-to-multipoint PVCs are configured using static maps. The ipv6 atm-vc command utilizes static maps.

Point-to point-mode—Each PVC is given a subinterface and is configured as a standard point-to-point link.


Note We recommend configuring ATM PVCs in point-to-point mode.


Examples

The following example maps neighbor 2001:0DB8::5 to ATM point-to-multipoint PVC 1, virtual path identifier (VPI) 3, and virtual channel identifier (VCI) 5:

Router(config)# interface atm 1/0
Router(config-if)# atm pvc 1 3 5 aal5snap
Router(config-if)# map-group cisco

Router(config)# map-list cisco
Router(config-map-list)# ipv6 2001:0DB8::5 atm-vc 1

Related Commands

Command
Description

show ipv6 interface

Displays the usability status of interfaces configured for IPv6.


ipv6 authentication key-chain eigrp

To enable authentication of Enhanced Interior Gateway Routing Protocol (EIGRP) for IPv6 packets, use the ipv6 authentication key-chain eigrp command in interface configuration mode. To disable authentication of EIGRP for IPv6 packets, use the no form of this command.

ipv6 authentication key-chain eigrp as-number key-chain

no ipv6 authentication key-chain eigrp as-number key-chain

Syntax Description

as-number

Autonomous system number.

key-chain

Name of the authentication key chain.


Command Default

No authentication is provided for EIGRP for IPv6 packets.

Command Modes

Interface configuration

Command History

Release
Modification

12.4(6)T

This command was introduced.

12.2(33)SRB

This command was integrated into Cisco IOS Release 12.2(33)SRB.

12.2(33)SXH

This command was integrated into Cisco IOS Release 12.2(33)SXH.

Cisco IOS XE Release 2.1

This command was introduced on Cisco ASR 1000 Series Routers.


Usage Guidelines

EIGRP for IPv6 route authentication provides Message Digest 5 (MD5) authentication of routing updates from the EIGRP for IPv6 routing protocol. The MD5 keyed digest in each EIGRP for IPv6 packet prevents the introduction of unauthorized or false routing messages from unapproved sources.

Each key has its own key identifier, which is stored locally. The combination of the key identifier and the interface associated with the message uniquely identifies the authentication algorithm and MD5 authentication key in use.

You can configure multiple keys with lifetimes. Only one authentication packet is sent, regardless of how many valid keys exist. The software examines the key numbers in order from lowest to highest, and uses the first valid key it encounters.

Examples

The following example enables authentication for EIGRP for IPv6 for AS 1, using a key chain named chain1:

Router(config-if)# ipv6 authentication key-chain eigrp 1 chain1

Related Commands

Command
Description

accept-lifetime

Sets the time period during which the authentication key on a key chain is received as valid.

ipv6 authentication mode eigrp

Specifies the type of authentication used in EIGRP for IPv6 packets.

key

Identifies an authentication key on a key chain.

key chain

Enables authentication of routing protocols.

key-string (authentication)

Specifies the authentication string for a key.

send-lifetime

Sets the time period during which an authentication key on a key chain is valid to be sent.


ipv6 authentication mode eigrp

To specify the type of authentication used in Enhanced Interior Gateway Routing Protocol (EIGRP) packets for IPv6, use the ipv6 authentication mode eigrp command in interface configuration mode. To disable the type of authentication, use the no form of this command.

ipv6 authentication mode eigrp as-number md5

no ipv6 authentication mode eigrp as-number md5

Syntax Description

as-number

Autonomous system number.

md5

Specifies keyed message digest 5 (MD5) authentication.


Command Default

No authentication is provided for EIGRP for IPv6 packets.

Command Modes

Interface configuration

Command History

Release
Modification

12.4(6)T

This command was introduced.

12.2(33)SRB

This command was integrated into Cisco IOS Release 12.2(33)SRB.

12.2(33)SXH

This command was integrated into Cisco IOS Release 12.2(33)SXH.

Cisco IOS XE Release 2.1

This command was introduced on Cisco ASR 1000 Series Routers.


Usage Guidelines

Use the ipv6 authentication mode eigrp command to configure authentication to prevent unapproved sources from introducing unauthorized or false routing messages. When authentication is configured, an MD5 keyed digest is added to each EIGRP for IPv6 packet in the specified autonomous system.

Examples

The following example configures the interface to use MD5 authentication in EIGRP for IPv6 packets in autonomous system 1:

Router(config-if)# ipv6 authentication mode eigrp 1 md5

Related Commands

Command
Description

accept-lifetime

Sets the time period during which the authentication key on a key chain is received as valid.

ipv6 authentication key-chain eigrp

Enables authentication of EIGRP packets for IPv6.

key

Identifies an authentication key on a key chain.

key chain

Enables authentication of routing protocols.

key-string (authentication)

Specifies the authentication string for a key.

send-lifetime

Sets the time period during which an authentication key on a key chain is valid to be sent.


ipv6 bandwidth-percent eigrp

To configure the percentage of bandwidth that may be used by Enhanced Interior Gateway Routing Protocol (EIGRP) for IPv6 on an interface, use the ipv6 bandwidth-percent eigrp command in interface configuration mode. To restore the default value, use the no form of this command.

ipv6 bandwidth-percent eigrp as-number percent

no ipv6 bandwidth-percent eigrp as-number percent

Syntax Description

as-number

Autonomous system number.

percent

Percentage of bandwidth that EIGRP for IPv6 may use.


Command Default

Percentage of bandwidth used is 50 percent.

Command Modes

Interface configuration

Command History

Release
Modification

12.4(6)T

This command was introduced.

12.2(33)SRB

This command was integrated into Cisco IOS Release 12.2(33)SRB.

12.2(33)SXH

This command was integrated into Cisco IOS Release 12.2(33)SXH.

Cisco IOS XE Release 2.1

This command was introduced on Cisco ASR 1000 Series Routers.


Usage Guidelines

EIGRP for IPv6 uses as much as 50 percent of the bandwidth of a link, as defined by the bandwidth command. The ipv6 bandwidth-percent eigrp command may be used if some other fraction of the bandwidth is desired.

Note that values greater than 100 percent may be configured. The configuration option may be useful if the bandwidth is set artificially low for other reasons.

Examples

The following example allows EIGRP for IPv6 to use up to 75 percent (42 kbps) of a 56-kbps serial link in autonomous system 1:

interface serial 0
 bandwidth 56
 ipv6 bandwidth-percent eigrp 1 75

Related Commands

Command
Description

bandwidth (interface)

Sets a bandwidth value for an interface.


ipv6 cef

To enable Cisco Express Forwarding for IPv6, use the ipv6 cef command in global configuration mode. To disable Cisco Express Forwarding for IPv6, use the no form of this command.

ipv6 cef

no ipv6 cef

Syntax Description

This command has no arguments or keywords.

Command Default

Cisco Express Forwarding for IPv6 is disabled by default.

Command Modes

Global configuration (config)

Command History

Release
Modification

12.0(22)S

This command was introduced.

12.2(13)T

This command was integrated into Cisco IOS Release 12.2(13)T.

12.2(14)S

This command was integrated into Cisco IOS Release 12.2(14)S.

12.2(28)SB

This command was integrated into Cisco IOS Release 12.2(28)SB.

12.2(25)SG

This command was integrated into Cisco IOS Release 12.2(25)SG.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

12.2(33)SXH

This command was integrated into Cisco IOS Release 12.2(33)SXH.

Cisco IOS XE Release 2.1

This command was implemented on Cisco ASR 1000 Series Aggregation Services Routers.


Usage Guidelines

The ipv6 cef command is similar to the ip cef command, except that it is IPv6-specific.

The ipv6 cef command is not available on the Cisco 12000 series Internet routers because this distributed platform operates only in distributed Cisco Express Forwarding for IPv6 mode.


Note The ipv6 cef command is not supported in interface configuration mode.



Note Some distributed architecture platforms, such as the Cisco 7500 series routers, support both Cisco Express Forwarding for IPv6 and distributed Cisco Express Forwarding for IPv6. When Cisco Express Forwarding for IPv6 is configured on distributed platforms, Cisco Express Forwarding switching is performed by the Route Processor (RP).



Note You must enable Cisco Express Forwarding for IPv4 by using the ip cef global configuration command before enabling Cisco Express Forwarding for IPv6 by using the ipv6 cef global configuration command.


Cisco Express Forwarding for IPv6 is advanced Layer 3 IP switching technology that functions the same and offer the same benefits as Cisco Express Forwarding for IPv4. Cisco Express Forwarding for IPv6 optimizes network performance and scalability for networks with dynamic, topologically dispersed traffic patterns, such as those associated with web-based applications and interactive sessions.

Examples

The following example enables standard Cisco Express Forwarding for IPv4 operation and then standard Cisco Express Forwarding for IPv6 operation globally on the router.

ip cef
ipv6 cef

Related Commands

Command
Description

ip route-cache

Controls the use of high-speed switching caches for IP routing.

ipv6 cef accounting

Enables Cisco Express Forwarding for IPv6 and distributed Cisco Express Forwarding for IPv6 network accounting.

ipv6 cef distributed

Enables distributed Cisco Express Forwarding for IPv6.

show cef

Displays which packets the line cards dropped or displays which packets were not express-forwarded.

show ipv6 cef

Displays entries in the IPv6 FIB.


ipv6 cef accounting

To enable Cisco Express Forwarding for IPv6 and distributed Cisco Express Forwarding for IPv6 network accounting, use the ipv6 cef accounting command in global configuration mode or interface configuration mode. To disable Cisco Express Forwarding for IPv6 network accounting, use the no form of this command.

ipv6 cef accounting accounting-types

no ipv6 cef accounting accounting-types

Specific Cisco Express Forwarding Accounting Information Through Interface Configuration Mode

ipv6 cef accounting non-recursive {external | internal}

no ipv6 cef accounting non-recursive {external | internal}

Syntax Description

accounting-types

The accounting-types argument must be replaced with at least one of the following keywords. Optionally, you can follow this keyword by any or all of the other keywords, but you can use each keyword only once.

load-balance-hash—Enables load balancing hash bucket counters.

non-recursive—Enables accounting through nonrecursive prefixes.

per-prefix—Enables express forwarding of the collection of the number of packets and bytes to a destination (or prefix).

prefix-length—Enables accounting through prefix length.

non-recursive

Enables accounting through nonrecursive prefixes.

This keyword is optional when used in global configuration mode after another keyword is entered. See the accounting-types argument.

external

Counts input traffic in the nonrecursive external bin.

internal

Counts input traffic in the nonrecursive internal bin.


Command Default

Cisco Express Forwarding for IPv6 network accounting is disabled by default.

Command Modes

Global configuration (config)
Interface configuration (config-if)

Command History

Release
Modification

12.0(22)S

This command was introduced.

12.2(13)T

This command was integrated into Cisco IOS Release 12.2(13)T.

12.2(14)S

This command was integrated into Cisco IOS Release 12.2(14)S.

12.2(25)S

The non-recursive and load-balance-hash keywords were added.

