Cisco IOS Multiprotocol Label Switching Command Reference

mpls traffic-eng lsp attributes

To create or modify a label switched path (LSP) attribute list, use thempls traffic-eng lsp attributes command in global configuration mode. To remove a specified LSP attribute list from the device configuration, use the no form of this command.

mpls traffic-eng lsp attributes string

no mpls traffic-eng lsp attributes string

Syntax Description


`string`	LSP attributes list identifier.

Command Default

An LSP attribute list is not created unless you create one.

Command Modes

Global configuration (config)

Command History


Release	Modification
12.0(26)S	This command was introduced.
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

This command sets up an LSP attribute list and enters LSP Attributes configuration mode, in which you can enter LSP attributes.

To associate the LSP attributes and LSP attribute list with a path option for an LSP, you must configure the tunnel mpls traffic-eng path option attributes string command, where string is the identifier for the specific LSP attribute list.

An LSP attribute referenced by the path option takes precedence over the values configured on the tunnel interface. If an attribute is not specified in the LSP attribute list, the devices takes the attribute from the tunnel configuration. LSP attribute lists do not have default values. If the attribute is not configured on the tunnel, then the device uses tunnel default values.

Once you type the mpls traffic-eng lsp attributes command, you enter the LSP Attributes configuration mode where you define the attributes for the LSP attribute list that you are creating.

The mode commands are as follows:

affinity —Specifies attribute flags for links that make up an LSP.
auto-bw —Specifies automatic bandwidth configuration.
bandwidth —Specifies LSP bandwidth.
lockdown —Disables reoptimization for the LSP.
priority —Specifies LSP priority.
protection —Enables failure protection.
record-route —Records the route used by the LSP.

The following monitoring and management commands are also available in the LSP Attributes configuration mode:

exit —Exits from LSP Attributes configuration mode.
list —Relists all the entries in the LSP attribute list.
no —Removes a specific attribute from the LSP attribute list.

Examples

The following example shows how to set up an LSP attribute list identified with the numeral 6 with the bandwidth and priority mode commands. The example also shows how to use the list mode command:


Device(config)# mpls traffic-eng lsp attributes 6
Device(config-lsp-attr)# bandwidth 500
Device(config-lsp-attr)# list
LIST 6
 bandwidth 500
 
Device(config-lsp-attr)# priority 1 1
Device(config-lsp-attr)# list
LIST 6
 bandwidth 500
 priority 1 1
Device(config-lsp-attr)# exit

Related Commands


Command	Description
show mpls traffic-eng lsp attributes	Displays global LSP attributes lists.

mpls traffic-eng mesh-group

To configure a mesh group in an Interior Gateway Protocol (IGP) to allow Multiprotocol Label Switching (MPLS) traffic engineering (TE) label switch routers (LSRs) that belong to the same mesh group to signal tunnels to the local router, use the mpls traffic-eng mesh-group command in router configuration mode. To disable signaling of tunnels from LSRs in the same mesh group to the local router, use the no form of this command.

mpls traffic-eng mesh-group mesh-group-id type number area area-id

no mpls traffic-eng mesh-group mesh-group-id type number area area-id

Syntax Description


`mesh-group-id`	Number that identifies a specific mesh group.
`type`	Type of interface.
`number`	Interface number.
area `area-id`	Specifies an IGP area.

Command Default

No tunnels are signaled for routers in the same mesh group.

Command Modes

Router configuration (config-router)#

Command History


Release	Modification
12.0(29)S	This command was introduced.
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.
Cisco IOS XE Release 3.6S	This command was integrated into Cisco IOS XE Release 3.6S.

Usage Guidelines

Use this command to configure a mesh group in an IGP. This allows the MPLS TE LSRs that belong to the specified mesh group to signal tunnels to the local router. The IGP floods mesh group configuration to all routers belonging to the same mesh group. An autotemplate determines how a router participates in an autotunnel. A router can participate in a mesh group through two-way tunnels or one-way tunnels.

Open Shortest Path First (OSPF) is the only IGP supported for the MPLS Traffic Engineering--AutoTunnel Mesh Groups feature.

Examples

The following example shows how to configure OSPF to allow LSRs that belong to the same mesh group (mesh group 10) to signal tunnels to the local router:


Router(config)# router ospf 100
Router(config-router)# mpls traffic-eng mesh-group 10 loopback 0 area 100

Related Commands


Command	Description
tunnel destination mesh-group	Configures an autotemplate to signal tunnels to all other members of a specified mesh group.

mpls traffic-eng multicast-intact

To configure a router running Intermediate System-to-Intermediate System (IS-IS) or Open Shortest Path First (OSPF) so that Protocol-Independent Multicast (PIM) and Multiprotocol Label Switching (MPLS) traffic engineering (TE) can work together, use the mpls traffic-eng multicast-intact command in router configuration mode. To disable interoperability between PIM and MPLS TE, use the no form of this command.

mpls traffic-eng multicast-intact

no mpls traffic-eng multicast-intact

Syntax Description

This command has no arguments or keywords.

Command Default

PIM and MPLS TE do not work together.

Command Modes

Router configuration (config-router)

Command History


Release	Modification
12.0(12)S	This command was introduced.
12.1(5)T	This command was integrated into Cisco IOS Release 12.1(5)T.
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.

Usage Guidelines

The mpls traffic-eng multicast-intact command allows PIM to use the native hop-by-hop neighbors while unicast routing is using MPLS TE tunnels.

This command works only for OSPF and IS-IS protocols.

Examples

The following example shows how to enable PIM and MPLS TE to interoperate:


Router(config)# router ospf 1
Router(config-router)# mpls traffic-eng multicast-intact

Related Commands


Command	Description
mpls traffic-eng interface	Configures a router running OSPF or IS-IS so that it floods MPLS TE link information in the indicated OSPF area or IS-IS level.
show ospf routes multicast intact	Displays multicast-intact paths of OSPF routes.

mpls traffic-eng nsr

To enable Multiprotocol Label Switching (MPLS) Traffic Engineering (TE) Nonstop Routing (NSR) support on a device, use the mpls traffic-eng nsr command in global configuration mode. To disable MPLS TE NSR support, use the no form of this command.

mpls traffic-eng nsr

no mpls traffic-eng nsr

This command has no arguments or keywords.

Command Default

MPLS TE NSR support is not enabled.

Command Modes

Global configuration (config)

Command History


Release	Modification
Cisco IOS Release XE 3.10S	This command was introduced.

Examples

The following example shows how to enable MPLS TE NSR support using the use the mpls traffic-eng nsr command.


enable
	configure terminal
		ip cef
		mpls traffic-eng nsr
  end

Related Commands


Command	Description
show mpls traffic-eng nsr	Displays information about MPLS TE NSR.

mpls traffic-eng passive-interface

To configure a link as a passive interface between two Autonomous System Boundary Routers (ASBRs), use the mpls traffic-eng passive-interface command in interface configuration mode. To disable the passive link, use the no form of this command.

mpls traffic-eng passive-interface nbr-te-id te-router-id [nbr-if-addr if-addr] [nbr-igp-id {isis sysid | ospf sysid}]

no mpls traffic-eng passive-interface nbr-te-id te-router-id [nbr-if-addr if-addr] [nbr-igp-id {isis sysid | ospf sysid}]

Syntax Description


nbr-te-id `te-router-id`	Traffic engineering router ID of the neighbor router on the remote side of the link where this command is configured.
nbr-if-addr `if-addr`	(Optional) Interface address of the remote ASBR.
nbr-igp-id	(Optional) Specifies a unique `sysid` for neighboring Interior Gateway Protocols (IGPs) when two or more autonomous systems use different IGPs and have more than one neighbor on the link. Enter the nbr-igp-id keyword (followed by the isis or ospf keyword) and the `sysid` for each IGP. The `sysid` must be unique for each neighbor.
isis `sysid`	System identification of Intermediate System-to-Intermediate System (IS-IS).
ospf `sysid`	System identification of Open Shortest Path First (OSPF).

Command Default

None

Command Modes

Interface configuration (config-if)

Command History


Release	Modification
12.0(29)S	This command was introduced.
12.2(33)SRA	The nbr-if-addr keyword was added.
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.
Cisco IOS XE Release 3.5S	This command was integrated into Cisco IOS XE Release 3.5S.

Usage Guidelines

The mpls traffic-eng passive-interface command sets the next-hop address for a passive interface. The command is required only for a broadcast link.

Enter the mpls traffic-eng passive-interface command only on the outgoing interface on which the label-switched path (LSP) will exit; you do not have to enter this command on both ends of the interautonomous system (Inter-AS) link.

On a point-to-point link or on a multiaccess link where there is only one neighbor, you do not have to enter the isis or ospf keyword (or the sysid argument).

If two autonomous systems use different IGPs and have more than one neighbor on the link, you must enter the nbr-igp-id keyword followed by isis or ospf and the sysid . The sysid must be unique for each neighbor.

For a broadcast link (that is, other Resource Reservation Protocol (RSVP)) features are using the passive link), you must enter the nbr-if-addr keyword.

For an RSVP Hello configuration on an Inter-AS link, all keywords are required.

Examples

In the following example there is only one neighbor:


Router(config-if)# mpls traffic-eng passive-interface nbr-te-id 10.10.10.10

In the following example, two autonomous systems use different IGPs and have more than one neighbor on the link:


Router(config-if)# mpls traffic-eng passive-interface nbr-te-id 10.10.11.12 nbr-igp-id ospf 10.10.15.18

If autonomous system 1 (AS1) is running IS-IS and AS2 is running OSPF, the unique ID on A1 must be in the system ID format. To form the system ID, we recommend that you append zeros to the router ID of the neighbor. For example, if the AS2 router is 10.20.20.20, then you could enter a system ID of 10.0020.0020.0020.00 for IS-IS on the AS1 router.

In the following example there is a remote ASBR and an IS-IS:


Router(config-if)# mpls traffic-eng passive-interface nbr-te-id 10.20.20.20 nbr-igp-id isis 10.0020.0020.0020.00

In the following example, there is a broadcast link and the interface address of the remote ASBR is 10.0.0.2:


Router(config-if)# mpls traffic-eng passive-interface nbr-te-id 10.10.10.10 nbr-if-addr 10.0.0.2

mpls traffic-eng path-option list

To configure a path option list, use the mpls traffic-eng path-option list command in global configuration mode. To disable this function, use the no form of this command.

mpls traffic-eng path-option list [name pathlist-name | identifier pathlist-number]

no mpls traffic-eng path-option list [name pathlist-name | identifier pathlist-number]

Syntax Description


name `pathlist-name`	Specifies the name of the path option list.
identifier `pathlist-number`	Specifies the identification number of the path option list. The range is 1 through 65535.

Command Default

There are no path option lists.

Command Modes

Global configuration (config)

Command History


Release	Modification
12.2(33)SRE	This command was introduced.
Cisco IOS XE Release 3.5S	This command was integrated into Cisco IOS XE Release 3.5S.

Usage Guidelines

A path option list contains a list of backup paths for a primary path option. You can specify a path option list by entering its name or identifier.

After you enter the mpls traffic-eng path-option list command, the router enters path option list configuration mode and you can enter the following commands:

path-option --Specifies the name or identification number of the next path option to add, edit, or delete.
list --Lists all path options.
no --Deletes a specified path option.
exit --Exits from path option list configuration mode.

Then you can specify explicit backup paths by entering their name or identifier.

Examples

The following example configures the path option list named pathlist-01, adds path option 10, lists the backup path that is in the path option list, and exits from path option list configuration mode:


Router(config)# mpls traffic-eng path-option list name pathlist-01
Router(cfg-pathoption-list)# path-option 10 explicit name bk-path-01
Router(cfg-pathoption-list)# list
 path-option 10 explicit name bk-path-01
Router(cfg-pathoption-list)# exit

Related Commands


Command	Description
tunnel mpls traffic-eng path option	Configures a path option for an MPLS TE tunnel.
tunnel mpls traffic-eng path-option protect	Configures a secondary path option or a path option list for an MPLS TE tunnel.

mpls traffic-eng path-selection metric

To specify the metric type to use for path selection for tunnels for which the metric type has not been explicitly configured, use the mpls traffic-eng path-selection metric command in global configuration mode. To remove the specified metric type, use the no form of this command.

mpls traffic-eng path-selection metric {igp | te}

no mpls traffic-eng path-selection metric

Syntax Description


igp	Use the Interior Gateway Protocol (IGP) metric.
te	Use the traffic engineering metric.

Command Default

The default is the te metric.

Command Modes

Global configuration

Command History


Release	Modification
12.0(18)ST	This command was introduced.
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.
12.4	This command was integrated into Cisco IOS Release 12.4.
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

Use this command to specify the metric type to be used for traffic engineering (TE) tunnels for which the tunnel mpls traffic-eng path-selection metric command has not been specified.

The metric type to be used for path calculation for a given tunnel is determined as follows:

If the tunnel mpls traffic-eng path-selection metric command was entered to specify a metric type for the tunnel, use that metric type.
Otherwise, if the mpls traffic-eng path-selection metric was entered to specify a metric type, use that metric type.
Otherwise, use the default (te ) metric.

Examples

The following command specifies that if a metric type was not specified for a given TE tunnel, the igp metric should be used for tunnel path calculation:


Router(config)# mpls traffic-eng path-selection metric igp

Related Commands


Command	Description
tunnel mpls traffic-eng path-selection metric	Specifies the metric type to use when calculating a tunnel’s path.

mpls traffic-eng reoptimize

To force immediate reoptimization of all traffic engineering tunnels, use the mpls traffic-eng reoptimize command in privileged EXEC mode.

mpls traffic-eng reoptimize

Syntax Description

This command has no arguments or keywords.

Command Modes

Privileged EXEC (#)

Command History


Release	Modification
12.0(5)ST	This command was introduced.
12.1(3)T	This command was integrated into Cisco IOS Release 12.1(3)T.
12.0(22)S	This command was integrated into Cisco IOS Release 12.0(22)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.
12.2SX	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.

Examples

The following example shows how to reoptimize all traffic engineering tunnels immediately:


Router# mpls traffic-eng reoptimize

Related Commands


Command	Description
mpls traffic-eng reoptimize timers delay	Delays removal of old LSPs or installation of new LSPs after tunnel reoptimization.

mpls traffic-eng reoptimize events

To turn on automatic reoptimization of Multiprotocol Label Switching (MPLS) traffic engineering when certain events occur, such as when an interface becomes operational, use the mpls traffic-eng reoptimize events command in global configuration mode. To disable automatic reoptimization, use the no form of this command.

mpls traffic-eng reoptimize events link-up

no mpls traffic-eng reoptimize events link-up

Syntax Description


link-up	Triggers automatic reoptimization whenever an interface becomes operational.

