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Table of Contents

BGP Commands

BGP Commands

Use the commands in this chapter to configure and monitor Border Gateway Protocol (BGP). For BGP configuration information and examples, refer to the "Configuring BGP" chapter of the Network Protocols Configuration Guide, Part 1.

aggregate-address

To create an aggregate entry in a BGP routing table, use the aggregate-address router configuration command. To disable this function, use the no form of this command.

aggregate-address address mask [as-set] [summary-only] [suppress-map map-name]
[advertise-map map-name] [attribute-map map-name]
no aggregate-address address mask [as-set] [summary-only] [suppress-map map-name]
[advertise-map map-name] [attribute-map map-name]

Syntax Description

address

Aggregate address.

mask

Aggregate mask.

as-set

(Optional) Generates autonomous system set path information.

summary-only

(Optional) Filters all more specific routes from updates.

suppress-map map-name

(Optional) Name of route map used to select the routes to be suppressed.

advertise-map map-name

(Optional) Name of route map used to select the routes to create AS-SET origin communities.

attribute-map map-name

(Optional) Name of route map used to set the attribute of the aggregate route.

Default

Disabled

Command Mode

Router configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 10.0.

You can implement aggregate routing in BGP either by redistributing an aggregate route into BGP or by using this conditional aggregate routing feature.

Using the aggregate-address command with no arguments will create an aggregate entry in the BGP routing table if there are any more-specific BGP routes available that fall in the specified range. The aggregate route will be advertised as coming from your autonomous system and has the atomic aggregate attribute set to show that information might be missing. (By default, the atomic aggregate attribute is set unless you specify the as-set keyword.)

Using the as-set keyword creates an aggregate entry using the same rules that the command follows without this keyword, but the path advertised for this route will be an AS_SET consisting of all elements contained in all paths that are being summarized. Do not use this form of aggregate-address when aggregating many paths, because this route must be continually withdrawn and re-updated as autonomous system path reachability information for the summarized routes changes.

Using the summary-only keyword not only creates the aggregate route (for example, 193.*.*.*) but will also suppress advertisements of more-specific routes to all neighbors. If you only want to suppress advertisements to certain neighbors, you may use the neighbor distribute-list command, with caution. If a more specific route leaks out, all BGP speakers will prefer that route over the less-specific aggregate you are generating (using longest-match routing).

Using the suppress-map keyword creates the aggregate route but suppresses advertisement of specified routes. You can use the match clauses of route maps to selectively suppress some more specific routes of the aggregate and leave others unsuppressed. IP access lists and autonomous system path access lists match clauses are supported.

Example

The following example creates an aggregate address. The path advertised for this route will be an AS_SET consisting of all elements contained in all paths that are being summarized.

router bgp 5
 aggregate-address 193.0.0.0 255.0.0.0 as-set

Related Commands

You can use the master indexes or search online to find documentation of related commands.

match as-path
match ip address
route-map

auto-summary

To restore the default behavior of automatic summarization of subnet routes into network-level routes, use the auto-summary router configuration command. To disable this feature and transmit subprefix routing information across classful network boundaries, use the no form of this command.

auto-summary
no auto-summary

Syntax Description

This command has no arguments or keywords.

Default

Enabled (the software summarizes subprefixes to the classful network boundary when crossing classful network boundaries).

Command Mode

Router configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 10.0.

Route summarization reduces the amount of routing information in the routing tables.

By default, BGP does not accept subnets redistributed from IGP. To advertise and carry subnet routes in BGP, use an explicit network command or the no auto-summary command. If you disable auto-summarization and have not entered a network command, you will not advertise network routes for networks with subnet routes unless they contain a summary route.

Example

In the following example, network numbers are not summarized automatically:

router bgp 6
 no auto-summary

bgp always-compare-med

To allow the comparison of the Multi Exit Discriminator (MED) for paths from neighbors in different autonomous systems, use the bgp always-compare-med router configuration command. To disallow the comparison, use the no form of this command.

bgp always-compare-med
no
bgp always-compare-med

Syntax Description

This command has no arguments or keywords.

Default

The Cisco IOS software does not compare MEDs for paths from neighbors in different autonomous systems.

Command Mode

Router configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 11.0.

The MED is one of the parameters that is considered when selecting the best path among many alternative paths. The path with a lower MED is preferred over a path with a higher MED.

By default, during the best-path selection process, MED comparison is done only among paths from the same autonomous system. This command changes the default behavior by allowing comparison of MEDs among paths regardless of the autonomous system from which the paths are received.

Example

The following example configures the BGP speaker in autonomous system 100 to compare MEDs among alternative paths, regardless of the autonomous system from which the paths are received:

router bgp 109
 bgp always-compare-med

bgp bestpath as-path ignore

To prevent the router from considering as-path as a factor in the algorithm for choosing a route, use the bgp bestpath as-path ignore router configuration command. To allow the router to consider as-path in choosing a route, use the no form of this command.

bgp bestpath as-path ignore
no bgp bestpath as-path ignore

Syntax Description

This command has no arguments or keywords.

Default

The router considers as-path in choosing a route.

Command Mode

Router configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 12.0.

Example

The following example preventes the BGP router from considering as-path as a factor in choosing a route.

router bgp 210 
bgp bestpath as-path ignore

Related Commands

show ip bgp neighbor


bgp bestpath med-confed

To enable MED comparison among paths learned from confederation peers, use the bgp bestpath med-confed router configuration command. To prevent the software from considering the MED attribute in comparing paths, use the no form of this command.

bgp bestpath med-confed
no bgp bestpath med-confed

Syntax Description

This command has no arguments or keywords.

Default

The software does not consider the MED attribute when choosing among paths learned from confederation peers.

Command Mode

Router configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 12.0.

The comparison between MEDs is only made if there are no external ASs in the path (an external AS is an AS that is not within the confederation). If there is an external AS in the path, then the external MED is passed transparently through the confederation, and the comparison is not made.

For example, assume that AS 65000, 65001, 65002, and 65004 are part of the confederation; AS1 is not; and we are comparing route A with four paths. If bgp bestpath med-confed is enabled, path 1 would be chosen. The fourth path has a lower MED, but it is not involved in the MED comparision because there is an external AS in this path.

path= 65000 65004, med=2

path= 65001 65004, med=3

path= 65002 65004, med=4

path= 65003 1, med=1

Example

The following command enables the BGP router to compare MED values for paths learned from confederation peers.

router bgp 210
 bgp bestpath med-confed

Related Commands

show ip bgp
show ip bgp neighbors

bgp bestpath missing-as-worst

To have Cisco IOS software consider a missing MED attribute in a path as having a value of infinity, making the path without a MED value the least desirable path, use the bgp bestpath missing-as-worst router configuration command. To return the router to the default (assign a value of 0 to the missing MED), use the no form of this command.

bgp bestpath missing-as-worst
no bgp bestpath missing-as-worst

Syntax Description

This command has no arguments or keywords.

Default

The software assigns a value of 0 to the missing MED, causing the path with the missing MED attribute to be considered the best path.

Command Mode

Router configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 12.0.

Example

The following command specifies that the BGP router to consider a missing MED attribute in a path as having a value of infinity, making this path the least desirable path.

router bgp 210
 bgp bestpath missing-as-worst

Related Commands

show ip bgp
show ip bgp neighbors


bgp client-to-client reflection

To restore route reflection from a BGP route reflector to clients, use the bgp client-to-client reflection router configuration command. To disable client-to-client reflection, use the no form of this command.

bgp client-to-client reflection
no bgp client-to-client reflection

Syntax Description

This command has no arguments or keywords.

Default

When a route reflector is configured, the route reflector reflects routes from a client to other clients.

Command Mode

Router configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 11.1.

By default, the clients of a route reflector are not required to be fully meshed and the routes from a client are reflected to other clients. However, if the clients are fully meshed, route reflection is not required. Use the no bgp client-to-client reflection command to disable client-to-client reflection.

If client-to-client reflection is enabled, the clients of a route reflector cannot be members of a peer group.

Example

In the following example, the local router is a route reflector. The three neighbors are fully meshed, so client-to-client reflection is disabled.

router bgp 5
 neighbor 155.24.95.22 route-reflector-client
 neighbor 155.24.95.23 route-reflector-client
 neighbor 155.24.95.24 route-reflector-client
 no bgp client-to-client reflection

Related Commands

You can use the master indexes or search online to find documentation of related commands.

bgp cluster-id
neighbor route-reflector-client
show ip bgp

bgp cluster-id

To configure the cluster ID if the BGP cluster has more than one route reflector, use the bgp  cluster-id router configuration command. To remove the cluster ID, use the no form of this command.

bgp cluster-id cluster-id
no bgp cluster-id cluster-id

Syntax Description

cluster-id

Cluster ID of this router acting as a route reflector; maximum of 4 bytes.

Default

The router ID of the single route reflector in a cluster

Command Mode

Router configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 11.0.

Together, a route reflector and its clients form a cluster.

Usually a cluster of clients will have a single route reflector. In that case, the cluster is identified by the router ID of the route reflector. In order to increase redundancy and avoid a single point of failure, a cluster might have more than one route reflector. In this case, all route reflectors in the cluster must be configured with the 4-byte cluster ID so that a route reflector can recognize updates from route reflectors in the same cluster.

If the cluster has more than one route reflector, use this command to configure the cluster ID.

Example

In the following example, the local router is one of the route reflectors serving the cluster. It is configured with the cluster ID to identify the cluster.

router bgp 5
 neighbor 198.92.70.24 route-reflector-client
 bgp cluster-id 50000

Related Commands

You can use the master indexes or search online to find documentation of related commands.

bgp client-to-client reflection
neighbor route-reflector-client
show ip bgp

bgp confederation identifier

To specify a BGP confederation identifier, use the bgp confederation identifier router configuration command. To remove the confederation identifier, use the no form of this command.

bgp confederation identifier autonomous-system
no bgp confederation identifier autonomous-system

Syntax Description

autonomous-system

Autonomous system number that internally includes multiple autonomous systems.

Default

No confederation identifier is configured.

Command Mode

Router configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 10.3.

Another way to reduce the IBGP mesh is to divide an autonomous system into multiple autonomous systems and group them into a single confederation. Each autonomous system is fully meshed within itself, and has a few connections to another autonomous system in the same confederation. Even though the peers in different autonomous systems have EBGP sessions, they exchange routing information as if they are IBGP peers. Specifically, the next-hop and local preference information is preserved. This enables to you to retain a single Interior Gateway Protocol (IGP) for all the autonomous systems. To the outside world, the confederation looks like a single autonomous system.

Example

In the following example, the autonomous system is divided into autonomous systems 4001, 4002, 4003, 4004, 4005, 4006, and 4007 and identified by the confederation identifier 5. Neighbor 1.2.3.4 is someone inside your routing domain confederation. Neighbor 3.4.5.6 is someone outside your routing domain confederation. To the outside world, there appears to be a single autonomous system with the number 5.

router bgp 4001
 bgp confederation identifier 5
 bgp confederation peers 4002 4003 4004 4005 4006 4007
 neighbor 1.2.3.4 remote-as 4002
 neighbor 3.4.5.6 remote-as 510

Related Commands

You can use the master indexes or search online to find documentation of related commands.

bgp confederation peers

bgp confederation peers

To configure the autonomous systems that belong to the confederation, use the bgp  confederation  peers router configuration command. To remove an autonomous system from the confederation, use the no form of this command.

bgp confederation peers autonomous-system [autonomous-system]
no bgp confederation peers autonomous-system [autonomous-system]

Syntax Description

autonomous-system

Autonomous system number.

Default

No confederation peers are configured.

Command Mode

Router configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 10.3.

The autonomous systems specified in this command are visible internally to a confederation. Each autonomous system is fully meshed within itself. The bgp confederation identifier command specifies the confederation to which the autonomous systems belong.

Example

The following example specifies that autonomous systems 1090, 1091, 1092, and 1093 belong to a single confederation:

router bgp 1090
 bgp confederation peers 1091 1092 1093

Related Commands

You can use the master indexes or search online to find documentation of related commands.

bgp confederation identifier

bgp dampening

To enable BGP route dampening or change various BGP route dampening factors, use the bgp dampening global configuration command. To disable the function or restore the default values, use the no form of this command.

bgp dampening [half-life reuse suppress max-suppress-time] [route-map map]
no bgp dampening [half-life reuse suppress max-suppress-time] [route-map map]

Syntax Description

half-life

(Optional) Time (in minutes) after which a penalty is decreased. Once the route has been assigned a penalty, the penalty is decreased by half after the half-life period (which is 15 minutes by default). The process of reducing the penalty happens every 5 seconds. The range of the half-life period is 1  to 45  minutes. The default is 15  minutes.

reuse

(Optional) If the penalty for a flapping route decreases enough to fall below this value, the route is unsuppressed. The process of unsuppressing routes occurs at 10-second increments. The range of the reuse value is 1 to 20000; the default is 750.

suppress

(Optional) A route is suppressed when its penalty exceeds this limit. The range is 1 to 20000; the default is 2000.

max-suppress-time

(Optional) Maximum time (in minutes) a route can be suppressed. The range is 1 to 20000; the default is 4 times the half-life. If the half-life value is allowed to default, the maximum suppress time defaults to 60 minutes.

route-map map

(Optional) Name of route map that controls where BGP route dampening is enabled.

Default

Disabled by default.

half-life is 15 minutes
reuse is 750
suppress is 2000
max-suppress-time is 4 times half-life

Command Mode

Global configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 11.0.

If this command is used with no arguments, it enables BGP route dampening. The arguments half-life, reuse, suppress, and max-suppress-time are position-dependent. Therefore, if any of them are used, they must all be specified.

Example

The following example sets the half-life to 30 minutes, the reuse value to 1500, the suppress value to 10000; and the maximum suppress time to 120 minutes:

bgp dampening 30 1500 10000 120

Related Commands

You can use the master indexes or search online to find documentation of related commands.

clear ip bgp dampening
clear ip bgp flap-statistics
show ip bgp dampened-paths
show ip bgp flap-statistics

bgp default local-preference

To change the default local preference value, use the bgp default local-preference router configuration command. To return to the default setting, use the no form of this command.

bgp default local-preference value
no bgp default local-preference value

Syntax Description

value

Local preference value from 0 to 4294967295. Higher is more preferred.

Default

Local preference value of 100

Command Mode

Router configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 10.0.

Generally, the default value of 100 allows you to easily define a particular path as less preferable than paths with no local preference attribute. The preference is sent to all routers and access servers in the local autonomous system.

Example

The following example raises the default local preference value from the default of 100 to 200:

router bgp 200
 bgp default local-preference 200

Related Commands

You can use the master indexes or search online to find documentation of related commands.

set local-preference

bgp deterministic med

To have Cisco IOS software compare the MED variable when choosing among routes advertised by the same sub-AS within a confederation, use the bgp deterministic med router configuration command. To disallow the comparison, use the no form of this command.

bgp deterministic med
no bgp deterministic med

Syntax Description

This command has no arguments or keywords.