12.2(28)SB

This command was integrated into Cisco IOS Release 12.2(28)SB.

12.2(25)SG

This command was integrated into Cisco IOS Release 12.2(25)SG.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

12.2(33)SXH

This command was integrated into Cisco IOS Release 12.2(33)SXH.

Cisco IOS XE Release 2.1

This command was introduced on Cisco ASR 1000 Series Routers.

12.4(20)T

This command was integrated into Cisco IOS Release 12.4(20)T.


Usage Guidelines

The ipv6 cef accounting command is similar to the ip cef accounting command, except that it is IPv6-specific.

Configuring Cisco Express Forwarding for IPv6 network accounting enables you to collect statistics on Cisco Express Forwarding for IPv6 traffic patterns in your network.

When you enable network accounting for Cisco Express Forwarding for IPv6 by using the ipv6 cef accounting command in global configuration mode, accounting information is collected at the Route Processor (RP) when Cisco Express Forwarding for IPv6 mode is enabled and at the line cards when distributed Cisco Express Forwarding for IPv6 mode is enabled. You can then display the collected accounting information using the show ipv6 cef EXEC command.

For prefixes with directly connected next hops, the non-recursive keyword enables express forwarding of the collection of packets and bytes through a prefix. This keyword is optional when this command is used in global configuration mode after you enter another keyword on the ipv6 cef accounting command.

This command in interface configuration mode must be used in conjunction with the global configuration command. The interface configuration command allows a user to specify two different bins (internal or external) for the accumulation of statistics. The internal bin is used by default. The statistics are displayed through the show ipv6 cef detail command.

Per-destination load balancing uses a series of 16 hash buckets into which the set of available paths are distributed. A hash function operating on certain properties of the packet is applied to select a bucket that contains a path to use. The source and destination IP addresses are the properties used to select the bucket for per-destination load balancing. Use the load-balance-hash keyword with the ipv6 cef accounting command to enable per-hash-bucket counters. Enter the show ipv6 cef prefix internal command to display the per-hash-bucket counters.

Examples

The following example enables the collection of Cisco Express Forwarding for IPv6 accounting information for prefixes with directly connected next hops:

Router(config)# ipv6 cef accounting non-recursive

Related Commands

Command
Description

ip cef accounting

Enable Cisco Express Forwarding network accounting (for IPv4).

show cef

Displays information about packets forwarded by Cisco Express Forwarding.

show ipv6 cef

Displays entries in the IPv6 FIB.


ipv6 cef distributed

To enable distributed Cisco Express Forwarding for IPv6, use the ipv6 cef distributed command in global configuration mode. To disable Cisco Express Forwarding for IPv6, use the no form of this command.

ipv6 cef distributed

no ipv6 cef distributed

Syntax Description

This command has no arguments or keywords.

Command Default

Distributed Cisco Express Forwarding for IPv6 is disabled on the Cisco 7500 series routers and enabled on the Cisco 12000 series Internet routers.

Command Modes

Global configuration (config)

Command History

Release
Modification

12.0(22)S

This command was introduced.

12.2(13)T

This command was integrated into Cisco IOS Release 12.2(13)T.

12.2(14)S

This command was integrated into Cisco IOS Release 12.2(14)S.

12.2(28)SB

This command was integrated into Cisco IOS Release 12.2(28)SB.

12.2(25)SG

This command was integrated into Cisco IOS Release 12.2(25)SG.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

12.2(33)SXH

This command was integrated into Cisco IOS Release 12.2(33)SXH.

Cisco IOS XE Release 2.1

This command was implemented on Cisco ASR 1000 Series Aggregation Services Routers.


Usage Guidelines

The ipv6 cef distributed command is similar to the ip cef distributed command, except that it is IPv6-specific.

Enabling distributed Cisco Express Forwarding for IPv6 globally on the router by using the ipv6 cef distributed in global configuration mode distributes the Cisco Express Forwarding processing of IPv6 packets from the Route Processor (RP) to the line cards of distributed architecture platforms.


Note The ipv6 cef distributed command is not supported on the Cisco 12000 series Internet routers because distributed Cisco Express Forwarding for IPv6 is enabled by default on this platform.



Note To forward distributed Cisco Express Forwarding for IPv6 traffic on the router, configure the forwarding of IPv6 unicast datagrams globally on your router by using the ipv6 unicast-routing global configuration command, and configure an IPv6 address and IPv6 processing on an interface by using the ipv6 address interface configuration command.



Note You must enable distributed Cisco Express Forwarding for IPv4 by using the ip cef distributed global configuration command before enabling distributed Cisco Express Forwarding for IPv6 by using the ipv6 cef distributed global configuration command.


Cisco Express Forwarding is advanced Layer 3 IP switching technology. Cisco Express Forwarding optimizes network performance and scalability for networks with dynamic, topologically dispersed traffic patterns, such as those associated with web-based applications and interactive sessions.

Examples

The following example enables distributed Cisco Express Forwarding for IPv6 operation:

ipv6 cef distributed

Related Commands

Command
Description

ip route-cache

Controls the use of high-speed switching caches for IP routing.

show ipv6 cef

Displays entries in the IPv6 FIB.


ipv6 cef load-sharing algorithm

To select a Cisco Express Forwarding load-balancing algorithm for IPv6, use the ipv6 cef load-sharing algorithm command in global configuration mode. To return to the default universal load-balancing algorithm, use the no form of this command.

ipv6 cef load-sharing algorithm {original | universal [id] | include-ports {source [id] | [destination] [id] | source [id] destination [id]}}

no ipv6 cef load-sharing algorithm

Syntax Description

original

Sets the load-balancing algorithm to the original algorithm based on a source and destination hash.

universal

Sets the load-balancing algorithm to the universal algorithm that uses a source and destination and an ID hash.

id

(Optional) Fixed identifier in hexadecimal format.

include-ports source

Sets the load-balancing algorithm to the include-ports algorithm that uses a Layer 4 source port.

include-ports destination

Sets the load-balancing algorithm to the include-ports algorithm that uses a Layer 4 destination port.

include-ports source destination

Sets the load balancing algorithm to the include-ports algorithm that uses Layer 4 source and destination ports.


Command Default

The universal load-balancing algorithm is selected. If you do not configure the fixed identifier for a load-balancing algorithm, the router automatically generates a unique ID.

Command Modes

Global configuration (config)

Command History

Release
Modification

12.2(25)S

This command was introduced.

12.2(28)SB

This command was integrated into Cisco IOS Release 12.2(28)SB.

12.2(25)SG

This command was integrated into Cisco IOS Release 12.2(25)SG.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

12.2SX

This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.

12.4(20)T

This command was integrated into Cisco IOS Release 12.4(20)T.


Usage Guidelines

The ipv6 cef load-sharing algorithm command is similar to the ip cef load-sharing algorithm command, except that it is IPv6-specific.

When the Cisco Express Forwarding for IPv6 load-balancing algorithm is set to universal mode, each router on the network can make a different load-sharing decision for each source-destination address pair.

The include-ports algorithm allows you to use the Layer 4 source and destination ports as part of the load-balancing decision. This method benefits traffic streams running over equal-cost paths that are not load-shared because the majority of the traffic is between peer addresses that use different port numbers, such as Real-Time Protocol (RTP) streams.

Examples

The following example shows how to enable the Cisco Express Forwarding load-balancing algorithm for IPv6 for Layer-4 source and destination ports:

Router(config)# ipv6 cef load-sharing algorithm include-ports source destination

The router automatically generates fixed IDs for the algorithm.

Related Commands

Command
Description

debug ipv6 cef hash

Displays debug messages for Cisco Express Forwarding for IPv6 and distributed Cisco Express Forwarding for IPv6 load-sharing hash algorithm events.

ip cef load-sharing algorithm

Selects a Cisco Express Forwarding load-balancing algorithm (for IPv4).


ipv6 cef optimize neighbor resolution

To configure address resolution optimization from Cisco Express Forwarding for IPv6 for directly connected neighbors, use the ipv6 cef optimize neighbor resolution command in global configuration mode. To disable address resolution optimization from Cisco Express Forwarding for IPv6 for directly connected neighbors, use the no form of this command.

ipv6 cef optimize neighbor resolution

no ipv6 cef optimize neighbor resolution

Syntax Description

This command has no arguments or keywords.

Command Default

If this command is not configured, Cisco Express Forwarding for IPv6 does not optimize the address resolution of directly connected neighbors.

Command Modes

Global configuration (config)

Command History

Release
Modification

12.2(25)S

This command was introduced.

12.2(28)SB

This command was integrated into Cisco IOS Release 12.2(28)SB.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

12.2(33)SXH

This command was integrated into Cisco IOS Release 12.2(33)SXH.

12.4(20)T

This command was integrated into Cisco IOS Release 12.4(20)T.


Usage Guidelines

The ipv6 cef optimize neighbor resolution command is very similar to the ip cef optimize neighbor resolution command, except that it is IPv6-specific.

Use this command to trigger Layer 2 address resolution of neighbors directly from Cisco Express Forwarding for IPv6.

Examples

The following example shows how to optimize address resolution from Cisco Express Forwarding for IPv6 for directly connected neighbors:

Router(config)# ipv6 cef optimize neighbor resolution 

Related Commands

Command
Description

ip cef optimize neighbor resolution

Configures address resolution optimization from Cisco Express Forwarding for IPv4 for directly connected neighbors.


ipv6 cga modifier rsakeypair

To generate an IPv6 cryptographically generated address (CGA) modifier for a specified Rivest, Shamir, and Adelman (RSA) key pair, use the ipv6 cga modifier rsakeypair command in global configuration mode. To disable this function, use the no form of this command.

ipv6 cga modifier rsakeypair key-label sec-level {0 | 1}

no ipv6 cga modifier rsakeypair

Syntax Description

key-label

The name to be used for RSA key pair

sec-level {0 | 1}

Specifies the security level, which can be either 0 or 1. The most secure level is 1.


Command Default

No CGA exists for an RSA key.

Command Modes

Global configuration (config)

Command History

Release
Modification

12.4(24)T

This command was introduced.


Usage Guidelines

Use this command to generate the CGA modifier for a specified RSA key pair, which enables the key to be used by Secure Neighbor Discovery (SeND).

Once the RSA key is generated, the modifier must be generated as well, using the ipv6 cga modifier rsakeypair command.

A CGA has a security parameter that determines its strength against brute-force attacks. The security level can be either 0 or 1.

Examples

The following example enables the specified key to be used by SeND (that is, generates the modifier):

Router(config)# ipv6 cga modifier rsakeypair SEND sec-level 1

Related Commands

Command
Description

crypto key generate rsa

Generates RSA key pairs.

ipv6 cga modifier rsakeypair

Generates the CGA modifier for a specified RSA key.

ipv6 cga modifier rsakeypair (interface)

Binds a SeND key to a specified interface.

ipv6 cga rsakeypair

Specifies which RSA key should be used on an interface.


ipv6 cga rsakeypair

To bind a Secure Neighbor Discovery (SeND) key to a specified interface, use the ipv6 cga rsakeypair command in interface configuration mode. To disable this function, use the no form of this command.

ipv6 cga rsakeypair key-label

no ipv6 cga rsakeypair

Syntax Description

key-label

The name to be used for the Rivest, Shamir, and Adelman (RSA) key pair.


