Table Of Contents

enabled (aggregation cache)

encapsulation (Any Transport over MPLS)

encapsulation dot1q

encapsulation isl

encapsulation sde

exit-address-family

export

export map

extended-port

holding-time

import map

index

interface xtagatm

ip cache-invalidate-delay

ip cef

ip cef accounting

ip cef linecard ipc memory

ip cef load-sharing algorithm

ip cef table adjacency-prefix

ip cef table adjacency-prefix override

ip cef table consistency-check

ip cef table event-log

ip cef table resolution-timer

ip explicit-path

ip flow-aggregation cache

ip flow-cache entries

ip flow-export

ip flow-export destination

ip flow-export source

ip flow ingress

enabled (aggregation cache)

To enable a NetFlow accounting aggregation cache, use the enabled command in NetFlow aggregation cache configuration mode. To disable a NetFlow accounting aggregation cache, use the no form of this command.

enabled

no enabled

Syntax Description

This command has no arguments or keywords.

Defaults

No aggregation cache is enabled.

Command Modes

NetFlow aggregation cache configuration

Command History

Release	Modification
12.0(3)T	This command was introduced.

Usage Guidelines

You must have NetFlow accounting configured on your router before you can use this command.

Examples

The following example shows how to enable a NetFlow protocol-port aggregation cache:

Router(config)# ip flow-aggregation cache protocol-port

Router(config-flow-cache)# enabled

The following example shows how to disable a NetFlow protocol-port aggregation cache:

Router(config)# ip flow-aggregation cache protocol-port

Router(config-flow-cache)# no enabled

Related Commands

Command	Description
cache	Defines operational parameters for NetFlow accounting aggregation caches.
export destination (aggregation cache)	Enables the exporting of NetFlow accounting information from NetFlow aggregation caches.
ip flow-aggregation cache	Enables NetFlow accounting aggregation cache schemes.
mask (IPv4)	Specifies the source or destination prefix mask for a NetFlow accounting prefix aggregation cache.
show ip cache flow aggregation	Displays the NetFlow accounting aggregation cache statistics.
show ip cache flow	Displays a summary of the NetFlow accounting statistics.
show ip cache verbose flow	Displays a detailed summary of the NetFlow accounting statistics.
show ip flow interface	Displays NetFlow accounting configuration on interfaces.

encapsulation (Any Transport over MPLS)

To configure the ATM adaptation layer (AAL) for an Any Transport over MPLS (AToM) ATM permanent virtual circuit (PVC), use the encapsulation command in AToM VC configuration mode. To remove an encapsulation from an AToM PVC, use the no form of this command.

encapsulation layer-type

no encapsulation layer-type

Syntax Description

layer-type

The adaptation layer type. Possible values are: aal5—ATM adaptation layer 5 aal0—ATM adaptation layer 0

Defaults

The default encapsulation is AAL5.

Command Modes

AToM VC configuration

Command History

Release	Modification
12.0(23)S	This command was introduced.
12.2(14)S	This command was integrated into Cisco IOS Release 12.2(14)S.
12.2(15)T	This command was integrated into Cisco IOS Release 12.2(15)T.

Usage Guidelines

The pvc command and the encapsulation command work together. How you use the commands for AToM is slightly different than for all other applications. The following table shows the differences in how the commands are used:

Other Applications	AToM
pvc 1/100 encapsulation aal5snap	pvc 1/100 l2transport encapsulation aal5

The following list highlights the differences:

•pvc command: For most applications, you create a PVC by using the pvc vpi/vci command. For AToM, you must add the l2transport keyword to the pvc command. The l2transport keyword enables the PVC to transport Layer 2 packets.

•encapsulation command: The encapsulation command for AToM has only two keyword values: aal5 or aal0. You cannot specify an encapsulation type. In contrast, the encapsulation aal5 command you use for most other applications requires you to specify the encapsulation type, such as aal5snap.

•pvc command and encapsulation command: The AToM encapsulation command works only with the pvc command. You cannot create switched virtual circuits or VC bundles to transport Layer 2 packets. You can only use PVCs to transport Layer 2 packets.