Default

The software does not compare the MED variable for paths advertised by a sub-AS.

Command Mode

Router configuration mode

Usage Guidelines

This command first appeared in Cisco IOS Release 12.0.

If bgp always-compare-med is enabled, all paths are fully comparable, including those from other ASes in the confederation, even if bgp deterministic med is also enabled.

Example

The following example specifies that the BGP router compare MED variables when choosing among routes advertised by the same sub-AS within a confederation.

router 204
 bgp deterministic med

Related Commands

show ip bgp
show ip bgp neighbors

bgp log-neighbor-changes

To enable logging of BGP neighbor resets, use the bgp log-neighbor-changes router configuration command. To disable the logging of changes in BGP neighbor adjacencies, use the no form of this command.

bgp log-neighbor-changes
no bgp log-neighbor-changes

Syntax Description

This command has no arguments or keywords.

Default

No BGP neighbor changes are logged.

Command Mode

Router configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 11.1 CC and 12.0.

The bgp log-neighbor-changes command enables logging of BGP neighbor status changes (up or down) and resets for troubleshooting network connectivity problems and measuring network stability. Unexpected neighbor resets might indicate high error rates or high packet loss in the network and should be investigated.

Using the bgp log-neighbo-changes command to enable status change message logging does not create a significant performance hit, unlike, for example, enabling per BGP update debugging. If the UNIX syslog facility is enabled, messages are sent to the UNIX host running the syslog daemon so that the messages can be stored and archived. If the UNIX syslog facility is not enabled, the status change messages are retained in the router's internal buffer, and are not stored to disk. You can set the size of this buffer, which is dependent upon the available RAM, using the logging buffered command.

The neighbor status change messages are not tracked if bgp log-neighbor changes is not enabled, except for the reset reason, which is always available as output of the show ip bgp neighbor command.

The log messages display the following reasons for changes in a neighbor's status:

BGP protocol initialization

No memory for path entry

No memory for attribute entry

No memory for prefix entry

No memory for aggregate entry

No memory for dampening info

No memory for BGP updates

BGP Notification received

Erroneous BGP Update received

User reset request

Peer timeout

Password change

Error during connection collision

Peer closing down the session

Peer exceeding maximum prefix limit

Interface flap

Router ID changed

Neighbor deleted

Member added to peergroup

Administratively shutdown

Remote AS changed

RR client configuration modification

Soft reconfiguration modification

The eigrp log-neighbor-changes command enables logging of Enhanced IGRP neighbor adjacencies, but messages for BGP neighbors are logged only if they are specifically enabled with the bgp log-neighbor-changes command.

Use the show logging command to display the log for the BGP neighbor changes.

Example

The following configuration will log neighbor changes for BGP:

bgp router 100

       bgp log-neighbor-changes

Related Commands

You can use the master indexes or search online to find documentation of related commands.

logging buffered
show ip bgp neighbor
show logging

bgp fast-external-fallover

To immediately reset the BGP sessions of any directly adjacent external peers if the link used to reach them goes down, use the bgp fast-external-fallover router configuration command. To disable this function, use the no form of this command.

bgp fast-external-fallover
no
bgp fast-external-fallover

Syntax Description

This command has no arguments or keywords.

Default

Enabled

Command Mode

Router configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 10.0.

Example

The following example disables the automatic resetting of BGP sessions:

router bgp 109
 no bgp fast-external-fallover
 

clear ip bgp

To reset a BGP connection using BGP soft reconfiguration, use the clear ip bgp EXEC command at the system prompt.

clear ip bgp {* | address | peer-group name} [soft [in | out]]

Syntax Description

*

Resets all current BGP sessions.

address

Resets only the identified BGP neighbor.

peer-group-name

Resets the specified BGP peer group.

soft

(Optional) Soft reconfiguration.

in | out

(Optional) Triggers inbound or outbound soft reconfiguration. If the in or out option is not specified, both inbound and outbound soft reconfiguration are triggered.

Command Mode

EXEC

Usage Guidelines

This command first appeared in Cisco IOS Release 10.0.

If you specify BGP soft reconfiguration, by including the soft keyword, the sessions are not reset and the router sends all routing updates again. To generate new inbound updates without resetting the BGP session, the local BGP speaker should store all received updates without modification regardless of whether it is accepted by the inbound policy, using the neighbor soft-reconfiguration command. This process is memory intensive and should be avoided if possible. Outbound BGP soft configuration does not have any memory overhead. You can trigger an outbound reconfiguration on the other side of the BGP session to make the new inbound policy take effect.

Use this command whenever any of the following changes occur:

Example

The following example resets all current BGP sessions:

clear ip bgp *

Related Commands

You can use the master indexes or search online to find documentation of related commands.

clear ip bgp
neighbor soft-reconfiguration
show ip bgp
timers bgp

clear ip bgp dampening

To clear BGP route dampening information and unsuppress the suppressed routes, use the clear ip bgp dampening EXEC command.

clear ip bgp dampening [address mask]

Syntax Description

address

(Optional) IP address of the network about which to clear dampening information.

mask

(Optional) Network mask applied to the address.

Command Mode

EXEC

Usage Guidelines

This command first appeared in Cisco IOS Release 11.0.

Example

The following example clears route dampening information about the route to network 150.0.0.0 and unsuppresses its suppressed routes:

clear ip bgp dampening 150.0.0.0 255.255.0.0

Related Commands

You can use the master indexes or search online to find documentation of related commands.

bgp dampening
show ip bgp dampened-paths

clear ip bgp flap-statistics

To clear BGP flap statistics, use the clear ip bgp flap-statistics EXEC command.

clear ip bgp flap-statistics [{regexp regexp} | {filter-list list} | {address mask}]
clear ip bgp address flap-statistics

Syntax Description

regexp regexp

(Optional) Clears flap statistics for all the paths that match the regular expression.

filter-list list

(Optional) Clears flap statistics for all the paths that pass the access list.

address

(Optional) Clears flap statistics for a single entry at this IP address. If this argument is placed before flap-statistics, the router clears flap statistics for all paths from the neighbor at this address.

mask

(Optional) Network mask applied to the address.

Command Mode

EXEC

Usage Guidelines

This command first appeared in Cisco IOS Release 11.0.

If no arguments or keywords are specified, the router clear flap statistics for all routes.

The flap statistics for a route are also cleared when a BGP peer is reset. Although the reset withdraws the route, there is no penalty applied in this instance even though route flap dampening is enabled.

Example

The following example clears all of the flap statistics for paths that pass access list 3:

clear ip bgp flap-statistics filter-list 3

Related Commands

You can use the master indexes or search online to find documentation of related commands.

bgp dampening

clear ip bgp peer-group

To remove all the members of a BGP peer group, use the clear ip bgp peer-group EXEC command.

clear ip bgp peer-group tag

Syntax Description

tag

Name of the BGP peer group to clear.

Command Mode

EXEC

Usage Guidelines

This command first appeared in Cisco IOS Release 11.0.

Example

The following example removes all members from the BGP peer group internal:

clear ip bgp peer-group internal

Related Commands

You can use the master indexes or search online to find documentation of related commands.

neighbor peer-group (assigning members)

default-information originate (BGP)

To allow the redistribution of network 0.0.0.0 into BGP, use the default-information originate router configuration command. To disable this function, use the no form of this command.

default-information originate
no default-information originate

Syntax Description

This command has no arguments or keywords.

Default

Disabled

Command Mode

Router configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 10.0.

The same functionality will result from the network 0.0.0.0 command, using the network router configuration command.

Example

The following example configures BGP to redistribute network 0.0.0.0 into BGP:

router bgp 164
 default-information originate

Related Commands

You can use the master indexes or search online to find documentation of related commands.

neighbor ebgp-multihop

default-metric (BGP, OSPF, and RIP)

To set default metric values for the BGP, OSPF, and RIP routing protocols, use this form of the default-metric router configuration command. To return to the default state, use the no form of this command.

default-metric number
no default-metric number

Syntax Description

number

Default metric value appropriate for the specified routing protocol.

Default

Built-in, automatic metric translations, as appropriate for each routing protocol

Command Mode

Router configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 10.0.

The default-metric command is used in conjunction with the redistribute router configuration command to cause the current routing protocol to use the same metric value for all redistributed routes. A default metric helps solve the problem of redistributing routes with incompatible metrics. Whenever metrics do not convert, using a default metric provides a reasonable substitute and enables the redistribution to proceed.

In BGP, this sets the Multi Exit Discriminator (MED) metric. (The name of this metric for BGP Versions 2 and 3 is INTER_AS.)

Example

The following example shows a router in autonomous system 109 using both the RIP and the OSPF routing protocols. The example advertises OSPF-derived routes using the RIP protocol and assigns the IGRP-derived routes a RIP metric of 10.

router rip
 default-metric 10
 redistribute ospf 109

Related Commands

You can use the master indexes or search online to find documentation of related commands.

redistribute

distance bgp

To allow the use of external, internal, and local administrative distances that could be a better route to a node, use the distance bgp router configuration command. To return to the default values, use the no form of this command.

distance bgp external-distance internal-distance local-distance
no distance bgp

Syntax Description

external-distance

Administrative distance for BGP external routes. External routes are routes for which the best path is learned from a neighbor external to the autonomous system. Acceptable values are from 1 to 255. The default is 20. Routes with a distance of 255 are not installed in the routing table.

internal-distance

Administrative distance for BGP internal routes. Internal routes are those routes that are learned from another BGP entity within the same autonomous system. Acceptable values are from 1 to 255. The default is 200. Routes with a distance of 255 are not installed in the routing table.

local-distance

Administrative distance for BGP local routes. Local routes are those networks listed with a network router configuration command, often as back doors, for that router or for networks that are being redistributed from another process. Acceptable values are from 1 to 255. The default is 200. Routes with a distance of 255 are not installed in the routing table.

Defaults

external-distance: 20
internal-distance: 200
local-distance: 200

Command Mode

Router configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 10.0.

An administrative distance is a rating of the trustworthiness of a routing information source, such as an individual router or a group of routers. Numerically, an administrative distance is an integer between 0 and 255. In general, the higher the value, the lower the trust rating. An administrative distance of 255 means the routing information source cannot be trusted at all and should be ignored.

Use this command if another protocol is known to be able to provide a better route to a node than was actually learned via external BGP, or if some internal routes should really be preferred by BGP.


Note Changing the administrative distance of BGP internal routes is considered dangerous and is not recommended. One problem that can arise is the accumulation of routing table inconsistencies, which can break routing.

Example

In the following example, internal routes are known to be preferable to those learned through the IGP, so the administrative distance values are set accordingly:

router bgp 109
 network 131.108.0.0
 neighbor 129.140.6.6 remote-as 123
 neighbor 128.125.1.1 remote-as 47
 distance bgp 20 20 200

ip as-path access-list

To define a BGP-related access list, use the ip as-path access-list global configuration command. To disable use of the access list, use the no form of this command.

ip as-path access-list access-list-number {permit | deny} as-regular-expression
no ip as-path access-list access-list-number {permit | deny} as-regular-expression

Syntax Description

access-list-number

Integer from 1 to 199 that indicates the regular expression access list number.

permit

Permits access for matching conditions.

deny

Denies access to matching conditions.

as-regular-expression

Autonomous system in the access list using a regular expression. See the "Regular Expressions" appendix in the Dial Solutions Command Reference for information about forming regular expressions.

Default

No access lists are defined.

Command Mode

Global configuration

Usage Guidelines

This command first appeared in Cisco IOS Release  10.0.

You can specify an access list filter on both inbound and outbound BGP routes. In addition, you can assign weights based on a set of filters. Each filter is an access list based on regular expressions. If the regular expression matches the representation of the autonomous system path of the route as an ASCII string, then the permit or deny condition applies. The autonomous system path does not contain the local autonomous system number. Use the ip  as-path  access-list global configuration command to define an BGP access list, and the neighbor router configuration command to apply a specific access list.

Example

The following example specifies that the BGP neighbor with IP address 128.125.1.1 is not sent advertisements about any path through or from the adjacent autonomous system 123:

ip as-path access-list 1 deny _123_
ip as-path access-list 1 deny ^123$
 
router bgp 109
 network 131.108.0.0
 neighbor 129.140.6.6 remote-as 123
 neighbor 128.125.1.1 remote-as 47
 neighbor 128.125.1.1 filter-list 1 out

Related Commands

You can use the master indexes or search online to find documentation of related commands.

neighbor distribute-list
neighbor filter-list

ip bgp-community new-format

To display BGP communities in the format AA:NN (AS-community number/2-byte number), use the ip bgp-community new-format global configuration command.To re-enable the previous display format for BGP communities (NN:AA), use the no form of this command.

ip bgp-community new-format
no ip bgp-community new-format

Syntax Description

This command has no argument or keywords.

Usage Guidelines

This command first appeared in Cisco IOS Release 12.0.

The BGP communities RFC specifies that a BGP community is made up of two parts 2 bytes long. The first part is the AS number and the second part is a 2 byte number. In the most recent version of the RFC, a community is of the form AA:NN.The Cisco default community format is in the format NNAA. The ip bgp-community new-format command changes the community forma to AANN to conform to the most recent RFC.

Example

router# show ip bgp community 12345:111 local-as 
 BGP table version is 10, local router ID is 224.0.0.10
 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal
 Origin codes: i - IGP, e - EGP, ? - incomplete
  
    Network          Next Hop          Metric LocPrf Weight Path
 *> 2.2.2.2/32       158.43.222.2           0             0 222 ?
 *> 111.0.0.0        158.43.222.2           0             0 222 ?
 *> 158.43.0.0       158.43.222.2           0             0 222 ?
 *> 158.43.44.44/32  158.43.222.2           0             0 222 ?

Related Command

show ip bgp x.x.x.x

ip community-list

To create a community list for BGP and control access to it, use the ip community-list global configuration command. To delete the community list, use the no form of this command.

ip community-list community-list-number {permit | deny} community-number
no ip community-list community-list-number

Syntax Description

community-list-number

Integer from 1 to 99 that identifies one or more permit or deny groups of communities.

permit

Permits access for a matching condition.

deny

Denies access for a matching condition.

community-number

Community number configured by a set community command. Valid value is one of the following:

· A number from 1 to 4294967200. You can specify a single number or multiple numbers separated by a space.

· internet---The Internet community.

· no-export---Routes with this community are sent to peers in other sub-autonomous systems within a confederation. Do not advertise this route to an EBGP peer. External systems are those outside the confederation. If there is no confederation, an external system is any EBGP peer.

· local-as Send this route to peers in other sub-autonomous systems within the local confederation. Do not advertise this route to an external system.

· no-advertise---Do not advertise this route to any peer (internal or external).

Default

Once you permit a value for the community number, the community list defaults to an implicit deny for everything else that has not been permitted.

Command Mode

Global configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 10.3. The local-as attribute was added in Cisco IOS Release 12.0.

