Cisco Systems Cisco IOS XR manual BGP Configuration Limits, Feature Limit Description

Chapter 5 Configuring Additional Router Features

Configuration Limiting

RP/0/RP1/CPU0:router(config-router)# end

Uncommitted changes found, commit them? [yes]: y

RP/0/RP1/CPU0:Mar 30 18:05:13 : config[65740]: %LIBTARCFG-6-COMMIT : Configurati

on committed by user 'cisco'. Use 'show configuration commit changes 1000000542' to view the changes.

RP/0/RP1/CPU0:Mar 30 18:05:13 : config[65740]: %SYS-5-CONFIG_I : Configured from console by cisco

RP/0/RP1/CPU0:router#

BGP Configuration Limits

The maximum number of BGP neighbors (peers) that can be configured is 1024. This number cannot be changed through configuration. Any attempt to configure additional neighbors beyond the limit fails.

To prevent neighbors (peers) from flooding BGP with advertisements, a limit is placed on the number of prefixes that can be accepted from a peer for each supported address family.

You can override the default limits for an address family with the maximum-prefixcommand. Table 5-7summarizes the maximum configuration limits for BGP.

Table 5-7	BGP Configuration Limits and Commands
		Default	Absolute
		Maximum	Maximum	Configuration Command	Show Current Settings Command
Feature Limit Description		Limit	Limit	(Router Configuration Mode)	(EXEC Mode)
Maximum number of neighbors		1024	1024	None. This limit cannot be	None
(peers)				changed or exceeded.
IPv4 unicast maximum prefixes		524,288	4,294,967,	maximum-prefix n	show bgp neighbor IP_address
that can be received from a			295
neighbor
IPv4 multicast maximum prefixes		131,072	4,294,967,	maximum-prefix n	show bgp neighbor IP_address
that can be received from a			295
neighbor
IPv6 unicast maximum prefixes		131,072	4,294,967,	maximum-prefix n	show bgp neighbor IP_address
that can be received from a			295
neighbor
Maximum equal-cost parallel		1	8	maximum-paths n	show running-config
routes to external peers					Note This command shows
					only changes to the
					default value. If the
					maximum paths
					command does not
					appear, the router is set
					to the default value.

	Cisco IOS XR Getting Started Guide
5-20	OL-10957-02