Command Default

A SeND key is not bound to an interface.

Command Modes

Interface configuration (config-if)

Command History

Release
Modification

12.4(24)T

This command was introduced.


Usage Guidelines

The SeND key is used to generate an IPv6 modifier for a specified Rivest, Shamir and Adelman (RSA) key pair. A SeND key must be bound to the interface prior to its being used in the ipv6 address command. Use the ipv6 cga rsakeypair command to bind a SeND key to a specified interface.

You can then use the ipv6 address command to add the Cryptographic Addresses (CGA).

Examples

The following example binds a SeND key to Ethernet interface 0/0:

Router(config)# interface Ethernet0/0
Router(config-if)# ip address 10.0.1.1 255.255.255.0
Router(config-if)# ipv6 cga rsakeypair SEND

Related Commands

Command
Description

ipv6 address

Configures an IPv6 address based on an IPv6 general prefix and enables IPv6 processing on an interface.

crypto key generate rsa

Generates RSA key pairs.

ipv6 cga modifier rsakeypair (global configuration)

Generates the CGA modifier for a specified RSA key.

ipv6 cga modifier rsakeypair (interface configuration)

Binds a SeND key to a specified interface.

ipv6 cga rsakeypair

Specifies which RSA key should be used on an interface.


ipv6 crypto map

To enable an IPv6 crypto map on an interface, use the ipv6 crypto map command in interface configuration mode. To disable, use the no form of this command.

ipv6 crypto map map-name

no ipv6 crypto map

Syntax Description

map-name

Identifies the crypto map set.


Command Default

No IPv6 crypto maps are enabled on the interface.

Command Modes

Interface configuration (config-if)

Command History

Release
Modification

15.1(4)M

This command was introduced.


Usage Guidelines

This command differentiates IPv6 and IPv4 crypto maps.

Examples

The following example shows how to enable an IPv6 crypto map on an interface:

Router# configure terminal
Router(config)# interface ethernet 0/0
Router(config-if)# ipv6 crypto map CM_V4

Related Commands

Command
Description

crypto map (global IPsec)

Creates or modifies a crypto map entry.


ipv6 dhcp binding track ppp

To configure Dynamic Host Configuration Protocol (DHCP) for IPv6 to release any bindings associated with a PPP connection when that connection closes, use the ipv6 dhcp binding track ppp command in global configuration mode. To return to the default behavior, use the no form of this command.

ipv6 dhcp binding track ppp

no ipv6 dhcp binding track ppp

Syntax Description

This command has no arguments or keywords.

Command Default

When a PPP connection closes, the DHCP bindings associated with that connection are not released.

Command Modes

Global configuration (config)

Command History

Release
Modification

Cisco IOS XE Release 2.5

This command was introduced.


Usage Guidelines

The ipv6 dhcp binding track ppp command configures DHCP for IPv6 to automatically release any bindings associated with a PPP connection when that connection is closed. The bindings are released automatically to accommodate subsequent new registrations by providing sufficient resource.

A binding table entry on the DHCP for IPv6 server is automatically:

Created whenever a prefix is delegated to a client from the configuration pool.

Updated when the client renews, rebinds, or confirms the prefix delegation.

Deleted when the client releases all the prefixes in the binding voluntarily, all prefixes' valid lifetimes have expired, or an administrator clears the binding.

Examples

The following example shows how to release the prefix bindings associated with the PPP:

Router(config)# ipv6 dhcp binding track ppp

ipv6 dhcp client information refresh minimum

To configure the minimum acceptable Dynamic Host Configuration Protocol (DHCP) for IPv6 client information refresh time on a specified interface, use the ipv6 dhcp client information refresh minimum command in interface configuration mode. To remove the configured refresh time, use the no form of this command.

ipv6 dhcp client information refresh minimum seconds

no ipv6 dhcp client information refresh minimum seconds

Syntax Description

seconds

The refresh time, in seconds. The minimum value that can be used is 600 seconds.


Command Default

The default is 86,400 seconds (24 hours).

Command Modes

Interface configuration

Command History

Release
Modification

12.4(15)T

This command was introduced.


Usage Guidelines

The ipv6 dhcp client information refresh minimum command specifies the minimum acceptable information refresh time. If the server sends an information refresh time option of less than the configured minimum refresh time, the configured minimum refresh time will be used instead.

This command may be configured in several situations:

In unstable environments where unexpected changes are likely to occur.

For planned changes, including renumbering. An administrator can gradually decrease the time as the planned event nears.

Limit the amount of time before new services or servers are available to the client, such as the addition of a new Simple Network Time Protocol (SNTP) server or a change of address of a Domain Name System (DNS) server.

Examples

The following example configures an upper limit of 2 hours:

ipv6 dhcp client information refresh minimum 7200

ipv6 dhcp client pd

To enable the Dynamic Host Configuration Protocol (DHCP) for IPv6 client process and enable request for prefix delegation through a specified interface, use the ipv6 dhcp client pd command in interface configuration mode. To disable requests for prefix delegation, use the no form of this command.

ipv6 dhcp client pd {prefix-name | hint ipv6-prefix} [rapid-commit]

no ipv6 dhcp client pd

Syntax Description

prefix-name

IPv6 general prefix name.

hint

An IPv6 prefix sent as a hint.

ipv6-prefix

IPv6 general prefix.

rapid-commit

(Optional) Allow two-message exchange method for prefix delegation.


Command Default

Prefix delegation is disabled on an interface.

Command Modes

Interface configuration

Command History

Release
Modification

12.3(4)T

This command was introduced.

12.2(18)SXE

This command was integrated into Cisco IOS Release 12.2(18)SXE.

Cisco IOS XE Release 2.1

This command was integrated into Cisco IOS XE Release 2.1.

12.2(33)SRE

This command was modified. It was integrated into Cisco IOS Release 12.2(33)SRE.


Usage Guidelines

Enabling the ipv6 dhcp client pd command starts the DHCP for IPv6 client process if this process is not yet running.

The ipv6 dhcp client pd command enables request for prefix delegation through the interface on which this command is configured. When prefix delegation is enabled and a prefix is successfully acquired, the prefix is stored in the IPv6 general prefix pool with an internal name defined by the ipv6-prefix argument. Other commands and applications (such as the ipv6 address command) can then refer to the prefixes in the general prefix pool.

The hint keyword with the ipv6-prefix argument enables the configuration of an IPv6 prefix that will be included in DHCP for IPv6 solicit and request messages sent by the DHCP for IPv6 client on the interface as a hint to prefix-delegating routers. Multiple prefixes can be configured by issuing the ipv6 dhcp client pd hint ipv6-prefix command multiple times. The new prefixes will not overwrite old ones.

The rapid-commit keyword enables the use of the two-message exchange for prefix delegation and other configuration. If it is enabled, the client will include the rapid commit option in a solicit message.

The DHCP for IPv6 client, server, and relay functions are mutually exclusive on an interface. When one of these functions is already enabled and a user tries to configure a different function on the same interface, one of the following messages is displayed: "Interface is in DHCP client mode," "Interface is in DHCP server mode," or "Interface is in DHCP relay mode."

Examples

The following example enables prefix delegation:

Router(config-if)# ipv6 dhcp client pd dhcp-prefix

The following example configures a hint for prefix-delegating routers:

Router(config-if)# ipv6 dhcp client pd hint 2001:0DB8:1/48

Related Commands

Command
Description

clear ipv6 dhcp client

Restarts the DHCP for IPv6 client on an interface.

show ipv6 dhcp interface

Displays DHCP for IPv6 interface information.


ipv6 dhcp database

To configure a Dynamic Host Configuration Protocol (DHCP) for IPv6 binding database agent, use the ipv6 dhcp database command in global configuration mode. To delete the database agent, use the no form of this command.

ipv6 dhcp database agent [write-delay seconds] [timeout seconds]

no ipv6 dhcp database agent

Syntax Description

agent

A flash, local bootflash, compact flash, NVRAM, FTP, TFTP, or Remote Copy Protocol (RCP) uniform resource locator.

write-delay seconds

(Optional) How often (in seconds) DHCP for IPv6 sends database updates. The default is 300 seconds. The minimum write delay is 60 seconds.

timeout seconds

(Optional) How long, in seconds, the router waits for a database transfer.


Command Default

Write-delay default is 300 seconds.
Timeout default is 300 seconds.

Command Modes

Global configuration

Command History

Release
Modification

12.3(4)T

This command was introduced.

12.2(18)SXE

This command was integrated into Cisco IOS Release 12.2(18)SXE.

12.2(33)SRE

This command was modified. It was integrated into Cisco IOS Release 12.2(33)SRE.


Usage Guidelines

The ipv6 dhcp database command specifies DHCP for IPv6 binding database agent parameters. The user may configure multiple database agents.

A binding table entry is automatically created whenever a prefix is delegated to a client from the configuration pool, updated when the client renews, rebinds, or confirms the prefix delegation, and deleted when the client releases all the prefixes in the binding voluntarily, all prefixes' valid lifetimes have expired, or administrators enable the clear ipv6 dhcp binding command. These bindings are maintained in RAM and can be saved to permanent storage using the agent argument so that the information about configuration such as prefixes assigned to clients is not lost after a system reload or power down. The bindings are stored as text records for easy maintenance.

Each permanent storage to which the binding database is saved is called the database agent. A database agent can be a remote host such as an FTP server or a local file system such as NVRAM.

The write-delay keyword specifies how often, in seconds, that DHCP sends database updates. By default, DHCP for IPv6 server waits 300 seconds before sending any database changes.

The timeout keyword specifies how long, in seconds, the router waits for a database transfer. Infinity is defined as 0 seconds, and transfers that exceed the timeout period are aborted. By default, the DHCP for IPv6 server waits 300 seconds before aborting a database transfer. When the system is going to reload, there is no transfer timeout so that the binding table can be stored completely.

Examples

The following example specifies DHCP for IPv6 binding database agent parameters and stores binding entries in TFTP:

ipv6 dhcp database tftp://10.0.0.1/dhcp-binding

The following example specifies DHCP for IPv6 binding database agent parameters and stores binding entries in bootflash:

ipv6 dhcp database bootflash

Related Commands

Command
Description

clear ipv6 dhcp binding

Deletes automatic client bindings from the DHCP for IPv6 server binding table

show ipv6 dhcp database

Displays DHCP for IPv6 binding database agent information.


ipv6 dhcp debug redundancy

To display debugging output for IPv6 DHCP high availability (HA) processing, use the ipv6 dhcp debug redundancy command in privileged EXEC mode. To disable debugging output, use the no form of this command.

ipv6 dhcp debug redundancy

no ipv6 dhcp debug redundancy

Syntax Description

This command has no arguments or keywords.