Example

In the following example, Cisco IOS software permits all routes except the routes with the communities 5 and 10 or 10 and 15:

ip community-list 1 deny 5 10
ip community-list 1 deny 10 15
ip community-list 1 permit internet
 

The following example permits all routes within the local autonomous system:

ip community-list 1 permit local-as

Related Commands

You can use the master indexes or search online to find documentation of related commands.

set community
show ip bgp community

match as-path

To match a BGP autonomous system path access list, use the match as-path route-map configuration command. To remove a path list entry, use the no form of this command.

match as-path path-list-number
no match as-path path-list-number

Syntax Description

path-list-number

Autonomous system path access list. An integer from 1 to  199.

Default

No path lists are defined.

Command Mode

Route-map configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 10.0.

The values set by the match and set commands override global values. For example, the weights assigned with the match as-path and set weight route-map commands override the weights assigned using the neighbor weight and neighbor filter-list commands.

A route map can have several parts. Any route that does not match at least one match clause relating to a route-map command will be ignored; that is, the route will not be advertised for outbound route maps and will not be accepted for inbound route maps. If you want to modify only some data, you must configure a second route-map section with an explicit match specified.

The implemented weight is based on the first matched autonomous system path.

Example

The following example sets the autonomous system path to match BGP autonomous system path access list 20:

route-map igp2bgp
 match as-path 20

Related Commands

You can use the master indexes or search online to find documentation of related commands.

match community-list
match interface
match ip address
match ip next-hop
match ip route-source
match metric
match route-type
match tag
route-map
set as-path
set automatic-tag
set community
set level
set local-preference
set metric
set metric-type
set next-hop
set origin
set tag
set weight

match community-list

To match a BGP community, use the match community-list route-map configuration command. To remove the community list entry, use the no form of this command.

match community-list community-list-number [exact]
no match community-list community-list-number [exact]

Syntax Description

community-list-number

Community list number in the range 1 to 99.

exact

(Optional) Indicates an exact match is required. All of the communities and only those communities in the community list must be present.

Default

No community list is defined.

Command Mode

Route-map configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 10.3.

A route map can have several parts. Any route that does not match at least one match clause relating to a route-map command will be ignored; that is, the route will not be advertised for outbound route maps and will not be accepted for inbound route maps. If you want to modify only some data, you must configure a second route-map section with an explicit match specified.

Matching based on community list is one of the types of match clauses applicable to BGP.

Examples

In the following example, the routes that match community list 1 will have the weight set to 100. Any route that has community 109 will have the weight set to 100.

ip community-list 1 permit 109
!
route-map set_weight
 match community-list 1
 set weight 100
 

In the following example, the routes that match community list 1 will have the weight set to 200. Any route that has community 109 alone will have the weight set to 200.

ip community-list 1 permit 109
!
route-map set_weight
 match community-list 1 exact
 set weight 200

Related Commands

You can use the master indexes or search online to find documentation of related commands.

route-map
set weight

neighbor advertisement-interval

To set the minimum interval between the sending of BGP routing updates, use the neighbor advertisement-interval router configuration command. To remove an entry, use the no form of this command.

neighbor {ip-address | peer-group-name} advertisement-interval seconds
no neighbor {ip-address | peer-group-name} advertisement-interval seconds

Syntax Description

ip-address

Neighbor's IP address.

peer-group-name

Name of a BGP peer group.

seconds

Time in seconds. Integer from 0 to 600.

Default

30 seconds for external peers and 5 seconds for internal peers.

Command Mode

Router configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 10.0.

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.

Example

The following example sets the minimum time between sending BGP routing updates to 10  seconds:

router bgp 5
 neighbor 4.4.4.4 advertisement-interval 10

Related Commands

You can use the master indexes or search online to find documentation of related commands.

neighbor peer-group (creating)

neighbor default-originate

To allow a BGP speaker (the local router) to send the default route 0.0.0.0 to a neighbor for use as a default route, use the neighbor default-originate router configuration command. To send no route as a default, use the no form of this command.

neighbor {ip-address | peer-group-name} default-originate [route-map map-name]
no neighbor {ip-address | peer-group-name} default-originate [route-map map-name]

Syntax Description

ip-address

Neighbor's IP address.

peer-group-name

Name of a BGP peer group.

route-map map-name

(Optional) Name of the route map. The route map allows route 0.0.0.0 to be injected conditionally.

Default

No default route is sent to the neighbor.

Command Mode

Router configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 11.0. Modifications to permit extended access lists first appeared in Cisco IOS Release 12.0.

This command does not require the presence of 0.0.0.0 in the local router. When used with a route map, the default route 0.0.0.0 is injected if the route map contains a match ip address clause and there is a route that matches the IP access list exactly. The route map can contain other match clauses also.

You can use standard or extended access lists with the neighbor default-originate command.

Examples

In the following example, the local router injects route 0.0.0.0 to the neighbor 160.89.2.3 unconditionally:

router bgp 109
 network 160.89.0.0
 neighbor 160.89.2.3 remote-as 200
 neighbor 160.89.2.3 default-originate
 

In the following example, the local router injects route 0.0.0.0 to the neighbor 160.89.2.3 only if there is a route to 198.92.68.0 (that is, if a route with any mask exists, such as 255.255.255.0 or 255.255.0.0):

router bgp 109
 network 160.89.0.0
 neighbor 160.89.2.3 remote-as 200
 neighbor 160.89.2.3 default-originate route-map default-map
!
route-map default-map 10 permit
 match ip address 1
!
access-list 1 permit 198.92.68.0
 

In the following example, the last line of the configuration has been changed to show the use of an extended access list. The local router injects route 0.0.0.0 to the neighbor 160.89.2.3 only if there is a route to 198.92.68.0 with a mask of 255.255.0.0:

router bgp 109
 network 160.89.0.0
 neighbor 160.89.2.3 remote-as 200
 neighbor 160.89.2.3 default-originate route-map default-map
!
route-map default-map 10 permit
 match ip address 1
!
access-list 100 permit ip host 198.92.68.0 host 255.255.255.0

Related Commands

You can use the master indexes or search online to find documentation of related commands.

neighbor ebgp-multihop

neighbor description

To associate a description with a neighbor, use the neighbor description router configuration command. To remove the description, use the no form of this command.

neighbor {ip-address | peer-group-name} description text
no neighbor {ip-address | peer-group-name} description [text]

Syntax Description

ip-address

Neighbor's IP address.

peer-group-name

Name of a BGP peer group.

text

Text (up to 80 characters) that describes the neighbor.

Default

There is no description of the neighbor.

Command Mode

Router configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 11.3.

Example

In the following example, the description of the neighbor is "peer with abc.com":

router bgp 109
 network 160.89.0.0
 neighbor 160.89.2.3 description peer with abc.com

neighbor distribute-list

To distribute BGP neighbor information as specified in an access list, use the neighbor  distribute-list router configuration command. To remove an entry, use the no form of this command.

neighbor {ip-address | peer-group-name} distribute-list {access-list-number | name/prefix-list prefixlistname} {in | out}
no neighbor {ip-address | peer-group-name} distribute-list {access-list-number | name} {in |
out}

Syntax Description

ip-address

Neighbor's IP address.

peer-group-name

Name of a BGP peer group.

access-list-number | name

Number or name of a standard or extended access list. It can be an integer from 1 to 199.

in

Access list is applied to incoming advertisements to that neighbor.

out

Access list is applied to outgoing advertisements from that neighbor.

Default

No BGP neighbor is specified.

Command Mode

Router configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 10.0. The peer-group-name argument first appeared in Cisco IOS Release 11.0. The access-list-name argument first appeared in Cisco IOS Release 11.2.

Using distribute lists is one of two ways to filter BGP advertisements. The other way is to use AS-path filters, as with the ip as-path access-list global configuration command and the neighbor filter-list command.

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. Specifying the command with an IP address will override the value inherited from the peer group.

Example

The following example applies list 39 to incoming advertisements to neighbor 120.23.4.1:

router bgp 109
 network 131.108.0.0
 neighbor 120.23.4.1 distribute-list 39 in

Related Commands

You can use the master indexes or search online to find documentation of related commands.

ip as-path access-list
neighbor filter-list
neighbor peer-group (creating)

neighbor ebgp-multihop

To accept and attempt BGP connections to external peers residing on networks that are not directly connected, use the neighbor ebgp-multihop router configuration command. To return to the default, use the no form of this command.

neighbor {ip-address | peer-group-name} ebgp-multihop [ttl]
no neighbor {ip-address | peer-group-name} ebgp-multihop

Syntax Description

ip-address

IP address of the BGP-speaking neighbor.

peer-group-name

Name of a BGP peer group.

ttl

(Optional) Time-to-live in the range 1 to 255 hops.

Default

Only directly connected neighbors are allowed.

Command Mode

Router configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 10.0. The peer-group-name argument first appeared in Cisco IOS Release 11.0.

This feature should only be used under the guidance of technical support staff.

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.

To prevent the creation of loops through oscillating routes,, the multihop will not be established if the only route to the multihop peer is the default route (0.0.0.0).

Example

The following example allows connections to or from neighbor 131.108.1.1, which resides on a network that is not directly connected:

router bgp 109
 neighbor 131.108.1.1 ebgp-multihop

Related Commands

You can use the master indexes or search online to find documentation of related commands.

neighbor default-originate
neighbor peer-group (creating)
network (BGP)

neighbor filter-list

To set up a BGP filter, use the neighbor filter-list router configuration command. To disable this function, use the no form of this command.

neighbor {ip-address | peer-group-name} filter-list access-list-number {in | out |
weight weight}
no neighbor {ip-address | peer-group-name} filter-list access-list-number {in | out |
weight weight}

Syntax Description

ip-address

IP address of the neighbor.

peer-group-name

Name of a BGP peer group.

access-list-number

Number of an autonomous system path access list. You define this access list with the ip  as-path  access-list command.

in

Access list to incoming routes.

out

Access list to outgoing routes.

weight weight

Assigns a relative importance to incoming routes matching autonomous system paths. Acceptable values are 0 to 65535.

Default

Disabled

Command Mode

Router configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 10.0.

This command establishes filters on both inbound and outbound BGP routes. Any number of weight filters are allowed on a per-neighbor basis, but only one in or out filter is allowed. The weight of a route affects BGP's route-selection rules.

The implemented weight is based on the first matched autonomous system path. Weights indicated when an autonomous system path is matched override the weights assigned by global neighbor commands. In other words, the weights assigned with the match as-path and set weight route-map commands override the weights assigned using the neighbor weight and neighbor filter-list commands.

See the "Regular Expressions" appendix in the Dial Solutions Command Reference for information on forming regular expressions.

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. Specifying the command with an IP address will override the value inherited from the peer group.

Example

In the following example, the BGP neighbor with IP address 128.125.1.1 is not sent advertisements about any path through or from the adjacent autonomous system 123:

ip as-path access-list 1 deny _123_
ip as-path access-list 1 deny ^123$
 
router bgp 109
 network 131.108.0.0
 neighbor 129.140.6.6 remote-as 123
 neighbor 128.125.1.1 remote-as 47
 neighbor 128.125.1.1 filter-list 1 out

Related Commands

You can use the master indexes or search online to find documentation of related commands.

ip as-path access-list
neighbor distribute-list
neighbor peer-group (creating)
neighbor weight

neighbor maximum-prefix

To control how many prefixes can be received from a neighbor, use the neighbor maximum-prefix router configuration command. To disable this function, use the no form of this command.

neighbor {ip-address | peer-group-name} maximum-prefix maximum [threshold]
[warning-only]
no neighbor {ip-address | peer-group-name} maximum-prefix maximum

Syntax Description

ip-address

IP address of the neighbor.

peer-group-name

Name of a BGP peer group.

maximum

Maximum number of prefixes allowed from this neighbor.

threshold

(Optional) Integer specifying at what percentage of maximum the router starts to generate a warning message. The range 1 to 100; the default is 75 (percent).

warning-only

(Optional) Allows the router to generate log message when the maximum is exceeded, instead of terminating the peering.

Default

Disabled; there is no limit on the number of prefixes.

Command Mode

Router configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 11.3.

This command allows you to configure a maximum number of prefixes a BGP router is allowed to receive from a peer. It adds another mechanism (in addition to distribute lists, filter lists, and route maps) to control prefixes received from a peer.

When the number of received prefixes exceeds the maximum number configured, the router terminates the peering (by default). However, if the keyword warning-only is configured, the router instead only sends a log message, but continues peering with the sender. If the peer is terminated, the peer stays down until the clear ip bgp command is issued.

Example

The following example sets the maximum number of prefixes allowed from the neighbor at 129.140.6.6 to 1000:

router bgp 109
 network 131.108.0.0
 neighbor 129.140.6.6 maximum-prefix 1000

Related Commands

You can use the master indexes or search online to find documentation of related commands.

clear ip bgp

neighbor next-hop-self

To disable next-hop processing of BGP updates on the router, use the neighbor  next-hop-self router configuration command. To disable this feature, use the no form of this command.

neighbor {ip-address | peer-group-name} next-hop-self
no neighbor {ip-address | peer-group-name} next-hop-self

Syntax Description

ip-address

IP address of the BGP-speaking neighbor.

peer-group-name

Name of a BGP peer group.

Default

Disabled

Command Mode

Router configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 10.0. The peer-group-name argument first appeared in Cisco IOS Release 11.0.

This command is useful in nonmeshed networks (such as Frame Relay or X.25) where BGP neighbors may not have direct access to all other neighbors on the same IP subnet.

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. Specifying the command with an IP address will override the value inherited from the peer group.

For a finer granularity of control, see the set ip next-hop command.

Example

The following example forces all updates destined for 131.108.1.1 to advertise this router as the next hop:

router bgp 109
 neighbor 131.108.1.1 next-hop-self

Related Commands

You can use the master indexes or search online to find documentation of related commands.

neighbor peer-group (creating)
set ip next-hop

neighbor password

To enable MD5 authentication on a TCP connection between two BGP peers, use the neighbor password router configuration command. To disable this function, use the no form of this command.

neighbor {ip-address | peer-group-name} password string
no neighbor {ip-address | peer-group-name} password

Syntax Description

ip-address

IP address of the BGP-speaking neighbor.

peer-group-name

Name of a BGP peer group.

string

Case-sensitive password of up to 80 characters. The first character cannot be a number. The string can contain any alphanumeric characters, including spaces. You cannot specify a password in the format number-space-anything. The space after the number causes problems.

Default

Disabled

Command Mode

Router configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 11.0.

You can invoke authentication between two BGP peers, causing each segment sent on the TCP connection between them to be verified. This feature must be configured with the same password on both BGP peers; otherwise, the connection between them will not be made. The authentication feature uses the MD5 algorithm. Specifying this command causes the generation and checking of the MD5 digest on every segment sent on the TCP connection.

Configuring a password for a neighbor will cause an existing session to be torn down and a new one established.

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.