When you use the aal5 keyword, incoming cells (except Operation, Administration, and Maintenance [OAM] cells) on that PVC are treated as AAL5 encapsulated packets. The router reassembles the packet from the incoming cells. The router does not check the contents of the packet, so it does not need to know the encapsulation type (such as aal5snap, aal5mux, and so on). After imposing the Multiprotocol Label Switching (MPLS) label stack, the router sends the reassembled packet over the MPLS core network.

When you use the aal0 keyword, the router strips the header error control (HEC) byte from the cell header and adds the MPLS label stack. The router sends the cell over the MPLS core network.

Examples

The following example shows how to configure a PVC to transport ATM Cell Relay packets for AToM:

Router(config-if)# pvc 1/100 l2transport

Router(config-atm-vc)# encapsulation aal0 

Related Commands

Command	Description
pvc	Creates or assigns a name to an ATM PVC.

encapsulation dot1q

To enable IEEE 802.1Q encapsulation of traffic on a specified subinterface in a virtual LAN (VLAN), use the encapsulation dot1q command in interface range mode.

encapsulation dot1q vlan-id [native]

Syntax Description

vlan-id	Virtual LAN identifier. The allowed range is from 1 to 4095.
native	(Optional) Sets the VLAN ID value of the port to the value specified by the vlan-id argument.

Defaults

IEEE 802.1Q encapsulation is disabled.

Command Modes

Interface range

Command History

Release	Modification
12.0(1)T	This command was introduced.
12.1(3)T	The native keyword was added.
12.2(2)DD	Configuration of this command in interface range mode was introduced.
12.2(4)B	This command was integrated into Cisco IOS Release 12.2(4)B.
12.2(8)T	This command was integrated into Cisco IOS Release 12.2(8)T.

Usage Guidelines

IEEE 802.1Q encapsulation is configurable on Fast Ethernet interfaces. IEEE 802.1Q is a standard protocol for interconnecting multiple switches and routers and for defining VLAN topologies.

Use the encapsulation dot1q command in interface range mode to apply a VLAN ID to each subinterface within the range specified by the interface range command. The VLAN ID specified by the vlan-id argument is applied to the first subinterface in the range. Each subsequent interface is assigned a VLAN ID, which is the specified vlan-id plus the subinterface number minus the first subinterface number (VLAN ID + subinterface number - first subinterface number).

Do not configure encapsulation on the native VLAN of an IEEE 802.1Q trunk without the native keyword. (Always use the native keyword when vlan-id is the ID of the IEEE 802.1Q native VLAN.)

Examples

The following example shows how to create the subinterfaces within the range 0.11 and 0.60 and apply VLAN ID 101 to the Fast Ethernet0/0.11 subinterface, VLAN ID 102 to Fast Ethernet0/0.12 (vlan-id = 101 + 12 - 11 = 102), and so on up to VLAN ID 150 to Fast Ethernet0/0.60 (vlan-id = 101 + 60 - 11 = 150):

Router(config)# interface range fastethernet0/0.11 - fastethernet0/0.60

Router(config-int-range)# encapsulation dot1q 101

Related Commands

Command	Description
encapsulation isl	Enables the Inter-Switch Link (ISL), which is a Cisco proprietary protocol for interconnecting multiple switches and maintaining VLAN information as traffic goes between switches.
encapsulation sde	Enables IEEE 802.10 encapsulation of traffic on a specified subinterface in VLANs.

encapsulation isl

To enable the Inter-Switch Link (ISL), use the encapsulation isl command in subinterface configuration mode.

encapsulation isl vlan-identifier

Syntax Description

vlan-identifier

Virtual LAN (VLAN) identifier. The allowed range is from 1 to 1000.

Defaults

ISL is disabled.

Command Modes

Subinterface configuration

Command History

Release	Modification
11.1	This command was introduced.

Usage Guidelines

ISL is a Cisco protocol for interconnecting multiple switches and routers, and for defining VLAN topologies.

ISL encapsulation is configurable on Fast Ethernet interfaces.

ISL encapsulation adds a 26-byte header to the beginning of the Ethernet frame. The header contains a 10-bit VLAN identifier that conveys VLAN membership identities between switches.

