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Cisco IOS Software Releases 12.2 T

Dialer CEF

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Table Of Contents

Dialer CEF

Restrictions for Dialer CEF

Information about Dialer CEF

DDR-Dependent Implementation Decisions

Dialer Profiles

Legacy DDR

Benefits

Configuration Tasks

Monitoring and Maintaining Dialer Cisco Express Forwarding Interfaces

Configuration Examples

Additional References

Related Documents

Standards

MIBs

RFCs

Technical Assistance

Command Reference

debug ip cef

show adjacency

show ip interface


Dialer CEF

First Published: 12.2(4)T
Last Updated: April 18, 2006

History for the Dialer CEF Feature

Release
Modification

12.2(4)T

This feature was introduced.

12.2(28)SB

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


This document describes the Dialer CEF feature.

It includes the following sections:

•Restrictions for Dialer CEF

•Information about Dialer CEF

•Configuration Tasks

•Monitoring and Maintaining Dialer Cisco Express Forwarding Interfaces

•Configuration Examples

•Additional References

•Command Reference

Restrictions for Dialer CEF

The Dialer CEF feature is not supported when a static route is pointing to the Dialer without specifying a next hop IP address. When using the Cisco IOS Release 12.3(11)T and higher, the ppp ipcp default route command may be used in Dialer interface configuration mode to work around this restriction.

Information about Dialer CEF

The Dialer CEF feature introduces Cisco Express Forwarding support for dialer interfaces. The Dialer Cisco Express Forwarding feature allows packets to be Cisco Express Forwarding switched across dialer interfaces rather than being low-end switched (LES) or fast switched. Compared to fast switching, Cisco Express Forwarding switching support improves switching performance by decreasing CPU utilization and lowering the packet loss rate.

DDR-Dependent Implementation Decisions

You must decide whether to implement legacy dial-on-demand routing (DDR) or the newer dialer profiles.

Dialer Profiles

The dialer profiles implementation of DDR is based on a separation between logical and physical interface configuration. Dialer profiles also allow the logical and physical configurations to be bound together dynamically on a per-call basis.

Dialer profiles are advantageous in the following situations:

•When you want to share an interface (ISDN, asynchronous, or synchronous serial) to place or receive calls.

•When you want to change any configuration on a per-user basis.

•When you want to maximize ISDN channel usage using the Dynamic Multiple Encapsulations feature to configure various encapsulation types and per-user configurations on the same ISDN B channel at different times according to the type of call.

•When you want to bridge to many destinations and avoiding split horizon problems.

Most routed protocols are supported; however, International Organization for Standardization Connectionless Network Service (ISO CLNS) is not supported.

If you decide to configure dialer profiles, you must disable validation of source addresses for the routed protocols you support.

For detailed dialer profiles information, see the "Configuring Peer-to-Peer DDR with Dialer Profiles" chapter in the Cisco IOS Dial Technologies Configuration Guide, Release 12.2.

For more information about Dynamic Multiple Encapsulations, see the "Dialer Profiles Configuration Task List" section in the Cisco IOS Dial Technologies Configuration Guide, Release 12.2.

Legacy DDR

Legacy DDR is powerful and comprehensive, but its limitations affect scaling and extensibility. Legacy DDR is based on a static binding between the per-destination call specification and the physical interface configuration.

However, legacy DDR also has many strengths. It supports Frame Relay, ISO CLNS, LAPB, snapshot routing, and all routed protocols that are supported on Cisco routers. By default, legacy DDR supports fast switching.

For information about simple legacy DDR spoke configurations, see the "Configuring Legacy DDR Spokes" chapter in the Cisco IOS Dial Technologies Configuration Guide, Release 12.2. For information about simple legacy DDR hub configurations, see the "Configuring Legacy DDR Hubs" chapter in the Cisco IOS Dial Technologies Configuration Guide, Release 12.2.

Benefits

Improved Performance

Cisco Express Forwarding is less CPU-intensive than fast switching route caching. More CPU processing power can be dedicated to Layer 3 services such as quality of service (QoS) and encryption.

Resilience

Cisco Express Forwarding offers an unprecedented level of switching consistency and stability in large dynamic networks. In dynamic networks, fast-switched cache entries are frequently invalidated due to routing changes. These changes can cause traffic to be process switched using the routing table, rather than fast switched using the route cache. Because the Forwarding Information Base (FIB) lookup table contains all known routes that exist in the routing table, it eliminates route cache maintenance and the fast-switch or process-switch forwarding scenario. Cisco Express Forwarding can switch traffic more efficiently than typical demand caching schemes.