Command Default

Event-based reoptimization is disabled.

Command Modes

Global configuration (config)

Command History


Release	Modification
12.1(3)T	This command was introduced.
12.0(10)ST	This command was integrated into Cisco IOS Release 12.0(10)ST.
12.0(22)S	This command was integrated into Cisco IOS Release 12.0(22)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.
12.2SX	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.

Examples

The following example shows how to turn on automatic reoptimization whenever an interface becomes operational:


Router(config)# mpls traffic-eng reoptimize events link-up

Related Commands


Command	Description
mpls traffic-eng logging lsp	Controls the frequency with which tunnels with established LSPs are checked for better LSPs.
mpls traffic-eng reoptimize	Reoptimizes all traffic engineering tunnels immediately.
mpls traffic-eng reoptimize timers delay	Delays removal of old LSPs or installation of new LSPs after tunnel reoptimization.

mpls traffic-eng reoptimize timers delay

To delay the removal of old label switched paths (LSPs) or installation of new LSPs after tunnel reoptimization, use the mpls traffic-eng reoptimize timers delay command in global configuration mode. To restore the default value, use the no form of this command.

mpls traffic-eng reoptimize timers delay {cleanup delay-time | installation delay-time}

no mpls traffic-eng reoptimize timers delay {cleanup delay-time | installation delay-time}

Syntax Description


cleanup `delay-time`	Delays the removal of old LSPs after tunnel reoptimization for the specified number of seconds. The range is from 0 to 300. A value of 0 disables the delay. The default is 10.
installation `delay-time`	Delays the installation of new LSPs with new labels, for the specified number of seconds, after tunnel reoptimization. The range is from 0 to 3600. A value of 0 disables the delay. The default is 3.

Command Default

Removal of old LSPs and installation of new LSPs is not delayed.

Command Modes

Global configuration (config)

Command History


Release	Modification
12.0(32)S	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(33)SRA	This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2(33)SRE7	This command was integrated into Cisco IOS Release 12.2(33)SRE7. The maximum value for the cleanup `delay-time` argument was changed from 60 to 300 seconds.
15.0(1)S6	This command was modified. The maximum value for the cleanup `delay-time` argument was changed from 60 to 300 seconds.

Usage Guidelines

A device with Multiprotocol Label Switching traffic engineering (MPLS-TE) tunnels periodically examines tunnels with established LSPs to discover if more efficient LSPs (paths) are available. If a better LSP is available, the device signals the more efficient LSP. If the signaling is successful, the device replaces the older LSP with the new, more efficient LSP.

Sometimes, the slower router-point nodes may not utilize the new label’s forwarding plane. In this case, if the headend node replaces the labels quickly, packet loss can occur. The packet loss is avoided by delaying the cleanup of the old LSP by using the mpls traffic-eng reoptimize timers delay cleanup command. Until the cleanup of the old LSP is performed, subsequent reoptimizations for the tunnel are prevented.

Examples

The following example shows how to set the reoptimization cleanup delay time to one minute:

Device# configure terminal
Device(config)# mpls traffic-eng reoptimize timers delay cleanup 60

The following example shows how to set the reoptimization installation delay time to one hour:

Device# configure terminal
Device(config)# mpls traffic-eng reoptimize timers delay installation 3600

Related Commands


Command	Description
mpls traffic-eng reoptimize	Forces immediate reoptimization of all traffic engineering tunnels.
mpls traffic-eng reoptimize events	Turns on automatic reoptimization of MPLS traffic engineering when certain events occur, such as when an interface becomes operational.
mpls traffic-eng reoptimize timers frequency	Controls the frequency with which tunnels with established LSPs are checked for better LSPs.

mpls traffic-eng reoptimize timers frequency

To control the frequency with which tunnels with established label switched paths (LSPs) are checked for better LSPs, use the mpls traffic-eng reoptimize timers frequency command in global configuration mode. To disable this function, use the no form of this command.

mpls traffic-eng reoptimize timers frequency seconds

no mpls traffic-eng reoptimize timers frequency

Syntax Description


`seconds`	Sets the frequency of reoptimization (in seconds). A value of 0 disables reoptimization. The range is 0 to 604800 seconds (1 week).

Command Default

3600 seconds (1 hour)

Command Modes

Global configuration (config)

Command History


Release	Modification
12.0(5)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.
12.2SX	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.

Usage Guidelines

A device with traffic engineering tunnels periodically examines tunnels with established LSPs to learn if better LSPs are available. If a better LSP seems to be available, the device attempts to signal the better LSP; if the signaling is successful, the device replaces the old, inferior LSP with the new, better LSP.

Note

If the lockdown keyword is specified with the tunnel mpls traffic-eng path-option command, then a reoptimize check is not done on the tunnel.

If you configure a traffic engineering tunnel with an explicit path that is not fully specified (a series of router IDs or a combination of router IDs and interface addresses), then reoptimization may not occur.

Note

If you specify a low reoptimization frequency (for example, less than 30 seconds), there may be an increase in CPU utilization for configurations with a large number of traffic engineering tunnels.

Examples

The following example shows how to set the reoptimization frequency to 1 day:


Router(config)# mpls traffic-eng reoptimize timers frequency 86400

Related Commands


Command	Description
mpls traffic-eng reoptimize	Reoptimizes all traffic engineering tunnels immediately.
mpls traffic-eng reoptimize timers delay	Delays removal of old LSPs or installation of new LSPs after tunnel reoptimization.
tunnel mpls traffic-eng path-option	Configures a path option for an MPLS traffic engineering tunnel.

mpls traffic-eng router-id

To specify that the traffic engineering router identifier for the node is the IP address associated with a given interface, use the mpls traffic-eng router-id command in router configuration mode. To remove the traffic engineering router identifier, use the no form of this command.

mpls traffic-eng router-id interface-name

no mpls traffic-eng router-id

Syntax Description


`interface-name`	Interface whose primary IP address is the router’s identifier.

Command Default

No traffic engineering router identifier is specified.

Command Modes

Router configuration (config-router)

Command History


Release	Modification
12.0(5)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.
12.2SX	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.
Cisco IOS XE Release 2.3	This command was integrated into Cisco IOS XE Release 2.3.
15.2(2)SNG	This command was integrated into Cisco ASR 901 Series Aggregation Services Routers.

Usage Guidelines

This router identifier acts as a stable IP address for the traffic engineering configuration. This IP address is flooded to all nodes. For all traffic engineering tunnels originating at other nodes and ending at this node, you must set the tunnel destination to the traffic engineering router identifier of the destination node, because that is the address that the traffic engineering topology database at the tunnel head uses for its path calculation.

You should configure the same traffic engineering router id for all Interior Gateway Protocol (IGP) routing processes.

Examples

The following example shows how to specify the traffic engineering router identifier as the IP address associated with interface Loopback0:


Router(config-router)# mpls traffic-eng router-id Loopback0

Related Commands


Command	Description
mpls atm control-vc	Turns on flooding of MPLS traffic engineering link information in the indicated IGP level/area.

mpls traffic-eng scanner

To specify how often Intermediate System-to-Intermediate System (IS-IS) extracts traffic engineering type, length, values (TLVs) objects from flagged label switched paths (LSPs) and passes them to the traffic engineering topology database, and the maximum number of LSPs that the router can process immediately, use the mpls traffic-eng scanner command in router configuration mode. To disable the frequency that IS-IS extracts traffic engineering TLVs and the maximum number of LSPs IS-IS passes to the traffic engineering topology database, use the no form of this command.

mpls traffic-eng scanner [interval seconds] [max-flash LSPs]

no mpls traffic-eng scanner

Syntax Description


interval `seconds`	(Optional) Frequency, in seconds, at which IS-IS sends traffic engineering TLVs into the traffic engineering database. The range is 1 to 60. The default value is 5.
max-flash `LSPs`	(Optional) Maximum number of LSPs that the router can process immediately without incurring a delay. The range is 0 to 200. The default value is 15.

Command Default

IS-IS sends traffic engineering TLVs into the traffic engineering topology database every 5 seconds after the first 15 LSPs are processed.

Command Modes

Router configuration (config-router)

Command History


Release	Modification
12.0(14)ST	This command was introduced.
12.2(11)S	This command was integrated into Cisco IOS Release 12.2(11)S.
12.0(22)S	This command was integrated into Cisco IOS Release 12.0(22)S.
12.4(2)T	This command was integrated into Cisco IOS Release 12.4(2)T.
12.4	This command was integrated into Cisco IOS Release 12.4.
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.
12.2SX	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

When IS-IS receives a new LSP, it inserts it into the IS-IS database. If the LSP contains traffic engineering TLVs, IS-IS flags the LSPs for transmission to the traffic engineering database. Depending on the default or user-specified interval, traffic engineering TLVs are extracted and sent to the traffic engineering database. Users can also specify the maximum number of LSPs that the router can process immediately. Processing entails checking for traffic engineering TLVs, extracting them, and passing them to the traffic engineering database. If more than 50 LSPs need to be processed, there is a delay of 5 seconds for subsequent LSPs.

The first 15 LSPs are sent without a delay into the traffic engineering database. If more LSPs are received, the default delay of 5 seconds applies.

If you specify the no form of this command, there is a delay of 5 seconds before IS-IS scans its database and passes traffic engineering TLVs associated with flagged LSPs to the traffic engineering database

Examples

In the following example, the router is allowed to process up to 50 IS-IS LSPs without any delay.


Router(config)# router isis
Router(config-router)# mpls traffic-eng scanner interval 5 max-flash 50

Related Commands


Command	Description
mpls traffic-eng	Configures a router running IS-IS so that it floods MPLS traffic engineering link information into the indicated IS-IS level.
mpls traffic-eng router-id	Specifies that the traffic engineering router identifier for the node is the IP address associated with a given interface.
router isis	Enables the IS-IS routing protocol and specifies an IS-IS process.

mpls traffic-eng signalling advertise explicit-null

Note

Effective with Cisco IOS Release 15.2(2)S, the mpls traffic-eng signalling advertise implicit-null command is deprecated by the mpls traffic-eng signalling advertise explicit-null command because the IOS MPLS-TE tail router now advertises the implicit-null label in signaling messages sent to neighbors by default. Prior to this release, the IOS MPLS-TE tail router advertised the explicit-null label by default.

To configure the MPLS-TE tail router to override the new default (implicit-null label) to use the MPLS encoding for the explicit-null label in signaling messages advertised to neighbors, use the mpls traffic-eng signalling advertise explicit-null command in global configuration mode. To disable this feature, use the no form of this command.

mpls traffic-eng signalling advertise explicit-null [acl-number]

no mpls traffic-eng signalling advertise explicit-null

Syntax Description


`acl-number`	(Optional) Matches the number of the IP access list to determine applicable signalling peers.

Command Default

The IOS MPLS-TE tail router now advertises the implicit-null label in signaling messages sent to neighbors.

Command Modes

Global configuration (config)#

Command History


Release	Modification
15.2(2)S	This command was introduced. This command replaces the mpls traffic-eng signalling advertise implicit-null command.
Cisco IOS-XE Release 3.6	This command was introduced.

Usage Guidelines

If the mpls traffic-eng signalling advertise implicit-null command exists your configuration we recommend that you remove it from your configuration.

The mpls traffic-eng signalling advertise explicit-null command is used on an IOS or IOS-XE MPLS-TE tail router to advertise explicit-null label in signaling messages. If the mpls traffic-eng signalling advertise explicit-null command is not configured, an implicit-null label (IETF label 3) is advertised in signaling messages.

Examples

The following example shows how to configure the router to use MPLS encoding for the explicit-null label when it sends signaling messages to all peers:


Router(config)# mpls traffic-eng signalling advertise explicit-null

mpls traffic-eng signalling advertise implicit-null

Note

Effective with Cisco IOS Release 15.2(2)S, the mpls traffic-eng signalling advertise implicit-null command is deprecated by the mpls traffic-eng signalling advertise explicit-null command because the IOS MPLS-TE tail router now advertises the implicit-null label in signaling messages sent to neighbors by default. Prior to this release, the IOS MPLS-TE tail router advertised the explicit-null label by default. See the mpls traffic-eng signalling advertise explicit-null command if you want to configure the IOS MPLS-TE tail router to override the new default (implicit-null label) and advertise the explicit-null label to neighbors instead.

To use MPLS encoding for the implicit-null label in signaling messages sent to neighbors, use the mpls traffic-eng signalling advertise implicit-null command in global configuration mode. To disable this feature, use the no form of this command.

mpls traffic-eng signalling advertise implicit-null [acl-number]

no mpls traffic-eng signalling advertise implicit-null

Syntax Description


`acl-number`	(Optional) Matches the number of the IP access list to determine applicable signalling peers.

Command Default

None

Command Modes

Global configuration (config)#

Command History


Release	Modification
12.0(5)ST	This command was introduced.
12.1(3)T	This command was integrated into Cisco IOS Release 12.1(3)T.
12.0(22)S	This command was integrated into Cisco IOS Release 12.0(22)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.
12.2SX	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.
15.2(2)S	This command was replaced by the mpls traffic-eng signalling advertise explicit-null command.

Usage Guidelines

The mpls traffic-eng signalling advertise implicit-null command is typically used on an IOS MPLS-TE tail router to advertise the IETF implicit-null label "3" signalling message to an non-IOS router.

Examples

The following example shows how to configure the router to use MPLS encoding for the implicit-null label when it sends signaling messages to certain peers:


Router(config)# mpls traffic-eng signalling advertise implicit-null

mpls traffic-eng srlg

To configure the Shared Risk Link Group (SRLG) membership of a link (interface), use the mpls traffic-eng srlg command in interface configuration mode. To remove a link from membership of one or more SRLGs, use the no form of this command.

mpls traffic-eng srlg [num]

no mpls traffic-eng srlg [num]

Syntax Description


`num`	(Optional) SRLG identifier. The range is 0 to 4294967295.

Command Default

A link does not have membership in any SRLG.