Examples

The following example shows how to enable ISL on Fast Ethernet subinterface 2/1.20:

Router(config)# interface FastEthernet 2/1.20 

Router(config-subif)# encapsulation isl 400

Related Commands

Command	Description
bridge-group	Assigns each network interface to a bridge group.
show interfaces	Displays statistics for all interfaces configured on the router or access server.
show vlans	Displays VLAN subinterfaces.

encapsulation sde

To enable IEEE 802.10 encapsulation of traffic on a specified subinterface in virtual LANs (VLANs), use the encapsulation sde command in subinterface configuration mode.

encapsulation sde sa-id

Syntax Description

sa-id

Security association identifier. This value is used as the VLAN identifier. The valid range is from 0 to 0xFFFFFFFE.

Defaults

IEEE 802.10 encapsulation is disabled.

Command Modes

Subinterface configuration

Command History

Release	Modification
10.3	This command was introduced.

Usage Guidelines

IEEE 802.10 is a standard protocol for interconnecting multiple switches and routers and for defining VLAN topologies.

Secure Data Exchange (SDE) encapsulation is configurable only on the following interface types:

•IEEE 802.10 routing: FDDI

•IEEE 802.10 transparent bridging:

–Ethernet

–FDDI

–HDLC serial

–Transparent mode

–Token Ring

Examples

The following example shows how to enable SDE on FDDI subinterface 2/0.1 and assigns a VLAN identifier of 9999:

Router(config)# interface fddi 2/0.1

Router(config-subif)# encapsulation sde 9999

Related Commands

Command	Description
bridge-group	Assigns each network interface to a bridge group.
show interfaces	Displays statistics for all interfaces configured on the router or access server.
show vlans	Displays VLAN subinterfaces.

exit-address-family

To exit from the address family configuration submode, use the exit-address-family command in address family configuration submode.

exit-address-family

Syntax Description

This command has no arguments or keywords.

Defaults

This command has no default behavior or values.

Command Modes

Address family configuration submode

Command History

Release	Modification
12.0(5)T	This command was introduced.

Usage Guidelines

This command can be abbreviated to exit.

Examples

The following example shows how to exit the address family configuration mode:

(config-router-af)# exit-address-family

Related Commands

Command	Description
address-family	Enters the address family submode for configuring routing protocols, such as BGP, RIP, and static routing.

export

To enable the exporting of NetFlow accounting information from NetFlow aggregation caches, use the export command in NetFlow aggregation cache configuration mode. To disable the export of NetFlow accounting information from NetFlow aggregation caches, use the no form of this command.

export {destination ip-address | hostname} udp-port | version [8 | 9] | template [refresh-rate packets | timeout-rate minutes]}

no export {destination ip-address | hostname} udp-port | version | template [refresh-rate | timeout-rate]}

Syntax Description

destination ip-address | hostname udp-port	IP address or hostname of the workstation to which you want to send the NetFlow information and the number of the UDP port on which the workstation is listening for this input.
version [8 | 9]	(Optional) Version of the format for the export.
template	Enables the refresh-rate and timeout-rate keywords for configuring Version 9 export templates.
refresh-rate packets	(Optional) Specifies the number of export datagrams that are sent before the templates are resent. You can specify from 1 to 600 packets. The default is 20 packets.
timeout-rate minutes	(Optional) Specifies the interval (in minutes) between which the templates are resent. You can specify from 1 to 3600 minutes. The default is 30 minutes.

Defaults

A NetFlow aggregation cache export destination is not set.
The default version format is Version 8.
The default for refresh-rate is 20 packets.
The default for timeout-rate is 30 minutes.

Command Modes

NetFlow aggregation cache configuration

Command History

Release	Modification
12.0(3)T	This command was introduced.
12.0(24)S	The version, template, refresh-rate, and timeout-rate keywords were added.
12.3(1)	This command was integrated into Cisco IOS Release 12.3(1).

Usage Guidelines

You must have NetFlow accounting configured on your router before you can use this command.

export destination

You can configure a maximum of two concurrent destinations per-cache using the destination keyword with the export command.

Determine the Appropriate Export Version for Your Requirements

NetFlow aggregation caches export data in UDP datagrams using either the Version 9 or Version 8 export format. Table 2 describe how to determine the most appropriate export format for your requirements.