Although you can use Cisco Express Forwarding in any part of a network, it is designed for high-performance, highly resilient Layer 3 IP backbone switching.

Configuration Tasks

None

Monitoring and Maintaining Dialer Cisco Express Forwarding Interfaces

To monitor and maintain Dialer Cisco Express Forwarding interfaces, use the following EXEC commands:

Command
Purpose

Router# debug ip cef

Displays debugging information about various Cisco Express Forwarding events.

Router# show adjacency

Displays Cisco Express Forwarding adjacency table information.

Router# show ip interface

Displays network layer IP information about a specified interface.


Configuration Examples

None

Additional References

The following sections provide references related to the Dialer Cisco Express Forwarding feature.

Related Documents

Related Topic
Document Title

Dial Technologies Configuration Tasks

Cisco IOS Dial Technologies Configuration Guide, Release 12.2

Dial Technologies Commands List

Cisco IOS Dial Technologies Command Reference, Release 12.2


Standards

Standard
Title

None

—


MIBs

MIB
MIBs Link

None

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

http://www.cisco.com/go/mibs


RFCs

RFC
Title

None

—


Technical Assistance

Description
Link

The Cisco Technical Support & Documentation website contains thousands of pages of searchable technical content, including links to products, technologies, solutions, technical tips, and tools. Registered Cisco.com users can log in from this page to access even more content.

http://www.cisco.com/techsupport


Command Reference

This section documents modified commands.

•debug ip cef

•show adjacency

•show ip interface

debug ip cef

To troubleshoot various Cisco Express Forwarding (CEF) events, use the debug ip cef command in privileged EXEC mode. To disable debugging output, use the no form of this command.

debug ip cef {drops [rpf [access-list]] [access-list] | receive [access-list] | events [access-list] | interface | dialer}

no debug ip cef {drops [rpf [access-list]] [access-list] | receive [access-list] | events [access-list] | interface | dialer}

Specific to IPC Records

debug ip cef {ipc | interface-ipc | prefix-ipc [access-list]}

no debug ip cef {ipc | interface-ipc | prefix-ipc [access-list]}

Syntax Description

drops

Records dropped packets.

rpf

(Optional) Records the result of the Reverse Path Forwarding (RPF) check for packets.

access-list

(Optional) Limits debugging collection to packets that match the list.

receive

Records packets that are ultimately destined to the router, as well as packets destined to a tunnel endpoint on the router. If the decapsulated tunnel is IP, it is CEF switched; otherwise packets are process switched.

events

Records general CEF events.

interface

Records IP CEF interface events.

dialer

Records IP CEF interface events for dialer interfaces.

ipc

Records information related to Interprocess communications (IPC) in CEF. Possible types of events include the following:

•Transmission status of IPC messages

•Status of buffer space for IPC messages

•IPC messages received out of sequence

•Status of resequenced messages

•Throttle requests sent from a line card to the Route Processor

interface-ipc

Records IPC updates related to interfaces. Possible reporting includes an interface coming up or going down, and updates to fibhwidb, fibidb, and so on.

prefix-ipc

Records updates related to IP prefix information. Possible updates include the following:

•Debugging of IP routing updates in a line card

•Reloading of a line card with a new table

•Updates related to exceeding the maximum number of routes

•Control messages related to Forwarding Information Base (FIB) table prefixes


Defaults

Disabled

Command Modes

Privileged EXEC

Command History

Release
Modification

11.2GS

This command was introduced.

11.1CC

Multiple platform support was added.

12.0(5)T

The rpf keyword was added.

12.2(4)T

The dialer keyword was added.

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.


Usage Guidelines

This command gathers additional information for the handling of CEF interface, IPC, or packet events.

Note For packet events, we recommend that you use an access control list (ACL) to limit the messages recorded.

Examples

The following is sample output from the debug ip cef rpf command for a packet that is dropped when it fails the RPF check. IP address 172.17.249.252 is the source address, and Ethernet 2/0/0 is the input interface: 

Router# debug ip cef drops rpf


IP CEF drops for RPF debugging is on

00:42:02:CEF-Drop:Packet from 172.17.249.252 via Ethernet2/0/0 -- unicast rpf check

The following is sample output for CEF packets that are not switched using information from the FIB table but are received and sent to the next switching layer: 

Router# debug ip cef receive


IP CEF received packets debugging is on

00:47:52:CEF-receive:Receive packet for 10.1.104.13

Table 1 describes the significant fields shown in the display.