Command Modes

Interface configuration (config-if)

Command History


Release	Modification
12.0(28)S	This command was introduced.
12.4(20)T	This command was integrated into Cisco IOS Release 12.4(20)T.
Cisco IOS XE Release 3.5S	This command was integrated into Cisco IOS XE Release 3.5S.

Usage Guidelines

You can enter the mpls traffic-eng srlg command multiple times to make a link a member of multiple SRLGs.

Examples

The following example makes the interface a member of SRLG 5:


Router(config-if)# mpls traffic-eng srlg 5

If you enter the following commands, the interface is a member of both SRLG 5 and SRLG 6:


Router(config-if)# mpls traffic-eng srlg 5
Router(config-if)# mpls traffic-eng srlg 6

To remove a link from membership of SRLG 5, enter the following command:


Router(config-if)# no mpls traffic-eng srlg 5

To remove a link from membership of all SRLGs, enter the following command:


Router(config-if)# no mpls traffic-eng srlg

Related Commands


Command	Description
mpls traffic-eng auto-tunnel backup srlg exclude	Specifies that autocreated backup tunnels should avoid SRLGs of the protected interface.

mpls traffic-eng topology holddown sigerr

To specify the amount of time that a router ignores a link in its traffic engineering topology database in tunnel path Constrained Shortest Path First (CSPF) computations following a traffic engineering tunnel error on the link, use the mpls traffic-eng topology holddown sigerr command in global configuration mode. To disable the time set to ignore a ink following a traffic engineering tunnel error on the link, use the no form of this command.

mpls traffic-eng topology holddown sigerr seconds

no mpls traffic-eng topology holddown sigerr

Syntax Description


`seconds`	Length of time (in seconds) a router should ignore a link during tunnel path calculations following a traffic engineering tunnel error on the link. The range is 0 to 300.

Command Default

If you do not specify this command, tunnel path calculations ignore a link on which there is a traffic engineering error until either 10 seconds have elapsed or a topology update is received from the Interior Gateway Protocol (IGP).

Command Modes

Global configuration (config)

Command History


Release	Modification
12.0(14)ST	This command was introduced.
12.2(11)S	This command was integrated into Cisco IOS Release 12.2(11)S.
12.0(22)S	This command was integrated into Cisco IOS Release 12.0(22)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.
12.2SX	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

A router that is at the headend for traffic engineering tunnels might receive a Resource Reservation Protocol (RSVP) No Route error message for an existing tunnel or for one being signaled due to the failure of a link the tunnel traffic traverses before the router receives a topology update from the IGP routing protocol announcing that the link is down. In such a case, the headend router ignores the link in subsequent tunnel path calculations to avoid generating paths that include the link and are likely to fail when signaled. The link is ignored until the router receives a topology update from its IGP or a link hold-down timeout occurs. You can use the mpls traffic-eng topology holddown sigerr command to change the link hold-down time from its 10-second default value.

Examples

In the following example, the link hold-down time for signaling errors is set at 15 seconds:


Router(config)# mpls traffic-eng topology holddown sigerr 15

Related Commands


Command	Description
show mpls traffic-eng topology	Displays the MPLS traffic engineering global topology as currently known at the node.

mpls traffic-eng tunnels (global configuration)

To enable Multiprotocol Label Switching (MPLS) traffic engineering tunnel signaling on a device, use the mpls traffic-eng tunnels command in global configuration mode. To disable MPLS traffic engineering tunnel signaling, use the no form of this command.

mpls traffic-eng tunnels

no mpls traffic-eng tunnels

Syntax Description

This command has no arguments or keywords.

Command Default

The command is disabled.

Command Modes

Global configuration (config)

Command History


Release	Modification
12.0(5)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.
12.2SX	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.
Cisco IOS XE Release 2.3	This command was integrated into Cisco IOS XE Release 2.3.

Usage Guidelines

This command enables MPLS traffic engineering on a device. For you to use the feature, MPLS traffic engineering must also be enabled on the desired interfaces.

Examples

The following example shows how to turn on MPLS traffic engineering tunnel signaling:


Router(config)# mpls traffic-eng tunnels

Related Commands


Command	Description
mpls traffic-eng tunnels (interface configuration)	Enables MPLS traffic engineering tunnel signaling on an interface.

mpls traffic-eng tunnels (interface configuration)

To enable Multiprotocol Label Switching (MPLS) traffic engineering (TE) tunnel signaling on an interface (assuming that it is enabled on the device), use the mpls traffic-eng tunnels command in interface configuration mode. To disable MPLS traffic engineering tunnel signaling on the interface, use the no form of this command.

mpls traffic-eng tunnels

no mpls traffic-eng tunnels

Syntax Description

This command has no arguments or keywords.

Command Default

The MPLS TE is disabled on all interfaces.

Command Modes

Interface configuration (config-if)

Command History


Release	Modification
12.0(5)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.
12.2SX	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.
Cisco IOS XE Release 3.3S	This command was integrated into Cisco IOS XE Release 3.3S.
15.2(1)T	This command was integrated into Cisco IOS Release 15.2(1)T.
15.2(2)SNG	This command was integrated into Cisco ASR 901 Series Aggregation Services Routers.

Usage Guidelines

Before you enable MPLS TE on the interface, you must enable MPLS TE on the device. An enabled interface has its resource information flooded into the appropriate Interior Gateway Protocol (IGP) link-state database and accepts traffic engineering tunnel signaling requests.

You can use this command to enable MPLS traffic engineering on an interface, thereby eliminating the need to use the ip rsvp bandwidth command. However, if your configuration includes Call Admission Control (CAC) for IPv4 Resource Reservation Protocol (RSVP) flows, you must use the ip rsvp bandwidth rsvp bandwidth command.

Examples

The following example shows how to enable MPLS traffic engineering on Ethernet interface 0/0:


Router(config)# interface Ethernet0/0
Router(config-if)# mpls traffic-eng tunnels

Related Commands


Command	Description
ip rsvp bandwidth	Enables RSVP for IP on an interface.
mpls traffic-eng tunnels (global configuration)	Enables MPLS traffic engineering tunnel signaling on a device.

mpls ttl-dec

To specify standard Multiprotocol Label Switching (MPLS) tagging, use the mpls ttl-dec command in global configuration mode. To return to the default settings, use the no form of this command.

mpls ttl-dec

no mpls ttl-dec

Syntax Description

This command has no arguments or keywords.

Command Default

Optimized MPLS tagging (no mpls ttl-dec ).

Command Modes

Global configuration (config)

Command History


Release	Modification
12.2(18)SXE	This command was introduced on the Supervisor Engine 720.
12.2(33)SRA	This command was integrated into Cisco IOS Release 12.2(33)SRA.

Usage Guidelines

In Cisco IOS Release 12.2(18)SXE and later releases, MPLS tagging has been optimized to allow the rewriting of the original packet’s IP type of service (ToS) and Time to Live (TTL) values before the MPLS label is pushed onto the packet header. This change can result in a slightly lower performance for certain types of traffic. If the packet’s original ToS/TTL values are not significant, you enter the mpls ttl-dec command for standard MPLS tagging.

Examples

This example shows how to configure the Cisco 7600 series router to use standard MPLS tagging behavior:


Router(config)# mpls ttl-dec
Router(config)#

This example shows how to configure the Cisco 7600 series router to use optimized MPLS tagging behavior:


Router(config)# no mpls ttl-dec
Router(config)#

Related Commands


Command	Description
mpls l2transport route	Enables routing of Layer 2 packets over MPLS.

mtu

To adjust the maximum packet size or maximum transmission unit (MTU) size, use the mtu command in interface configuration mode, connect configuration mode, or xconnect subinterface configuration mode. To restore the MTU value to its original default value, use the no form of this command.

mtu bytes

no mtu

Syntax Description


`bytes`	MTU size, in bytes.

Command Default

The table below lists default MTU values according to media type.

Table 1. Default Media MTU Values
Media Type	Default MTU (Bytes)
Ethernet	1500
Serial	1500
Token Ring	4464
ATM	4470
FDDI	4470
HSSI (HSA)	4470

Command Modes

Interface configuration (config-if)
Connect configuration (xconnect-conn-config)
xconnect subinterface configuration (config-if-xconn)

Command History


Release	Modification
10.0	This command was introduced.
12.0(26)S	This command was modified. This command was updated to support the connect configuration mode for Frame Relay Layer 2 interworking.
12.2(14)SX	This command was integrated into Cisco IOS Release 12.2(14)SX. Support for this command was introduced on the Supervisor Engine 720.
12.2(17d)SXB	This command was modified. Support for this command was introduced on the Supervisor Engine 2.
12.2(33)SRA	This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.4(11)T	This command was integrated into Cisco IOS Release 12.4(11)T.
12.2(33)SCB	This command was integrated into Cisco IOS Release 12.2(33)SCB.
Cisco IOS XE Release 2.4	This command was integrated into Cisco IOS XE Release 2.4. This command supports xconnect subinterface configuration mode.
Cisco IOS XE Release 3.7S	This command was modified as part of the MPLS-based Layer 2 VPN (L2VPN) command modifications for cross-OS support. This command was made available in template configuration mode.
15.3(1)S	This command was integrated in Cisco IOS Release 15.3(1)S.

Usage Guidelines

Each interface has a default maximum packet size or MTU size. This number generally defaults to the largest size possible for that interface type. On serial interfaces, the MTU size varies but cannot be set to a value less than 64 bytes.

Note

The connect configuration mode is used only for Frame Relay Layer 2 interworking.

Changing the MTU Size

Changing the MTU size is not supported on a loopback interface.

Changing the MTU size on a Cisco 7500 series router results in the recarving of buffers and resetting of all interfaces. The following message is displayed: RSP-3-Restart:cbus complex .

You can configure native Gigabit Ethernet ports on the Cisco 7200 series router to a maximum MTU size of 9216 bytes. The MTU values range from 1500 to 9216 bytes. The MTU values can be configured to any range that is supported by the corresponding main interface.

MTU Size for an IPSec Configuration

In an IPSec configuration, such as in a crypto environment, an MTU value that is less than 256 bytes is not accepted. If you configure an MTU value less than 256 bytes, then the MTU value is automatically overwritten and given a value of 256 bytes.

Protocol-Specific Versions of the mtu Command

Changing the MTU value with the mtu interface configuration command can affect values for the protocol-specific versions of the command (the ip mtu command, for example). If the value specified with the ip mtu interface configuration command is the same as the value specified with the mtu interface configuration command, and you change the value for the mtu interface configuration command, the ip mtu value automatically matches the new mtu interface configuration command value. However, changing the values for the ip mtu configuration commands has no effect on the value for the mtu interface configuration command.

ATM and LANE Interfaces

ATM interfaces are not bound by what is configured on the major interface. By default, the MTU on a subinterface is equal to the default MTU (4490 bytes). A client is configured with the range supported by the corresponding main interface. The MTU can be changed on subinterfaces, but it may result in recarving of buffers to accommodate the new maximum MTU on the interface.

VRF-Aware Service Infrastructure Interfaces

The mtu command does not support the VRF-Aware Service Infrastructure (VASI) type interface.

Cisco 7600 Valid MTU Values

On the Cisco 7600 platform, the following valid values are applicable:

For the SVI ports: from 64 to 9216 bytes
For the GE-WAN+ ports: from 1500 to 9170 bytes
For all other ports: from 1500 to 9216 bytes

You can receive jumbo frames on access subinterfaces also. The MTU values can be configured to any range that is supported by the corresponding main interface. If you enable the jumbo frames, the default is 64 bytes for the SVI ports and 9216 bytes for all other ports. The jumbo frames are disabled by default.

Cisco uBR10012 Universal Broadband Router

While configuring the interface MTU size on a Gigabit Ethernet SPA on a Cisco uBR10012 router, consider the following guidelines:

The default interface MTU size accommodates a 1500-byte packet, plus 22 additional bytes to cover the following overhead:
- Layer 2 header--14 bytes
- Dot1Q header--4 bytes
- CRC--4 bytes
If you are using MPLS, be sure that the mpls mtu command is configured with a value less than or equal to the interface MTU.
If you are using MPLS labels, you should increase the default interface MTU size to accommodate the number of MPLS labels. Each MPLS label adds 4 bytes of overhead to a packet.

Note

For the Gigabit Ethernet SPAs on the Cisco uBR10012 router, the default MTU size is 1500 bytes. When the interface is being used as a Layer 2 port, the maximum configurable MTU is 9000 bytes.

Examples

The following example shows how to specify an MTU of 1000 bytes:


Device(config)# interface serial 1
Device(config-if)# mtu 1000

Examples

The following example shows how to specify an MTU size on a Gigabit Ethernet SPA on the Cisco uBR10012 router:


Device(config)# interface GigabitEthernet3/0/0
Device(config-if)# mtu 1800

Examples

The following example shows how to specify an MTU size on a pseudowire interface:


Device(config)#  interface pseudowire 100
Device(config-if)# encapsulation mpls
Device(config-if)# mtu 1800

Examples

The following example shows how to configure a template and specify an MTU size in template configuration mode: :


Device(config)#  template type pseudowire template1
Device(config-if)# encapsulation mpls
Device(config-if)# mtu 1800

Related Commands


Command	Description
encapsulation (pseudowire)	Specifies an encapsulation type for tunneling Layer 2 traffic over a pseudowire.
encapsulation smds	Enables SMDS service on the desired interface.
ip mtu	Sets the MTU size of IP packets sent on an interface.

name (MST)

To set the name of a Multiple Spanning Tree (MST) region, use the name command in MST configuration submode. To return to the default name, use the no form of this command.

name name

no name name

Syntax Description


name	Name to give the MST region. It can be any string with a maximum length of 32 characters.

Command Default

Empty string

Command Modes

MST configuration (config-mst)

Command History


Release	Modification
12.2(14)SX	Support for this command was introduced on the Supervisor Engine 720.
12.2(17d)SXB	Support for this command on the Supervisor Engine 2 was extended to Release 12.2(17d)SXB.
12.2(33)SRA	This command was integrated into Cisco IOS Release 12.2(33)SRA.
Cisco IOS XE Release XE 3.7S	This command was integrated into Cisco IOS XE Release XE 3.7S.

Usage Guidelines

Two or more Cisco 7600 series routers with the same VLAN mapping and configuration version number are considered to be in different MST regions if the region names are different.

Caution

Be careful when using the name command to set the name of an MST region. If you make a mistake, you can put the Cisco 7600 series router in a different region. The configuration name is a case-sensitive parameter.