If a router has a password configured for a neighbor, but the neighbor router does not, a message such as the following will appear on the console while the routers attempt to establish a BGP session between them:

%TCP-6-BADAUTH: No MD5 digest from [peer's IP address]:11003 to [local router's IP address]:179
 

Similarly, if the two routers have different passwords configured, a message such as the following will appear on the console:

%TCP-6-BADAUTH: Invalid MD5 digest from [peer's IP address]:11004 to [local router's IP address]:179

Example

The following example enables the authentication feature between this router and the BGP neighbor at 131.102.1.1. The password that must also be configured for the neighbor is bla4u00=2nkq.

router bgp 109
 neighbor 131.108.1.1 password bla4u00=2nkq

Related Commands

You can use the master indexes or search online to find documentation of related commands.

neighbor peer-group (creating)

neighbor peer-group (assigning members)

To configure a BGP neighbor to be a member of a peer group, use the neighbor peer-group router configuration command. To remove the neighbor from the peer group, use the no form of this command.

neighbor ip-address peer-group peer-group-name
no neighbor ip-address peer-group peer-group-name

Syntax Description

ip-address

IP address of the BGP neighbor who belongs to the peer group specified by the tag.

peer-group-name

Name of the BGP peer group to which this neighbor belongs.

Default

There are no BGP neighbors in a peer group.

Command Mode

Router configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 11.0.

The neighbor at the IP address indicated inherits all the configured options of the peer group.

Example

The following example assigns three neighbors to the peer group named internal:

router bgp 100
 neighbor internal peer-group
 neighbor internal remote-as 100
 neighbor internal update-source loopback 0
 neighbor internal route-map set-med out
 neighbor internal filter-list 1 out
 neighbor internal filter-list 2 in
 neighbor 171.69.232.53 peer-group internal
 neighbor 171.69.232.54 peer-group internal
 neighbor 171.69.232.55 peer-group internal
 neighbor 171.69.232.55 filter-list 3 in

Related Commands

You can use the master indexes or search online to find documentation of related commands.

neighbor peer-group (creating)

neighbor shutdown

neighbor peer-group (creating)

To create a BGP peer group, use the neighbor peer-group router configuration command. To remove the peer group and all of its members, use the no form of this command.

neighbor peer-group-name peer-group
no neighbor peer-group-name peer-group

Syntax Description

peer-group-name

Name of the BGP peer group.

Default

There is no BGP peer group.

Command Mode

Router configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 11.0.

Often in a BGP speaker, there are many neighbors configured with the same update policies (that is, same outbound route maps, distribute lists, filter lists, update source, and so on). Neighbors with the same update policies can be grouped into peer groups to simplify configuration and make update calculation more efficient.

Peer group members can spanned multiple logical IP subnets, and can transit, or pass along, routes from one peer group member to another.

Once a peer group is created with the neighbor peer-group command, it can be configured with the neighbor commands. By default, members of the peer group inherit all the configuration options of the peer group. Members can also be configured to override the options that do not affect outbound updates.

Peer group members will always inherit the following configuration options: remote-as (if configured), version, update-source, out-route-map, out-filter-list, out-dist-list, minimum-advertisement-interval, and next-hop-self. All the peer group members will inherit changes made to the peer group.

If a peer group is not configured with a remote-as, the members can be configured with the neighbor  {ip-address | peer-group-name} remote-as command. This command allows you to create peer groups containing EBGP neighbors.

Example for an IBGP Peer Group

In the following example, the peer group named internal configures the members of the peer group to be IBGP neighbors. By definition, this is an IBGP peer group because the router bgp command and the neighbor remote-as command indicate the same autonomous system (in this case, AS  100). All the peer group members use loopback 0 as the update source and use set-med as the outbound route-map. The neighbor internal filter-list 2 in command shows that, except for 171.69.232.55, all the neighbors have filter-list 2 as the inbound filter list.

router bgp 100
 neighbor internal peer-group
 neighbor internal remote-as 100
 neighbor internal update-source loopback 0
 neighbor internal route-map set-med out
 neighbor internal filter-list 1 out
 neighbor internal filter-list 2 in
 neighbor 171.69.232.53 peer-group internal
 neighbor 171.69.232.54 peer-group internal
 neighbor 171.69.232.55 peer-group internal
 neighbor 171.69.232.55 filter-list 3 in

Example for an EBGP Peer Group

The following example defines the peer group named external-peers without the neighbor remote-as command. This is what makes it an EBGP peer group. Each individual member of the peer group is configured with its respective AS-number separately. Thus the peer group consists of members from autonomous systems 200, 300, and 400. All the peer group members have set-metric route map as an outbound route map and filter-list 99 as an outbound filter list. Except for neighbor 171.69.232.110, all of them have 101 as the inbound filter list.

router bgp 100
 neighbor external-peers peer-group
 neighbor external-peers route-map set-metric out
 neighbor external-peers filter-list 99 out
 neighbor external-peers filter-list 101 in
 neighbor 171.69.232.90 remote-as 200
 neighbor 171.69.232.90 peer-group external-peers
 neighbor 171.69.232.100 remote-as 300
 neighbor 171.69.232.100 peer-group external-peers
 neighbor 171.69.232.110 remote-as 400
 neighbor 171.69.232.110 peer-group external-peers
 neighbor 171.69.232.110 filter-list 400 in

Related Commands

You can use the master indexes or search online to find documentation of related commands.

clear ip bgp peer-group
neighbor peer-group (assigning members)
show ip bgp peer-group

neighbor prefix-list

To distribute BGP neighbor information as specified in a prefix list, use the neighbor  access-list router configuration command. To remove an entry, use the no form of this command.

neighbor {ip-address | peer-group-name} prefix-list prefix-listname {in | out}
no neighbor {ip-address | peer-group-name} prefix-list prefix-listname {in |out}

Syntax Description

ip-address

Neighbor's IP address.

peer-group-name

Name of a BGP peer group.

prefix-list

Applies a prefix list to the route to be matched.

prefix-listname

Name of a prefix list.

in

Access list is applied to incoming advertisements to that neighbor.

out

Access list is applied to outgoing advertisements from that neighbor.

Default

No BGP neighbor is specified.

Command Mode

Router configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 12.0.

Using prefix lists is one of two ways to filter BGP advertisements. The other way is to use AS-path filters, as with the ip as-path access-list global configuration command and the neighbor filter-list command, and access or prefix lists, as with the neighbor distribute-list command.

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. Specifying the command with an IP address will override the value inherited from the peer group.


Note Do not use both neighbor access-list and neighbor prefix-list commands for a single BGP peer. Do not apply both a neighbor distribute-list and a neighbor prefix-list command to the same neighbor.

Examples

The following example applies prefix list abc to incoming advertisements to neighbor 120.23.4.1:

router bgp 109
 network 131.108.0.0
 neighbor 120.23.4.1 prefix-list abc in
 

The following example applies prefix list CustomerA to incoming advertisements to neighbor 120.23.4.1:

router bgp 109
 network 131.108.0.0
 neighbor 120.23.4.1 prefix-list CustomerA in

Related Commands

You can use the master indexes or search online to find documentation of related commands.

clear ip prefix-list
ip as-path access-list
ip prefix-list
ip prefix-list description
ip prefix-list sequence-number
neighbor filter-list
neighbor peer-group (creating)
show ip prefix-list

neighbor remote-as

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

neighbor {ip-address | peer-group-name} remote-as number
no neighbor {ip-address | peer-group-name} remote-as number

Syntax Description

ip-address

Neighbor's IP address.

peer-group-name

Name of a BGP peer group.

number

Autonomous system to which the neighbor belongs.

Default

There are no BGP neighbor peers.

Command Mode

Router configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 10.0. The peer-group-name argument first appeared in Cisco IOS Release 11.0.

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.

Examples

The following example specifies that a router at the address 131.108.1.2 is a neighbor in autonomous system number 109:

router bgp 110
 network 131.108.0.0
 neighbor 131.108.1.2 remote-as 109
 

The following example assigns a BGP router to autonomous system 109, 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 131.108.0.0 and 192.31.7.0 with the neighbor routers. The first router listed is in the same Class B network address space, but in a different autonomous system; the second neighbor command illustrates specification of an internal neighbor (with the same autonomous system number) at address 131.108.234.2; and the last neighbor command specifies a neighbor on a different network.

router bgp 109
 network 131.108.0.0
 network 192.31.7.0
 neighbor 131.108.200.1  remote-as 167
 neighbor 131.108.234.2  remote-as 109
 neighbor 150.136.64.19  remote-as  99

Related Commands

You can use the master indexes or search online to find documentation of related commands.

neighbor peer-group (creating)

neighbor route-map

To apply a route map to incoming or outgoing routes, use the neighbor route-map router configuration command. To remove a route map, use the no form of this command.

neighbor {ip-address | peer-group-name} route-map map-name {in | out}
no neighbor {ip-address | peer-group-name} route-map map-name {in | out}

Syntax Description

ip-address

Neighbor's IP address.

peer-group-name

Name of a BGP peer group.

map-name

Name of route map.

in

Apply to incoming routes.

out

Apply to outgoing routes.

Default

No route maps are applied to a peer.

Command Mode

Router configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 10.0.

If an outbound route map is specified, it is proper behavior to only advertise routes that match at least one section of the route map.

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. Specifying the command with an IP address will override the value inherited from the peer group.

Example

The following example applies a route map named internal-map to incoming route from 198.92.70.24:

router bgp 5
 neighbor 198.92.70.24 route-map internal-map in
!
route-map internal-map
 match as-path 1
 set local-preference 100

Related Commands

You can use the master indexes or search online to find documentation of related commands.

neighbor peer-group (creating)

neighbor route-reflector-client

To configure the router as a BGP route reflector and configure the specified neighbor as its client, use the neighbor route-reflector-client router configuration command. To indicate that the neighbor is not a client, use the no form of this command. When all the clients are disabled, the local router is no longer a route reflector.

neighbor ip-address route-reflector-client
no neighbor
ip-address route-reflector-client

Syntax Description

ip-address

IP address of the BGP neighbor being identified as a client.

Default

There is no route reflector in the autonomous system.

Command Mode

Router configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 11.1.

By default, all IBGP speakers in an autonomous system must be fully meshed, and neighbors do not readvertise IBGP learned routes to neighbors, thus preventing a routing information loop.

If you use route reflectors, all IBGP speakers need not be fully meshed. In the route reflector model, an internal BGP peer is configured to be a route  reflector responsible for passing IBGP learned routes to IBGP neighbors. This scheme eliminates the need for each router to talk to every other router.

Use the neighbor route-reflector-client command to configure the local router as the route reflector and the specified neighbor as one of its clients. All the neighbors configured with this command will be members of the client group and the remaining IBGP peers will be members of the nonclient group for the local route reflector.

If client-to-client reflection is enabled (by default it is enabled), clients of a route reflector cannot be members of a peer group. The bgp client-to-client reflection command controls client-to-client reflection.

Example

In the following example, the local router is a route reflector. It passes learned IBGP routes to the neighbor at 198.92.70.24.

router bgp 5
 neighbor 198.92.70.24 route-reflector-client

Related Commands

You can use the master indexes or search online to find documentation of related commands.

bgp client-to-client reflection
bgp cluster-id
show ip bgp

neighbor send-community

To specify that a COMMUNITIES attribute should be sent to a BGP neighbor, use the neighbor send-community router configuration command. To remove the entry, use the no form of this command.

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

Syntax Description

ip-address

Neighbor's IP address.

peer-group-name

Name of a BGP peer group.

Default

No COMMUNITIES attribute is sent to any neighbor.

Command Mode

Router configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 10.3. The peer-group-name argument first appeared in Cisco IOS Release 11.0.

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.

Example

In the following example, the router belongs to autonomous system 109 and is configured to send the COMMUNITIES attribute to its neighbor at IP address 198.92.70.23:

router bgp 109
 neighbor 198.92.70.23 send-community

Related Commands

You can use the master indexes or search online to find documentation of related commands.

match community-list
neighbor peer-group (creating)
set community

neighbor shutdown

To disable a neighbor or peer group, use the neighbor shutdown router configuration command.To re-enable the neighbor or peer group, use the no form of this command.

neighbor {ip-address | peer-group-name} shutdown
no neighbor
{ip-address | peer-group-name} shutdown

Syntax Description

ip-address

Neighbor's IP address.

peer-group-name

Name of a BGP peer group.

Default

No change is made to the status of any BGP neighbor or peer group.

Command Mode

Router configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 12.0.

The neighbor shutdown command terminates any active session for the specified neighbor or peer group, and removes all associated routing information. In the case of a peer group, this could mean a large number of peering sessions are suddenly terminated.

To view a summary of BGP neighbors and peer-group connections, use the show ip bgp summary command. Those neighbors with an Idle status and the Admin entry have been disabled by the neighbor shutdown command.

"State/PfxRcd" shows the current state of the BGP session/the number of prefixes the router has received from a neighbor or peer group. When the maximum number (as set by the neighbor maximum prefix command) is reached, the string "PfxRcd" appears in the entry, the neighbor is shut down, and the connection is Idle.

Related Commands

You can use the master indexes or search online to find documentation of related commands.

neighbor maximum prefix
show ip bgp summary

neighbor soft-reconfiguration

To configure the Cisco IOS software to start storing updates, use the neighbor soft-reconfiguration router configuration command. To not store received updates, use the no form of this command.

neighbor {ip-address | peer-group-name} soft-reconfiguration [inbound]
no neighbor {ip-address | peer-group-name} soft-reconfiguration [inbound]

Syntax Description

ip-address

IP address of the BGP-speaking neighbor.

peer-group-name

Name of a BGP peer group.

inbound

Keyword indicating that the update to be stored is an incoming update.

Inbound is currently required with this command, since a keyword is required and no other keywords are available.

Default

Soft reconfiguration is not enabled

Command Mode

Router configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 11.2.

This command requires at least one keyword. Currently the only keyword available is inbound, so the use of inbound is not optional.

Entering this command starts the storage of updates, required to do inbound soft reconfiguration. Outbound BGP soft reconfiguration does not require inbound soft reconfiguration to be enabled.

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.

Example

The following example enables inbound soft-reconfiguration for the neighbor 131.108.1.1. All the updates received from this neighbor will be stored unmodified, regardless of the inbound policy. When inbound soft reconfiguration is done later, the stored information will be used to generate a new set of inbound updates.

router bgp 100
 neighbor 131.108.1.1 remote-as 200
 neighbor 131.108.1.1 soft-reconfiguration inbound 

Related Commands

You can use the master indexes or search online to find documentation of related commands.

clear ip bgp
neighbor peer-group (creating)

neighbor timers

To set the timers for a specific BGP peer or peer group, use the neighbor timers router configuration command. To clear the timers for a specific BGP peer or peer group, use the no form of this command.

neighbor [ip-address | peer-group-name] timers keepalive holdtime
no neighbor [ip-address | peer-group-name] timers keepalive holdtime

Syntax Description

ip-address

(Optional) A BGP peer or peer group IP address.

peer-group-name

(Optional) Name of the BGP peer group.

keepalive

Frequency, in seconds, with which the Cisco IOS software sends keepalive messages to its peer. The default is 60 seconds.

holdtime

Interval, in seconds, after not receiving a keepalive message that the software declares a peer dead. The default is 180 seconds.