Table 1 debug ip cef receive Field Descriptions

Field
Description

CEF-Drop:Packet from 172.17.249.252 via Ethernet2/0/0 -- unicast rpf check

A packet from IP address 172.17.249.252 is dropped because it failed the reverse path forwarding check.

CEF-receive:Receive packet for 10.1.104.13

CEF has received a packet addressed to the router.


The following is sample output from the debug ip cef dialer command for a legacy dialer: 

Router# debug ip cef dialer


00:19:50:CEF-Dialer (legacy):add link to 10.10.10.2 via Dialer1 through BRI0/0:1

00:19:50:CEF-Dialer:adjacency added:0x81164850

00:19:50:CEF-Dialer:adjacency found:0x81164850; fib->count:1

00:19:50:CEF-Dialer:setup loadinfo with 1 paths

The following is sample output from the debug ip cef dialer command for a dialer profile: 

Router# debug ip cef dialer


00:31:44:CEF-Dialer (profile dynamic encap (not MLP)):add link to 10.10.10.2 via Dialer1 
through Dialer1

00:31:44:CEF-Dialer:adjacency added:0x81164850

00:31:44:CEF-Dialer:adjacency found:0x81164850; fib->count:1

Table 2 describes the significant fields shown in the display.

Table 2 debug ip cef dialer Field Descriptions

Field
Description

CEF-Dialer (legacy):add link to 10.10.10.2 via Dialer1 through BRI0/0:1

A link was added to IP address 10.10.10.2 for legacy Dialer1 through physical interface BRI0/0:1.

CEF-Dialer (profile dynamic encap (not MLP)):add link to 10.10.10.2 via Dialer1 through Dialer1

A link was added to IP address 10.10.10.2 for dialer profile Dialer1 through Dialer1.


Related Commands

Command
Description

ip cef

Enables Cisco Express Forwarding on the RPC card.

show ip cef

Displays entries in the FIB or displays a summary of the FIB.


show adjacency

To display information about the Cisco Express Forwarding (CEF) adjacency table or the hardware Layer 3-switching adjacency table, use the show adjacency command in user EXEC or privileged EXEC mode.

show adjacency [summary [interface interface-number]] | [prefix] [interface interface-number] [connectionid id] [link {ipv4 | ipv6 | mpls}] [detail]

Note On the Cisco 10000 series routers IPv6 is supported on 12.2(28)SBD or later releases.

Syntax Description

summary

(Optional) Displays a summary of CEF adjacency information.

interface

(Optional) Interface type.

interface-number

(Optional) Specifies the module and port number. Valid values depend on the specified interface type and the chassis and module that are used.

For example, on a Cisco 7000 series router, if you specify a Gigabit Ethernet interface and have a 48-port 10/100BASE-T Ethernet module that is installed in a 13-slot chassis, valid values for the module number are from 2 to 13, and valid values for the port number are from 1 to 48.

For line cards, you must specify the linecard if_number (interface number). Use the show cef interface command to obtain linecard if_numbers.

null interface-number specifies the null interface; the valid value is 0.

port-channel number specifies an Ethernet channel of interfaces; valid values are a maximum of 64 values from 1 to 256.

prefix

(Optional) Specifies an IP address or IPv6 address.

Note On the Cisco 10000 series routers IPv6 is supported on 12.2(28)SBD or later releases.

connectionid id

(Optional) Specifies the client connection identification number.

link {ipv4 | ipv6 | mpls}

(Optional) Specifies the link type (IP, IPv6, or MPLS traffic) of the adjacency.

Note On the Cisco 10000 series routers IPv6 is supported on 12.2(28)SBD or later releases.

detail

(Optional) Displays the protocol detail and timer information.


Defaults

This command has no default settings.

Command Modes

User EXEC
Privileged EXEC

Command History

Release
Modification

11.2GS

This command was introduced.

11.1CC

Multiple platform support was added.

12.0(7)XE

Support was added for the Cisco 7600 series routers.

12.1(1)E

Support for the Cisco 7600 series routers was integrated into Cisco IOS Release 12.1(1)E.