Examples

This example shows how to name a region:

Device(config-mst)# name Cisco
Device(config-mst)#

Related Commands


Command	Description
instance	Maps a VLAN or a set of VLANs to an MST instance.
revision	Sets the revision number for the MST configuration.
show	Verifies the MST configuration.
show spanning-tree mst	Displays the information about the MST protocol.
spanning-tree mst configuration	Enters MST configuration submode.

neighbor (MPLS)

To specify the peer IP address and virtual circuit (VC) ID value of a Layer 2 VPN (L2VPN) pseudowire, use the neighbor command in interface configuration mode. To remove the peer IP address and VC ID value of an L2VPN pseudowire, use the no form of this command.

neighbor peer-address vcid-value

no neighbor

Syntax Description


`peer-address`	IP address of the provider edge (PE) peer.
`vcid-value`	VC ID value. The range is from 1 to 4294967295.

Command Default

Peer address and VC ID value of a pseudowire are not specified.

Command Modes

Interface configuration (config-if)

Command History


Release	Modification
Cisco IOS XE Release 3.7S	This command was introduced as part of the Multiprotocol Label Switching (MPLS)-based L2VPN command modifications for cross-OS support. This command will replace the `peer-ip-addressandvc-id` arguments in the xconnect command in future releases.
15.3(1)S	This command was integrated in Cisco IOS Release 15.3(1)S.

Usage Guidelines

You must configure the neighbor command for the pseudowire to be functional.

Examples

The following example shows how to specify a peer IP address of 10.1.2.3 and VC ID value of 100.

Device(config)# interface pseudowire 100
Device(config-if)# neighbor 10.1.2.3 100

Related Commands


Command	Description
label (interface pseudowire)	Configures an AToM static pseudowire connection by defining local and remote circuit labels.
neighbor (L2VPN Pseudowire Switching)	Specifies the routers that should form a point-to-point L2 VFI connection.

neighbor activate

To enable the exchange of information with a Border Gateway Protocol (BGP) neighbor, use the neighbor activate command in address family configuration mode or router configuration mode. To disable the exchange of an address with a BGP neighbor, use the no form of this command.

neighbor {ip-address | peer-group-name | ipv6-address%}activate

no neighbor {ip-address | peer-group-name | ipv6-address%}activate

Syntax Description


`ip-address`	IP address of the neighboring router.
`peer-group-name`	Name of the BGP peer group.
`ipv6-address`	IPv6 address of the BGP neighbor.
%	(Optional) IPv6 link-local address identifier. This keyword needs to be added whenever a link-local IPv6 address is used outside the context of its interface.

Command Default

The exchange of addresses with BGP neighbors is enabled for the IPv4 address family. Enabling address exchange for all other address families is disabled.

Note

Address exchange for address family IPv4 is enabled by default for each BGP routing session configured with the neighbor remote-as command unless you configure the no bgp default ipv4-activate command before configuring the neighbor remote-as command, or you disable address exchange for address family IPv4 with a specific neighbor by using the no neighbor activate command.

Command Modes

Address family configuration (config-router-af)

Router configuration (config-router)

Command History


Release	Modification
11.0	This command was introduced.
12.0(5)T	Support for address family configuration mode and the IPv4 address family was added.
12.2(2)T	The `ipv6-address` argument and support for the IPv6 address family were added.
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)SRB	The % keyword was added
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.
15.1(2)SNG	This command was implemented on the Cisco ASR 901 Series Aggregation Services Routers.

Usage Guidelines

Use this command to advertise address information in the form of an IP or IPv6 prefix. The address prefix information is known as Network Layer Reachability Information (NLRI) in BGP.

The % keyword is used whenever link-local IPv6 addresses are used outside the context of their interfaces. This keyword does not need to be used for non-link-local IPv6 addresses.

Note

The use of the no form of the neighbor activate command will remove all configurations associated with the neighbor both inside and outside address family configuration mode. This command is not the same as the neighbor shutdown command, and you should not use this command to disconnect a BGP adjacency.

Examples

The following example shows how to enable address exchange for address family vpnv4 for all neighbors in the BGP peer group named PEPEER and for the neighbor 10.0.0.44:


Router(config)# address-family vpnv4
Router(config-router-af)# neighbor PEPEER activate
Router(config-router-af)# neighbor 10.0.0.44 activate
Router(config-router-af)# exit-address-family

Examples

The following example shows how to enable address exchange for address family IPv4 unicast for all neighbors in the BGP peer group named group1 and for the BGP neighbor 172.16.1.1:


Device(config)# address-family ipv4 unicast
Device(config-router-af)# neighbor group1 activate
Device(config-router-af)# neighbor 172.16.1.1 activate

Examples

The following example shows how to enable address exchange for address family IPv6 for all neighbors in the BGP peer group named group2 and for the BGP neighbor 7000::2:


Device(config)# address-family ipv6
Device(config-router-af)# neighbor group2 activate
Device(config-router-af)# neighbor 7000::2 activate

The following example shows that the no command will remove all configurations associated with a neighbor both inside and outside the address family configuration mode. The first set of commands shows the configuration for a specific neighbor.


Device(config)# router bgp 64496
Device(config-router)# bgp log neighbor changes
Device(config-router)# neighbor 10.0.0.1 remote-as 64497
Device(config-router)# neighbor 10.0.0.1 update-source Loopback0
Device(config-router)# address-family ipv4
Device(config-router-af)# no synchronization
Device(config-router-af)# no neighbor 10.0.0.1 activate
Device(config-router-af)# no auto-summary
Device(config-router-af)# exit-address-family
Device(config-router)address-family vpnv4
Device(config-router-af)# neighbor 10.0.0.1 activate
Device(config-router-af)# neighbor 10.0.0.1 send-community extended
Device(config-router-af)# exit-address-family
Device(config-router)# address-family ipv4 vrf vrf1
Device(config-router-af)# no synchronization
Device(config-router-af)# redistribute connected
Device(config-router-af)# neighbor 192.168.1.4 remote-as 100
Device(config-router-af)# neighbor 192.168.1.4 version 4
Device(config-router-af)# neighbor 192.168.1.4 activate
Device(config-router-af)# neighbor 192.168.1.4 weight 200
Device(config-router-af)# neighbor 192.168.1.4 prefix-list test out
Device(config-router-af)# exit-address-family

The following example shows the router configuration after the use of the no command.


Device(config)# router bgp 64496
Device(config-router)# address-family ipv4 vrf vrf1
Device(config-router-af)# no neighbor 192.168.1.4 activate
01:01:19: %BGP_SESSION-5-ADJCHANGE: neighbor 192.168.1.4 IPv4 Unicast vpn vrf vrf1 topology base removed from session  Neighbor deleted
01:01:19: %BGP-5-ADJCHANGE: neighbor 192.168.1.4 vpn vrf vrf1 Down Neighbor deleted
Device(config-router-af)# do show running-config | begin router bgp 

router bgp 64496
bgp log-neighbor-changes
neighbor 10.0.0.1 remote-as 64496
neighbor 10.0.0.1 update-source Loopback0
!
address-family ipv4
  no synchronization
  no neighbor 10.0.0.1 activate
  no auto-summary
exit-address-family
!
address-family vpnv4
  neighbor 10.0.0.1 activate
  neighbor 10.0.0.1 send-community extended
exit-address-family
!
address-family ipv4 vrf vrf1
  no synchronization
  redistribute connected
exit-address-family

This example shows the router configuration when the neighbor is reactivated.


Device(config)# router bgp 64496
Device(config-router)# address-family ipv4 vrf vrf1
Device(config-router-af)# neighbor 192.168.1.4 activate
01:02:26: %BGP-5-ADJCHANGE: neighbor 192.168.1.4 vpn vrf vrf1 Up
Device(config-router-af)# do show running-config | begin router bgp 

router bgp 64496
bgp log-neighbor-changes
neighbor 10.0.0.1 remote-as 64496
neighbor 10.0.0.1 update-source Loopback0
!
address-family ipv4
  no synchronization
  no neighbor 10.0.0.1 activate
  no auto-summary
exit-address-family
!
address-family vpnv4
  neighbor 10.0.0.1 activate
  neighbor 10.0.0.1 send-community extended
exit-address-family
!
address-family ipv4 vrf vrf1
  no synchronization
  redistribute connected
  neighbor 192.168.1.4 remote-as 100
  neighbor 192.168.1.4 version 4
  neighbor 192.168.1.4 activate
exit-address-family

Related Commands


Command	Description
address-family ipv4	Places the router in address family configuration mode for configuring routing sessions, such as BGP, that use standard IPv4 address prefixes.
address-family ipv6	Places the router in address family configuration mode for configuring routing sessions, such as BGP, that use standard IPv6 address prefixes.
address-family vpnv4	Places the router in address family configuration mode for configuring routing sessions, such as BGP, that use standard VPNv4 address prefixes.
address-family vpnv6	Places the router in address family configuration mode for configuring routing sessions, such as BGP, that use standard VPNv6 address prefixes.
exit-address-family	Exits from the address family submode.
neighbor remote-as	Adds an entry to the BGP or multiprotocol BGP neighbor table.

neighbor allowas-in

To configure provider edge (PE) routers to allow readvertisement of all prefixes containing duplicate autonomous system numbers (ASNs), use the neighbor allowas-in command in router configuration mode. To disable the readvertisement of the ASN of the PE router, use the no form of this command.

neighbor ip-address allowas-in [number]

no neighbor allowas-in [number]

Syntax Description


`ip-address`	IP address of the neighboring router.
`number`	(Optional) Specifies the number of times to allow the advertisement of a PE router’s ASN. The range is 1 to 10. If no number is supplied, the default value of 3 times is used.

Command Default

Readvertisement of all prefixes containing duplicate ASNs is disabled by default.

Command Modes

Router configuration (config-router)

Command History


Release	Modification
12.0(7)T	This command was introduced.
12.1	This command was integrated into Cisco IOS Release 12.1.
12.2	This command was integrated into Cisco IOS Release 12.2.
12.3	This command was integrated into Cisco IOS Release 12.3.
12.3T	This command was integrated into Cisco IOS Release 12.3T.
12.4	This command was integrated into Cisco IOS Release 12.4.
12.4T	This command was integrated into Cisco IOS Release 12.4T.
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.

Usage Guidelines

In a hub and spoke configuration, a PE router readvertises all prefixes containing duplicate autonomous system numbers. Use the neighbor allowas-in command to configure two VRFs on each PE router to receive and readvertise prefixes are as follows:

One Virtual Private Network routing and forwarding (VRF) instance receives prefixes with ASNs from all PE routers and then advertises them to neighboring PE routers.
The other VRF receives prefixes with ASNs from the customer edge (CE) router and readvertises them to all PE routers in the hub and spoke configuration.

You control the number of times an ASN is advertised by specifying a number from 1 to 10.

Examples

The following example shows how to configure the PE router with ASN 100 to allow prefixes from the VRF address family Virtual Private Network (VPN) IPv4 vrf1. The neighboring PE router with the IP address 192.168.255.255 is set to be readvertised to other PE routers with the same ASN six times.


Router(config)# router bgp 100
Router(config-router)# address-family ipv4 vrf vrf1
Router(config-router)# neighbor 192.168.255.255 allowas-in 6

Related Commands


Command	Description
address-family	Enters the address family configuration submode used to configure routing protocols such as BGP, OSPF, RIP, and static routing.

neighbor as-override

To configure a provider edge (PE) router to override the autonomous system number (ASN) of a site with the ASN of a provider, use the neighbor as-override command in router configuration mode. To remove Virtual Private Network (VPN) IPv4 prefixes from a specified router, use the no form of this command.

neighbor ip-address as-override

no neighbor ip-address as-override

Syntax Description


`ip-address`	Specifies the IP address of the router that is to be overridden with the ASN provided.

Command Default

Automatic override of the ASN is disabled.

Command Modes

Router configuration

Command History


Release	Modification
12.0(7)T	This command was introduced.
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.

Usage Guidelines

This command is used in conjunction with the site-of-origin feature, identifying the site where a route originated, and preventing routing loops between routers within a VPN.

Examples

The following example shows how to configure a router to override the ASN of a site with the ASN of a provider:


Router(config)# router bgp 100
Router(config-router)# neighbor 192.168.255.255 remote-as 109
Router(config-router)# neighbor 192.168.255.255 update-source loopback0
Router(config-router)# address-family ipv4 vrf vpn1
Router(config-router)# neighbor 192.168.255.255 activate
Router(config-router)# neighbor 192.168.255.255 as-override

Related Commands


Command	Description
neighbor activate	Enables the exchange of information with a BGP neighboring router.
neighbor remote-as	Allows a neighboring router’s IP address to be included in the BGP routing table.
neighbor update-source	Allows internal BGP sessions to use any operational interface for TCP/IP connections.
route-map	Redistributes routes from one routing protocol to another.

neighbor inter-as-hybrid

To configure the Exterior Border Gateway Protocol (eBGP) peer router, which is the neighboring Autonomous System Boundary Router (ASBR), as an Inter-AS Option AB peer, use the neighbor inter-as-hybrid command in address family configuration mode. The Inter-AS Option AB feature is a hybrid of Inter-AS Option (10)A and Inter-AS Option (10)B network configurations, enabling the interconnection of different autonomous systems to provide Virtual Private Network (VPN) services. To remove the peer router configuration, use the no form of this command.

neighbor {ip-address | peer-group-name} inter-as-hybrid

no neighbor {ip-address | peer-group-name} inter-as-hybrid

Syntax Description


`ip-address`	The IP address of the Inter-AS AB neighbor.
`peer-group-name`	The name of a Border Gateway Protocol (BGP) peer group.

Command Default

No Inter-AS AB neighbor eBGP (ASBR) router is specified.

Command Modes

Address family configuration (config-router-af)

Command History


Release	Modification
12.2(33)SRC	This command was introduced.
15.0(1)M	This command was integrated into Cisco IOS Release 15.0(1)M.
15.0(1)S	This command was integrated into Cisco IOS Release 15.0(1)S.
15.0(1)SY	This command was integrated into Cisco IOS Release 15.0(1)SY.

Usage Guidelines

Advertised routes have the route targets (RTs) that are configured on the virtual private network (VPN) routing and forwarding (VRF) instance. Advertised routes do not have their original RTs.

If any prefixes are imported into Option AB VRFs, then the imported paths are advertised to this peer.