Table 2 When to Select a Particular NetFlow Export Format  

Export Format	Select When...
Version 9	You need a flexible and extensible format, which provides the versatility needed for support of new fields and record types. This format accommodates new NetFlow-supported technologies such as Multicast, IPv6 NetFlow, Egress NetFlow, NetFlow Layer 2 and security exports, Multiprotocol Label Switching (MPLS), and Border Gateway Protocol (BGP) next hop. Version 9 export format enables you to use the same version for main and aggregation caches, and the format is extendable, so you can use the same export format with future features
Version 8	You need to export data from aggregation caches or you need to export data from a Catalyst 6000 series switch with a Multilayer Switch Feature Card (MSFC). You do not plan to support new features. Version 8 export format is available only for export from aggregation caches.

NetFlow Version 9 Data Export Format Overview

The NetFlow Version 9 Export Format feature was introduced in Cisco IOS Release 12.0(24)S and was integrated into Cisco IOS Release 12.3(1) and Cisco IOS Release 12.2(18)S.

NetFlow Version 9 is a flexible and extensible means for transferring NetFlow records from a network node to a collector. NetFlow Version 9 has definable record types and is self-describing for easier NetFlow Collection Engine configuration.

Third-party business partners who produce applications that provide NetFlow Collection Engine or display services for NetFlow do not need to recompile their applications each time a new NetFlow technology is added. Instead, with the NetFlow v9 Export Format feature, they can use an external data file that documents the known template formats and field types.

NetFlow Version 9 has the following characteristics:

•Record formats are defined by templates.

•Template descriptions are communicated from the router to the NetFlow Collection Engine.

•Flow records are sent from the router to the NetFlow Collection Engine with minimal template information so that the NetFlow Collection Engine can relate the records to the appropriate template.

•Version 9 is independent of the underlying transport (UDP, TCP, SCTP, and so on).

NetFlow Version 9 Template-Based Flow Record Format

The main feature of NetFlow Version 9 export format is that it is template based. A template describes a NetFlow record format and the attributes of the fields (such as type and length) within the record. The router assigns each template an ID, which is communicated to the NetFlow Collection Engine along with the template description. The template ID is used for all further communication from the router to the NetFlow Collection Engine.

NetFlow Version 9 Export Flow Records

The basic output of NetFlow is a flow record. In NetFlow Version 9 export format, a flow record follows the same sequence of fields that is found in the template definition. The template to which NetFlow flow records belong is determined by the prefixing of the template ID to the group of NetFlow flow records that belong to a template. For a complete discussion of existing NetFlow flow-record formats, see the NetFlow Services Solutions Guide.

NetFlow Version 9 Export Packet

In NetFlow Version 9, an export packet consists of the packet header and flowsets. The packet header identifies identifies the NetFlow Export version'. Flowsets are of two types: template flowsets and data flowsets. The template flowset describes the fields that will be in the data flowsets (or flow records). Each data flowset contains the values or statistics of one or more flows that have the same template ID. When the NetFlow Collection Engine receives a template flowset, it stores the flowset and export source address so that subsequent data flowsets that match the flowset ID and source combination are parsed according to the field definitions in the template flowset. Version 9 is supported by NetFlow Collection Engine Version 4.0.

For a complete description of the Version 9 packet headers, template flowsets, and data flowsets, see the Cisco IOS NetFlow Version 9 Flow-Record Format white paper.

NetFlow Version 8 Data Export Format Overview

The Version 8 data export format is the NetFlow export format used when the router-based NetFlow aggregation feature is enabled on Cisco IOS router platforms. The Version 8 format allows for export datagrams to contain a subset of the Version 5 export data that is based on the configured aggregation cache scheme. For example, a certain subset of the Version 5 export data is exported for the destination prefix aggregation scheme, and a different subset is exported for the source-prefix aggregation scheme.

The Version 8 export format was introduced in Cisco IOS 12.0(3)T for the Cisco IOS NetFlow Aggregation feature. An additional six aggregation schemes that also use Version 8 format were defined for the NetFlow ToS-Based Router Aggregation feature introduced in Cisco IOS 12.0(15)S and integrated into Cisco IOS Releases 12.2(4)T and 12.2(14)S.