Command Modes

Privileged EXEC (#)

Command History

Release
Modification

12.2(33)SRE

This command was introduced.


Usage Guidelines

Use the ipv6 dhcp debug redundancy command to display stateful switchover (SSO) state transitions and errors.

Examples

The following example enables IPv6 DHCP redundancy debugging:

Router# ipv6 dhcp debug redundancy

ipv6 dhcp framed password

To assign a framed prefix when using a RADIUS server, use the ipv6 dhcp framed password command in interface configuration mode. To remove the framed prefix, use the no form of this command.

ipv6 dhcp framed password password

no ipv6 dhcp framed password

Syntax Description

password

Password to be used with the RADIUS server.


Command Default

No framed prefix is assigned.

Command Modes

Interface configuration (config-if)

Command History

Release
Modification

Cisco IOS XE Release 2.5

This command was introduced.


Usage Guidelines

The ipv6 dhcp framed password command enables a user to request a framed prefix of a RADIUS server. When a PPPoE client requests a prefix from a network using the framed-prefix system, the RADIUS server should assign an address. However, the RADIUS server is configured to receive a password. Because the client does not send a password, the RADIUS server does not send a framed prefix.


Note Ordinarily, the ipv6 dhcp framed password command will not need to be used because a client will have been authenticated as part of PPP session establishment.


Examples

The following example shows how to configure a password to be used with the RADIUS server:

Router(config-if)# ipv6 dhcp framed password password1

ipv6 dhcp ping packets

To specify the number of packets a Dynamic Host Configuration Protocol for IPv6 (DHCPv6) server sends to a pool address as part of a ping operation, use the ipv6 dhcp ping packets command in global configuration mode. To prevent the server from pinging pool addresses, use the no form of this command.

ipv6 dhcp ping packets number

ipv6 dhcp ping packets

Syntax Description

number

The number of ping packets sent before the address is assigned to a requesting client. The valid range is from 0 to 10.


Command Default

No ping packets are sent before the address is assigned to a requesting client.

Command Modes

Global configuration (config)

Command History

Release
Modification

12.4(24)T

This command was introduced.

12.2(33)SRE

This command was modified. It was integrated into Cisco IOS Release 12.2(33)SRE.


Usage Guidelines

The DHCPv6 server pings a pool address before assigning the address to a requesting client. If the ping is unanswered, the server assumes, with a high probability, that the address is not in use and assigns the address to the requesting client.

Setting the number argument to 0 turns off the DHCPv6 server ping operation

Examples

The following example specifies four ping attempts by the DHCPv6 server before further ping attempts stop:

Router(config)# ipv6 dhcp ping packets 4

Related Commands

Command
Description

clear ipv6 dhcp conflict

Clears an address conflict from the DHCPv6 server database.

show ipv6 dhcp conflict

Displays address conflicts found by a DHCPv6 server, or reported through a DECLINE message from a client.


ipv6 dhcp pool

To configure a Dynamic Host Configuration Protocol (DHCP) for IPv6 server configuration information pool and enter DHCP for IPv6 pool configuration mode, use the ipv6 dhcp pool command in global configuration mode. To delete a DHCP for IPv6 pool, use the no form of this command.

ipv6 dhcp pool poolname

no ipv6 dhcp pool poolname

Syntax Description

poolname

User-defined name for the local prefix pool. The pool name can be a symbolic string (such as "Engineering") or an integer (such as 0).


Command Default

DHCP for IPv6 pools are not configured.

Command Modes

Global configuration

Command History

Release
Modification

12.3(4)T

This command was introduced.

12.2(18)SXE

This command was integrated into Cisco IOS Release 12.2(18)SXE.

12.4(24)T

This command was integrated into Cisco IOS Release 12.4(24)T.

Cisco IOS XE Release 2.1

This command was integrated into Cisco IOS XE Release 2.1.

12.2(33)SRE

This command was modified. It was integrated into Cisco IOS Release 12.2(33)SRE.

12.2(33)XNE

This command was modified. It was integrated into Cisco IOS Release 12.2(33)XNE.


Usage Guidelines

Use the ipv6 dhcp pool command to create a DHCP for IPv6 server configuration information pool. When the ipv6 dhcp pool command is enabled, the configuration mode changes to DHCP for IPv6 pool configuration mode. In this mode, the administrator can configure pool parameters, such as prefixes to be delegated and Domain Name System (DNS) servers, using the following commands:

address prefix IPv6-prefix [lifetime {valid-lifetime preferred-lifetime | infinite}] sets an address prefix for address assignment. This address must be in hexadecimal, using 16-bit values between colons.

link-address IPv6-prefix sets a link-address IPv6 prefix. When an address on the incoming interface or a link-address in the packet matches the specified IPv6-prefix, the server uses the configuration information pool. This address must be in hexadecimal, using 16-bit values between colons.

vendor-specific vendor-id enables DHCPv6 vendor-specific configuration mode. Specify a vendor identification number. This number is the vendor IANA Private Enterprise Number. The range is 1 to 4294967295. The following configuration command is available:

suboption number sets vendor-specific suboption number. The range is 1 to 65535. You can enter an IPv6 address, ASCII text, or a hex string as defined by the suboption parameters.


Note The hex value used under the suboption keyword allows users to enter only hex digits (0-f). Entering an invalid hex value does not delete the previous configuration.


Once the DHCP for IPv6 configuration information pool has been created, use the ipv6 dhcp server command to associate the pool with a server on an interface. If you do not configure an information pool, you need to use the ipv6 dhcp server interface configuration command to enable the DHCPv6 server function on an interface.

When you associate a DHCPv6 pool with an interface, only that pool services requests on the associated interface. The pool also services other interfaces. If you do not associate a DHCPv6 pool with an interface, it can service requests on any interface.

Not using any IPv6 address prefix means that the pool returns only configured options.

The link-address command allows matching a link-address without necessarily allocating an address. You can match the pool from multiple relays by using multiple link-address configuration commands inside a pool.

Since a longest match is performed on either the address pool information or the link information, you can configure one pool to allocate addresses and another pool on a subprefix that returns only configured options.

Examples

The following example specifies a DHCP for IPv6 configuration information pool named cisco1 and places the router in DHCP for IPv6 pool configuration mode:

Router(config)# ipv6 dhcp pool cisco1
Router(config-dhcpv6)#

The following example shows how to configure an IPv6 address prefix for the IPv6 configuration pool cisco1:

Router(config-dhcpv6)# address prefix 2001:1000::0/64
Router(config-dhcpv6)# end

The following example shows how to configure a pool named engineering with three link-address prefixes and an IPv6 address prefix:

Router# configure terminal
Router(config)# ipv6 dhcp pool engineering
Router(config-dhcpv6)# link-address 2001:1001::0/64
Router(config-dhcpv6)# link-address 2001:1002::0/64
Router(config-dhcpv6)# link-address 2001:2000::0/48
Router(config-dhcpv6)# address prefix 2001:1003::0/64
Router(config-dhcpv6)# end

The following example shows how to configure a pool named 350 with vendor-specific options:

Router# configure terminal
Router(config)# ipv6 dhcp pool 350
Router(config-dhcpv6)# vendor-specific 9
Router(config-dhcpv6-vs)# suboption 1 address 1000:235D::1
Router(config-dhcpv6-vs)# suboption 2 ascii "IP-Phone"
Router(config-dhcpv6-vs)# end



Related Commands

Command
Description

ipv6 dhcp server

Enables DHCP for IPv6 service on an interface.

show ipv6 dhcp pool

Displays DHCP for IPv6 configuration pool information.


ipv6 dhcp relay destination

To specify a destination address to which client messages are forwarded and to enable Dynamic Host Configuration Protocol (DHCP) for IPv6 relay service on the interface, use the ipv6 dhcp relay destination command in interface configuration mode. To remove a relay destination on the interface or to delete an output interface for a destination, use the no form of this command.

ipv6 dhcp relay destination ipv6-address [interface-type interface-number | vrf vrf-name | global]

no ipv6 dhcp relay destination ipv6-address [interface-type interface-number | vrf vrf-name | global]

Syntax Description

ipv6-address

Relay destination address. There are two types of relay destination address:

Link-scoped unicast or multicast IPv6 address. A user must specify an output interface for this kind of address.

Global or site-scoped unicast or multicast IPv6 address.

This argument must be in the form documented in RFC 2373 where the address is specified in hexadecimal using 16-bit values between colons.

interface-type interface-number

(Optional) Interface type and number that specifies the output interface for a destination. If this argument is configured, client messages are forwarded to the destination address through the link to which the output interface is connected.

vrf vrf-name

(Optional) Specifies the virtual routing and forwarding (VRF) associated with the relay destination IPv6 address.

global

(Optional) Specifies the relay destination when the relay destination is in the global address space and when the relay source is in a VRF.


Command Default

The relay function is disabled, and there is no relay destination on an interface.

Command Modes

Interface configuration (config-if)

Command History

Release
Modification

12.3(11)T

This command was introduced.

12.2(33)SXI

This command was integrated into Cisco IOS Release 12.2(33)SXI.

12.2(33)SRE

This command was modified. It was integrated into Cisco IOS Release 12.2(33)SRE.

15.1(2)S

This command was modified. The vrf vrf-name keyword and argument were added. The global keyword was added.

Cisco IOS XE Release 3.3S

This command was modified. The vrf vrf-name keyword and argument were added.


Usage Guidelines

The ipv6 dhcp relay destination command specifies a destination address to which client messages are forwarded, and it enables DHCP for IPv6 relay service on the interface. When relay service is enabled on an interface, a DHCP for IPv6 message received on that interface will be forwarded to all configured relay destinations. The incoming DHCP for IPv6 message may have come from a client on that interface, or it may have been relayed by another relay agent.

The relay destination can be a unicast address of a server or another relay agent, or it may be a multicast address. There are two types of relay destination addresses:

A link-scoped unicast or multicast IPv6 address, for which a user must specify an output interface

A global or site-scoped unicast or multicast IPv6 address. A user can optionally specify an output interface for this kind of address.

If no output interface is configured for a destination, the output interface is determined by routing tables. In this case, it is recommended that a unicast or multicast routing protocol be running on the router.

Multiple destinations can be configured on one interface, and multiple output interfaces can be configured for one destination. When the relay agent relays messages to a multicast address, it sets the hop limit field in the IPv6 packet header to 32.

Unspecified, loopback, and node-local multicast addresses are not acceptable as the relay destination. If any one of them is configured, the message "Invalid destination address" is displayed.

Note that it is not necessary to enable the relay function on an interface for it to accept and forward an incoming relay reply message from servers. By default, the relay function is disabled, and there is no relay destination on an interface. The no form of the command removes a relay destination on an interface or deletes an output interface for a destination. If all relay destinations are removed, the relay service is disabled on the interface.

The DHCP for IPv6 client, server, and relay functions are mutually exclusive on an interface. When one of these functions is already enabled and a user tries to configure a different function on the same interface, one of the following messages is displayed: "Interface is in DHCP client mode," "Interface is in DHCP server mode," or "Interface is in DHCP relay mode."