Examples

The following example shows how to configure an Inter-AS AB neighbor eBGP (ASBR) router:


Router(config)# router bgp 100
Router(config-router)# neighbor 192.168.0.1 remote-as 200
Router(config-router)# address-family vpnv4
Router(config-router-af)# neighbor 192.168.0.1 activate
Router(config-router-af)# neighbor 192.168.0.1 inter-as-hybrid

Related Commands


Command	Description
address-family vpnv4	Enters address family configuration mode for configuring routing sessions, such as BGP, that use standard VPNv4 address prefixes.
inter-as-hybrid	Specifies a VRF as an Option AB VRF.
neighbor	Adds an entry to the BGP or multiprotocol BGP neighbor table.
neighbor activate	Enables the exchange of information with a neighboring router.

neighbor override-capability-neg

To enable the IPv6 address family for a Border Gateway Protocol (BGP) neighbor that does not support capability negotiation, use the neighbor override-capability-neg command in address family configuration mode. To disable the IPv6 address family for a BGP neighbor that does not support capability negotiation, use the no form of this command.

neighbor {peer-group-name | ipv6-address} override-capability-neg

no neighbor {peer-group-name | ipv6-address} override-capability-neg

Syntax Description


`peer-group-name`	Name of a BGP peer group.
`ipv6-address`	IPv6 address of the BGP neighbor. This 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

Capability negotiation is enabled.

Command Modes

Address family 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

Capability negotiation is used to establish a connection between BGP-speaking peers. If one of the BGP peers does not support capability negotiation, the connection is automatically terminated. The neighbor override-capability-neg command overrides the capability negotiation process and enables BGP-speaking peers to establish a connection.

The neighbor override-capability-neg command is supported only in address family configuration mode for the IPv6 address family.

Examples

The following example enables the IPv6 address family for BGP neighbor 7000::2:


Router(config)# address-family ipv6
Router(config-router-af)# neighbor 7000::2 override-capability-neg

The following example enables the IPv6 address family for all neighbors in the BGP peer group named group1:


Router(config)# address-family ipv6
Router(config-router-af)# neighbor group1 override-capability-neg

Related Commands


Command	Description
address-family ipv6	Places the router in address family configuration mode for configuring routing sessions, such as BGP, that use standard IPv6 address prefixes.

neighbor remote-as

To add an entry to the BGP or multiprotocol BGP neighbor table, use the neighbor remote-as command in router configuration mode. To remove an entry from the table, use the no form of this command.

neighbor {ip-address | ipv6-address% | peer-group-name}remote-as autonomous-system-number [alternate-as autonomous-system-number ...]

no neighbor {ip-address | ipv6-address% | peer-group-name}remote-as autonomous-system-number [alternate-as autonomous-system-number ...]

Syntax Description


`ip-address`	IP address of the neighbor.
`ipv6-address`	IPv6 address of the neighbor.
%	(Optional) IPv6 link-local address identifier. This keyword needs to be added whenever a link-local IPv6 address is used outside the context of its interface.
`peer-group-name`	Name of a BGP peer group.
`autonomous-system-number`	Number of an autonomous system to which the neighbor belongs in the range from 1 to 65535. In Cisco IOS Release 12.0(32)SY8, 12.0(33)S3, 12.2(33)SRE, 12.2(33)XNE, 12.2(33)SXI1, Cisco IOS XE Release 2.4, and later releases, 4-byte autonomous system numbers are supported in the range from 65536 to 4294967295 in asplain notation and in the range from 1.0 to 65535.65535 in asdot notation. In Cisco IOS Release 12.0(32)S12, 12.4(24)T, and Cisco IOS XE Release 2.3, 4-byte autonomous system numbers are supported in the range from 1.0 to 65535.65535 in asdot notation only. For more details about autonomous system number formats, see the router bgp command. When used with the alternate-as keyword, up to five autonomous system numbers may be entered.
alternate-as	(Optional) Specifies an alternate autonomous system in which a potential dynamic neighbor can be identified. Up to five autonomous system numbers may be entered when this keyword is specified.

Command Default

There are no BGP or multiprotocol BGP neighbor peers.

Command Modes

Router configuration (config-router)

Command History


Release	Modification
10.0	This command was introduced.
11.0	The `peer-group-name` argument was added.
11.1(20)CC	The nlri unicast , nlri multicast , and nlri unicast multicast keywords were added.
12.0(7)T	The nlri unicast , nlri multicast , and nlri unicast multicast keywords were removed.
12.2(4)T	Support for the IPv6 address family was added.
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)SRB	This command was modified. The % keyword was added.
12.2(33)SXH	This command was integrated into Cisco IOS Release 12.2(33)SXH. The alternate-as keyword was added to support BGP dynamic neighbors.
12.2(33)SB	This command was integrated into Cisco IOS Release 12.2(33)SB.
Cisco IOS XE Release 2.1	This command was introduced on Cisco ASR 1000 Series Routers.
12.0(32)S12	This command was modified. Support for 4-byte autonomous system numbers in asdot notation only was added.
12.0(32)SY8	This command was modified. Support for 4-byte autonomous system numbers in asplain and asdot notation was added.
12.4(24)T	This command was modified. Support for 4-byte autonomous system numbers in asdot notation only was added.
Cisco IOS XE Release 2.3	This command was modified. Support for 4-byte autonomous system numbers in asdot notation only was added.
12.2(33)SXI1	This command was modified. Support for 4-byte autonomous system numbers in asplain and asdot notation was added.
12.0(33)S3	This command was modified. Support for asplain notation was added and the default format for 4-byte autonomous system numbers is now asplain.
Cisco IOS XE Release 2.4	This command was modified. Support for asplain notation was added and the default format for 4-byte autonomous system numbers is now asplain.
12.2(33)SRE	This command was modified. Support for 4-byte autonomous system numbers in asplain and asdot notation was added.
12.2(33)XNE	This command was modified. Support for 4-byte autonomous system numbers in asplain and asdot notation was added.
15.0(1)S	This command was integrated into Cisco IOS Release 15.0(1)S.
15.1(1)SG	This command was modified. Support for 4-byte autonomous system numbers in asplain and asdot notation was added.
Cisco IOS XE Release 3.3SG	This command was modified. Support for 4-byte autonomous system numbers in asplain and asdot notation was added.
15.1(2)SNG	This command was implemented on the Cisco ASR 901 Series Aggregation Services Routers.
15.2(1)E	This command was integrated into Cisco IOS Release 15.2(1)E.

Usage Guidelines

Specifying a neighbor with an autonomous system number that matches the autonomous system number specified in the router bgp global configuration command identifies the neighbor as internal to the local autonomous system. Otherwise, the neighbor is considered external.

If you specify a BGP peer group by using the peer-group-name argument, all the members of the peer group will inherit the characteristic configured with this command.

By default, neighbors that are defined using the neighbor remote-as command in router configuration mode exchange only unicast address prefixes. To exchange other address prefix types, such as multicast and Virtual Private Network (VPN) Version 4, neighbors must also be activated in the appropriate address family configuration mode.

Use the alternate-as keyword introduced in Cisco IOS Release 12.2(33)SXH to specify up to five alternate autonomous systems in which a dynamic BGP neighbor may be identified. BGP dynamic neighbor support allows BGP peering to a group of remote neighbors that are defined by a range of IP addresses. BGP dynamic neighbors are configured using a range of IP addresses and BGP peer groups. After a subnet range is configured and associated with a BGP peer group using the bgp listen command and a TCP session is initiated for an IP address in the subnet range, a new BGP neighbor is dynamically created as a member of that group. The new BGP neighbor will inherit any configuration or templates for the group.

The % keyword is used whenever link-local IPv6 addresses are used outside the context of their interfaces. This keyword does not need to be used for non-link-local IPv6 addresses.

In Cisco IOS Release 12.0(32)SY8, 12.0(33)S3, 12.2(33)SRE, 12.2(33)XNE, 12.2(33)SXI1, Cisco IOS XE Release 2.4, and later releases, the Cisco implementation of 4-byte autonomous system numbers uses asplain--65538 for example--as the default regular expression match and output display format for autonomous system numbers, but you can configure 4-byte autonomous system numbers in both the asplain format and the asdot format as described in RFC 5396. To change the default regular expression match and output display of 4-byte autonomous system numbers to asdot format, use the bgp asnotation dot command followed by the clear ip bgp * command to perform a hard reset of all current BGP sessions.

In Cisco IOS Release 12.0(32)S12, 12.4(24)T, and Cisco IOS XE Release 2.3, the Cisco implementation of 4-byte autonomous system numbers uses asdot--1.2 for example--as the only configuration format, regular expression match, and output display, with no asplain support.

Note

In Cisco IOS releases that include 4-byte ASN support, command accounting and command authorization that include a 4-byte ASN number are sent in the asplain notation irrespective of the format that is used on the command-line interface.

To ensure a smooth transition, we recommend that all BGP speakers within an autonomous system that is identified using a 4-byte autonomous system number, be upgraded to support 4-byte autonomous system numbers.

Examples

The following example specifies that a router at the address 10.108.1.2 is an internal BGP (iBGP) neighbor in autonomous system number 65200:


router bgp 65200
 network 10.108.0.0
 neighbor 10.108.1.2 remote-as 65200

The following example specifies that a router at the IPv6 address 2001:0DB8:1:1000::72a is an external BGP (eBGP) neighbor in autonomous system number 65001:


router bgp 65300
 address-family ipv6 vrf site1
 neighbor 2001:0DB8:1:1000::72a remote-as 65001

The following example assigns a BGP router to autonomous system 65400, and two networks are listed as originating in the autonomous system. Then the addresses of three remote routers (and their autonomous systems) are listed. The router being configured will share information about networks 10.108.0.0 and 192.168.7.0 with the neighbor routers. The first router is a remote router in a different autonomous system from the router on which this configuration is entered (an eBGP neighbor); the second neighbor remote-as command shows an internal BGP neighbor (with the same autonomous system number) at address 10.108.234.2; and the last neighbor remote-as command specifies a neighbor on a different network from the router on which this configuration is entered (also an eBGP neighbor).


router bgp 65400
 network 10.108.0.0
 network 192.168.7.0
 neighbor 10.108.200.1 remote-as 65200
 neighbor 10.108.234.2 remote-as 65400
 neighbor 172.29.64.19 remote-as 65300

The following example configures neighbor 10.108.1.1 in autonomous system 65001 to exchange only multicast routes:


router bgp 65001
 neighbor 10.108.1.1 remote-as 65001
 neighbor 172.31 1.2 remote-as 65001
 neighbor 172.16.2.2 remote-as 65002
 address-family ipv4 multicast
  neighbor 10.108.1.1 activate
  neighbor 172.31 1.2 activate
  neighbor 172.16.2.2 activate
  exit-address-family

The following example configures neighbor 10.108.1.1 in autonomous system 65001 to exchange only unicast routes:


router bgp 65001
 neighbor 10.108.1.1 remote-as 65001
 neighbor 172.31 1.2 remote-as 65001
 neighbor 172.16.2.2 remote-as 65002

The following example, configurable only in Cisco IOS Release 12.2(33)SXH and later releases, configures a subnet range of 192.168.0.0/16 and associates this listen range with a BGP peer group. Note that the listen range peer group that is configured for the BGP dynamic neighbor feature can be activated in the IPv4 address family using the neighbor activate command. After the initial configuration on Router 1, when Router 2 starts a BGP router session and adds Router 1 to its BGP neighbor table, a TCP session is initiated, and Router 1 creates a new BGP neighbor dynamically because the IP address of the new neighbor is within the listen range subnet.

Examples


enable
configure terminal
router bgp 45000
 bgp log-neighbor-changes
 neighbor group192 peer-group 
 bgp listen range 192.168.0.0/16 peer-group group192   
 neighbor group192 remote-as 40000 alternate-as 50000
 address-family ipv4 unicast 
 neighbor group192 activate
 end

Examples


enable
configure terminal
router bgp 50000
 neighbor 192.168.3.1 remote-as 45000
 exit

If the show ip bgp summary command is now entered on Router 1, the output shows the dynamically created BGP neighbor, 192.168.3.2.


Router1# show ip bgp summary
BGP router identifier 192.168.3.1, local AS number 45000
BGP table version is 1, main routing table version 1
Neighbor        V    AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
*192.168.3.2    4 50000       2       2        0    0    0 00:00:37        0
* Dynamically created based on a listen range command
Dynamically created neighbors: 1/(200 max), Subnet ranges: 1
BGP peergroup group192 listen range group members: 
  192.168.0.0/16

The following example configures a BGP process for autonomous system 65538 and configures two external BGP neighbors in different autonomous systems using 4-byte autonomous system numbers in asplain format. This example is supported only on Cisco IOS Release 12.0(32)SY8, 12.0(33)S3, 12.2(33)SRE, 12.2(33)XNE, 12.2(33)SXI1, Cisco IOS XE Release 2.4, or later releases.


router bgp 65538
 neighbor 192.168.1.2 remote-as 65536
 neighbor 192.168.3.2 remote-as 65550
 neighbor 192.168.3.2 description finance
 !
 address-family ipv4
  neighbor 192.168.1.2 activate
  neighbor 192.168.3.2 activate
  no auto-summary
  no synchronization
  network 172.17.1.0 mask 255.255.255.0
  exit-address-family

The following example configures a BGP process for autonomous system 1.2 and configures two external BGP neighbors in different autonomous systems using 4-byte autonomous system numbers in asdot format. This example requires Cisco IOS Release 12.0(32)SY8, 12.0(32)S12, 12.2(33)SRE, 12.2(33)XNE, 12.2(33)SXI1, 12.4(24)T, Cisco IOS XE Release 2.3, or a later release.


router bgp 1.2
 neighbor 192.168.1.2 remote-as 1.0
 neighbor 192.168.3.2 remote-as 1.14
 neighbor 192.168.3.2 description finance
 !
 address-family ipv4
  neighbor 192.168.1.2 activate
  neighbor 192.168.3.2 activate
  no auto-summary
  no synchronization
  network 172.17.1.0 mask 255.255.255.0
  exit-address-family

Related Commands


Command	Description
bgp asnotation dot	Changes the default display and the regular expression match format of BGP 4-byte autonomous system numbers from asplain (decimal values) to dot notation.
bgp listen	Associates a subnet range with a BGP peer group and activates the BGP dynamic neighbors feature.
neighbor peer-group	Creates a BGP peer group.
router bgp	Configures the BGP routing process.

neighbor send-community

To specify that a communities attribute should be sent to a BGP neighbor, use the neighbor send-community command in address family or router configuration mode. To remove the entry, use the no form of this command.

neighbor {ip-address | ipv6-address | peer-group-name} send-community [both | standard | extended]

no neighbor {ip-address | ipv6-address | peer-group-name} send-community

Syntax Description


`ip-address`	IP address of the neighbor.
`ipv6-address`	IPv6 address of the neighbor.
`peer-group-name`	Name of a BGP peer group.
both	(Optional) Specifies that both standard and extended communities will be sent.
standard	(Optional) Specifies that only standard communities will be sent.
extended	(Optional) Specifies that only extended communities will be sent.