The Version 8 datagram consists of a header with the version number (which is 8) and time stamp information, followed by one or more records corresponding to individual entries in the NetFlow cache.

Table 3 lists the NetFlow Version 8 export packet header field names and descriptions.

Table 3 NetFlow Version 8 Export Packet Header Field Names and Descriptions 

Field Name	Description
Version	Flow export format version number. In this case 8.
Count	Number of export records in the datagram.
System Uptime	Number of milliseconds since the router last booted.
UNIX Seconds	Number of seconds since 0000 UTC 1970.
UNIX NanoSeconds	Number of residual nanoseconds since 0000 UTC 1970.
Flow Sequence Number	Sequence counter of total flows sent for this export stream.
Engine Type	The type of switching engine. RP = 0 and LC = 1.
Engine ID	Slot number of the NetFlow engine.
Aggregation	Type of aggregation scheme being used.
Agg Version	Aggregation subformat version number. The current value is 2.
Sampling Interval	Interval value used if Sampled NetFlow is configured.
Reserved	Zero field.

For version 8 data exports, the maximum number of aggregated flow records and the maximum size in bytes of each UDP datagram are shown in Table 4.

Table 4 NetFlow Version 8 Aggregation Scheme, Number of Flow Records and UDP Packet Size

Aggregation Scheme	Maximum Number of Flow Records	UDP Packet Size
BGP Autonomous System	51	1456 bytes
Destination Prefix	44	1436 bytes
Prefix	35	1428 bytes
Protocol Port	51	1456 bytes
Source Prefix	44	1436 bytes

Examples

The following example shows how to configure two export destinations for a NetFlow accounting protocol-port aggregation cache scheme:

Router(config)# ip flow-aggregation cache protocol-port

Router(config-flow-cache)# export destination 10.41.41.1 9992

Router(config-flow-cache)# export destination 172.16.89.1 9992

Router(config-flow-cache)# enabled

'The following example shows how to configure the Version 9 template refresh-rate and timeout-rate parameters for a NetFlow accounting protocol-port aggregation cache scheme:

Router(config)# ip flow-aggregation cache protocol-port

Router(config-flow-cache)# version 9

Router(config-flow-cache)# export template refresh-rate 100

Router(config-flow-cache)# export template timeout-rate 120

Router(config-flow-cache)# enabled

Related Commands

Command	Description
cache	Defines operational parameters for NetFlow accounting aggregation caches.
enabled (aggregation cache)	Enables a NetFlow accounting aggregation cache.
ip flow-aggregation cache	Enables NetFlow accounting aggregation cache schemes.
mask (IPv4)	Specifies the source or destination prefix mask for a NetFlow accounting prefix aggregation cache.
show ip cache flow aggregation	Displays the NetFlow accounting aggregation cache statistics.
show ip cache flow	Displays a summary of the NetFlow accounting statistics.
show ip cache verbose flow	Displays a detailed summary of the NetFlow accounting statistics.
show ip flow interface	Displays NetFlow accounting configuration for interfaces.

export map

To associate an export map with a VPN Routing and Forwarding (VRF) instance, use the export map command in VRF configuration mode.

export map route-map

Syntax Description

route-map

Specifies the route map to be used as an export map.

Defaults

No default behavior or values

Command Modes

IP VPN Routing/Forwarding configuration mode

Command History

Release	Modification
12.0(5)T	This command was introduced.

Usage Guidelines

The export map command is used to associate a route map with the specified VRF. The export map is used to filter routes that are eligible for export out of a VRF, based on the route target extended community attributes of the route. Only one export route map can be configured for a VRF.

An export route map can be used when an application requires finer control over the routes that are exported out of a VRF than the control that is provided by import and export extended communities configured for the importing and exporting VRFs.