Examples

The following example sets the relay destination address on Ethernet interface 4/3:

ipv6 dhcp relay destination FE80::250:A2FF:FEBF:A056 ethernet 4/3

Related Commands

Command
Description

show ipv6 dhcp interface

Displays DHCP for IPv6 interface information.


ipv6 dhcp-relay option vpn

To enable the DHCP for IPv6 relay VRF-aware feature, use the ipv6 dhcp-relay option vpn command in global configuration mode. To disable the feature, use the no form of this command.

ipv6 dhcp-relay option vpn

no ipv6 dhcp-relay option vpn

Syntax Description

This command has no arguments or keywords.

Command Default

The DHCP for IPv6 relay VRF-aware feature is not enabled on the router.

Command Modes

Global configuration (config)

Command History

Release
Modification

15.1(2)S

This command was introduced.

Cisco IOS XE Release 3.3S

This command was integrated into Cisco IOS XE Release 3.3S.


Usage Guidelines

The ipv6 dhcp-relay option vpn command allows the DHCPv6 relay VRF-aware feature to be enabled globally on the router. If the ipv6 dhcp relay option vpn command is enabled on a specified interface, it overrides the global ipv6 dhcp-relay option vpn command.

Examples

The following example enables the DHCPv6 relay VRF-aware feature globally on the router:

Router(config)# ipv6 dhcp-relay option vpn

Related Commands

Command
Description

ipv6 dhcp relay option vpn

Enables the DHCPv6 relay VRF-aware feature on an interface.


ipv6 dhcp relay source-interface

To configure an interface to use as the source when relaying messages received on this interface, use the ipv6 dhcp relay source-interface command in interface configuration mode. To remove the interface from use as the source, use the no form of this command.

ipv6 dhcp relay source-interface type number

no ipv6 dhcp relay source-interface type number

Syntax Description

type number

Interface type and number that specifies output interface for a destination. If these arguments are configured, client messages are forwarded to the destination address through the link to which the output interface is connected.


Command Default

The address of the server-facing interface is used as the IPv6 relay source.

Command Modes

Interface configuration (config-if)

Command History

Release
Modification

12.2(33)SRE

This command was introduced.

12.2(33)XNE

This command was modified. It was integrated into Cisco IOS Release 12.2(33)XNE.


Usage Guidelines

If the configured interface is shut down, or if all of its IPv6 addresses are removed, the relay will revert to its standard behavior.

The interface configuration (using the ipv6 dhcp relay source-interface command in interface configuration mode) takes precedence over the global configuration if both have been configured.

Examples

The following example configures the Loopback 0 interface to be used as the relay source:

Router(config-if)# ipv6 dhcp relay source-interface loopback 0

Related Commands

Command
Description

ipv6 dhcp-relay source-interface

Enables DHCP for IPv6 service on an interface.



ipv6 dhcp-relay show bindings

To enable the DHCPv6 relay agent to list prefix delegation (PD) bindings, use the ipv6 dhcp-relay show bindings command in global configuration mode. To disable PD binding tracking, use the no form of this command.

ipv6 dhcp-relay show bindings

no ipv6 dhcp-relay show bindings

Syntax Description

This command has no arguments or keywords.

Command Modes

Global configuration (config)

Command History

Release
Modification

12.2(33)SRE

This command was introduced.


Usage Guidelines

The ipv6 dhcp-relay show bindings command lists the PD bindings that the relay agent is tracking. The command lists the bindings in the relay's radix tree, lists DHCPv6 relay routes, and prints each entry's prefix and length, client identity association identification (IAID), and lifetime.

Examples

The following example enables the DHCPv6 relay agent to list PD bindings:

Router# ipv6 dhcp-relay show bindings

ipv6 dhcp-relay source-interface

To configure an interface to use as the source when relaying messages, use the ipv6 dhcp-relay source-interface command in global configuration mode. To remove the interface from use as the source, use the no form of this command.

ipv6 dhcp-relay source-interface {interface-type interface-number}

no ipv6 dhcp-relay source-interface {interface-type interface-number}

Syntax Description

interface-type interface-number

(Optional) Interface type and number that specifies output interface for a destination. If this argument is configured, client messages are forwarded to the destination address through the link to which the output interface is connected.


Command Default

The address of the server-facing interface is used as the IPv6 relay source.

Command Modes

Global configuration (config)

Command History

Release
Modification

12.2(33)SRE

This command was introduced.

12.2(33)XNE

This command was modified. It was integrated into Cisco IOS Release 12.2(33)XNE.


Usage Guidelines

If the configured interface is shut down, or if all of its IPv6 addresses are removed, the relay will revert to its standard behavior.

The interface configuration (using the ipv6 dhcp relay source-interface command in interface configuration mode) takes precedence over the global configuration if both have been configured.

Examples

The following example configures the Loopback 0 interface to be used as the relay source:

Router(config)# ipv6 dhcp-relay source-interface loopback 0

Related Commands

Command
Description

ipv6 dhcp relay source-interface

Enables DHCP for IPv6 service on an interface.



ipv6 dhcp-relay bulk-lease

To configure bulk lease query parameters, use the ipv6 dhcp-relay bulk-lease command in global configuration mode. To remove the bulk-lease query configuration, use the no form of this command.

ipv6 dhcp-relay bulk-lease {data-timeout seconds | retry number} [disable]

no ipv6 dhcp-relay bulk-lease [disable]

Syntax Description

data-timeout

(Optional) Bulk lease query data transfer timeout.

seconds

(Optional) The range is from 60 seconds to 600 seconds. The default is 300 seconds.

retry

(Optional) Sets the bulk lease query retries.

number

(Optional) The range is from 0 to 5. The default is 5.

disable

(Optional) Disables the DHCPv6 bulk lease query feature.


Command Default

Bulk lease query is enabled automatically when the DHCP for IPv6 (DHCPv6) relay agent feature is enabled.

Command Modes

Global configuration (config)

Command History

Release
Modification

15.1(1)S

This command was introduced.


Usage Guidelines

Use the ipv6 dhcp-relay bulk-lease command in global configuration mode to configure bulk lease query parameters, such as data transfer timeout and bulk-lease TCP connection retries.

The DHCPv6 bulk lease query feature is enabled automatically when the DHCPv6 relay agent is enabled. The DHCPv6 bulk lease query feature itself cannot be enabled using this command. To disable this feature, use the ipv6 dhcp-relay bulk-lease command with the disable keyword.

Examples

The following example shows how to set the bulk lease query data transfer timeout to 60 seconds:

Router(config)# ipv6 dhcp-relay bulk-lease data-timeout 60

Related Commands

Command
Description
   

ipv6 dhcp-relay option vpn

To enable the DHCP for IPv6 relay VRF-aware feature, use the ipv6 dhcp-relay option vpn command in global configuration mode. To disable the feature, use the no form of this command.

ipv6 dhcp-relay option vpn

no ipv6 dhcp-relay option vpn

Syntax Description

This command has no arguments or keywords.

Command Default

The DHCP for IPv6 relay VRF-aware feature is not enabled on the router.

Command Modes

Global configuration (config)

Command History

Release
Modification

15.1(2)S

This command was introduced.

Cisco IOS XE Release 3.3S

This command was integrated into Cisco IOS XE Release 3.3S.


Usage Guidelines

The ipv6 dhcp-relay option vpn command allows the DHCPv6 relay VRF-aware feature to be enabled globally on the router. If the ipv6 dhcp relay option vpn command is enabled on a specified interface, it overrides the global ipv6 dhcp-relay option vpn command.

Examples

The following example enables the DHCPv6 relay VRF-aware feature globally on the router:

Router(config)# ipv6 dhcp-relay option vpn

Related Commands

Command
Description

ipv6 dhcp relay option vpn

Enables the DHCPv6 relay VRF-aware feature on an interface.


ipv6 dhcp server

To enable Dynamic Host Configuration Protocol (DHCP) for IPv6 service on an interface, use the ipv6 dhcp server in interface configuration mode. To disable DHCP for IPv6 service on an interface, use the no form of this command.

ipv6 dhcp server [poolname | automatic] [rapid-commit] [preference value] [allow-hint]

no ipv6 dhcp server

Syntax Description

poolname

(Optional) User-defined name for the local prefix pool. The pool name can be a symbolic string (such as "Engineering") or an integer (such as 0).

automatic

(Optional) Enables the server to automatically determine which pool to use when allocating addresses for a client.

rapid-commit

(Optional) Allows the two-message exchange method for prefix delegation.

preference value

(Optional) Specifies the preference value carried in the preference option in the advertise message sent by the server. The range is from 0 to 255. The preference value defaults to 0.

allow-hint

(Optional) Specifies whether the server should consider delegating client suggested prefixes. By default, the server ignores client-hinted prefixes.


Command Default

DHCP for IPv6 service on an interface is disabled.

Command Modes

Interface configuration

Command History

Release
Modification

12.3(4)T

This command was introduced.

12.2(18)SXE

This command was integrated into Cisco IOS Release 12.2(18)SXE.

12.4(24)T

The automatic keyword was added.

Cisco IOS XE Release 2.1

This command was integrated into Cisco IOS XE Release 2.1.

12.2(33)SRE

This command was modified. It was integrated into Cisco IOS Release 12.2(33)SRE.

12.2(33)XNE

This command was modified. It was integrated into Cisco IOS Release 12.2(33)XNE.


Usage Guidelines

The ipv6 dhcp server command enables DHCP for IPv6 service on a specified interface using the pool for prefix delegation and other configuration through that interface.

The automatic keyword enables the system to automatically determine which pool to use when allocating addresses for a client. When an IPv6 DHCP packet is received by the server, the server determines if it was received from a DHCP relay or if it was directly received from the client. If the packet was received from a relay, the server verifies the link-address field inside the packet associated with the first relay that is closest to the client. The server matches this link address against all address prefix and link-address configurations in IPv6 DHCP pools to find the longest prefix match. The server selects the pool associated with the longest match.

If the packet was directly received from the client, the server performs this same matching, but it uses all the IPv6 addresses configured on the incoming interface when performing the match. Once again, the server selects the longest prefix match.

The rapid-commit keyword enables the use of the two-message exchange for prefix delegation and other configuration. If a client has included a rapid commit option in the solicit message and the rapid-commit keyword is enabled for the server, the server responds to the solicit message with a reply message.

If the preference keyword is configured with a value other than 0, the server adds a preference option to carry the preference value for the advertise messages. This action affects the selection of a server by the client. Any advertise message that does not include a preference option is considered to have a preference value of 0. If the client receives an advertise message that includes a preference option with a preference value of 255, the client immediately sends a request message to the server from which the advertise message was received.

If the allow-hint keyword is specified, the server will delegate a valid client-suggested prefix in the solicit and request messages. The prefix is valid if it is in the associated local prefix pool and it is not assigned to a device. If the allow-hint keyword is not specified, a hint is ignored and a prefix is delegated from the free list in the pool.