12.1(3a)E3

The number of valid values for port-channel number changed.

12.1(5c)EX

This command was modified to include Layer 3 information.

12.1(11b)E

The pos, atm, and ge-wan keywords were added.

12.2(8)T

The detail keyword output was modified to show the epoch value for each entry of the adjacency table.

The summary keyword output was modified to show the table epoch for the adjacency table.

12.2(14)SX

Support for this command was introduced on the Supervisor Engine 720.

12.2(25)S

This command was integrated into Cisco IOS Release 12.2(25)S and updated with new keywords.

12.2(27)SBC

This command was integrated into Cisco IOS Release 12.2(27)SBC.

12.2(28)SB

Support for the Cisco 10000 series routers was added.


Usage Guidelines

This command is used to verify that an adjacency exists for a connected device, that the adjacency is valid, and that the MAC header rewrite string is correct.

You can use any combination of the prefix, interface, connectionid id, and link {ipv4 | ipv6 | mpls} keywords and arguments (in any order) as a filter to enable the display of a specified subset of adjacencies.

Note On the Cisco 10000 series routers IPv6 is supported on 12.2(28)SBD or later releases.

The information displayed by the show adjacency commands includes the following:

•Protocol

•Interface

•Type of routed protocol traffic using this adjacency

•Next hop address

•Adjacency source (for example, address resolution protocol (ARP) or ATM Map)

•Encapsulation prepended to packet switched through this adjacency

•Chain of output chain elements applied to packets after an adjacency

•Packet and byte counts

•HA epoch and summary event epoch

Examples

The following example shows how to display adjacency information:

For a Cisco 7000 Series Router 

Router# show adjacency


Protocol Interface                 Address

IP       FastEthernet2/3           172.20.52.1(3045)

IP       FastEthernet2/3           172.20.52.22(11)

Router#

The following example shows how to display adjacency information for a specific interface: 

Router# show adjacency fastethernet 0/0


Protocol Interface                 Address

IP       FastEthernet0/0           10.4.9.2(5)

IP       FastEthernet0/0           10.4.9.3(5)

Router#

For a Cisco 10000 Series Router 

Router# show adjacency


Protocol Interface                 Address

IP       FastEthernet2/0/0         172.20.52.1(3045)

IP       FastEthernet2/0/0         172.20.52.22(11)

Router#

The following example shows how to display adjacency information for a specific interface: 

Router# show adjacency fastethernet 2/0/0


Protocol Interface                 Address

IP       FastEthernet2/0/0         10.4.9.2(5)

IP       FastEthernet2/0/0         10.4.9.3(5)

The following example shows how to display detailed adjacency information for adjacent IPv6 routers: 

Router#  show adjacency detail


Protocol Interface                 Address

IP       Tunnel0                   point2point(6)

                                    0 packets, 0 bytes

                                    00000000

                                    CEF   expires: 00:02:57

                                          refresh: 00:00:57

                                    Epoch: 0

IPV6     Tunnel0                   point2point(6)

                                    0 packets, 0 bytes

                                    00000000

                                    IPv6 CEF   never

                                    Epoch: 0

IPV6     Ethernet2/0               FE80::A8BB:CCFF:FE01:9002(3)

                                    0 packets, 0 bytes

                                    AABBCC019002AABBCC012C0286DD

                                    IPv6 ND    never

                                    Epoch: 0

IPV6     Ethernet2/0               3FFE:2002::A8BB:CCFF:FE01:9002(5)

                                    0 packets, 0 bytes

                                    AABBCC019002AABBCC012C0286DD

                                    IPv6 ND    never

                                    Epoch: 0

Table 3 describes the significant fields shown in the displays.

Table 3 show adjacency Field Descriptions 

Field
Description

Protocol

Type of Internet protocol.

Interface

Outgoing interface.

172.20.52.1(3045)

Next hop address.