Default

keepalive: 60 seconds
holdtime: 180 seconds

Command Mode

Router configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 12.0

The timers configured for a specific neighbor or peer group override the timers configured for all BGP neighbors using the command timers bgp.

Example

The following example changes the keepalive timer to 70 seconds and the holdtime timer to 210  seconds for the BGP peer 192.98.47.0:

router bgp 109
 neighbor 192.98.47.0 timers 70 210

neighbor update-source

To have the Cisco IOS software allow internal BGP sessions to use any operational interface for TCP connections, use the neighbor update-source router configuration command. 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 | peer-group-name} update-source interface
no neighbor {ip-address | peer-group-name} update-source interface

Syntax Description

ip-address

IP address of the BGP-speaking neighbor.

peer-group-name

Name of a BGP peer group.

interface

Loopback interface.

Default

Best local address

Command Mode

Router configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 10.0.

This feature works in conjunction with the loopback interface feature described in the "Interface Configuration Overview" chapter of the Cisco IOS Interface 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.

Example

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

router bgp 110
 network 160.89.0.0
 neighbor 160.89.2.3 remote-as 110
neighbor 160.89.2.3 update-source Loopback0

Related Commands

You can use the master indexes or search online to find documentation of related commands.

neighbor peer-group (creating)

neighbor version

To configure the Cisco IOS software to accept only a particular BGP version, use the neighbor  version router configuration command. To use the default version level of a neighbor, use the no form of this command.

neighbor {ip-address | peer-group-name} version value
no neighbor {ip-address | peer-group-name} version value

Syntax Description

ip-address

IP address of the BGP-speaking neighbor.

peer-group-name

Name of a BGP peer group.

value

BGP version number. The version can be set to 2 to force the software to only use Version 2 with the specified neighbor. The default is to use Version 4 and dynamically negotiate down to Version 2 if requested.

Default

BGP Version 4

Command Mode

Router configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 10.0.

Entering this command disables dynamic version negotiation.

Our implementation of BGP supports BGP Versions 2, 3, and 4. If the neighbor does not accept default Version 4, dynamic version negotiation is implemented to negotiate down to Version 2.

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.

Example

The following example locks down to Version 4 of the BGP protocol:

router bgp 109
neighbor 131.104.27.2 version 4

Related Commands

You can use the master indexes or search online to find documentation of related commands.

neighbor peer-group (creating)

neighbor weight

To assign a weight to a neighbor connection, use the neighbor weight router configuration command. To remove a weight assignment, use the no form of this command.

neighbor {ip-address | peer-group-name} weight weight
no neighbor {ip-address | peer-group-name} weight weight

Syntax Description

ip-address

Neighbor's IP address.

peer-group-name

Name of a BGP peer group.

weight

Weight to assign. Acceptable values are 0 to 65535.

Default

Routes learned through another BGP peer have a default weight of 0 and routes sourced by the local router have a default weight of 32768.

Command Mode

Router configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 10.0.

All routes learned from this neighbor will have the assigned weight initially. The route with the highest weight will be chosen as the preferred route when multiple routes are available to a particular network.

The weights assigned with the match as-path and set weight route-map commands override the weights assigned using the neighbor weight and neighbor filter-list commands.


Note For weight changes to take effect, it may be necessary to use clear ip bgp peer-group *.

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.

Example

The following example sets the weight of all routes learned via 151.23.12.1 to 50:

router bgp 109
neighbor 151.23.12.1 weight 50

Related Commands

You can use the master indexes or search online to find documentation of related commands.

neighbor distribute-list
neighbor filter-list
neighbor peer-group (creating)

network (BGP)

To specify the list of networks for the BGP routing process, use this form of the network router configuration command. To remove an entry, use the no form of this command.

network network-number [mask network-mask]
no network network-number [mask network-mask]

Syntax Description

network-number

Network that BGP will advertise.

mask

Network or subnetwork mask.

network-mask

(Optional) Network mask address.

Default

No networks are specified.

Command Mode

Router configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 10.0. The limit of 200 network commands per BGP router was removed in Cisco IOS Release 12.0.

These types of networks can be learned from connected routes, dynamic routing, and from static route sources.

The maximum number of network commands you can use is determined by the router's resources, such as the configured NVRAM or RAM..

Example

The following example sets up network 131.108.0.0 to be included in the BGP updates:

router bgp 120
 network 131.108.0.0

Related Commands

You can use the master indexes or search online to find documentation of related commands.

default-information originate (BGP)
neighbor ebgp-multihop
network backdoor
network mask
network weight
router bgp

network backdoor

To specify a backdoor route to a BGP border router that will provide better information about the network, use the network backdoor router configuration command. To remove an address from the list, use the no form of this command.

network address backdoor
no network address backdoor

Syntax Description

address

IP address of the network to which you want a backdoor route.

Default

No network is advertised.

Command Mode

Router configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 10.0.

A backdoor network is treated as a local network, except that it is not advertised.

Example

The following example configures network 131.108.0.0 as a local network and network 192.31.7.0 as a backdoor network:

router bgp 109
 network 131.108.0.0
 network 192.31.7.0 backdoor

network weight

To assign an absolute weight to a BGP network, use the network weight router configuration command. To delete an entry, use the no form of the command.

network address mask weight weight [route-map map-name]
no network address mask weight weight [route-map map-name]

Syntax Description

address

IP address of the network.

mask

Network mask of the network.

weight

Absolute weight, or importance. It can be an integer from 0 to  65535.

route-map map-name

(Optional) Name of route-map.

Default

Weight is unmodified. Weight is zero if the original default weight has not been modified by other router configuration commands.

Command Mode

Router configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 10.0.

The weight specified by this command overrides a weight assigned by the redistribute command.

Example

In the following example, the BGP network has a weight of 100:

router bgp 5
 network 193.0.0.0 255.0.0.0 weight 100

router bgp

To configure the Border Gateway Protocol (BGP) routing process, use the router bgp global configuration command. To remove a routing process, use the no form of this command.

router bgp autonomous-system
no router bgp autonomous-system

Syntax Description

autonomous-system

Number of an autonomous system that identifies the router to other BGP routers and tags the routing information passed along.

Default

No BGP routing process is enabled by default.

Command Mode

Global configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 10.0.

This command allows you to set up a distributed routing core that automatically guarantees the loop-free exchange of routing information between autonomous systems.

Example

The following example configures a BGP process for autonomous system 120:

router bgp 120

Related Commands

You can use the master indexes or search online to find documentation of related commands.

network (BGP)
timers bgp

set as-path

To modify an autonomous system path for BGP routes, use the set as-path route map configuration command. To not modify the autonomous system path, use the no form of this command.

set as-path {tag | prepend as-path-string}
no set as-path {tag | prepend as-path-string}

Syntax Description

tag

Converts the tag of a route into an autonomous system path. Applies only when redistributing routes into BGP.

prepend as-path-string

Appends the string following the keyword prepend to the as-path of the route that is matched by the route map. Applies to inbound and outbound BGP route maps.

Default

Autonomous system path is not modified.

Command Mode

Route map configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 11.0.

The only global BGP metric available to influence the best path selection is the AS-PATH length. By varying the length of the AS-PATH, a BGP speaker can influence the best path selection by a peer further away.

By allowing you to convert the tag into an autonomous system path, the set as-path tag variation of this command modifies the autonomous system length. The set as-path prepend variation allows you to "prepend" an arbitrary autonomous system path string to BGP routes. Usually the local autonomous system number is prepended multiple times. This increases the autonomous system path length.

Examples

The following example converts the tag of a redistributed route into an autonomous system path:

route-map set-as-path-from-tag
 match as-path 2
 set as-path prepend 100 100 100
!
router bgp 100
 redistribute ospf 109 route-map se	t-as-path-from-tag
 

The following example prepends 100 100 100 to all the routes advertised to 131.108.1.1:

route-map set-as-path
 match as-path 1
 set as-path prepend 100 100 100
!
router bgp 100
 neighbor 131.108.1.1 route-map set-as-path out

Related Commands

You can use the master indexes or search online to find documentation of related commands.

match as-path
match community-list
match interface
match ip address
match ip next-hop
match ip route-source
match metric
match route-type
match tag
route-map
set automatic-tag
set community
set level
set local-preference
set metric
set metric-type
set next-hop
set origin
set tag
set weight

set comm-list delete

To remove communities from the community attribute of an inbound or outbound update, use the set comm-list delete configuration command. To negate a previous set comm-list delete command, use the no form of this command.

set comm-list list-num delete
no set comm-list
list-num delete

Syntax Description

list-num

A standard or extended community list number.

Default

No communities are removed.

Command Mode

Router configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 12.0.

This route-map set command removes communities from the community attribute of an inbound or outbound update using a route map to filter and determine the communities to be deleted. Depending upon whether the route map is applied to the inbound or outbound update for a neighbor, each community that passes the route map "permit" clause and matches the given community list will be removed from the community attribute being received from or sent to the BGP neighbor.

Each entry of a standard community list should list only one community when used with the set comm-list delete command. For example, in order to be able to delete communities 10:10 and 10:20, you must use the following format to create the entries:

ip community-list 5 permit 10:10
ip community-list 5 permit 10:20

The following format for a community list entry, while acceptable otherwise, does not work with the set comm-list delete command:

config ip community-list 5 permit 10:10 10:20
 

When both the set community comm and set comm-list list-num delete commands are configured in the same sequence of a route-map attribute, the deletion operation (set comm-list list-num delete) is performed before the set operation (set community comm).

Example

In the following example, the communities 100:10 and 100:20 (if present) will be deleted from updates received from 171.69.233.33. Also, except for 100:50, all communities beginning with 100: will be deleted from updates sent to 171.69.233.33.

router bgp 100
neighbor 171.69.233.33 remote-as 120
neighbor 171.69.233.33 route-map ROUTEMAPIN in
neighbor 171.69.233.33 route-map ROUTEMAPOUT out
!
ip community-list 1 permit 100:10
ip community-list 1 permit 100:20
!
ip community-list 120 deny 100:50
ip community-list 120 permit 100:.*
!
route-map ROUTEMAPIN permit 10
set comm-list 1 delete
!
route-map ROUTEMAPOUT permit 10
set comm-list 120 delete

Related Commands

You can use the master indexes or search online to find documentation of related commands.

set community comm

set community

To set the BGP COMMUNITIES attribute, use the set community route-map configuration command. To delete the entry, use the no form of this command.

set community {community-number [additive]} | none
no set community
{community-number [additive]} | none

Syntax Description

community-number

Valid values are 1 to 4294967200, no-export, or no-advertise.

additive

(Optional) Adds the community to the already existing communities.

none

Removes the COMMUNITY attribute from the prefixes that pass the route-map.

Default

No BGP COMMUNITIES attributes exist.

Command Mode

Route-map configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 10.3.

You must have a match clause (even if it points to a "permit everything" list) if you want to set tags.

Use the route-map global configuration command, and the match and set route-map configuration commands, to define the conditions for redistributing routes from one routing protocol into another. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria---the conditions under which redistribution is allowed for the current route-map command. The set commands specify the set actions---the particular redistribution actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.

The set route-map configuration commands specify the redistribution set actions to be performed when all of a route map's match criteria are met. When all match criteria are met, all set actions are performed.

Examples

In the following example, routes that pass the autonomous system path access list 1 have the community set to 109. Routes that pass the autonomous system path access list 2 have the community set to no-export (these routes will not be advertised to any EBGP peers).

route-map set_community 10 permit
 match as-path 1
 set community 109
 
route-map set_community 20 permit
 match as-path 2
 set community no-export
 

In the following similar example, routes that pass the autonomous system path access list 1 have the community set to 109. Routes that pass the autonomous system path access list 2 have the community set to local-as (the router will not advertise this route to an EBGP peer outside the local autonomous system.

route-map set_community 10 permit
 match as-path 1
 set community 109
 
route-map set_community 20 permit
 match as-path 2
 set community local-as

Related Commands

You can use the master indexes or search online to find documentation of related commands.

ip community-list
match community-list
route-map
set comm-list delete
show ip bgp community

set dampening

To set the BGP route dampening factors, use the set dampening route-map configuration command. To disable this function, use the no form of this command.

set dampening half-life reuse suppress max-suppress-time
no set dampening

Syntax Description

half-life

Time (in minutes) after which a penalty is decreased. Once the route has been assigned a penalty, the penalty is decreased by half after the half-life period (which is 15 minutes by default). The process of reducing the penalty happens every 5 seconds. The range of the half-life period is 1 to 45  minutes. The default is 15  minutes.

reuse

If the penalty for a flapping route decreases enough to fall below this value, the route is unsuppressed. The process of unsuppressing routes occurs at 10-second increments. The range of the reuse value is 1 to 20000; the default is 750.

suppress

A route is suppressed when its penalty exceeds this limit. The range is 1 to 20000; the default is 2000.

max-suppress-time

Maximum time (in minutes) a route can be suppressed. The range is 1 to 20000; the default is 4 times the half-life. If the half-life value is allowed to default, the maximum suppress time defaults to 60 minutes.

Default

Disabled

Command Mode

Route-map configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 11.0.

You must have a match clause (even if it points to a "permit everything" list) if you want to set tags.

Use the route-map global configuration command, and the match and set route-map configuration commands, to define the conditions for redistributing routes from one routing protocol into another. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria---the conditions under which redistribution is allowed for the current route-map command. The set commands specify the set actions---the particular redistribution actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.

The set route-map configuration commands specify the redistribution set actions to be performed when all of a route map's match criteria are met. When all match criteria are met, all set actions are performed.

When a BGP peer is reset, the route is withdrawn and the flap statistics cleared. In this instance, the withdrawal does not incur a penalty even though route flap dampening is enabled.

Example

The following example sets the half-life to 30 minutes, the reuse value to 1500, the suppress value to 10000; and the maximum suppress time to 120 minutes:

route-map tag
 match as path 10
 set dampening 30 1500 10000 120
!
router bgp 100
 neighbor 171.69.233.52 route-map tag in

Related Commands

You can use the master indexes or search online to find documentation of related commands.

match as-path
match community-list
match interface
match ip address
match ip next-hop
match ip route-source
match metric
match route-type
match tag
route-map
set as-path
set automatic-tag
set community
set level
set local-preference
set metric
set metric-type
set next-hop
set origin
set tag
set weight
show route-map

set ip next-hop

To indicate where to output packets that pass a match clause of a route map for policy routing, use the set ip next-hop route map configuration command. To delete an entry, use the no form of this command.

set ip next-hop ip-address [...ip-address] [peer-address]
no set ip next-hop ip-address [...ip-address] [peer-address]

Syntax Description

ip-address

IP address of the next hop to which packets are output. It need not be an adjacent router.

peer-address

(Optional) Sets the next hop to be the BGP peering address.

Default

Disabled

Command Mode

Route map configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 11.0. The keyword peer-address first appeared in Cisco IOS Release 12.0.

Use the ip policy route-map interface configuration command, the route-map global configuration command, and the match and set route map configuration commands, to define the conditions for policy routing packets. The ip policy route-map command identifies a route map by name. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria---the conditions under which policy routing occurs. The set commands specify the set actions---the particular routing actions to perform if the criteria enforced by the match commands are met.