The DHCP for IPv6 client, server, and relay functions are mutually exclusive on an interface. When one of these functions is already enabled and a user tries to configure a different function on the same interface, one of the following messages is displayed:

Interface is in DHCP client mode
Interface is in DHCP server mode
Interface is in DHCP relay mode

Examples

The following example enables DHCP for IPv6 for the local prefix pool named server1:

Router(config-if)# ipv6 dhcp server server1

Related Commands

Command
Description

ipv6 dhcp pool

Configures a DHCP for IPv6 pool and enters DHCP for IPv6 pool configuration mode.

show ipv6 dhcp interface

Displays DHCP for IPv6 interface information.


ipv6 dhcp server vrf enable

To enable the DHCP for IPv6 server VRF-aware feature, use the ipv6 dhcp server vrf enable command in global configuration mode. To disable the feature, use the no form of this command.

ipv6 dhcp server vrf enable

no ipv6 dhcp server vrf enable

Syntax Description

This command has no arguments or keywords.

Command Default

The DHCPv6 server VRF-aware feature is not enabled on the router.

Command Modes

Global configuration (config)

Command History

Release
Modification

15.1(2)S

This command was introduced.

Cisco IOS XE Release 3.3S

This command was integrated into Cisco IOS XE Release 3.3S.


Usage Guidelines

The ipv6 dhcp server option vpn command allows the DHCPv6 server VRF-aware feature to be enabled globally on the router.

Examples

The following example enables the DHCPv6 server VRF-aware feature globally on the router:

Router(config)# ipv6 dhcp server option vpn

ipv6 eigrp

To enable Enhanced Interior Gateway Routing Protocol (EIGRP) for IPv6 on a specified interface, use the ipv6 eigrp command in interface configuration mode. To disable EIGRP for IPv6, use the no form of this command.

ipv6 eigrp as-number

no ipv6 eigrp as-number

Syntax Description

as-number

Autonomous system number.


Command Default

EIGRP is not enabled on an IPv6 interface.

Command Modes

Interface configuration

Command History

Release
Modification

12.4(6)T

This command was introduced.

12.2(33)SRB

This command was integrated into Cisco IOS Release 12.2(33)SRB.

12.2(33)SXH

This command was integrated into Cisco IOS Release 12.2(33)SXH.


Usage Guidelines

Use the ipv6 eigrp command to enable EIGRP for IPv6 on a per-interface basis.

If an autonomous system is specified, EIGRP for IPv6 is enabled only for the specified autonomous system. Otherwise, EIGRP for IPv6 is specified throughout the interface.

Examples

The following example enables EIGRP for IPv6 for AS 1 on Ethernet interface 0:

Router(config)# interface ethernet0
Router(config-if)# ipv6 eigrp 1

Related Commands

Command
Description

ipv6 enable

Enables IPv6 processing on an interface that has not been configured with an explicit IPv6 address.

ipv6 router eigrp

Configures the EIGRP routing process in IPv6.


ipv6 enable

To enable IPv6 processing on an interface that has not been configured with an explicit IPv6 address, use the ipv6 enable command in interface configuration mode. To disable IPv6 processing on an interface that has not been configured with an explicit IPv6 address, use the no form of this command.

ipv6 enable

no ipv6 enable

Syntax Description

This command has no arguments or keywords.

Command Default

IPv6 is disabled.

Command Modes

Interface configuration

Command History

Release
Modification

12.2(2)T

This command was introduced.

12.0(21)ST

This command was integrated into Cisco IOS Release 12.0(21)ST.

12.0(22)S

This command was integrated into Cisco IOS Release 12.0(22)S.

12.2(14)S

This command was integrated into Cisco IOS Release 12.2(14)S.

12.2(28)SB

This command was integrated into Cisco IOS Release 12.2(28)SB.

12.2(25)SG

This command was integrated into Cisco IOS Release 12.2(25)SG.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

12.2(33)SXH

This command was integrated into Cisco IOS Release 12.2(33)SXH.


Usage Guidelines

The ipv6 enable command automatically configures an IPv6 link-local unicast address on the interface while also enabling the interface for IPv6 processing. The no ipv6 enable command does not disable IPv6 processing on an interface that is configured with an explicit IPv6 address.

Examples

The following example enables IPv6 processing on Ethernet interface 0/0:

Router(config)# interface ethernet 0/0
Router(config-if)# ipv6 enable

Related Commands

Command
Description

ipv6 address link-local

Configures an IPv6 link-local address for an interface and enables IPv6 processing on the interface.

ipv6 address eui-64

Configures an IPv6 address and enables IPv6 processing on an interface using an EUI-64 interface ID in the low-order 64 bits of the address.

ipv6 unnumbered

Enables IPv6 processing on an interface without assigning an explicit IPv6 address to the interface.

show ipv6 interface

Displays the usability status of interfaces configured for IPv6.


ipv6 flow


Note Effective with Cisco IOS Release 12.4(20)T, the ipv6 flow command is not available in Cisco software.


To enable or disable accounting for IPv6 packets arriving on an interface configured for 6PE, use the ipv6 flow command in interface configuration mode. To disable NetFlow on a subinterface, use the no form of this command.

ipv6 flow {ingress | egress}

no ipv6 flow {ingress | egress}

Syntax Description

egress

Enables IPv6 flow capture on outgoing packets.

ingress

Enables IPv6 flow capture for incoming packets.


Command Default

This command is not configured by default.

Command Modes

Interface configuration (config-if)

Command History

Release
Modification

12.3(7)T

This command was introduced.

12.2(30)S

This command was integrated into Cisco IOS Release 12.2(30)S.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

12.2(33)SXH

This command was integrated into Cisco IOS Release 12.2(33)SXH.

12.4(20)T

This command was removed.


Usage Guidelines


Note The NetFlow for IPv6 feature has been replaced by the IPv6 Flexible NetFlow feature. For information on this feature, see the Cisco IOS Flexible NetFlow Features Roadmap.


This command must be configured on all interfaces and subinterfaces where NetFlow capture should be enabled. Two commands for ingress and egress can be specified on the same interface. If a switched packet belongs to a flow that is captured at both the ingress and the egress point, it will be counted twice.

If you configure the ipv6 flow ingress command on a few selected subinterfaces and then configure the ip flow ingress command on the main interface, enabling the main interface will overwrite the ip flow ingress command and data collection will start from the main interface and from all the subinterfaces. In a scenario where you configure the ipv6 flow ingress command and then configure the ip route-cache flow command on the main interface, you can restore subinterface data collection by using the no ip route-cache flow command. This configuration will disable data collection from the main interface and restore data collection to the subinterfaces you originally configured with the ipv6 flow ingress command.

Examples

The following example shows how to configure NetFlow on FastEthernet subinterface 6/3.0:

Router(config)# interface FastEthernet6/3.0
Router(config-subif)# ipv6 flow ingress

Related Commands

Command
Description

ip flow ingress

Enables NetFlow accounting for inbound (received) network traffic.

ipv6 flow mask

Records a specified number of bits of the source or destination address in the flow record.

show ipv6 flow cache

Displays a summary of the NetFlow cache statistics.

show ip cache flow

Displays a summary of NetFlow statistics.

show ip interface

Displays the usability status of interfaces configured for IP.


ipv6 flow mask

To specify the maximum number of source or destination address bits for IPv6 flow capture on a per-interface basis, use the ipv6 flow mask command in interface configuration mode. To disable the capture of address bits on an interface, use the no form of this command.

ipv6 flow mask {source | destination} maximum max-address-length

no ipv6 flow {source | destination}

Syntax Description

source

Specifies that the source address for the flow record is to be used.

destination

Specifies that the destination address for the flow record is to be used.

maximum

Specifies the maximum number of address bits to capture in the flow record. The value can be 1 to 128.


Command Default

This command is not configured by default.

Command Modes

Interface configuration

Command History

Release
Modification

12.3(7)T

This command was introduced.

12.2(30)S

This command was integrated into Cisco IOS Release 12.2(30)S.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

12.2(33)SXH

This command was integrated into Cisco IOS Release 12.2(33)SXH.


Usage Guidelines

This command records only the indicated number of bits of the source or destination address in the flow record. As a consequence, flows are aggregated.

Examples

The following example shows a router configured to capture the first 64 bits of the source address for packets entering this interface:

Router(config)# interface FastEthernet6/3.0
Router(config-subif)# ipv6 flow mask source maximum 64

Related Commands

Command
Description

ipv6 flow mask option headers

Enables option headers for IPv6 capture on a per-interface basis.


ipv6 flow mask option-headers

To enable capture of specific IPv6 option headers on a per-interface basis, use the ipv6 flow mask option-headers command in subinterface configuration mode. To disable masking of IPv6 option headers on a subinterface, use the no form of this command.

ipv6 flow mask option-headers value

no ipv6 flow mask option-headers

Syntax Description

value

The configurable value for the option headers. Value is specified in hexadecimal in the range 0x0 through 0xFFFFFFFF.


Command Default

This command is not enabled.

Command Modes

Subinterface configuration

Command History

Release
Modification

12.3(7)T

This command was introduced.

12.2(30)S

This command was integrated into Cisco IOS Release 12.2(30)S.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

12.2(33)SXH

This command was integrated into Cisco IOS Release 12.2(33)SXH.


Usage Guidelines

The ipv6 flow mask option-headers command records option headers for all of the flows in the main cache. When this command is not enabled, flows are aggregated by whatever IPv6 option headers are found in the packet.

NetFlow Version 9 Options Template Format

The options template (and its corresponding options data record) is a new record type for NetFlow Version 9. Options are used to supply metadata about the NetFlow process itself. The format of the options template is detailed in Table 28 and field descriptions are given in Table 29.

Table 28 NetFlow Version 9 Options Template

0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
           

FlowSet ID = 1

           
             

Length

             
         

Reserved Template ID > 255

         
         

Option Scope Length

         
           

Option Length

           
           

Scope Field 1 Type

           
           

Scope Field 1 Length

           
           

Option 1 Field Type

           
           

Option 1 Field Length

         
           

IPv6 Option Headers

         

Table 29 NetFlow Version 9 Options Template Field Definitions

Field Name
Description

FlowSet ID = 1

The FlowSet ID is used to distinguish template records from data records. A template record always has a FlowSet ID of 1. A data record always has a nonzero FlowSet ID of greater than 255.

Length

This field gives the total length of this FlowSet. Because an individual template FlowSet may contain multiple template IDs, the length value should be used to determine the position of the next FlowSet record, which could be either a template or a data FlowSet.

Length is expressed in type, length, value (TLV) format, meaning that the value includes the bytes used for the FlowSet ID and the length bytes themselves, and the combined lengths of all template records included in this FlowSet.

Reserved Template ID >255

As a router generates different template FlowSets to match the type of NetFlow data it will export, each template is given a unique ID. This uniqueness is local to the router that generated the template ID.

Option Scope Length

This field gives the length in bytes of any scope fields contained in this options template.