Command Default

No communities attribute is sent to any neighbor.

Command Modes

Address family configuration (config-router-af)

Router configuration (config-router)

Command History


Release	Modification
10.3	This command was introduced.
11.0	The `peer-group-name` argument was added.
12.0(7)T	Address family configuration mode was added.
12.2(33)SRA	This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2(33)SRB	The `ipv6-address` argument was added.
12.2(33)SB	This command was integrated into Cisco IOS Release 12.2(33)SB.
12.2(33)SXI	This command was integrated into Cisco IOS Release 12.2(33)SXI.
Cisco IOS XE Release 3.7S	This command was integrated into Cisco IOS XE Release 3.7S.
15.1(2)SNG	This command was implemented on the Cisco ASR 901 Series Aggregation Services Routers.

Usage Guidelines

If you specify a BGP peer group by using the peer-group-name argument, all the members of the peer group will inherit the characteristic configured with this command.

Examples

In the following router configuration mode example, the router belongs to autonomous system 109 and is configured to send the communities attribute to its neighbor at IP address 172.16.70.23:

router bgp 109
 neighbor 172.16.70.23 send-community

In the following address family configuration mode example, the router belongs to autonomous system 109 and is configured to send the communities attribute to its neighbor at IP address 172.16.70.23:

router bgp 109
address-family ipv4 multicast
 neighbor 172.16.70.23 send-community

Related Commands


Command	Description
address-family ipv4 (BGP)	Places the router in address family configuration mode for configuring routing sessions such as BGP, RIP, or static routing sessions that use standard IP Version 4 address prefixes.
address-family ipv6	Places the router in address family configuration mode for configuring routing sessions such as BGP that use standard IPv6 address prefixes.
address-family vpnv4	Places the router in address family configuration mode for configuring routing sessions such as BGP, RIP, or static routing sessions that use standard VPN Version 4 address prefixes.
address-family vpnv6	Places the router in address family configuration mode for configuring routing sessions, such as BGP, that use standard VPNv6 address prefixes.
match community	Matches a BGP community.
neighbor remote-as	Creates a BGP peer group.
set community	Sets the BGP communities attribute.

neighbor send-label

To enable a Border Gateway Protocol (BGP) router to send Multiprotocol Label Switching (MPLS) labels with BGP routes to a neighboring BGP router, use the neighbor send-label command in address family configuration mode or router configuration mode. To disable this feature, use the no form of this command.

neighbor {ip-address | ipv6-address | peer-group-name} send-label [explicit-null]

no neighbor {ip-address | ipv6-address | peer-group-name} send-label [explicit-null]

Syntax Description


`ip-address`	IP address of the neighboring router.
`ipv6-address`	IPv6 address of the neighboring router.
`peer-group-name`	Name of a BGP peer group.
send-label	Sends Network Layer Reachability Information (NLRI) and MPLS labels to this peer.
explicit-null	(Optional) Advertises the Explicit Null label.

Command Default

BGP routers distribute only BGP routes.

Command Modes

Address family configuration (config-router-af)
Router configuration (config-router)

Command History


Release	Modification
12.0(21)ST	This command was introduced.
12.0(22)S	This command was modified. The `ipv6-address` argument was added.
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)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 integrated into Cisco IOS XE Release 2.1.
15.1(2)SNG	This command was integrated into Cisco ASR 901 Series Aggregation Services Routers.
15.2(2)SNI	This command was implemented on the Cisco ASR 901 Series Aggregation Services Routers.

Usage Guidelines

The neighbor send-label command enables a router to use BGP to distribute MPLS labels along with IPv4 routes to a peer router. You must issue this command on both the local and the neighboring router.

This command has the following restrictions:

If a BGP session is running when you issue the neighbor send-label command, the BGP session flaps immediately after the command is issued.
In router configuration mode, only IPv4 addresses are distributed.

Use the neighbor send-label command in address family configuration mode, to bind and advertise IPv6 prefix MPLS labels. Using this command in conjunction with the mpls ipv6 source-interface global configuration command allows IPv6 traffic to run over an IPv4 MPLS network without any software or hardware configuration changes in the backbone. Edge routers configured to run both IPv4 and IPv6 traffic forward IPv6 traffic using MPLS and multiprotocol internal BGP (MP-iBGP).

Cisco IOS software installs /32 routes for directly connected external BGP (eBGP) peers when the BGP session for such a peer comes up. The /32 routes are installed only when MPLS labels are exchanged between such peers. Directly connected eBGP peers exchange MPLS labels for:

IP address families (IPv4 and IPv6) with the neighbor send-label command enabled for the peers
VPN address families (VPNv4 and VPNv6)

A single BGP session can include multiple address families. If one of the families exchanges MPLS labels, the /32 neighbor route is installed for the connected peer.

Examples

The following example shows how to enable a router in autonomous system 65000 to send MPLS labels with BGP routes to the neighboring BGP router at 192.168.0.1:


Router(config)# router bgp 65000
Router(config-router)# neighbor 192.168.0.1 remote-as 65001
Router(config-router)# neighbor 192.168.0.1 send-label

The following example shows how to enable a router in the autonomous system 65000 to bind and advertise IPv6 prefix MPLS labels and send the labels with BGP routes to the neighboring BGP router at 192.168.99.70:


Router(config)# router bgp 65000
Router(config-router)# neighbor 192.168.99.70 remote-as 65000
Router(config-router)# address-family ipv6
Router(config-router-af)# neighbor 192.168.99.70 activate
Router(config-router-af)# neighbor 192.168.99.70 send-label

Related Commands


Command	Description
address-family ipv6	Enters address family configuration mode for configuring routing sessions such as BGP that use standard IPv6 address prefixes.
neighbor activate	Enables the exchange of information with a neighboring router.
neighbor remote-as	Adds an entry to the BGP or multiprotocol BGP neighbor table.
mpls ipv6 source-interface	Specifies an IPv6 address of an interface to be used as the source address for locally generated IPv6 packets to be sent over an MPLS network.

neighbor send-label explicit-null

To enable a Border Gateway Protocol (BGP) router to send Multiprotocol Label Switching (MPLS) labels with explicit-null information for a CSC-CE router and BGP routes to a neighboring CSC-PE router, use the neighbor send-label explicit-null command in address family configuration mode or router configuration mode. To disable a BGP router from sending MPLS labels with explicit-null information, use the no form of this command.

neighbor ip-address send-label explicit-null

no neighbor ip-address send-label explicit-null

Syntax Description


`ip-address`	IP address of the neighboring router.

Command Default

None

Command Modes

Address family configuration (config-router-af)
Router configuration (config-router)

Command History


Release	Modification
12.0(27)S	This command was introduced.
12.4	This command was integrated into Cisco IOS Release 12.4
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

This command enables a CSC-CE router to use BGP to distribute MPLS labels with a value of zero for explicit-null instead of implicit-null along with IPv4 routes to a CSC-PE peer router.

You must issue this command only on the local CSC-CE router.

You can use this command only with IPv4 addresses.

Examples

In the following CSC-CE example, CSC is configured with BGP to distribute labels and to advertise explicit null for all its connected routes:


Router# configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
Router(config)# router bgp 100
Router(config-router)# neighbor 10.0.0.2 remote-as 300
Router(config-router)# address-family ipv4
Router(config-router-af)# neighbor 10.0.0.2 send-label explicit-null

In the following CSC-PE example, CSC is configured with BGP to distribute labels:


Router# configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
Router(config)# router bgp 300
Router(config-router)# neighbor 10.0.0.1 remote-as 100
Router(config-router)# address-family ipv4 vrf v1
Router(config-router-af)# neighbor 10.0.0.1 send-label

Note

Explicit null is not applicable on a CSC-PE router.

Related Commands


Command	Description
neighbor activate	Enables the exchange of information with a neighboring router.
neighbor send-label	Enables a BGP router to send MPLS labels with BGP routes to a neighboring BGP router.

neighbor suppress-signaling-protocol

To suppress a Virtual Private LAN Service (VPLS) signaling protocol use the neighbor suppress-signaling-protocol command in address family configuration or router configuration mode. To remove the entry, use the no form of this command.

neighbor {ipv4-address | ipv6-address | peer-group-name} suppress-signaling-protocol ldp

no neighbor {ipv4-address | ipv6-address | peer-group-name} suppress-signaling-protocol ldp

Syntax Description


`ipv4-address`	IP address of the neighbor.
`ipv6-address`	IPv6 address of the neighbor.
`peer-group-name`	Name of a BGP peer group.
ldp	Specifies that Label Distribution Protocol (LDP) signaling will be suppressed.

Command Default

LDP signaling is not suppressed.

Command Modes

Address family configuration (config-router-af)

Router configuration (config-router)

Command History


Release	Modification
Cisco IOS XE Release 3.8S	This command was introduced.

Usage Guidelines

If you specify that LDP signaling is suppressed by using the ldp keyword, BGP signaling will be enabled.

Examples


Device(config-router-af)# neighbor 10.10.10.1 suppress-signaling-protocol ldp

Related Commands


Command	Description
address-family ipv4 (BGP)	Places the router in address family configuration mode for configuring routing sessions such as BGP, RIP, or static routing sessions that use standard IP Version 4 address prefixes.
address-family ipv6	Places the router in address family configuration mode for configuring routing sessions such as BGP that use standard IPv6 address prefixes.
address-family vpnv4	Places the router in address family configuration mode for configuring routing sessions such as BGP, RIP, or static routing sessions that use standard VPN Version 4 address prefixes.
address-family vpnv6	Places the router in address family configuration mode for configuring routing sessions, such as BGP, that use standard VPNv6 address prefixes.
neighbor remote-as	Creates a BGP peer group.

neighbor update-source

To have the Cisco software allow Border Gateway Protocol (BGP) sessions to use any operational interface for TCP connections, use the neighbor update-source command in router configuration mode. To restore the interface assignment to the closest interface, which is called the best local address, use the no form of this command.

neighbor {ip-address | ipv6-address [%] | peer-group-name}update-source interface-type interface-number

Syntax Description


`ip-address`	IPv4 address of the BGP-speaking neighbor.
`ipv6-address`	IPv6 address of the BGP-speaking neighbor.
%	(Optional) IPv6 link-local address identifier. This keyword needs to be added whenever a link-local IPv6 address is used outside the context of its interface.
`peer-group-name`	Name of a BGP peer group.
`interface-type`	Interface type.
`interface-number`	Interface number.

Command Default

Best local address

Command Modes

Router configuration (config-router)

Command History


Release	Modification
10.0	This command was introduced.
12.2(4)T	The `ipv6-address` argument was added.
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)SRB	The % keyword was added.
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.
Cisco IOS XE Release 2.1	This command was introduced on Cisco ASR 1000 series routers.
15.1(2)SNG	This command was implemented on the Cisco ASR 901 Series Aggregation Services Routers.

Usage Guidelines

This command can work in conjunction with the loopback interface feature described in the “Interface Configuration Overview” chapter of the Cisco IOS Interface and Hardware Component Configuration Guide.

If you specify a BGP peer group by using the peer-group-name argument, all the members of the peer group will inherit the characteristic configured with this command.

The neighbor update-source command must be used to enable IPv6 link-local peering for internal or external BGP sessions.

The % keyword is used whenever link-local IPv6 addresses are used outside the context of their interfaces and for these link-local IPv6 addresses you must specify the interface they are on. The syntax becomes <IPv6 local-link address>%<interface name>, for example, FE80::1%Ethernet1/0. Note that the interface type and number must not contain any spaces, and be used in full-length form because name shortening is not supported in this situation. The % keyword and subsequent interface syntax is not used for non-link-local IPv6 addresses.

Examples

The following example sources BGP TCP connections for the specified neighbor with the IP address of the loopback interface rather than the best local address:


router bgp 65000
 network 172.16.0.0
 neighbor 172.16.2.3 remote-as 110
 neighbor 172.16.2.3 update-source Loopback0

The following example sources IPv6 BGP TCP connections for the specified neighbor in autonomous system 65000 with the global IPv6 address of loopback interface 0 and the specified neighbor in autonomous system 65400 with the link-local IPv6 address of Fast Ethernet interface 0/0. Note that the link-local IPv6 address of FE80::2 is on Ethernet interface 1/0.


router bgp 65000
 neighbor 3ffe::3 remote-as 65000 
 neighbor 3ffe::3 update-source Loopback0 
 neighbor fe80::2%Ethernet1/0 remote-as 65400 
 neighbor fe80::2%Ethernet1/0 update-source FastEthernet 0/0 
 address-family ipv6 
  neighbor 3ffe::3 activate 
  neighbor fe80::2%Ethernet1/0 activate 
  exit-address-family

Related Commands


Command	Description
neighbor activate	Enables the exchange of information with a BGP neighboring router.
neighbor remote-as	Adds an entry to the BGP or multiprotocol BGP neighbor table.

neighbor (VPLS transport mode)

To create pseudowires with specific provider edge (PE) routers in an L2VPN Advanced VPLS configuration, use the neighbor command in VPLS transport configuration mode. To remove the pseudowires, use the no form of this command.

neighbor remote-router-id [pw-class pw-class-name]

no neighbor remote-router-id

Syntax Description


`remote-router-id`	Remote peer router identifier. The remote router ID can be any IP address, as long as it is reachable.
pw-class	(Optional) Specifies the pseudowire class configuration from which the data encapsulation type is taken.
`pw-name-name`	Name of the pseudowire class.

Command Default

Pseudowires are not created.

Command Modes

VPLS transport configuration (config-if-transport)

Command History


Release	Modification
12.2(33)SXI4	This command was introduced.
15.1(1)SY	This command was integrated into Cisco IOS Release 15.1(1)SY.