If the first next hop specified with the set ip next-hop command is down, the optionally specified IP addresses are tried in turn.

When set ip next-hop is used with the peer-address keyword in an inbound route map of a BGP peer, the next hop of the received matching routes will be set to be the neighbor peering address, overriding any third-party next hops. This means that the same route map can be applied to multiple BGP peers to override third-party next hops.

When set ip next-hop is used with the peer-address keyword in an outbound route map of a BGP peer, the next hop of the advertised matching routes will be set to be the peering address of the local router, thus disabling the next hop calculation. This command has finer granularity than the per-neighbor neighbor next-hop-self command, since you can set the next hop for some routes, but not others. The neighbor next-hop-self sets the next hop for all routes sent to that neighbor

The set clauses can be used in conjunction with one another. They are evaluated in the following order:

set ip next-hop
set interface
set ip default next-hop
set default interface

Examples

In the following example, packets with a Level 3 length of 3 to 50 bytes are output to the router at IP address 161.14.2.2:

interface serial 0
 ip policy route-map thataway
!
route-map thataway
 match length 3 50
 set ip next-hop 161.14.2.2
 

In the following example, three routers are on the same FDDI LAN (with IP addresses 1.1.1.1, 1.1.1.2, and 1.1.1.3). Each is in a different autonomous system. The set ip next-hop peer-address command specifies that traffic from the router (1.1.1.3) in remote AS 300 for the router (1.1.1.1) in remote AS 100 that matches the route map is passed through the router bgp 200, rather than sent directly to the router (1.1.1.1) in AS 100 over their mutual connection to the LAN:

router bgp 200
neighbor 1.1.1.3 remote-as 100
neighbor 1.1.1.3 route-map set-peer-address out
neighbor 1.1.1.1 remote-as 100
route-map set-peer-address permit 10
set ip next-hop peer-address 

Related Commands

You can use the master indexes or search online to find documentation of related commands.

ip policy route-map
match ip address
match length
neighbor next-hop-self
route-map
set default interface
set interface
set ip default next-hop

set metric-type internal

To set the MED value on prefixes advertised to EBGP neighbors to match the IGP metric of the next hop, use the set metric internal route-map configuration command. To return to the default, use the no form of this command.

set metric-type internal
no set metric-type internal

Syntax Description

This command has no arguments or keywords.

Default

Disabled

Command Mode

Route-map configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 10.3.

This command will cause BGP to advertise a MED that corresponds to the IGP metric associated with the NEXT HOP of the route. This command applies to generated, iBGP-, and eBGP-derived routes.

If this command is used, multiple BGP speakers in a common AS can advertise different MEDs for a particular prefix. Also, note that if the IGP metric changes, BGP will not readvertise the route.

You must have a match clause (even if it points to a "permit everything" list) if you want to set tags.

Use the route-map global configuration command, and the match and set route-map configuration commands, to define the conditions for redistributing routes from one routing protocol into another. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria---the conditions under which redistribution is allowed for the current route-map command. The set commands specify the set actions---the particular redistribution actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.

The set route-map configuration commands specify the redistribution set actions to be performed when all of a route map's match criteria are met. When all match criteria are met, all set actions are performed.

Example

In the following example, the MED for all the advertised routes to neighbor 160.89.2.3 is set to the corresponding IGP metric of the nexthop:

router bgp 109
 network 160.89.0.0
 neighbor 160.89.2.3 remote-as 200
 neighbor 160.89.2.3 route-map setMED out
!
route-map setMED permit 10
 match as-path 1
 set metric-type internal
!
 ip as-path access-list 1 permit .*

Related Commands

You can use the master indexes or search online to find documentation of related commands.

route-map

set origin

To set the BGP origin code, use the set origin route-map configuration command. To delete an entry, use the no form of this command.

set origin {igp | egp autonomous-system | incomplete}

Syntax Description

igp

Remote IGP.

egp

Local EGP.

autonomous-system

Remote autonomous system. This is an integer from 0 to 65535.

incomplete

Unknown heritage.

Default

Default origin, based on route in main IP routing table.

Command Mode

Route-map configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 10.0.

You must have a match clause (even if it points to a "permit everything" list) if you want to set tags.

Use the route-map global configuration command with match and set route-map configuration commands to define the conditions for redistributing routes from one routing protocol into another. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria---the conditions under which redistribution is allowed for the current route-map command. The set commands specify the set actions---the particular redistribution actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.

The set route-map configuration commands specify the redistribution set actions to be performed when all of a route map's match criteria are met. When all match criteria are met, all set actions are performed.

Example

The following example sets the origin of routes that pass the route map to IGP:

route-map set_origin
 match as-path 10
 set origin igp

Related Commands

You can use the master indexes or search online to find documentation of related commands.

match as-path
match community-list
match interface
match ip address
match ip next-hop
match ip route-source
match metric
match route-type
match tag
route-map
set as-path
set automatic tag
set community
set level
set local-preference
set metric
set metric-type
set next-hop
set tag
set weight

set weight

To specify the BGP weight for the routing table, use the set weight route-map configuration command. To delete an entry, use the no form of this command.

set weight weight
no set weight weight

Syntax Description

weight

Weight value. It can be an integer from 0 to 65535.

Default

The weight is not changed by the specified route map.

Command Mode

Route-map configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 10.0.

You must have a match clause (even if it points to a "permit everything" list) if you want to set tags.

The implemented weight is based on the first matched autonomous system path. Weights indicated when an autonomous system path is matched override the weights assigned by global neighbor commands. In other words, the weights assigned with the match as-path and set weight route-map commands override the weights assigned using the neighbor weight and neighbor filter-list commands.

Example

The following example sets the BGP weight for the routes matching the autonomous system path access list to  200:

route-map set-weight
 match as-path 10
 set weight 200

Related Commands

You can use the master indexes or search online to find documentation of related commands.

match as-path
match community-list
match interface
match ip address
match ip next-hop
match ip route-source
match metric
match route-type
match tag
route-map
set as-path
set automatic-tag
set community
set level
set local-preference
set metric
set metric-type
set next-hop
set origin
set tag

show ip bgp

To display entries in the BGP routing table, use the show ip bgp EXEC command.

show ip bgp [network] [network-mask] [longer-prefixes]

Syntax Description

network

(Optional) Network number, entered to display a particular network in the BGP routing table.

network-mask

(Optional) Displays all BGP routes matching the address/mask pair.

longer-prefixes

(Optional) Displays route and more specific routes.

Command Mode

EXEC

Usage Guidelines

This command first appeared in Cisco IOS Release 10.0. The display of prefix advertisement statistics was added in release 12.0.

Sample Displays

The following is sample output from the show ip bgp command:

Router# show ip bgp
 
BGP table version is 716977, local router ID is 193.0.32.1
Status codes: s suppressed, * valid, > best, i - internal
Origin codes: i - IGP, e - EGP, ? - incomplete
 
   Network          Next Hop          Metric LocPrf Weight Path
* i3.0.0.0          193.0.22.1             0    100      0 1800 1239 ?
*>i                 193.0.16.1             0    100      0 1800 1239 ?
* i6.0.0.0          193.0.22.1             0    100      0 1800 690 568 ?
*>i                 193.0.16.1             0    100      0 1800 690 568 ?
* i7.0.0.0          193.0.22.1             0    100      0 1800 701 35 ?
*>i                 193.0.16.1             0    100      0 1800 701 35 ?
*                   198.92.72.24                         0 1878 704 701 35 ?
* i8.0.0.0          193.0.22.1             0    100      0 1800 690 560 ?
*>i                 193.0.16.1             0    100      0 1800 690 560 ?
*                   198.92.72.24                         0 1878 704 701 560 ?
* i13.0.0.0         193.0.22.1             0    100      0 1800 690 200 ?
*>i                 193.0.16.1             0    100      0 1800 690 200 ?
*                   198.92.72.24                         0 1878 704 701 200 ?
* i15.0.0.0         193.0.22.1             0    100      0 1800 174 ?
*>i                 193.0.16.1             0    100      0 1800 174 ?
* i16.0.0.0         193.0.22.1             0    100      0 1800 701 i
*>i                 193.0.16.1             0    100      0 1800 701 i
*                   198.92.72.24                         0 1878 704 701 i
 

Table 45 describes significant fields shown in the display.


Table 45: Show IP BGP Field Descriptions
Field Description

BGP table version

Internal version number of the table. This number is incremented whenever the table changes.

local router ID

IP address of the router.

Status codes

Status of the table entry. The status is displayed at the beginning of each line in the table. It can be one of the following values:

s---The table entry is suppressed.

*---The table entry is valid.

>---The table entry is the best entry to use for that network.

i---The table entry was learned via an internal BGP session.

Origin codes

Indicates the origin of the entry. The origin code is placed at the end of each line in the table. It can be one of the following values:

i---Entry originated from IGP and was advertised with a network router configuration command.

e---Entry originated from EGP.

?---Origin of the path is not clear Usually, this is a router that is redistributed into BGP from an IGP.

Network

IP address of a network entity.

Next Hop

IP address of the next system that is used when forwarding a packet to the destination network. An entry of 0.0.0.0 indicates that the router has some non-BGP routes to this network.

Metric

If shown, this is the value of the interautonomous system metric. This field is frequently not used.

LocPrf

Local preference value as set with the set local-preference route-map configuration command. The default value is 100.

Weight

Weight of the route as set via autonomous system filters.

Path

Autonomous system paths to the destination network. There can be one entry in this field for each autonomous system in the path.

The following is sample output from the show ip bgp command when you specify longer-prefixes:

Router# show ip bgp 198.92.0.0 255.255.0.0 longer-prefixes
 
BGP table version is 1738, local router ID is 198.92.72.24
Status codes: s suppressed, * valid, > best, i - internal
Origin codes: i - IGP, e - EGP, ? - incomplete
 
   Network          Next Hop          Metric LocPrf Weight Path
*> 198.92.0.0       198.92.72.30        8896         32768 ?
*                   198.92.72.30                         0 109 108 ?
*> 198.92.1.0       198.92.72.30        8796         32768 ?
*                   198.92.72.30                         0 109 108 ?
*> 198.92.11.0      198.92.72.30       42482         32768 ?
*                   198.92.72.30                         0 109 108 ?
*> 198.92.14.0      198.92.72.30        8796         32768 ?
*                   198.92.72.30                         0 109 108 ?
*> 198.92.15.0      198.92.72.30        8696         32768 ?
*                   198.92.72.30                         0 109 108 ?
*> 198.92.16.0      198.92.72.30        1400         32768 ?
*                   198.92.72.30                         0 109 108 ?
*> 198.92.17.0      198.92.72.30        1400         32768 ?
*                   198.92.72.30                         0 109 108 ?
*> 198.92.18.0      198.92.72.30        8876         32768 ?
*                   198.92.72.30                         0 109 108 ?
*> 198.92.19.0      198.92.72.30        8876         32768 ?
*                   198.92.72.30                         0 109 108 ?
 

The following is sample output from the show ip bp command, showing information for prefix 3.0.0.0:

show ip bgp 3.0.0.0
BGP routing table entry for 3.0.0.0/8, version 628
Paths: (1 available, best #1)
Advertised to peer-groups:
 ebgp
Advertised to non peer-group peers:
 171.69.232.162
109 65000 297 701 80
 171.69.233.56 from 171.69.233.56 (172.19.185.32)
  Origin incomplete, localpref 100, valid, external, best, ref 2
 

Note If a prefix has not been advertised to any peer, the display shows "Not advertised to any peer."

show ip bgp cidr-only

To display routes with nonnatural network masks (that is, classless interdomain routing, or CIDR), use the show ip bgp cidr-only privileged EXEC command.

show ip bgp cidr-only

Syntax Description

This command has no arguments or keywords.

Command Mode

Privileged EXEC

Usage Guidelines

This command first appeared in Cisco IOS Release 10.0.

Sample Display

The following is sample output from the show ip bgp cidr-only command:

Router# show ip bgp cidr-only 
 
BGP table version is 220, local router ID is 198.92.73.131
Status codes: s suppressed, * valid, > best, i - internal
Origin codes: i - IGP, e - EGP, ? - incomplete
 
   Network          Next Hop          Metric LocPrf Weight Path
*> 192.0.0.0/8      198.92.72.24                         0 1878 ?
*> 198.92.0.0/16    198.92.72.30                         0 108 ?
 

Table 46 describes significant fields shown in the display.


Table 46: Show IP BGP CIDR-Only Field Descriptions
Field Description

BGP table version is 220

Internal version number for the table. This number is incremented any time the table changes.

local router ID

An Internet address of the router.

Status codes

s---The table entry is suppressed.

*---The table entry is valid.

>---The table entry is the best entry to use for that network.

i---The table entry was learned via an internal BGP session.

Origin codes

Indicates the origin of the entry. The origin code is placed at the end of each line in the table. It can be one of the following values:

i---Entry originated from IGP and was advertised with a network router configuration command.

e---Entry originated from EGP.

?---Origin of the path is not clear Usually, this is a router that is redistributed into BGP from an IGP.

Network

Internet address of the network the entry describes.

Next Hop

IP address of the next system to use when forwarding a packet to the destination network. An entry of 0.0.0.0 indicates that the access server has some non-BGP route to this network.

Metric

If shown, this is the value of the interautonomous system metric. This field is frequently not used.

LocPrf

Local preference value. Default is 100.

Weight

Set through the use of autonomous system filters.

Path

Autonomous system paths to the destination network. There can be one entry in this field for each autonomous system in the path. At the end of the path is the origin code for the path.

i---The entry was originated with the IGP and advertised with a
           network router configuration command.

e---The route originated with EGP.

?---The origin of the path is not clear. Usually this is a path that is
           redistributed into BGP from an IGP.

show ip bgp community

To display routes that belong to specified BGP communities, use the show ip bgp community EXEC command.

show ip bgp community community-number [exact]

Syntax Description

community-number

Valid value is community number in the range 1 to 4294967200, internet, no-export, local-as, or no-advertise.

You must enter the numerical communities before the well-known communities. For example, the following does not work:

router#sh ip b community local-as 111:12345

Use the following instead:

router#sh ip b community 111:12345 local-as

exact

(Optional) Displays only routes that have exactly the same specified communities.

Command Mode

EXEC

Usage Guidelines

This command first appeared in Cisco IOS Release 10.3. The local-as community was added in Cisco IOS Release 12.0.

Sample Display

The following is sample output from the show ip bgp community command:

router# show ip bgp community 111:12345 local-as 
 BGP table version is 10, local router ID is 224.0.0.10
 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal
 Origin codes: i - IGP, e - EGP, ? - incomplete
  
    Network          Next Hop          Metric LocPrf Weight Path
 *> 2.2.2.2/32       158.43.222.2           0             0 222 ?
 *> 111.0.0.0        158.43.222.2           0             0 222 ?
 *> 158.43.0.0       158.43.222.2           0             0 222 ?
 *> 158.43.44.44/32  158.43.222.2           0             0 222 ?
 *  158.43.222.0/24  158.43.222.2           0             0 222 i
 *> 172.17.240.0/21  158.43.222.2           0             0 222 ?
 *> 192.168.212.0    158.43.222.2           0             0 222 i
 *> 203.9.1.0        158.43.222.2           0             0 222 ?
 