Options Length

This field gives the length (in bytes) of any Options field definitions contained in this options template.

Scope 1 Field Type

This field gives the relevant portion of the NetFlow process to which the options record refers. Values are as follows:

0x0001 System

0x0002 Interface

0x0003 Line Card

0x0004 NetFlow Cache

0x0005 Template

For example, sampled NetFlow can be implemented on a per-interface basis, so if the options record were reporting on how sampling is configured, the scope for the report would be 0x0002 (interface).

Scope 1 Field Length

This field gives the length (in bytes) of the Scope field, as it would appear in an options record.

Option 1 Field Type

This numeric value represents the type of the field that appears in the options record.

Option 1 Field Length

This number is the length (in bytes) of the field, as it would appear in an options record.

IPv6 Option Headers

This number exports encoded IPv6 option headers. Table 30 describes encoding for this field.


Table 30 provides information on encoding for the IPv6 Option Headers field.

Table 30 Encoded IPv6 Option Headers Fields

Bit 15
Bit 14
Bit 13
Bit 12
Bit 11
Bit 10
Bit 9
Bit 8

Reserved

Reserved

Reserved

Reserved

Reserved

Encrypted security payload (50)

Authentica-tion header (51)

Payload compres-
sion header (108)

Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0

Destination option header (60)

Hop-by-
hop option header (0)

Reserved

Cannot reach layer 4 header (for example, com-
pressed, encrypted, not supported)

Fragmenta-tion header (44)—first fragment

Routing header (43)

Fragmenta-tion header (44)—not first fragment

Reserved


Examples

The following example shows a router configured to capture the option headers for packets passing through this interface:

Router(config)# interface FastEthernet6/3.0
Router(config-subif)# ipv6 flow mask option-headers 0x40

Related Commands

Command
Description

ipv6 flow mask

Records a specified number of bits of the source or destination address in the flow record.

show ipv6 cache flow

Displays a summary of IPv6 NetFlow statistics.


ipv6 flow-aggregation cache


Note Effective with Cisco IOS Release 12.4(20)T, the ipv6 flow-aggregation cache command is not available in Cisco software.


To configure the aggregation cache configuration scheme and place the router in NetFlow aggregation cache configuration mode, use the ipv6 flow-aggregation cache command in global configuration mode. To disable aggregation cache configuration mode, use the no form of this command.

ipv6 flow-aggregation cache {as | bgp-nexthop | destination-prefix | prefix | protocol-port | source-prefix}

no ipv6 flow-aggregation cache {as | bgp-nexthop | destination-prefix | prefix | protocol-port | source-prefix}

Syntax Description

as

Configures the autonomous system aggregation cache scheme.

bgp-nexthop

Configures the bgp-nexthop aggregation cache scheme to record the next Border Gateway Protocol (BGP) hop.

destination-prefix

Configures the destination-prefix aggregation cache scheme.

prefix

Configures the prefix aggregation cache scheme.

protocol-port

Configures the protocol-port aggregation cache scheme.

source-prefix

Configures the source-prefix aggregation cache scheme.


Command Default

This command is disabled by default. No aggregation cache information is collected.

Command Modes

Global configuration (config)

Command History

Release
Modification

12.3(7)T

This command was introduced.

12.2(30)S

This command was integrated into Cisco IOS Release 12.2(30)S.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

12.2(33)SXH

This command was integrated into Cisco IOS Release 12.2(33)SXH.

12.4(20)T

This command was removed.


Usage Guidelines

You can enable only one aggregation cache configuration scheme per command line.


Note The NetFlow for IPv6 feature has been replaced by the IPv6 Flexible NetFlow feature. For information on this feature, see the Cisco IOS Flexible NetFlow Features Roadmap.


Examples

The following example shows how to configure an autonomous system aggregation scheme:

ipv6 flow-aggregation cache as

The following example shows how to configure multiple NetFlow export destinations on an aggregation cache:

ipv6 flow-aggregation cache destination-prefix
  export destination 2001::FFFE/64 9991
  export destination 2001::FFFC/64 1999

Related Commands

Command
Description

show ipv6 flow cache aggregation

Displays the IPv6 aggregation cache configuration.


ipv6 flow-cache entries


Note Effective with Cisco IOS Release 12.4(20)T, the ipv6 flow-cache entries command is not available in Cisco software.


To change the number of entries maintained in the NetFlow cache, use the ipv6 flow-cache entries command in global configuration mode. To return to the default number of entries, use the no form of this command.

ipv6 flow-cache entries number

no ipv6 flow-cache entries

Syntax Description

number

Number of entries to maintain in the NetFlow cache. The valid range is from 1024 to 524288 entries. The default is 65536 entries (64K).


Command Default

The default entry is used.

Command Modes

Global configuration (config)

Command History

Release
Modification

12.3(7)T

This command was introduced.

12.2(30)S

This command was integrated into Cisco IOS Release 12.2(30)S.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

12.2(33)SXH

This command was integrated into Cisco IOS Release 12.2(33)SXH.

12.4(20)T

This command was removed.


Usage Guidelines

Normally the default size of the NetFlow cache will meet your needs. However, you can increase or decrease the number of entries maintained in the cache to meet the needs of your flow traffic rates. For environments with a high amount of flow traffic (such as an internet core router), a larger value such as 131072 (128K) is recommended. To obtain information on your flow traffic, use the show ipv6 flow cache command in privileged EXEC mode.

The default is 64K flow cache entries. Each cache entry is approximately 64 bytes of storage. Assuming a cache with the default number of entries, approximately 4 MB of DRAM would be required. Each time a new flow is taken from the free flow queue, the number of free flows is checked. If only a few free flows remain, NetFlow attempts to age 30 flows using an accelerated timeout. If only one free flow remains, NetFlow automatically ages 30 flows regardless of their age. The intent is to ensure that free flow entries are always available.


Caution Cisco recommends that you do not change the NetFlow cache entries. To return to the default NetFlow cache entries, use the no ipv6 flow-cache entries global configuration command.


Note The NetFlow for IPv6 feature has been replaced by the IPv6 Flexible NetFlow feature. For information on this feature, see the Cisco IOS Flexible NetFlow Features Roadmap.


Examples

The following example shows how to increase the number of entries in the NetFlow cache to 131,072 (128K):

Router(config)# ipv6 flow-cache entries 131072

Related Commands

Command
Description

cache

Configures the aggregation cache operational parameters.

show ipv6 flow cache

Displays the cache flow statistics for IPv6 flows.


ipv6 flow-cache timeout


Note Effective with Cisco IOS Release 12.4(20)T, the ipv6 flow-cache timeout command is not available in Cisco software.


To change the timeout values for the NetFlow cache, use the ipv6 flow-cache timeout command in global configuration mode. To return the timeout to the default values, use the no form of this command.

ipv6 flow-cache timeout {active minutes | inactive seconds}

no ipv6 flow-cache timeout

Syntax Description

active minutes

(Optional) Specifies the number of minutes that an active entry is active. The range is from 1 to 60 minutes. The default is 30 minutes.

inactive seconds

(Optional) Specifies the number of seconds that an inactive entry will stay in the aggregation cache before it times out. The range is from 10 to 600 seconds. The default is 15 seconds.


Command Default

The timeout default values are used.

Command Modes

Global configuration (config)

Command History

Release
Modification

12.3(7)T

This command was introduced.

12.2(30)S

This command was integrated into Cisco IOS Release 12.2(30)S.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

12.2(33)SXH

This command was integrated into Cisco IOS Release 12.2(33)SXH.

12.4(20)T

This command was removed.


Examples

The following example shows how to adjust the timeout values. In this case, the active minutes are not specified so they remain at the default; the inactive seconds are set to 199.

ipv6 flow-cache timeout inactive 199

Note The NetFlow for IPv6 feature has been replaced by the IPv6 Flexible NetFlow feature. For information on this feature, see the Cisco IOS Flexible NetFlow Features Roadmap.


Related Commands

Command

Description

default-name

Enables an aggregation cache.

ipv6 flow-aggregation cache

Configures aggregation cache configuration scheme for NetFlow V9 for IPv6.

show ipv6 flow cache

Displays the IPv6 NetFlow cache, which is a table of current flows being fast-switched through the router.

show ipv6 cache flow aggregation

Displays the aggregation cache configuration.


ipv6 flow-export destination


Note Effective with Cisco IOS Release 12.4(20)T, the ipv6 flow-export destination command is not available in Cisco software.


To enable the exporting of information in NetFlow cache entries to a specific address or port, use the ipv6 flow-export destination command in global configuration mode. To disable the exporting of information, use the no form of this command.

ipv6 flow-export destination ip-address udp-port

no ipv6 flow-export destination ip-address udp-port

Syntax Description

ip-address

IPv4 address of the workstation to which you want to send the NetFlow information. IPv4 addresses only are supported as transport.

udp-port

User Datagram Protocol (UDP) protocol-specific port number.


Command Default

This command is disabled by default.

Command Modes

Global configuration (config)

Command History

Release
Modification

12.3(7)T

This command was introduced.

12.2(30)S

This command was integrated into Cisco IOS Release 12.2(30)S.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

12.2(33)SXH

This command was integrated into Cisco IOS Release 12.2(33)SXH.

12.4(20)T

This command was removed.


Usage Guidelines

To configure multiple NetFlow export destinations to a networking device, enter the ipv6 flow-export destination command twice—once for each destination. Do not enter the same IPv4 address twice. However, entering two different IPv4 addresses with the same UDP port number is configurable.

A NetFlow cache entry contains a great deal of information. When NetFlow is enabled, you can use the ipv6 flow-export destination command to configure the networking device to export the flow cache entry to a workstation when a flow expires. This command can be useful for purposes of gathering information about statistics, billing, and security.


Note The NetFlow for IPv6 feature has been replaced by the IPv6 Flexible NetFlow feature. For information on this feature, see the Cisco IOS Flexible NetFlow Features Roadmap.


Examples

The following example shows how to configure the networking device to export the NetFlow cache entry to multiple export destinations:

ipv6 flow-export destination 10.42.42.1 9991
ipv6 flow-export destination 10.0.101.254 9991

Related Commands

Command
Description

ipv6 flow-aggregation cache

Configures aggregation cache configuration scheme for NetFlow V9 for IPv6.

show ipv6 flow cache aggregation

Displays the IPv6 NetFlow cache, which is a table of current flows being fast-switched through the router.


ipv6 flow-export source


Note Effective with Cisco IOS Release 12.4(20)T, the ipv6 flow-export source command is not available in Cisco software.


To specify the source interface IPv6 address used in the NetFlow export datagram, use the ipv6 flow-export source command in global configuration mode. To remove the source address, use the no form of this command.

ipv6 flow-export source interface

no ipv6 flow-export source

Syntax Description

interface

Interface from which the router gets the source IP or IPv6 address for the packet.


Command Default

No source interface is specified.

Command Modes

Global configuration (config)

Command History

Release
Modification

12.3(7)T

This command was introduced.