Examples

In the following example, an export is configured under the VRF and an access list and route map are configured to specify which prefixes are exported:

Router(config)# ip vrf RED 

Router(config-vrf)# rd 1:1 

Router(config-vrf)# export map BLUE 

Router(config-vrf)# route-target import 2:1 

Router(config-vrf)# exit 

Router(config)# access-list 1 permit 192.168.0.0 0.0.255.255

Router(config)# route-map BLUE permit 10 

Router(config-route-map)# match ip address 1 

Router(config-route-map)# set extcommunity rt 2:1 

Router(config-route-map)# end 

Related Commands

Command	Description
import map	Configures an import route map for a VRF.
ip extcommunity-list	Creates an extended community list for BGP and controls access to it.
ip vrf	Configures a VRF routing table.
route-target	Creates a route-target extended community for a VRF.
show ip vrf	Displays the set of defined VRFs and associated interfaces.

extended-port

To associate the currently selected extended Multiprotocol Label Switching (MPLS) ATM (XTagATM) interface with a particular external interface on the remotely controlled ATM switch, use the extended-port command in interface configuration mode.

extended-port ctrl-if {bpx bpx-port-number | descriptor vsi-descriptor | vsi vsi-port-number}

Syntax Description

ctrl-if	Identifies the ATM interface used to control the remote ATM switch. You must configure Virtual Switch Interface (VSI) on this interface using the label-control-protocol interface configuration command.
bpx bpx-port-number	Specifies the associated Cisco BPX interface using the native BPX syntax. slot.port [.virtual port] You can use this form of the command only when the controlled switch is a Cisco BPX switch.
descriptor vsi-descriptor	Specifies the associated port by its VSI physical descriptor. The vsi-descriptor string must match the corresponding VSI physical descriptor.
vsi vsi-port-number	Specifies the associated port by its VSI port number. The vsi-port-number string must match the corresponding VSI physical port number.

Defaults

Extended MPLS ATM interfaces are not associated.

Command Modes

Interface configuration

Command History

Release	Modification
12.0(3)T	This command was introduced.

Usage Guidelines

The extended-port interface configuration command associates an XTagATM interface with a particular external interface on the remotely controlled ATM switch. The three alternate forms of the command permit the external interface on the controlled ATM switch to be specified in three different ways.

Examples

The following example shows how to associate an extended MPLS ATM interface and bind it to BPX port 2.3:

ATM(config)# interface XTagATM23

ATM(config-if)# extended-port atm0/0 bpx 2.3

The following example shows how to associate an extended MPLS ATM interface and bind it to port 2.4:

ATM(config)# interface XTagATM24

ATM(config-if)# extended-port atm0/0 descriptor 0.2.4.0

The following example shows how to associate an extended MPLS ATM interface and binds it to port 1622:

ATM(config)# interface XTagATM1622

ATM(config-if)# extended-port atm0/0 vsi 0x00010614

Related Commands

Command	Description
interface XTagATM	Enters interface configuration mode for an extended MPLS ATM (XTagATM) interface.
show controller vsi status	Displays a summary of each VSI-controlled interface.

holding-time

To specify the holding time value for the MPS-p7 variable of a Multiprotocol over ATM server (MPS), use the holding-time command in MPS configuration mode. To revert to the default value, use the no form of this command.

holding-time seconds

no holding-time seconds

Syntax Description

seconds

Specifies the holding time value in seconds. The default is 1200 seconds.

Defaults

The default holding time is 1200 seconds (20 minutes).

Command Modes

MPS configuration

Command History

Release	Modification
11.3(3a)WA4(5)	This command was introduced.

Examples

The following example shows how to set the holding time to 600 seconds (10 minutes):

holding-time 600

import map

To configure an import route map for a Virtual Private Network (VPN) routing/forwarding instance (VRF), use the import map command in VRF configuration submode.

import map route-map

Syntax Description

route-map

Specifies the route map to be used as an import route map for the VRF.

Defaults

No import route map is configured for a VRF.

Command Modes

VRF configuration submode

Command History

Release	Modification
12.0(5)T	This command was introduced.

Usage Guidelines

Use an import route map when an application requires finer control over the routes imported into a VRF than provided by the import and export extended communities configured for the importing and exporting VRF.

The import map command associates a route map with the specified VRF. You can use a route map to filter routes that are eligible for import into a VRF, based on the route target extended community attributes of the route. The route map might deny access to selected routes from a community that is on the import list.

The import map command does not replace the need for a route-target import in the VRF configuration. You use the import map command to further filter prefixes that match a route-target import statement in that VRF.