Table 47 describes significant fields shown in the display.


Table 47: Show IP BGP Community Field Descriptions
Field Description

BGP table version

Internal version number of the table. This number is incremented whenever the table changes.

local router ID

IP address of the router.

Status codes

Status of the table entry. The status is displayed at the beginning of each line in the table. It can be one of the following values:

s---The table entry is suppressed.

*---The table entry is valid.

>---The table entry is the best entry to use for that network.

i---The table entry was learned via an internal BGP session.

Origin codes

Indicates the origin of the entry. The origin code is placed at the end of each line in the table. It can be one of the following values:

i---Entry originated from IGP and was advertised with a network router configuration command.

e---Entry originated from EGP.

?---Origin of the path is not clear Usually, this is a router that is redistributed into BGP from an IGP.

Network

IP address of a network entity.

Next Hop

IP address of the next system that is used when forwarding a packet to the destination network. An entry of 0.0.0.0 indicates that the router has some non-BGP routes to this network.

Metric

If shown, this is the value of the interautonomous system metric. This field is frequently not used.

LocPrf

Local preference value as set with the set local-preference route-map configuration command. The default value is 100.

Weight

Weight of the route as set via autonomous system filters.

Path

Autonomous system paths to the destination network. There can be one entry in this field for each autonomous system in the path.

show ip bgp community-list

To display routes that are permitted by the BGP community list, use the show ip bgp community-list EXEC command.

show ip bgp community-list community-list-number [exact]

Syntax Description

community-list-number

Community list number in the range 1 to 99.

exact

(Optional) Displays only routes that have an exact match.

Command Mode

EXEC

Usage Guidelines

This command first appeared in Cisco IOS Release 10.3.

Sample Display

The following is sample output of the show ip bgp community-list command:

Router# show ip bgp community-list 20
 
BGP table version is 716977, local router ID is 193.0.32.1
Status codes: s suppressed, * valid, > best, i - internal
Origin codes: i - IGP, e - EGP, ? - incomplete
 
   Network          Next Hop          Metric LocPrf Weight Path
* i3.0.0.0          193.0.22.1             0    100      0 1800 1239 ?
*>i                 193.0.16.1             0    100      0 1800 1239 ?
* i6.0.0.0          193.0.22.1             0    100      0 1800 690 568 ?
*>i                 193.0.16.1             0    100      0 1800 690 568 ?
* i7.0.0.0          193.0.22.1             0    100      0 1800 701 35 ?
*>i                 193.0.16.1             0    100      0 1800 701 35 ?
*                   198.92.72.24                         0 1878 704 701 35 ?
* i8.0.0.0          193.0.22.1             0    100      0 1800 690 560 ?
*>i                 193.0.16.1             0    100      0 1800 690 560 ?
*                   198.92.72.24                         0 1878 704 701 560 ?
* i13.0.0.0         193.0.22.1             0    100      0 1800 690 200 ?
*>i                 193.0.16.1             0    100      0 1800 690 200 ?
*                   198.92.72.24                         0 1878 704 701 200 ?
* i15.0.0.0         193.0.22.1             0    100      0 1800 174 ?
*>i                 193.0.16.1             0    100      0 1800 174 ?
* i16.0.0.0         193.0.22.1             0    100      0 1800 701 i
*>i                 193.0.16.1             0    100      0 1800 701 i
*                   198.92.72.24                         0 1878 704 701 i
 

Table 48 describes significant fields shown in the display.


Table 48: Show IP BGP Community List Field Descriptions
Field Description

BGP table version

Internal version number of the table. This number is incremented whenever the table changes.

local router ID

IP address of the router.

Status codes

Status of the table entry. The status is displayed at the beginning of each line in the table. It can be one of the following values:

s---The table entry is suppressed.

*---The table entry is valid.

>---The table entry is the best entry to use for that network.

i---The table entry was learned via an internal BGP session.

Origin codes

Indicates the origin of the entry. The origin code is placed at the end of each line in the table. It can be one of the following values:

i---Entry originated from IGP and was advertised with a network router configuration command.

e---Entry originated from EGP.

?---Origin of the path is not clear Usually, this is a router that is redistributed into BGP from an IGP.

Network

IP address of a network entity.

Next Hop

IP address of the next system that is used when forwarding a packet to the destination network. An entry of 0.0.0.0 indicates that the router has some non-BGP routes to this network.

Metric

If shown, this is the value of the interautonomous system metric. This field is frequently not used.

LocPrf

Local preference value as set with the set local-preference route-map configuration command. The default value is 100.

Weight

Weight of the route as set via autonomous system filters.

Path

Autonomous system paths to the destination network. There can be one entry in this field for each autonomous system in the path.

show ip bgp dampened-paths

To display BGP dampened routes, use the show ip bgp dampened-paths EXEC command.

show ip bgp dampened-paths

Syntax Description

This command has no arguments or keywords.

Command Mode

EXEC

Usage Guidelines

This command first appeared in Cisco IOS Release 11.0.

Sample Display

The following is sample output from the show ip bgp dampened-paths command:

Router# show ip bgp dampened-paths
BGP table version is 10, local router ID is 171.69.232.182
Status codes: s suppressed, d damped, h history, * valid, > best, i -
internal
Origin codes: i - IGP, e - EGP, ? - incomplete
 
   Network          From             Reuse   Path
*d 10.0.0.0         171.69.232.177   00:18:4 100 ?
*d 12.0.0.0         171.69.232.177   00:28:5 100 ?
 

Table 49 describes the fields in the display.


Table 49: Show IP BGP Dampened-Paths Field Descriptions
Field Description

BGP table version

Internal version number for the table. This number is incremented any time the table changes.

local router

IP address of the router where route dampening is enabled.

*d Network

Route to the network indicated is dampened.

From

IP address of the peer that advertised this path.

Reuse

Time (in hours:minutes:seconds) after which the path will be made available.

Path

AS-path of the route that is being dampened.

Related Commands

You can use the master indexes or search online to find documentation of related commands.

bgp dampening
clear ip bgp dampening

show ip bgp filter-list

To display routes that conform to a specified filter list, use the show ip bgp filter-list privileged EXEC command.

show ip bgp filter-list access-list-number

Syntax Description

access-list-number

Number of an autonomous system path access list. It can be a number from 1 to  199.

Command Mode

Privileged EXEC

Usage Guidelines

This command first appeared in Cisco IOS Release 10.0.

Sample Display

The following is sample output from the show ip bgp filter-list command:

Router# show ip bgp filter-list 2
 
BGP table version is 1738, local router ID is 198.92.72.24
Status codes: s suppressed, * valid, > best, i - internal
Origin codes: i - IGP, e - EGP, ? - incomplete
 
   Network          Next Hop          Metric LocPrf Weight Path
*  198.92.0.0       198.92.72.30                         0 109 108 ?
*  198.92.1.0       198.92.72.30                         0 109 108 ?
*  198.92.11.0      198.92.72.30                         0 109 108 ?
*  198.92.14.0      198.92.72.30                         0 109 108 ?
*  198.92.15.0      198.92.72.30                         0 109 108 ?
*  198.92.16.0      198.92.72.30                         0 109 108 ?
*  198.92.17.0      198.92.72.30                         0 109 108 ?
*  198.92.18.0      198.92.72.30                         0 109 108 ?
*  198.92.19.0      198.92.72.30                         0 109 108 ?
*  198.92.24.0      198.92.72.30                         0 109 108 ?
*  198.92.29.0      198.92.72.30                         0 109 108 ?
*  198.92.30.0      198.92.72.30                         0 109 108 ?
*  198.92.33.0      198.92.72.30                         0 109 108 ?
*  198.92.35.0      198.92.72.30                         0 109 108 ?
*  198.92.36.0      198.92.72.30                         0 109 108 ?
*  198.92.37.0      198.92.72.30                         0 109 108 ?
*  198.92.38.0      198.92.72.30                         0 109 108 ?
*  198.92.39.0      198.92.72.30                         0 109 108 ?
 

Table 50 describes significant fields shown in the display.


Table 50: Show IP BGP Filter-List Field Descriptions
Field Description

BGP table version

Internal version number for the table. This number is incremented any time the table changes.

local router ID

An Internet address of the access server.

Status codes

s---The table entry is suppressed.

*---The table entry is valid.

>---The table entry is the best entry to use for that network.

i---The table entry was learned via an internal BGP session.

Origin codes

Indicates the origin of the entry. The origin code is placed at the end of each line in the table. It can be one of the following values:

i---Entry originated from IGP and was advertised with a network router configuration command.

e---Entry originated from EGP.

?---Origin of the path is not clear Usually, this is a router that is redistributed into BGP from an IGP.

Network

Internet address of the network the entry describes.

Next Hop

IP address of the next system to use when forwarding a packet to the destination network. An entry of 0.0.0.0 indicates that the access server has some non-BGP route to this network.

Metric

If shown, this is the value of the interautonomous system metric. This field is frequently not used.

LocPrf

Local preference value. Default is 100.

Weight

Set through the use of autonomous system filters.

Path

Autonomous system paths to the destination network. There can be one entry in this field for each autonomous system in the path. At the end of the path is the origin code for the path.

i---The entry was originated with the IGP and advertised with a
         network router configuration command.

e---The route originated with EGP.

?---The origin of the path is not clear. Usually this is a path that is
           redistributed into BGP from an IGP.

show ip bgp flap-statistics

To display BGP flap statistics, use the show ip bgp flap-statistics EXEC command.

show ip bgp flap-statistics [{regexp regexp} | {filter-list list} | {address mask [longer-prefix]}]

Syntax Description

regexp regexp

(Optional) Clears flap statistics for all the paths that match the regular expression.

filter-list list

(Optional) Clears flap statistics for all the paths that pass the access list.

address

(Optional) Clears flap statistics for a single entry at this IP address.

mask

(Optional) Network mask applied to the address.

longer-prefix

(Optional) Displays flap statistics for more specific entries.

Command Mode

EXEC

Usage Guidelines

This command first appeared in Cisco IOS Release 11.0.

If no arguments or keywords are specified, the router displays flap statistics for all routes.

Sample Display

The following is sample output from the show ip bgp flap-statistics command:

Router# show ip bgp flap-statistics
BGP table version is 10, local router ID is 171.69.232.182
Status codes: s suppressed, d damped, h history, * valid, > best, i -
internal
Origin codes: i - IGP, e - EGP, ? - incomplete
 
   Network          From            Flaps Duration Reuse    Path
*d 10.0.0.0         171.69.232.177  4     00:13:31 00:18:10 100 
*d 12.0.0.0         171.69.232.177  4     00:02:45 00:28:20 100 
 

Table 51 describes the significant fields in the display.


Table 51: Show IP BGP Flap-Statistics Field Descriptions
Field Description

BGP table version

Internal version number for the table. This number is incremented any time the table changes.

local router ID

IP address of the router where route dampening is enabled.

Network

Route to the network indicated is dampened.

From

IP address of the peer that advertised this path.

Flaps

Number of times the route has flapped.

Duration

Time (in hours:minutes:seconds) since the router noticed the first flap.

Reuse

Time (in hours:minutes:seconds) after which the path will be made available.

Path

AS-path of the route that is being dampened.

Related Commands

You can use the master indexes or search online to find documentation of related commands.

bgp dampening
clear ip bgp flap-statistics

show ip bgp inconsistent-as

To display routes with inconsistent originating autonomous systems, use the show ip bgp inconsistent-as privileged EXEC command.

show ip bgp inconsistent-as

Syntax Description

This command has no arguments or keywords.

Command Mode

Privileged EXEC

Usage Guidelines

This command first appeared in Cisco IOS Release 11.0.

Sample Display

The following is sample output from the show ip bgp inconsistent-as command:

Router# show ip bgp inconsistent-as
BGP table version is 87, local router ID is 172.19.82.53
Status codes: s suppressed, * valid, > best, i - internal
Origin codes: i - IGP, e - EGP, ? - incomplete
 
   Network          Next Hop          Metric LocPrf Weight Path
*  11.0.0.0         171.69.232.55          0             0 300 88 90 99 ?
*>                  171.69.232.52       2222             0 400 ?
*  171.69.0.0       171.69.232.55          0             0 300 90 99 88 200 ?
*>                  171.69.232.52       2222             0 400 ?
*  200.200.199.0    171.69.232.55          0             0 300 88 90 99 ?
*>                  171.69.232.52       2222             0 400 ?

show ip bgp neighbors

To display information about the TCP and BGP connections to neighbors, use the show ip bgp neighbors EXEC command.

show ip bgp neighbors [address] [received-routes | routes | advertised-routes | {paths
regular-expression} | dampened-routes]

Syntax Description

address

(Optional) Address of the neighbor whose routes you have learned from. If you omit this argument, all neighbors are displayed.

received-routes

(Optional) Displays all received routes (both accepted and rejected) from the specified neighbor.

routes

(Optional) Displays all routes that are received and accepted. This is a subset of the output from the received-routes keyword.

advertised-routes

(Optional) Displays all the routes the router has advertised to the neighbor.

paths regular-expression

(Optional) Regular expression that is used to match the paths received.

dampened-routes

(Optional) Displays the dampened routes to the neighbor at the IP address specified.

Command Mode

EXEC

Usage Guidelines

This command first appeared in Cisco IOS Release 10.0. The received-routes keyword first appeared in Cisco IOS Release 11.2.

Sample Displays

The following is sample output from the show ip bgp neighbors command:

Router# show ip bgp neighbors 171.69.232.178
 
BGP neighbor is 171.69.232.178,  remote AS 10, external link
 Index 1, Offset 0, Mask 0x2
  Inbound soft reconfiguration allowed
  BGP version 4, remote router ID 171.69.232.178
  BGP state = Established, table version = 27, up for 00:06:12
  Last read 00:00:12, hold time is 180, keepalive interval is 60 seconds
  Minimum time between advertisement runs is 30 seconds
  Received 19 messages, 0 notifications, 0 in queue
  Sent 17 messages, 0 notifications, 0 in queue
  Inbound path policy configured
  Route map for incoming advertisements is testing
  Connections established 2; dropped 1
Connection state is ESTAB, I/O status: 1, unread input bytes: 0
Local host: 171.69.232.181, Local port: 11002
Foreign host: 171.69.232.178, Foreign port: 179
 
Enqueued packets for retransmit: 0, input: 0, saved: 0
 
Event Timers (current time is 0x530C294):
Timer          Starts    Wakeups            Next
Retrans            12          0             0x0
TimeWait            0          0             0x0
AckHold            12         10             0x0
SendWnd             0          0             0x0
KeepAlive           0          0             0x0
GiveUp              0          0             0x0
PmtuAger            0          0             0x0
 
iss:  133981889  snduna:  133982166  sndnxt:  133982166     sndwnd:  16108
irs: 3317025518  rcvnxt: 3317025810  rcvwnd:      16093  delrcvwnd:    291
 
SRTT: 441 ms, RTTO: 2784 ms, RTV: 951 ms, KRTT: 0 ms
minRTT: 0 ms, maxRTT: 300 ms, ACK hold: 300 ms
Flags: higher precedence, nagle
 
Datagrams (max data segment is 1460 bytes):
Rcvd: 15 (out of order: 0), with data: 12, total data bytes: 291
Sent: 23 (retransmit: 0), with data: 11, total data bytes: 276
 

Table 52 describes the fields shown in the display.