The following example shows how to display a summary of adjacency information:

For a Cisco 7000 Series Router 

Router# show adjacency summary


Adjacency table has 7 adjacencies:

  each adjacency consumes 368 bytes (4 bytes platform extension)

  6 complete adjacencies

  1 incomplete adjacency

  4 adjacencies of linktype IP

    4 complete adjacencies of linktype IP

    0 incomplete adjacencies of linktype IP

    0 adjacencies with fixups of linktype IP

    2 adjacencies with IP redirect of linktype IP

  3 adjacencies of linktype IPV6

    2 complete adjacencies of linktype IPV6

    1 incomplete adjacency of linktype IPV6


Adjacency database high availability:

  Database epoch: 8 (7 entries at this epoch)


Adjacency manager summary event processing:

 Summary events epoch is 52

 Summary events queue contains 0 events (high water mark 113 events)

 Summary events queue can contain 49151 events

 Adj last sourced field refreshed every 16384 summary events

RP adjacency component enabled

For a Cisco 10000 Series Router 

Router# show adjacency summary


Adjacency table has 7 adjacencies:

  each adjacency consumes 368 bytes (4 bytes platform extension)

  6 complete adjacencies

  1 incomplete adjacency

  4 adjacencies of linktype IP

    4 complete adjacencies of linktype IP

    0 incomplete adjacencies of linktype IP

    0 adjacencies with fixups of linktype IP

    2 adjacencies with IP redirect of linktype IP


Adjacency database high availability:

  Database epoch: 8 (7 entries at this epoch)


Adjacency manager summary event processing:

 Summary events epoch is 52

 Summary events queue contains 0 events (high water mark 113 events)

 Summary events queue can contain 49151 events

 Adj last sourced field refreshed every 16384 summary events

RP adjacency component enabled

The following example shows how to display protocol detail and timer information:

For a Cisco 7000 Series Router 

Router# show adjacency detail


Protocol Interface                 Address

IP       FastEthernet0/0           10.4.9.2(5)

                                   0 packets, 0 bytes

                                   epoch 0

                                   sourced in sev-epoch 2

                                   Encap length 14

                                   00307131ABFC000500509C080800

                                   ARP

IP       FastEthernet0/0           10.4.9.3(5)

                                   0 packets, 0 bytes

                                   epoch 0

                                   sourced in sev-epoch 2

                                   Encap length 14

                                   000500506C08000500509C080800

                                   ARP

Router#

For a Cisco 10000 Series Router 

Router# show adjacency detail


Protocol Interface                 Address

IP       FastEthernet2/0/0           10.4.9.2(5)

                                   0 packets, 0 bytes

                                   epoch 0

                                   sourced in sev-epoch 2

                                   Encap length 14

                                   00307131ABFC000500509C080800

                                   ARP

IP       FastEthernet2/0/0           10.4.9.3(5)

                                   0 packets, 0 bytes

                                   epoch 0

                                   sourced in sev-epoch 2

                                   Encap length 14

                                   000500506C08000500509C080800

                                   ARP

Router#

The following example shows how to display protocol detail and timer adjacency information for IP links for a specific interface:

For a Cisco 7000 Series Router 

Router# show adjacency tunnel 1 link ip detail


Protocol Interface                 Address

IP       Tunnel1                   point2point(7)

                                   0 packets, 0 bytes

                                   epoch 1

                                   sourced in sev-epoch 4

                                   empty encap string

                                   P2P-ADJ

                                   Next chain element:

                                    label 16 TAG adj out of Ethernet1/0, addr 10.0.0.0

Router#

For a Cisco 10000 Series Router 

Router# show adjacency tunnel 1 link ip detail


Protocol Interface                Address

IP       Tunnel1                  point2point(7)

                                  0 packets, 0 bytes

                                  epoch 1

                                  sourced in sev-epoch 4

                                  empty encap string

                                  P2P-ADJ

                                  Next chain element:

                                   label 16 TAG adj out of FastEthernet1/0/0, addr 
10.0.0.0

Router#

Table 4 describes the significant fields shown in the displays.

Table 4 show adjacency detail Field Descriptions 

Field
Description

Protocol

Type of Internet protocol.

Interface

Outgoing interface.

10.4.9.2(5)

Next hop address.

ARP

Adjacency source (how the adjacency was created). For example, ARP or ATM Map.

Next chain element

Chain of output chain elements applied to packets after an adjacency.

0 packets, 0 bytes

Number of packets and bytes through the adjacency.

epoch 0

HA epoch.

sourced in sev-epoch 2

Summary event epoch.