Examples

The following example shows how to configure an import route map for a VRF:

Router(config)# ip vrf vrf_blue

Router(config-vrf)# import map blue_import_map

Related Commands

Command	Description
ip vrf	Configures a VRF routing table.
route-target	Creates a route-target extended community for a VRF.
show ip vrf	Displays the set of defined VRFs and associated interfaces.

index

To insert or modify a path entry at a specific index, use the index command in IP explicit path configuration mode. To remove the path entry at the specified index, use the no form of this command.

index index command

no index index

Syntax Description

index	Index number at which the path entry will be inserted or modified. Valid values are from 0 to 65534.
command	An IP explicit path configuration command that creates or modifies a path entry. (Currently you can use only the next-address command.)

Defaults

This command is disabled by default.

Command Modes

IP explicit path configuration

Command History

Release	Modification
12.0(5)S	This command was introduced.

Examples

The following example shows how to insert the next address at index 6:

Router(cfg-ip-expl-path)# index 6 next-address 3.3.29.3

Explicit Path identifier 6:

    6: next-address 3.3.29.3

Related Commands

Command	Description
append-after	Inserts the new path entry after the specified index number. Commands might be renumbered as a result.
interface fastethernet	Enters the command mode for IP explicit paths and creates or modifies the specified path.
list	Displays all or part of the explicit paths.
next-address	Specifies the next IP address in the explicit path.
show ip explicit-paths	Displays the configured IP explicit paths.

interface xtagatm

To create an extended Multiprotocol Label Switching (MPLS) ATM (XTagATM) interface, use the interface xtagatm command in global configuration mode.

interface xtagatm interface-number

Syntax Description

interface-number

The interface number.

Defaults

XTagATM interfaces are not created.No default behavior or values.

Command Modes

Global configuration

Command History

Release	Modification
12.0(5)T	This command was introduced.
12.2(4)T	This command was updated to reflect the MPLS IETF terminology.

Usage Guidelines

XTagATM interfaces are virtual interfaces that are created on reference-like tunnel interfaces. An XTagATM interface is created the first time the interface xtagatm command is issued for a particular interface number. These interfaces are similar to ATM interfaces, except that the former only supports LC-ATM encapsulation.

Examples

The following example shows how to create an XTagATM interface with interface number 62:

Router(config)# interface xtagatm62

Related Commands

Command	Description
extended-port	Associates the currently selected extended XTagATM interface with a remotely controlled switch.

ip cache-invalidate-delay

To control the invalidation rate of the IP route cache, use the ip cache-invalidate-delay command in global configuration mode. To allow the IP route cache to be immediately invalidated, use the no form of this command.

ip cache-invalidate-delay [minimum maximum quiet threshold]

no ip cache-invalidate-delay

Syntax Description

minimum	(Optional) Minimum time (in seconds) between invalidation request and actual invalidation. The default is 2 seconds.
maximum	(Optional) Maximum time (in seconds) between invalidation request and actual invalidation. The default is 5 seconds.
quiet	(Optional) Length of quiet period (in seconds) before invalidation.
threshold	(Optional) Maximum number of invalidation requests considered to be quiet.

Defaults

minimum: 2 seconds
maximum: 5 seconds, and 3 seconds with no more than zero invalidation requests

Command Modes

Global configuration

Command History

Release	Modification
10.0	This command was introduced.

Usage Guidelines

After you enter the ip cache-invalidate-delay command all cache invalidation requests are honored immediately.

---

Caution This command should only be used under the guidance of technical support personnel. Incorrect settings can seriously degrade network performance. The command-line-interface (CLI) will not allow you to enter the ip cache-invalidate-delay command until you configure the service internal command in global configuration mode.

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The IP fast-switching and autonomous-switching features maintain a cache of IP routes for rapid access. When a packet is to be forwarded and the corresponding route is not present in the cache, the packet is process switched and a new cache entry is built. However, when routing table changes occur (such as when a link or an interface goes down), the route cache must be flushed so that it can be rebuilt with up-to-date routing information.

This command controls how the route cache is flushed. The intent is to delay invalidation of the cache until after routing has settled down. Because route table changes tend to be clustered in a short period of time, and the cache may be flushed repeatedly, a high CPU load might be placed on the router.

