Bgp Configuration Limits - Cisco CRS-1 - Carrier Routing System Router Getting Started Manual

Chapter 5 Initial Configuration of the Cisco IOS XR Software
Number of Parallel Links (max-paths)
In the following example, the maximum paths command is used to set the maximum number of parallel
routes:
RP/0/RP1/CPU0:router# configure
RP/0/RP1/CPU0:router(config)# router ospf 100
RP/0/RP1/CPU0:router(config-router)# maximum paths 10
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 'lab'.
hanges.
RP/0/RP1/CPU0:Mar 30 18:05:13 : config[65740]: %SYS-5-CONFIG_I : Configured from
console by lab
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 will fail.
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-prefix command.
Table 5-10
Table 5-10 BGP Configuration Limits and Commands
Feature Limit Description
Maximum number of neighbors
(peers).
IPv4 unicast maximum prefixes
that can be received from a
neighbor
IPv4 multicast maximum prefixes
that can be received from a
neighbor
IPv6 unicast maximum prefixes
that can be received from a
neighbor
Maximum equal-cost parallel
routes to external peers
Use 'show commit changes 1000000542' to view the c
summarizes the maximum configuration limits for BGP.
Default Absolute
Maximum Maximum
Limit Limit
1,024 1,024
524,288 4,294,967,
295
131,072 4,294,967,
295
131,072 4,294,967,
295
1 8
Configuration Command
(Router Configuration Mode)
None. This limit cannot be
changed or exceeded.
maximum-prefix n
maximum-prefix n
maximum-prefix n
maximum-paths n
Cisco CRS-1 Series Carrier Routing System Getting Started Guide
Configuration Limiting
Show Current Settings Command
(EXEC Mode)
None
show bgp neighbor IP_address
show bgp neighbor IP_address
show bgp neighbor IP_address
show running-config
This command only
Note
shows changes to the
default value. If the
maximum paths
command does not
appear, the router is set
to the default value.
5-23