Related Commands

Command
Description

clear adjacency

Clears the CEF adjacency table.

clear arp-cache

Deletes all dynamic entries from the ARP cache.

show adjacency

Enables the display of information about the adjacency database.

show mls cef adjacency

Displays information about the hardware Layer 3 switching adjacency node.


show ip interface

To display the usability status of interfaces configured for IP, use the show ip interface command in privileged EXEC mode.

show ip interface [type number] [brief]

Syntax Description

type

(Optional) Interface type.

number

(Optional) Interface number.

brief

(Optional) Displays a summary of the usability status information for each interface.


Command Modes

Privileged EXEC

Command History

Release
Modification

10.0

This command was introduced.

12.0(3)T

This command was expanded to include the status of ip wccp redirect out and ip wccp redirect exclude add in commands.

12.2(14)S

This command was expanded to display the status of NetFlow on a subinterface.

12.2(15)T

The command output enhancements introduced in Cisco IOS Release 12.2(14)S were integrated into Cisco IOS Release 12.2(15)T.

12.3(6)

The command output was modified to identify the downstream VRF in the output.

12.3(11)T

This command was integrated into Cisco IOS Release 12.3(11)T.

12.3(14)YM2

This command was modified to show the usability status of interfaces configured for Multi-Processor Forwarding (MPF) and implemented on the Cisco 7301 and Cisco 7206VXR routers.

12.4(4)T

This command was integrated into Cisco IOS Release 12.4(4)T.

12.2(28)SB

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


Usage Guidelines

The Cisco IOS software automatically enters a directly connected route in the routing table if the interface is usable. A usable interface can send and receive packets. If an interface is not usable, the directly connected routing entry is removed from the routing table. Removing the entry allows the software to use dynamic routing protocols to determine backup routes to the network, if any.

If the interface can provide two-way communication, the line protocol is marked "up." If the interface hardware is usable, the interface is marked "up."

If you specify an optional interface type, you see information for that specific interface.

If you specify no optional arguments, you see information on all the interfaces.

When an asynchronous interface is encapsulated with PPP or Serial Line Internet Protocol (SLIP), IP fast switching is enabled. A show ip interface command on an asynchronous interface encapsulated with PPP or SLIP displays a message indicating that IP fast switching is enabled.

Examples

The following examples from Cisco IOS Release 12.3(14)YM2 show: 1) configuration information on interface Gigabit Ethernet0/3 where the IP flow egress feature is configured on the output side (where packets go out of the interface) and the policy route-map named PBR_NAME is configured on the input side (where packets come into the interface); and 2) interface information on interface Gigabit Ethernet0/3 showing that MPF is enabled and that both features are not supported by MPF and ignored.

The highlighted arrows (for documentation purposes only) show the configured output and input features and the additional MPF interface information. 

Router# show running-config interface g0/3


interface GigabitEthernet0/3

 ip address 192.1.1.1 255.255.0.0

 ip flow egress                   <== output

 ip policy route-map PBR_NAME     <== input

 duplex auto

 speed auto

 media-type gbic

 negotiation auto

end


Router# show ip interface g0/3


GigabitEthernet0/3 is up, line protocol is up

  Internet address is 192.1.1.1/16

  Broadcast address is 255.255.255.255

  Address determined by setup command

  MTU is 1500 bytes

  Helper address is not set

  Directed broadcast forwarding is disabled

  Outgoing access list is not set

  Inbound  access list is not set

  Proxy ARP is enabled

  Local Proxy ARP is disabled

  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 Feature Fast switching turbo vector

  IP VPN Flow CEF switching turbo vector

  IP multicast fast switching is enabled

  IP multicast distributed fast switching is disabled

  IP route-cache flags are Fast, 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

  Policy routing is enabled, using route map PBR

  Network address translation is disabled

  BGP Policy Mapping is disabled

  IP Multi-Processor Forwarding is enabled   <======== MPF information

     IP Input features, "PBR",

         are not supported by MPF and are IGNORED

     IP Output features, "NetFlow",

         are not supported by MPF and are IGNORED

The following example identifies a downstream VRF. The highlighted line (for documentation purposes only) identifies the downstream VRF. 

Router# show ip interface vi 3


Virtual-Access3 is up, line protocol is up

  Interface is unnumbered. Using address of Loopback2 (10.0.0.8)

  Broadcast address is 255.255.255.255

  Peer address is 10.8.1.1

  MTU is 1492 bytes

  Helper address is not set

  Directed broadcast forwarding is disabled

  Outgoing access list is not set

  Inbound  access list is not set

  Proxy ARP is enabled

  Local Proxy ARP is disabled

  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 CEF switching is enabled

  IP Feature Fast switching turbo vector

  IP VPN CEF switching turbo vector

  VPN Routing/Forwarding "U"

  Downstream VPN Routing/Forwarding "D" 

  IP multicast fast switching is disabled

  IP multicast distributed fast switching is disabled

  IP route-cache flags are Fast, 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

  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

Table 5 describes the significant fields shown in the display.