Usage Guidelines

The neighbor command uses default values for the VFI name, VPN ID, and encapsulation type.

Examples

The following example shows how two pseudowires are created with PE routers 10.2.2.2 and 10.3.3.3:


Router(config)# interface virtual-ethernet 1
Router(config-if)# transport vpls mesh
Router(config-if-transport)# neighbor 10.2.2.2 pw-class 1 
Router(config-if-transport)# neighbor 10.3.3.3 pw-class 1

Related Commands


Command	Description
transport vpls mesh	Creates a full mesh of pseudowires under a virtual private LAN switching (VPLS) domain.

neighbor (VPLS)

To specify the type of tunnel signaling and encapsulation mechanism for each Virtual Private LAN Service (VPLS) peer, use the neighbor command in L2 VFI manual configuration mode. To disable a split horizon, use the no form of this command.

neighbor remote-router-id vc-id {encapsulation encapsulation-type | pw-class pw-name} [no-split-horizon]

no neighbor remote-router-id [vc-id]

Syntax Description


`remote-router-id`	Remote peer router identifier. The remote router ID can be any IP address, as long as it is reachable.
`vc-id`	32-bit identifier of the virtual circuit between the routers.
encapsulation	Specifies tunnel encapsulation.
`encapsulation-type`	Specifies the tunnel encapsulation type; valid values are l2tpv3 and mpls .
pw-class	Specifies the pseudowire class configuration from which the data encapsulation type is taken.
`pw-name`	Name of the pseudowire class.
no-split-horizon	(Optional) Disables the Layer 2 split horizon forwarding in the data path.

Command Default

Split horizon is enabled.

Command Modes

L2 VFI manual configuration (config-vfi)

Command History


Release	Modification
12.2(18)SXF	This command was introduced on the Supervisor Engine 720.
12.2(33)SRA	This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2(33)SRB	This command was modified. This command was updated so that the remote router ID need not be the LDP router ID of the peer.
Cisco IOS XE Release XE 3.7S	This command was integrated into Cisco IOS XE Release XE 3.7S.

Usage Guidelines

In a full-mesh VPLS network, keep split horizon enabled to avoid looping.

With the introduction of VPLS Autodiscovery, the remote router ID no longer needs to be the LDP router ID. The address that you specify can be any IP address on the peer, as long as it is reachable. When VPLS Autodiscovery discovers peer routers for the VPLS, the peer router addresses might be any routable address.

Examples

This example shows how to specify the tunnel encapsulation type:

Device(config-vfi)# l2 vfi vfi-1 manual
Device(config-vfi)# vpn 1
Device(config-vfi)# neighbor 172.16.10.2 4 encapsulation mpls

This example shows how to disable the Layer 2 split horizon in the data path:

Device(config-vfi)# l2 vfi vfi-1 manual
Device(config-vfi)# vpn 1
Device(config-vfi)# neighbor 172.16.10.2 4 encapsulation mpls no-split-horizon

Related Commands


Command	Description
l2 vfi manual	Creates a Layer 2 VFI.

network (IPv6)

To configure the network source of the next hop to be used by the PE VPN, use the network command in router configuration mode. To disable the source, use the no form of this command.

network ipv6-address/prefix-length

no network ipv6-address/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.

Command Default

Next-hop network sources are not configured.

Command Modes

Address family configuration
Router configuration

Command History


Release	Modification
12.2(33)SRB	This command was introduced.
12.2(33)SB	This command was integrated into Cisco IOS Release 12.2(33)SB.
12.2(33)SXI	This command was integrated into Cisco IOS Release 12.2(33)SXI.
Cisco IOS XE Release 3.1S	This command was integrated into Cisco IOS XE Release 3.1S.
Cisco IOS XE Release 3.2SE	This command was integrated into Cisco IOS XE Release 3.2SE.

Usage Guidelines

The ipv6-address argument in this command configures the IPv6 network number.

Examples

The following example places the router in address family configuration mode and configures the network source to be used as the next hop:


Router(config)# router bgp 100
Router(config-router)# network 2001:DB8:100::1/128

Related Commands


Command	Description
address-family ipv6	Enters address family configuration mode for configuring routing sessions such as BGP that use standard IPv6 address prefixes.
address-family vpnv6	Places the router in address family configuration mode for configuring routing sessions that use standard VPNv6 address prefixes.

next-address

To specify the next IP address in the explicit path, use the next-address command in IP explicit path configuration mode.

next-address [loose | strict] ip-address

Syntax Description


loose	(Optional) Specifies that the previous address (if any) in the explicit path need not be directly connected to the next IP address, and that the router is free to determine the path from the previous address (if any) to the next IP address.
strict	(Optional) Specifies that the previous address (if any) in the explicit path must be directly connected to the next IP address.
`ip-address`	Next IP address in the explicit path.

Command Default

The next IP address in the explicit path is not specified.

Command Modes

IP explicit path configuration

Command History


Release	Modification
12.0(5)S	This command was introduced.
12.0(19)ST1	The loose and strict keywords were added.
12.0(21)ST	Support for the Cisco 12000 series router was added.
12.2(18)S	This command was integrated into Cisco IOS Release 12.2(18)S.
12.2(18)SXD	This command was integrated into Cisco IOS Release 12.2(18)SXD.
12.2(27)SBC	This command was integrated into Cisco IOS Release 12.2(27)SBC.
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.
12.4(20)T	This command was integrated into Cisco IOS Release 12.4(20)T.
Cisco IOS XE Release 2.3	This command was integrated into Cisco IOS XE Release 2.3.

Usage Guidelines

To specify an explicit path that includes only the addresses specified, specify each address in sequence by using the next-address command without the loose keyword.

To configure an interarea traffic engineering (TE) tunnel, configure the tunnel path options as loose explicit paths. Specify that each Autonomous System Boundary Router (ASBR) traversed by the tunnel label switched path (LSP) is a loose hop by entering the next-address loose command.

To use explicit paths for TE tunnels within an Interior Gateway Protocol (IGP) area, you can specify a combination of both loose and strict hops.

When specifying an explicit path for an MPLS TE tunnel, you can specify link or node addresses of the next-hop routers in an explicit path. You can also specify a mixture of link and node addresses. However, there are some restrictions:

In Cisco IOS Releases 12.2(33)SRD and 12.4(24)T, and Cisco XE Release 2.4 and earlier releases, you cannot specify an explicit path that uses a link address as the first hop and then node addresses as the subsequent hops. However, you can use a node address as the first hop andlink addresses as the subsequent hops.
In Cisco IOS Releases after 12.2(33)SRD, 12.4(24)T , and Cisco XE Release 2.4, you can use a link address as the first hop and then node addresses as the subsequent hops. There are no restrictions when specifying a mixture of link and node addresses.

When specifying an explicit path, if you specify the “forward” address (the address of the interface that forwards the traffic to the next router) as the next-hop address, the explicit path might not be used. Using the forward address allows that entry to be treated as a loose hop for path calculation. Cisco recommends that you use the “receive”address (the address of the interface that receives traffic from the sending router) as the next-hop address.

In the following example, router R3 sends traffic to router R1. The paths marked a,b and x,y between routers R1 and R2 are parallel paths.


R1(a)----(b)R2(c)--(d)R3
  (x)----(y)

If you configure an explicit path from R3 to R1 using the “forward” addresses (addresses d and b), the tunnel might reroute traffic over the parallel path (x,y) instead of the explicit path. To ensure that the tunnel uses the explicit path, specify the “receive” addresses as part of the next-address command, as shown in the following example:


ip explicit-path name path1
  next-address ©)
  next-address (a)

Examples

The following example shows how to assign the number 60 to the IP explicit path, enable the path, and specify 10.3.27.3 as the next IP address in the list of IP addresses:


Router(config)# ip explicit-path identifier 60 enable 
Router(cfg-ip-expl-path)# next-address 10.3.27.3
Explicit Path identifier 60:
    1: next-address 10.3.27.3

The following example shows a loose IP explicit path with ID 60. An interarea TE tunnel has a destination of 10.3.29.3 and traverses ASBRs 10.3.27.3 and 10.3.28.3.


Router(config)# ip explicit-path identifier 60
Router(cfg-ip-expl-path)# next-address loose 10.3.27.3 
Router(cfg-ip-expl-path)# next-address loose 10.3.28.3
Router(cfg-ip-expl-path)# next-address loose 10.3.29.3

Related Commands


Command	Description
append-after	Inserts the new path entry after the specified index number.
index	Inserts or modifies a path entry at a specified index.
ip explicit-path	Enters the subcommand mode for IP explicit paths and creates or modifies the specified path.
list	Displays all or part of the explicit paths.
show ip explicit-paths	Displays configured IP explicit paths.

passive-interface (IPv6)

To disable sending routing updates on an interface, use the passive-interface command in router configuration mode. To reenable the sending of routing updates, use the no form of this command.

passive-interface [default | interface-type interface-number]

no passive-interface [default | interface-type interface-number]

Syntax Description


default	(Optional) All interfaces become passive.
`interface-type` `interface-number`	(Optional) Interface type and number. For more information, use the question mark (? ) online help function.

Command Default

No interfaces are passive. Routing updates are sent to all interfaces on which the routing protocol is enabled.

Command Modes

Router configuration

Command History


Release	Modification
12.2(15)T	This command was introduced.
12.4(6)T	Support for Enhanced Internal Gateway Routing Protocol (EIGRP) IPv6 was added.
12.2(28)SB	This command was integrated into Cisco IOS Release 12.2(28)SB.
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 3.2SE	This command was integrated into Cisco IOS XE Release 3.2SE.

Usage Guidelines

If you disable the sending of routing updates on an interface, the particular address prefix will continue to be advertised to other interfaces, and updates from other routers on that interface continue to be received and processed.

The default keyword sets all interfaces as passive by default. You can then configure individual interfaces where adjacencies are desired using the no passive-interface command. The default keyword is useful in Internet service provider (ISP) and large enterprise networks where many of the distribution routers have more than 200 interfaces.

OSPF for IPv6 routing information is neither sent nor received through the specified router interface. The specified interface address appears as a stub network in the OSPF for IPv6 domain.

For the Intermediate System-to-Intermediate System (IS-IS) protocol, this command instructs IS-IS to advertise the IP addresses for the specified interface without actually running IS-IS on that interface. The no form of this command for IS-IS disables advertising IP addresses for the specified address.

Examples

The following example sets all interfaces as passive, then activates Ethernet interface 0:


Router(config-router)# passive-interface default
Router(config-router)# no passive-interface ethernet0/0

oam retry

To configure parameters related to Operation, Administration, and Maintenance (OAM) management for an ATM permanent virtual circuit (PVC), switched virtual circuit (SVC), VC class, or VC bundle, or label-controlled ATM (LC-ATM) VC, use the oam retry command in the appropriate command mode. To remove OAM management parameters, use the no form of this command.

oam retry up-count down-count retry-frequency

no oam retry

Syntax Description


`up-count`	Number of consecutive end-to-end F5 OAM loopback cell responses that must be received in order to change a connection state to up. This argument does not apply to SVCs.
`down-count`	Number of consecutive end-to-end F5 OAM loopback cell responses that are not received in order to change the state to down or tear down an SVC connection.
`retry-frequency`	The frequency (in seconds) at which end-to-end F5 OAM loopback cells are transmitted when a change in the up/down state is being verified. For example, if a PVC is up and a loopback cell response is not received after the `retry-frequency` (in seconds) argument is specified using the oam-pvc command, loopback cells are sent at the `retry-frequency` to verify whether the PVC is down.

Command Default

ATM PVCs and SVCs

up-count : 3down-count : 5retry-frequency : 1 second

LC-ATM VCs

up-count : 2down-count : 2retry-frequency : 2 seconds

Command Modes

Bundle configuration mode (for a VC bundle)
Control-VC configuration (for an LC-ATM VC)
Interface-ATM-VC configuration (for an ATM PVC or SVC)
PVC range configuration (for an ATM PVC range)
PVC-in-range configuration (for an individual PVC within a PVC range)
VC-class configuration (for a VC class)

Command History


Release	Modification
11.3T	This command was introduced.
12.0(3)T	This command was modified to allow configuration parameters related to OAM management for ATM VC bundles.
12.1(5)T	This command was implemented in PVC range and PVC-in-range configuration modes.
12.3(2)T	This command was implemented in control-VC configuration mode.
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.

Usage Guidelines

The following guidelines apply to PVCs, SVCs, and VC classes. They do not apply to LC-ATM VCs.

For ATM PVCs, SVCs, or VC bundles, if the oam retry command is not explicitly configured, the VC inherits the following default configuration (listed in order of precedence):
- Configuration of the oam retry command in a VC class assigned to the PVC or SVC itself.
- Configuration of the oam retry command in a VC class assigned to the PVC’s or SVC’s ATM subinterface.
- Configuration of the oam retry command in a VC class assigned to the PVC’s or SVC’s ATM main interface.
- Global default: up-count = 3, down-count = 5, retry-frequency = 1 second. This set of defaults assumes that OAM management is enabled using the oam-pvc or oam-svc command. The up-count and retry-frequency arguments do not apply to SVCs.
To use this command in bundle configuration mode, enter the bundle command to create the bundle or to specify an existing bundle before you enter this command.
If you use the oam retry command to configure a VC bundle, you configure all VC members of that bundle. VCs in a VC bundle are further subject to the following inheritance rules (listed in order of precedence):
- VC configuration in bundle-vc mode
- Bundle configuration in bundle mode (with the effect of assigned VC-class configuration)
- Subinterface configuration in subinterface mode

Examples

The following example shows how to configure the OAM management parameters with an up count of 3, a down-count of 3, and the retry frequency set at 10 seconds:


Router(cfg-mpls-atm-cvc)# oam retry 3 3 10

Related Commands


Command	Description
broadcast	Configures broadcast packet duplication and transmission for an ATM VC class, PVC, SVC, or VC bundle.
class-int	Assigns a VC class to an ATM main interface or subinterface.
class-vc	Assigns a VC class to an ATM PVC, SVC, or VC bundle member.
encapsulation	Sets the encapsulation method used by the interface.
inarp	Configures the Inverse ARP time period for an ATM PVC, VC class, or VC bundle.
oam-bundle	Enables end-to-end F5 OAM loopback cell generation and OAM management for a virtual circuit class that can be applied to a virtual circuit bundle.
oam-pvc	Enables end-to-end F5 OAM loopback cell generation and OAM management for an ATM PVC or virtual circuit class.
oam-svc	Enables end-to-end F5 OAM loopback cell generation and OAM management for an ATM SVC or virtual circuit class.
protocol (ATM)	Configures a static map for an ATM PVC, SVC, VC class, or VC bundle. Enables Inverse ARP or Inverse ARP broadcasts on an ATM PVC by either configuring Inverse ARP directly on the PVC, on the VC bundle, or in a VC class (applies to IP and IPX protocols only).
ubr	Configures UBR QoS and specifies the output peak cell rate for an ATM PVC, SVC, VC class, or VC bundle member.
ubr+	Configures UBR QoS and specifies the output peak cell rate and output minimum guaranteed cell rate for an ATM PVC, SVC, VC class, or VC bundle member.
vbr-nrt	Configures the VBR-NRT QoS and specifies output peak cell rate, output sustainable cell rate, and output maximum burst cell size for an ATM PVC, SVC, VC class, or VC bundle member.

oam-ac emulation-enable

To enable Operation, Administration, and Maintenance (OAM) cell emulation on ATM adaptation layer 5 (AAL5) over Multiprotocol Label Switching (MPLS) or Layer 2 Tunnel Protocol Version 3 (L2TPv3), use the oam-ac emulation-enable command in the appropriate configuration mode on both provider edge (PE) routers. To disable OAM cell emulation, use the no form of this command on both routers.

oam-ac emulation-enable [seconds]

no oam-ac emulation-enable

Syntax Description


`seconds`	(Optional) The rate (in seconds) at which the alarm indication signal (AIS) cells should be sent. The range is 0 to 60 seconds. If you specify 0, no AIS cells are sent. The default is 1 second, which means that one AIS cell is sent every second.