12.2(30)S

This command was integrated into Cisco IOS Release 12.2(30)S.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

12.2(33)SXH

This command was integrated into Cisco IOS Release 12.2(33)SXH.

12.4(20)T

This command was removed.


Usage Guidelines

This command specifies the interface that identifies the IPv4 address to which data is exported from the main IPv6 cache.

After you configure NetFlow data export, you can also specify the source interface used in the User Datagram Protocol (UDP) datagram that contains the export data. The NetFlow Collector on the workstation uses the IP address of the source interface to determine which router sent the information. The NetFlow Collector also performs Simple Network Management Protocol (SNMP) queries to the router using the IP address of the source interface. Because the IP address of the source interface can change (for example, the interface might flap so a different interface is used to send the data), Cisco recommends that you configure a loopback source interface. A loopback interface is always up and can respond to SNMP queries from the NetFlow Collector on the workstation.


Note The NetFlow for IPv6 feature has been replaced by the IPv6 Flexible NetFlow feature. For information on this feature, see the Cisco IOS Flexible NetFlow Features Roadmap.


Examples

The following example shows the configuration for a loopback source interface. The loopback interface has the IP address 10.0.0.1:

Router# configure terminal
Router(config)# interface loopback0
Router(config-if)# ip address 10.0.0.1
Router(config-if)# exit
Router(config-if)# ip unnumbered loopback0
Router(config-if)# no ip mroute-cache
Router(config-if)# encapsulation ppp
Router(config-if)# ipv6 flow cache
Router(config-if)# exit
Router(config)# ipv6 flow-export source loopback0
Router(config)# exit

Related Commands

Command
Description

ipv6 flow-cache export destination

Enables the exporting of information in NetFlow cache entries.


ipv6 flow-export template


Note Effective with Cisco IOS Release 12.4(20)T, the ipv6 flow-export template command is not available in Cisco software.


To enable the exporting of information in NetFlow cache entries, use the ipv6 flow-export template command in global configuration mode. To disable the exporting of information, use the no form of this command.

ipv6 flow-export template {refresh-rate packet-refresh-rate | timeout timeout-value}

no ipv6 flow-export template

Syntax Description

refresh-rate packet-refresh-rate

Specifies the number of packets between cache refreshes. Value is from 1 to 600 packets.

timeout timeout-value

Specifies the length of time to wait before the export time is up. Value is 1 to 3600 minutes.


Command Default

No template is defined.

Command Modes

Global configuration (config)

Command History

Release
Modification

12.3(7)T

This command was introduced.

12.2(30)S

This command was integrated into Cisco IOS Release 12.2(30)S.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

12.2(33)SXH

This command was integrated into Cisco IOS Release 12.2(33)SXH.

12.4(20)T

This command was removed.


Examples

The following example specifies that the NetFlow cache is refreshed after 150 packets are collected:

Router(config)# ipv6 flow-export template refresh-rate 150

Note The NetFlow for IPv6 feature has been replaced by the IPv6 Flexible NetFlow feature. For information on this feature, see the Cisco IOS Flexible NetFlow Features Roadmap.


Related Commands

Command
Description

ipv6 flow-aggregation cache

Configures aggregation cache configuration scheme for NetFlow V9 for IPv6.


ipv6 flow-export template options


Note Effective with Cisco IOS Release 12.4(20)T, the ipv6 flow-export template options command is not available in Cisco software.


To configure templates for IPv6 cache exports, use the ipv6 flow-export template options command in global configuration mode. To remove the template options from the NetFlow cache exports, use the no form of this command.

ipv6 flow-export template options {export-stats | refresh-rate packet-refresh-rate | timeout timeout-value}

no ipv6 flow-export template options

Syntax Description

export-stats

Exports the specified statistics.

refresh-rate packet-refresh-rate

Specifies the number of packets between cache refreshes. Value is from 1 to 600 packets.

timeout timeout-value

Specifies the length of time to wait before the export time is up. Value is 1 to 3600 minutes.


Command Default

No template is applied for flow exports.

Command Modes

Global configuration (config)

Command History

Release
Modification

12.3(7)T

This command was introduced.

12.2(30)S

This command was integrated into Cisco IOS Release 12.2(30)S.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

12.2(33)SXH

This command was integrated into Cisco IOS Release 12.2(33)SXH.

12.4(20)T

This command was removed.


Usage Guidelines

A NetFlow cache entry contains a great deal of information. When flow switching is enabled, you can use the ipv6 flow-export template options command to configure the router to export the flow cache entry to a workstation when a flow expires.


Note The NetFlow for IPv6 feature has been replaced by the IPv6 Flexible NetFlow feature. For information on this feature, see the Cisco IOS Flexible NetFlow Features Roadmap.


Examples

The following example shows the configuration for a loopback source interface. The loopback interface has the IP address 10.10.0.1 and is used by the serial interface in slot 5, port 0.

Router# configure terminal
Router(config)# interface loopback0
Router(config-if)# ipv6 address 2001:0DB8:1:1:FFFF:FFFF:FFFF:FFFE/64
Router(config-if)# exit
Router(config)# interface serial 5/0:0
Router(config-if)# ip unnumbered loopback0
Router(config-if)# no ip mroute-cache
Router(config-if)# encapsulation ppp
Router(config-if)# ipv6 flow cache
Router(config-if)# exit
Router(config)# ipv6 flow-export source loopback0
Router(config)# exit

Related Commands

Command
Description

ipv6 flow-cache entries

Enables the exporting of information in NetFlow cache entries.


ipv6 flow-export version 9


Note Effective with Cisco IOS Release 12.4(20)T, the ipv6 flow-export version 9 command is not available in Cisco software.


To enable the exporting of information in NetFlow cache entries, use the ipv6 flow-export version 9 command in global configuration mode. To disable the exporting of information, use the no form of this command.

ipv6 flow-export version 9 [origin-as | peer-as] [bgp-nexthop]

no ipv6 flow-export version 9

Syntax Description

origin-as

(Optional) Specifies that export statistics include the origin autonomous system for the source and destination.

peer-as

(Optional) Specifies that export statistics include the peer autonomous system for the source and destination.

bgp-nexthop

(Optional) Specifies that export statistics be collected for the next Border Gateway Protocol (BGP) hop.


Command Default

The default is version 9 export.

Command Modes

Global configuration (config)

Command History

Release
Modification

12.3(7)T

This command was introduced.

12.2(30)S

This command was integrated into Cisco IOS Release 12.2(30)S.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

12.2(33)SXH

This command was integrated into Cisco IOS Release 12.2(33)SXH.

12.4(20)T

This command was removed.


Usage Guidelines

NetFlow cache entries contain a great deal of information. When flow switching is enabled, you can use the ipv6 flow-export version 9 command to configure the router to export the flow cache entry to a workstation when a flow expires. This command can be useful for purposes of gathering information about statistics, billing, and security.


Note The NetFlow for IPv6 feature has been replaced by the IPv6 Flexible NetFlow feature. For information on this feature, see the Cisco IOS Flexible NetFlow Features Roadmap.


Examples

The following example configures the router to collect information about the next BGP hop in the destination path:

ipv6 flow-export version 9 bgp-nexthop

Related Commands

Command
Description

ipv6 flow-aggregation cache

Configures the aggregation cache configuration scheme for NetFlow V9 for IPv6.


ipv6 flowset

To configure flow-label marking in 1280-byte or larger packets sent by the router, use the ipv6 flowset command in global configuration mode. To remove flow-label marking from packets, use the no form of this command.

ipv6 flowset

no ipv6 flowset

Syntax Description

This command has no arguments or keywords.

Command Default

Flow-label setting is not configured.

Command Modes

Global configuration (config)

Command History

Release
Modification

Cisco IOS XE Release 2.6

This command was introduced.


Usage Guidelines

The ipv6 flowset command configures the router to track destinations to which the router has sent packets that are 1280 bytes or larger. The command configures such a destination to be added to the router's MTU cache and tracked. The router then will accept toobig messages only if they relate to a tracked destinations to which the router has sent packets within the last two minutes.

Examples

The following example configures the router to track destinations to which it has sent packets that are 1280 bytes or larger:

Router(config)# ipv6 flowset

Related Commands

Command
Description

clear ipv6 mtu

Clears the MTU cache of messages.


ipv6 general-prefix

To define an IPv6 general prefix, use the ipv6 general-prefix command in global configuration mode. To remove the IPv6 general prefix, use the no form of this command.

ipv6 general-prefix prefix-name {ipv6-prefix/prefix-length | 6to4 interface-type interface-number | 6rd interface-type interface-number}

no ipv6 general-prefix prefix-name

Syntax Description

prefix-name

The name assigned to the prefix.

ipv6-prefix

The IPv6 network assigned to the general prefix.

This argument must be in the form documented in RFC 2373 where the address is specified in hexadecimal using 16-bit values between colons.

When defining a general prefix manually, specify both the ipv6-prefix and /prefix-length arguments.

/prefix-length

The length of the IPv6 prefix. A decimal value that indicates how many of the high-order contiguous bits of the address comprise the prefix (the network portion of the address). A slash mark must precede the decimal value.

When defining a general prefix manually, specify both the ipv6-prefix and /prefix-length arguments.

6to4

Allows configuration of a general prefix based on an interface used for 6to4 tunneling.

When defining a general prefix based on a 6to4 interface, specify the 6to4 keyword and the interface-type interface-number argument.

interface-type interface-number

Interface type and number. For more information, use the question mark (?) online help function.

When defining a general prefix based on a 6to4 interface, specify the 6to4 keyword and the interface-type interface-number argument.

6rd

Allows configuration of a general prefix computed from an interface used for IPv6 rapid deployment (6RD) tunneling.


Command Default

No general prefix is defined.

Command Modes

Global configuration

Command History

Release
Modification

12.3(4)T

This command was introduced.

Cisco IOS XE Release 2.1

This command was integrated into Cisco IOS XE Release 2.1.

Cisco IOS XE Release 3.1S

The optional 6rd keyword was added.


Usage Guidelines

Use the ipv6 general-prefix command to define an IPv6 general prefix.

A general prefix holds a short prefix, based on which a number of longer, more specific, prefixes can be defined. When the general prefix is changed, all of the more specific prefixes based on it will change, too. This function greatly simplifies network renumbering and allows for automated prefix definition.

More specific prefixes, based on a general prefix, can be used when configuring IPv6 on an interface.

When defining a general prefix based on an interface used for 6to4 tunneling, the general prefix will be of the form 2002:a.b.c.d::/48, where "a.b.c.d" is the IPv4 address of the interface referenced.

Examples

The following example manually defines an IPv6 general prefix named my-prefix:

Router(config)# ipv6 general-prefix my-prefix 2001:DB8:2222::/48

The following example defines an IPv6 general prefix named my-prefix based on a 6to4 interface:

Router(config)# ipv6 general-prefix my-prefix 6to4 ethernet0

Related Commands

Command
Description

show ipv6 general-prefix

Displays information on general prefixes for an IPv6 addresses.