Table 52: Show IP BGP Neighbors Field Descriptions
Field Description

BGP neighbor

IP address of the BGP neighbor and its autonomous system number. If the neighbor is in the same autonomous system as the router, then the link between them is internal; otherwise, it is considered external.

BGP version

BGP version being used to communicate with the remote router; the neighbor's router ID (an IP address) is also specified.

BGP state

Internal state of this BGP connection.

table version

Indicates that the neighbor has been updated with this version of the primary BGP routing table.

up for

Amount of time that the underlying TCP connection has been in existence.

Last read

Time that BGP last read a message from this neighbor.

hold time

Maximum amount of time that can elapse between messages from the peer.

keepalive interval

Time period between sending keepalive packets, which help ensure that the TCP connection is up.

Received

Number of total BGP messages received from this peer, including keepalives.

notifications

Number of error messages received from the peer.

Sent

Total number of BGP messages that have been sent to this peer, including keepalives.

notifications

Number of error messages the router has sent to this peer.

Connections established

Number of times the router has established a TCP connection and the two peers have agreed speak BGP with each other.

dropped

Number of times that a good connection has failed or been taken down.

Connection state

State of BGP peer.

unread input bytes

Number of bytes of packets still to be processed.

Local host, Local port

Peering address of local router, plus port.

Foreign host, Foreign port

Neighbor's peering address.

Event Timers

Table displays the number of starts and wakeups for each timer.

iss

Initial send sequence number.

snduna

Last send sequence number the local host sent but has not received an acknowledgment for.

sndnxt

Sequence number the local host will send next.

sndwnd

TCP window size of the remote host.

irs

Initial receive sequence number.

rcvnxt

Last receive sequence number the local host has acknowledged.

rcvwnd

Local host's TCP window size.

delrecvwnd

Delayed receive window---data the local host has read from the connection, but has not yet subtracted from the receive window the host has advertised to the remote host. The value in this field gradually increases until it is larger than a full-sized packet, at which point it is applied to the rcvwnd field.

SRTT

A calculated smoothed round-trip timeout.

RTTO

Round-trip timeout.

RTV

Variance of the round-trip time.

KRTT

New round-trip timeout (using the Karn algorithm). This field separately tracks the round-trip time of packets that have been retransmitted.

minRTT

Smallest recorded round-trip timeout (hard wire value used for calculation).

maxRTT

Largest recorded round-trip timeout.

ACK hold

Time the local host will delay an acknowledgment in order to piggyback data on  it.

Flags

IP precedence of the BGP packets.

Datagrams: Rcvd

Number of update packets received from neighbor.

with data

Number of update packets received with data.

total data bytes

Total bytes of data.

Sent

Number of update packets sent.

with data

Number of update packets with data sent.

total data bytes

Total number of data bytes.

The following is sample output from the show ip bgp neighbors command with advertised-routes:

Router# show ip bgp neighbors 171.69.232.178 advertised-routes
 
BGP table version is 27, local router ID is 171.69.232.181
Status codes: s suppressed, d damped, h history, * valid, > best, i -
internal
Origin codes: i - IGP, e - EGP, ? - incomplete
 
   Network          Next Hop          Metric LocPrf Weight Path
*>i110.0.0.0        171.69.232.179         0    100      0 ?
*> 200.2.2.0        0.0.0.0                0         32768 i
 

The following is sample output from the show ip bgp neighbors command with routes:

Router# show ip bgp neighbors 171.69.232.178 routes
 
BGP table version is 27, local router ID is 171.69.232.181
Status codes: s suppressed, d damped, h history, * valid, > best, i -
internal
Origin codes: i - IGP, e - EGP, ? - incomplete
 
   Network          Next Hop          Metric LocPrf Weight Path
*> 10.0.0.0         171.69.232.178        40             0 10 ?
*> 20.0.0.0         171.69.232.178        40             0 10 ?
 

Table 53 describes the fields shown in the display.


Table 53: Show IP BGP Neighbors Advertised-Routes and
Routes Field Descriptions
Field Description

BGP table version

Internal version number of the table. This number is incremented whenever the table changes.

local router ID

IP address of the router.

Status codes

s---The table entry is suppressed.

*---The table entry is valid.

>---The table entry is the best entry to use for that network.

i---The table entry was learned via an internal BGP session.

Origin codes

Indicates the origin of the entry. The origin code is placed at the end of each line in the table. It can be one of the following values:

i---Entry originated from IGP and was advertised with a network router configuration command.

e---Entry originated from EGP.

?---Origin of the path is not clear Usually, this is a router that is redistributed into BGP from an IGP.

Network

IP address of a network entity.

Next Hop

IP address of the next system that is used when forwarding a packet to the destination network. An entry of 0.0.0.0 indicates that the router has some non-BGP routes to this network.

Metric

If shown, this is the value of the interautonomous system metric. This field is frequently not used.

LocPrf

Local preference value as set with the set local-preference route-map configuration command. The default value is 100.

Weight

Weight of the route as set via autonomous system filters.

Path

Autonomous system paths to the destination network. There can be one entry in this field for each autonomous system in the path.

The following is sample output from the show ip bgp neighbors command with paths:

Router# show ip bgp neighbors 171.69.232.178 paths ^10
 
Address    Refcount Metric Path
0x60E577B0        2     40 10 ?

show ip bgp paths

To display all the BGP paths in the database, use the show ip bgp paths EXEC command.

show ip bgp paths

Syntax Description

This command has no arguments or keywords.

Command Mode

EXEC

Usage Guidelines

This command first appeared in Cisco IOS Release 10.0.

Sample Display

The following is sample output from the show ip bgp paths command:

Router# show ip bgp paths
Address    Hash Refcount Metric Path
0x60E5742C    0        1      0 i
0x60E3D7AC    2        1      0 ?
0x60E5C6C0   11        3      0 10 ?
0x60E577B0   35        2     40 10 ?
 

Table 54 describes significant fields shown in the display.


Table 54: Show IP BGP Paths Field Descriptions
Field Description

Address

Internal address where the path is stored.

Hash

Hash bucket where path is stored.

Refcount

Number of routes using that path.

Metric

The multiple exit discriminator (MED) metric for the path. (The name of this metric for BGP versions 2 and 3 is INTER_AS.)

Path

The AS_PATH for that route, followed by the origin code for that route.

show ip bgp peer-group

To display information about BGP peer groups, use the show ip bgp peer-group EXEC command.

show ip bgp peer-group [tag] [summary]

Syntax Description

tag

(Optional) Displays information about that specific peer group.

summary

(Optional) Displays a summary of the status of all the members of a peer group.

Command Mode

EXEC

Usage Guidelines

This command first appeared in Cisco IOS Release 11.0.

Sample Display

The following is sample output from the show ip bgp peer-group command:

Router# show ip bgp peer-group0 internal
BGP neighbor is internal, peer-group leader
  BGP version 4
  Minimum time between advertisement runs is 5 seconds
  Incoming update AS path filter list is 2
  Outgoing update AS path filter list is 1
  Route map for outgoing advertisements is set-med
 

show ip bgp regexp

To display routes matching the regular expression, use the show ip bgp regexp privileged EXEC command.

show ip bgp regexp regular-expression

Syntax Description

regular-expression

Regular expression to match the BGP autonomous system paths.

Command Mode

Privileged EXEC

Usage Guidelines

This command first appeared in Cisco IOS Release 10.0.

Sample Display

The following is sample output from the show ip bgp regexp command:

Router# show ip bgp regexp 108$
 
BGP table version is 1738, local router ID is 198.92.72.24
Status codes: s suppressed, * valid, > best, i - internal
Origin codes: i - IGP, e - EGP, ? - incomplete
 
   Network          Next Hop          Metric LocPrf Weight Path
*  198.92.0.0       198.92.72.30                         0 109 108 ?
*  198.92.1.0       198.92.72.30                         0 109 108 ?
*  198.92.11.0      198.92.72.30                         0 109 108 ?
*  198.92.14.0      198.92.72.30                         0 109 108 ?
*  198.92.15.0      198.92.72.30                         0 109 108 ?
*  198.92.16.0      198.92.72.30                         0 109 108 ?
*  198.92.17.0      198.92.72.30                         0 109 108 ?
*  198.92.18.0      198.92.72.30                         0 109 108 ?
*  198.92.19.0      198.92.72.30                         0 109 108 ?
*  198.92.24.0      198.92.72.30                         0 109 108 ?
*  198.92.29.0      198.92.72.30                         0 109 108 ?
*  198.92.30.0      198.92.72.30                         0 109 108 ?
*  198.92.33.0      198.92.72.30                         0 109 108 ?
*  198.92.35.0      198.92.72.30                         0 109 108 ?
*  198.92.36.0      198.92.72.30                         0 109 108 ?
*  198.92.37.0      198.92.72.30                         0 109 108 ?
*  198.92.38.0      198.92.72.30                         0 109 108 ?
*  198.92.39.0      198.92.72.30                         0 109 108 ?
 

show ip bgp summary

To display the status of all BGP connections, use the show ip bgp summary EXEC command.

show ip bgp summary

Syntax Description

This command has no arguments or keywords.

Command Mode

EXEC

Usage Guidelines

This command first appeared in Cisco IOS Release 10.0. The PfxRcd and Admin entries first appeared in Cisco IOS Release 12.0.

Sample Display

The following is sample output from the show ip bgp summary command:

Router# show ip bgp summary
 
BGP table version is 717029, main routing table version 717029
19073 network entries (37544 paths) using 3542756 bytes of memory
691 BGP path attribute entries using 57200 bytes of memory
 
Neighbor        V    AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
193.0.16.1      4  1755   32642    2973   717029    0    0 1:27:11  
193.0.17.1      4  1755    4790    2973   717029    0    0 1:27:51  
193.0.18.1      4  1755    7722    3024   717029    0    0 1:28:13  
193.0.19.1      4  1755       0       0        0    0    0 2d02     Active
193.0.20.1      4  1755    3673    3049   717029    0    0 2:50:10  Idle (PfxRcd)
193.0.21.1      4  1755    3741    3048   717029    0    0 12:24:43 
193.0.22.1      4  1755   33129    3051   717029    0    0 12:24:48 
193.0.23.1      4  1755       0       0        0    0    0 2d02     Active
193.0.24.1      4  1755       0       0        0    0    0 2d02     Active
193.0.25.1      4  1755       0       0        0    0    0 2d02     Active
193.0.26.1      4  1755       0       0        0    0    0 2d02     Active
193.0.27.1      4  1755    4269    3049   717029    0    0 12:39:33 
193.0.28.1      4  1755    3037    3050   717029    0    0 2:08:15  
198.92.72.24    4  1878   11635   13300   717028    0    0 0:50:39  
198.92.72.36    4  1001       0       0        0    0    0 never    Idle (Admin)
 

Table 55 describes significant fields shown in the display.


Table 55: Show IP BGP Summary Field Descriptions
Field Description

BGP table version

Internal version number of BGP database.

main routing table version

Last version of BGP database that was injected into main routing table.

Neighbor

IP address of a neighbor.

V

BGP version number spoken to that neighbor.

AS

Autonomous system.

MsgRcvd

BGP messages received from that neighbor.

MsgSent

BGP messages sent to that neighbor.

TblVer

Last version of the BGP database that was sent to that neighbor.

InQ

Number of messages from that neighbor waiting to be processed.

OutQ

Number of messages waiting to be sent to that neighbor.

Up/Down

The length of time that the BGP session has been in state Established, or the current state if it is not Established.

State/PfxRcd

Current state of the BGP session/the number of prefixes the router has received from a neighbor or peer group. When the maximum number (as set by the neighbor maximum prefix command) is reached, the string "PfxRcd" appears in the entry, the neighbor is shut down, and the connection is Idle.

An (Admin) entry with Idle status indicates that the connection has been shut down using the neighbor shutdown command.

Related Commands

You can use the master indexes or search online to find documentation of related commands.

neighbor maximum-prefix
neighbor shutdown
show ip bgp summary

synchronization

To enable the synchronization between BGP and your IGP, use the synchronization router configuration command. To enable the Cisco IOS software to advertise a network route without waiting for the IGP, use the no form of this command.

synchronization
no synchronization

Syntax Description

This command has no arguments or keywords.

Default

Enabled

Command Mode

Router configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 10.0.

Usually, a BGP speaker does not advertise a route to an external neighbor unless that route is local or exists in the IGP. The no synchronization command allows the Cisco IOS software to advertise a network route without waiting for the IGP. This feature allows routers and access servers within an autonomous system to have the route before BGP makes it available to other autonomous systems.

Use synchronization if there are routers in the autonomous system that do not speak BGP.

Example

The following example enables a router to advertise a network route without waiting for the IGP:

router bgp 120
 no synchronization

table-map

To modify metric and tag values when the IP routing table is updated with BGP learned routes, use the table-map router configuration command. To disable this function, use the no form of the command.

table-map route-map-name
no table-map route-map-name

Syntax Description

route-map-name

Route-map name, from the route-map command.

Default

Disabled

Command Mode

Router configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 10.0.

This command adds the route-map name defined by the route-map command to the IP routing table. This command is used to set the tag name and the route metric to implement redistribution.

You can use match clauses of route maps in the table-map command. IP access list, autonomous system paths, and next-hop match clauses are supported.

Example

In the following example, the Cisco IOS software is configured to automatically compute the tag value for the BGP learned routes and to update the IP routing table.

route-map tag
 match as path 10
 set automatic-tag 
!
router bgp 100
 table-map tag

Related Commands

You can use the master indexes or search online to find documentation of related commands.

match as-path
match ip address
match ip next-hop
route-map

timers bgp

To adjust BGP network timers, use the timers bgp router configuration command. To reset the BGP timing defaults, use the no form of this command.

timers bgp keepalive holdtime
no timers bgp

Syntax Description

keepalive

Frequency, in seconds, with which the Cisco IOS software sends keepalive messages to its peer. The default is 60 seconds.

holdtime

Interval, in seconds, after not receiving a keepalive message that the software declares a peer dead. The default is 180  seconds.

Defaults

keepalive: 60 seconds
holdtime: 180 seconds

Command Mode

Router configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 10.0.

Example

The following example changes the keepalive timer to 70 seconds and the holdtime timer to 210  seconds:

timers bgp 70 210

Related Commands

You can use the master indexes or search online to find documentation of related commands.

clear ip bgp peer-group
router bgp
show ip bgp


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