When this feature is enabled, and the system requests that the route cache be flushed, the request is held for at least minimum seconds. Then the system determines whether the cache has been "quiet" (that is, less than threshold invalidation requests in the last quiet seconds). If the cache has been quiet, the cache is then flushed. If the cache does not become quiet within maximum seconds after the first request, it is flushed unconditionally.

Manipulation of these parameters trades off CPU utilization versus route convergence time. Timing of the routing protocols is not affected, but removal of stale cache entries is affected.

Examples

The following example shows how to set a minimum delay of 5 seconds, a maximum delay of 30 seconds, and a quiet threshold of no more than 5 invalidation requests in the previous 10 seconds:

Router(config)# service internal

Router(config)# ip cache-invalidate-delay 5 30 10 5

Related Commands

Command	Description
ip route-cache	Configures the high-speed switching caches for IP routing.

ip cef

To enable Cisco Express Forwarding (CEF) on the route processor card, use the ip cef command in global configuration mode. To disable CEF, use the no form of this command.

ip cef [distributed] [accounting type | load-sharing algorithm algorithm | table type | traffic-statistics]

no ip cef [distributed] [accounting type | load-sharing algorithm algorithm | table type | traffic-statistics]

Syntax Description

distributed	(Optional) Enables distributed CEF (dCEF) operation. Distributes CEF information to line cards. Line cards perform express forwarding.
accounting type	(Optional) Enables CEF accounting. The options for the type argument are as follows: •non-recursive—Enables accounting for traffic through non-recursive prefixes. •per-prefix—Enables per prefix accounting. •prefix-length—Enables prefix length accounting.
load-sharing algorithm algorithm	(Optional) Enables load sharing. The options for the algorithm argument are as follow: •original—Selects the original algorithm. •tunnel—Selects the algorithm for use in tunnel-only environments. •universal—Selects the algorithm for use in most environments.
table type	(Optional) Sets CEF forwarding table characteristics. The options for the type argument are as follows: •adjacency-prefix override—Sets adjacency prefixes to override other Forwarding Information Base (FIB) entries. •consistency-check—Sets consistency checking characteristics. •event-log—Sets table log characteristics. •resolution-timer—Sets background resolution timer. Valid entries are from 0 to 30 seconds. Note Set timer to 0 for automatic exponential back-off scheme.
traffic-statistics	(Optional) Enables the collection of traffic statistics.

Defaults

CEF is disabled by default, excluding these platforms:

•CEF is enabled on the Cisco 7100 series router.

•CEF is enabled on the Cisco 7200 series router.

•CEF is enabled on the Cisco 7500 series Internet router.

•Distributed CEF is enabled on the Cisco 6500 series router.

•Distributed CEF is enabled on the Cisco 12000 series Internet router.

Command Modes

Global configuration

Command History

Release	Modification
11.1 CC	This command was introduced.
12.2	The default for the ip cef command on Cisco 7200 series routers was changed from disabled to enabled.
12.2(11)T	This command was integrated into Cisco IOS Release 12.2(11)T and implemented on the following platforms: Cisco IAD2420 series, Cisco 2600 series, Cisco 3620 routers, Cisco 3640 routers, Cisco 3660 routers, Cisco 3700 series routers, and Cisco MC3810 multiservice access concentrators.

Usage Guidelines

The ip cef command is not available on the Cisco 12000 series because that router series operates only in dCEF mode.

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

If you enable CEF and then create an access list that uses the log keyword, the packets that match the access list are not CEF switched. They are fast switched. Logging disables CEF.

Use the ip cef command to control whether voice is switched on the router.

Examples

The following example shows how to enable standard CEF operation:

Router(config)# ip cef

The following example shows how to enables dCEF operation:

Router(config)# ip cef distributed 

The following example shows IP CEF configured for load sharing using the original algorithm:

Router(config)# ip cef load-sharing algorithm original

Related Commands

Command	Description
ip cache-route	Controls the use of high-speed switching caches for IP routing.

ip cef accounting

To enable Cisco Express Forwarding (CEF) network accounting, use the ip cef accounting command in global configuration mode or interface configuration mode. To disable network accounting of CEF, use the no form of this command.

ip cef accounting {[non-recursive] [per-prefix] [prefix-length]}

no ip cef accounting {[non-recursive] [per-prefix] [prefix-length]}