Table 5 show ip interface Field Descriptions 

Field
Description

Virtual-Access3 is up

If the interface hardware is usable, the interface is marked "up." For an interface to be usable, both the interface hardware and line protocol must be up.

Broadcast address is

Displays the broadcast address.

Peer address is

Displays the peer address.

MTU is

Displays the MTU value set on the interface.

Helper address

Displays a helper address, if one has been set.

Directed broadcast forwarding

Indicates whether directed broadcast forwarding is enabled.

Outgoing access list

Indicates whether the interface has an outgoing access list set.

Inbound access list

Indicates whether the interface has an incoming access list set.

Proxy ARP

Indicates whether Proxy Address Resolution Protocol (ARP) is enabled for the interface.

Security level

Specifies the IP Security Option (IPSO) security level set for this interface.

Split horizon

Indicates that split horizon is enabled.

ICMP redirects

Specifies whether redirect messages will be sent on this interface.

ICMP unreachables

Specifies whether unreachable messages will be sent on this interface.

ICMP mask replies

Specifies whether mask replies will be sent on this interface.

IP fast switching

Specifies whether fast switching has been enabled for this interface. It is generally enabled on serial interfaces, such as this one.

IP Flow switching

Specifies whether Flow switching is enabled for this interface.

IP CEF switching

Specifies whether Cisco Express Forwarding (CEF) is enabled for the interface.

Downstream VPN Routing/Forwarding "D"

Specifies the VRF where the PPP peer routes and AAA per-user routes are being installed.

IP multicast fast switching

Specifies whether multicast fast switching is enabled for the interface.

IP route-cache flags are Fast, Flow init, CEF, Ingress Flow

Specifies whether NetFlow has been enabled on an interface. Displays "Flow init" to specify that NetFlow is enabled on the interface. Displays "Ingress Flow" to specify that NetFlow is enabled on a subinterface using the ip flow ingress command. Specifies "Flow" to specify that NetFlow is enabled on a main interface using the ip route-cache flow command.

Router Discovery

Specifies whether the discovery process has been enabled for this interface. It is generally disabled on serial interfaces.

IP output packet accounting

Specifies whether IP accounting is enabled for this interface and what the threshold (maximum number of entries) is.

TCP/IP header compression

Indicates whether compression is enabled or disabled.

WCCP Redirect outbound is disabled

Indicates the status of whether packets received on an interface are redirected to a cache engine. Displays "enabled" or "disabled."

WCCP Redirect exclude is disabled

Indicates the status of whether packets targeted for an interface will be excluded from being redirected to a cache engine. Displays "enabled" or "disabled."


The following is sample output from the show ip interface brief command: 

Router# show ip interface brief


Interface     IP-Address     OK?  Method  Status                  Protocol

Ethernet0     151.108.0.5    YES  NVRAM   up                      up      

Ethernet1     unassigned     YES  unset   administratively down   down    

Loopback0     152.108.20.5   YES  NVRAM   up                      up      

Serial0       162.108.10.5   YES  NVRAM   up                      up      

Serial1       162.108.4.5    YES  NVRAM   up                      up      

Serial2       152.108.10.5   YES  manual  up                      up      

Serial3       unassigned     YES  unset   administratively down   down

The method field has the following possible values:

•RARP or SLARP—Reverse Address Resolution Protocol (RARP) or Serial Line Address Resolution Protocol (SLARP) request

•BOOTP—Bootstrap protocol

•TFTP—Configuration file obtained from Trivial File Transfer Protocol (TFTP) server

•manual—Manually changed by CLI command

•NVRAM—Configuration file in nonvolatile RAM (NVRAM)

•IPCP—ip address negotiated command

•DHCP—ip address dhcp command

•unassigned—No IP address

•unset—Unset

•other—Unknown


Any Internet Protocol (IP) addresses used in this document are not intended to be actual addresses. Any examples, command display output, and figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses in illustrative content is unintentional and coincidental.

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