Command Default

OAM cell emulation is disabled.

Command Modes

L2transport PVC configuration--for an ATM PVC
VC class configuration mode--for a VC class

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.
12.0(30)S	This command was updated to enable OAM cell emulation as part of a virtual circuit (VC) class.
12.0(31)S	This command was integrated into Cisco IOS Release 12.0(31)S.
12.2(27)SBC	This command was integrated into Cisco IOS Release 12.2(27)SBC.
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.
12.4(11)T	This command was integrated into Cisco IOS Release 12.4(11)T.
12.2(33)SXH	This command was integrated into Cisco IOS Release 12.2(33)SXH.
12.2(33)SRC	This command was integrated into Cisco IOS Release 12.2(33)SRC.
15.0(1)S	This command was integrated into Cisco IOS Release 15.0(1)S.
Cisco IOS XE Release 3.1S	This command was integrated into Cisco IOS XE Release 3.1S.

Usage Guidelines

This command is used with AAL5 over MPLS or L2TPv3 and is not supported with ATM cell relay over MPLS or L2TPv3.

Examples

The following example shows how to enable OAM cell emulation on an ATM permanent virtual circuit (PVC):


Router# interface ATM 1/0/0
Router(config-if)# pvc ½00 l2transport
Router(config-if-atm-l2trans-pvc)# oam-ac emulation-enable

The following example shows how to set the rate at which an AIS cell is sent every 30 seconds:


Router# interface ATM 1/0/0
Router(config-if)# pvc ½00 l2transport
Router(config-if-atm-l2trans-pvc)# oam-ac emulation-enable 30

The following example configures OAM cell emulation for ATM AAL5 over MPLS in VC class configuration mode. The VC class is then applied to an interface.


Router> enable
Router# configure terminal
Router(config)# vc-class atm oamclass
Router(config-vc-class)# encapsulation aal5
Router(config-vc-class)# oam-ac emulation-enable 30
Router(config-vc-class)# oam-pvc manage
Router(config)# interface atm1/0
Router(config-if)# class-int oamclass
Router(config-if)# pvc ½00 l2transport
Router(config-if-atm-l2trans-pvc)# xconnect 10.13.13.13 100 encapsulation mpls

Related Commands


Command	Description
show atm pvc	Displays all ATM PVCs and traffic information.

oam-pvc

To enable end-to-end F5 Operation, Administration, and Maintenance (OAM) loopback cell generation and OAM management for an ATM permanent virtual circuit (PVC), virtual circuit (VC) class, or label-controlled ATM (LC-ATM) VC, use the oam-pvc command in the appropriate command mode. To disable generation of OAM loopback cells and OAM management, use the no form of this command.

ATM VC

oam-pvc [frequency | manage [frequency] [auto-detect [optimum] | keep-vc-up [seg aisrdi failure] | loop-detection]]

no oam-pvc [frequency | manage [frequency] [auto-detect [optimum] | keep-vc-up [seg aisrdi failure] | loop-detection]]

VC Class

oam-pvc [frequency | manage [frequency [auto-detect [optimum] | loop-detection]]]

no oam-pvc [frequency | manage [frequency [auto-detect [optimum] | loop-detection]]]

Loopback Mode Detection

oam-pvc manage [frequency] loop-detection

no oam-pvc manage loop-detection

Cisco 10000 Series Router

oam-pvc [frequency | manage [frequency [auto-detect [optimum] | keep-vc-up [seg aisrdi failure]]]]

no oam-pvc [frequency | manage [frequency [auto-detect [optimum] | keep-vc-up [seg aisrdi failure]]]]

Syntax Description


`frequency`	(Optional) Specifies the time delay between transmittals of OAM loopback cells, in seconds. For ATM VCs or VC classes and loopback mode detection, the range is 0 to 600, and the default is 10. For LC-ATM VCs, the range is 0 to 255, and the default is 5.
manage	(Optional) for ATM VCs or VC classes; required for LC-ATM VCs) Enables OAM management. The default is disabled.
auto-detect	(Optional) Enables automatic detection of peer OAM command cells.
optimum	(Optional) Configures an optimum mode so that when the traffic-monitoring timer expires, the PVC sends an OAM command cell at the locally configured frequency instead of going into retry mode immediately. If there is no response, the PVC goes into retry mode.
keep-vc-up	(Optional) Specifies that the VC will be kept in the UP state when continuity check (CC) cells detect connectivity failure.
seg aisrdi failure	(Optional) Specifies that if segment alarm indication signal/remote defect indication (AIS/RDI) cells are received, the VC will not be brought down because of end CC failure or loopback failure.
loop-detection	(Optional) Enables automatic detection of whether the physically connected ATM switch is in loopback mode. The default is disabled.

Command Default

OAM management and loop detection are disabled.

Command Modes

ATM VC class configuration (config-vc-class)
ATM VC configuration (config-if-atm-vc)
Control-VC configuration (cfg-mpls-atm-cvc)
PVC-in-range configuration (cfg-if-atm-range-pvc)

Command History


Release	Modification
11.3	This command was introduced.
12.1(5)T	This command was implemented in PVC-in-range configuration mode.
12.3(2)T	This command was implemented for LC-ATM VCs.
12.0(30)S	This command was integrated into Cisco IOS Release 12.0(30)S, and the loop-detection keyword was added.
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.
12.2SX	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.
12.2(31)SB10	The loop-detection keyword was added.
Cisco IOS XE Release 2.3	This command was implemented on Cisco ASR 1000 series routers.

Usage Guidelines

If OAM management is enabled, further control of OAM management is configured by using the oam retry command.

ATM VC or VC Classes

If the oam-pvc command is not explicitly configured on an ATM PVC, the PVC inherits the following default configuration (in order of precedence):

Configuration from the oam-pvc command in a VC class assigned to the PVC itself.
Configuration from the oam-pvc command in a VC class assigned to the ATM subinterface of the PVC.
Configuration from the oam-pvc command in a VC class assigned to the ATM main interface of the PVC.
Global default: End-to-end F5 OAM loopback cell generation and OAM management are disabled, but if OAM cells are received, they are looped back. The default value for the frequency argument is 10 seconds.

Specifying the ATM VC or VC Classes

You can select the VCs or VC classes to which to apply OAM management and loop detection by using the oam-pvc command in any of the following command modes:

ATM VC class configuration--for a VC class
ATM VC configuration mode--for an ATM PVC or loopback mode detection
Control-VC configuration mode--for enabling OAM management on an LC-ATM VC
PVC-in-range configuration--for an individual PVC within a PVC range

Loopback Mode Detection

When a PVC traverses an ATM cloud and OAM is enabled, the router sends a loopback cell to the other end and waits for a response to determine whether the circuit is up. However, if an intervening router within the ATM cloud is in loopback mode, the router considers the circuit to be up, when in fact the other end is not reachable.

When enabled, the Loopback Mode Detection Through OAM feature detects when an intervening router is in loopback mode, in which case it sets the OAM state to NOT_VERIFIED. This prevents traffic from being routed on the PVC for as long as any intervening router is detected as being in loopback mode.

Examples

The following example shows how to enable end-to-end F5 OAM loopback cell transmission and OAM management on an ATM PVC with a transmission frequency of 3 seconds:


Router(cfg-mpls-atm-cvc)# oam-pvc manage 3

The following example shows how to enable end-to-end F5 OAM loopback cell transmission and OAM management on an LC-ATM interface with a transmission frequency of 2 seconds:


Router(config)# interface Switch1.10 mpls
Router(config-subif)# ip unnumbered Loopback0
Router(config-subif)# mpls atm control-vc 0 32
Router(cfg-mpls-atm-cvc)# oam-pvc manage 2

The following example shows how to create a PVC and enable loopback detection:


Router(config)# interface ATM1/0
Router(config-if)# pvc 4/100
Router(config-if-atm-vc)# oam-pvc manage loop-detection

Related Commands


Command	Description
ilmi manage	Enables ILMI management on an ATM PVC.
oam retry	Configures parameters related to OAM management for an ATM PVC, SVC, VC class, or LC-ATM VC.
show atm pvc	Displays all ATM PVCs and traffic information.

psc refresh interval

To configure the refresh interval for Protection State Coordination (PSC) Protocol messages, use the psc refresh interval command in MPLS TP global configuration mode. To remove the configuration, use the no form of this command.

psc {fast | slow | remote} refresh interval {time-in-msec | time-in-sec} [message-count num]

no psc {fast | slow | remote} refresh interval {time-in-msec | time-in-sec} [message-count num]

Syntax Description


fast	Specifies the fast refresh interval for PSC messages. The default is 1000 ms with a jitter of 50 percent. The range is from 1000 ms to 5000 sec.
slow	Specifies the slow refresh interval for PSC messages. The default is 5 sec. The range is from 5 secs to 86400 secs (24 hours).
remote	Specifies the remote-event expiration timer. By default, this timer is disabled. The remote refresh interval range is from 5 to 86400 sec (24 hours). The message count is from 5 to 1000. If you do not specify the message count value, it is set to 5, which is the default.
message-count `num`	(Optional) Indicates the number of messages.

Command Default

No intervals are specified.

Command Modes

MPLS TP global configuration mode (config-mpls-tp)

Command History


Release	Modification
Cisco IOS XE Release 3.9S	This command was introduced.

Examples

The following example configures a fast refresh interval of 1000 ms.


Device(config-mpls-tp)# psc fast refresh interval 1000

The following example configures a slow refresh interval of 60 sec.


Device(config-mpls-tp)# psc slow refresh interval 60

The following example configures a remote refresh interval of 2400 sec and a message count of 10.


Device(config-mpls-tp)# psc remote refresh interval 2400 message-count 10

Related Commands


Command	Description
emulated-lockout	Enables the sending of emulated lockout commands on working/protection transport entities.
manual-switch	Issues a local manual switch condition on a working LSP.
show mpls tp	Displays a summary of MPLS-TP settings or a detailed list of MPLS-TP tunnels.
debug mpls tp	Enables debugging for MPLS-TP.
clear mpls tp	Clears the counters or a remote event for PSC signaling messages based on a tunnel number or name.

ping mpls

To check Multiprotocol Label Switching (MPLS) label switched path (LSP) connectivity, use the ping mpls command in privileged EXEC mode.

ping mpls {ipv4 destination-address/destination-mask-length [destination address-start address-end increment] {ttl time-to-live} | pseudowire ipv4-address vc-id [segment [segment-number]] [destination address-start address-end increment] | traffic-eng tunnel-interface tunnel-number [ttl time-to-live]} [revision {1 | 2 | 3 | 4}] [source source-address] [repeat count] [timeout seconds] [size packet-size | minimum maximum size-increment] [pad pattern] [reply dscp dscp-value] [reply pad-tlv] [reply mode {ipv4 | router-alert}] [interval ms] [exp exp-bits] [verbose] [revision tlv-revision-number] [force-explicit-null ] [output interface tx-interface [nexthop ip-address]] [dsmap [hashkey {none | ipv4 bitmap bitmap-size}]] [flags fec]

Syntax Description


ipv4	Specifies the destination type as a Label Distribution Protocol (LDP) IPv4 address.
`destination-address`	Address prefix of the target to be tested.
/ `destination-mask-length`

Results

Chapter: mpls traffic-eng lsp attributes through route-target

mpls traffic-eng lsp attributes through route-target

mpls traffic-eng lsp attributes

Syntax Description

Command Default

Command Modes

Command History

Usage Guidelines

Examples

Related Commands

mpls traffic-eng mesh-group

Syntax Description

Command Default

Command Modes

Command History

Usage Guidelines

Examples

Related Commands

mpls traffic-eng multicast-intact

Syntax Description

Command Default

Command Modes

Command History

Usage Guidelines

Examples

Related Commands

mpls traffic-eng nsr

Command Default

Command Modes

Command History

Examples

Related Commands

mpls traffic-eng passive-interface

Syntax Description

Command Default

Command Modes

Command History

Usage Guidelines

Examples

mpls traffic-eng path-option list

Syntax Description

Command Default

Command Modes

Command History

Usage Guidelines

Examples

Related Commands

mpls traffic-eng path-selection metric

Syntax Description

Command Default

Command Modes

Command History

Usage Guidelines

Examples

Related Commands

mpls traffic-eng reoptimize

Syntax Description

Command Modes

Command History

Examples

Related Commands

mpls traffic-eng reoptimize events

Syntax Description

Command Default

Command Modes

Command History

Examples

Related Commands

mpls traffic-eng reoptimize timers delay

Syntax Description

Command Default

Command Modes

Command History

Usage Guidelines

Examples

Related Commands

mpls traffic-eng reoptimize timers frequency

Syntax Description