Cisco A9K-SIP-700 Configuration Guide

We strongly recommend that the bgp router-id command is configured to prevent unnecessary changes
to the router ID (and consequent flapping of BGP sessions).
Note
BGP Default Limits
Cisco IOS XR BGP imposes maximum limits on the number of neighbors that can be configured on the router
and on the maximum number of prefixes that are accepted from a peer for a given address family. This
limitation safeguards the router from resource depletion caused by misconfiguration, either locally or on the
remote neighbor. The following limits apply to BGP configurations:
•
The default maximum number of peers that can be configured is 4000. The default can be changed using
the bgp maximum neighbor command. The limit range is 1 to 15000. Any attempt to configure
additional peers beyond the maximum limit or set the maximum limit to a number that is less than the
number of peers currently configured will fail.
•
To prevent a peer from flooding BGP with advertisements, a limit is placed on the number of prefixes
that are accepted from a peer for each supported address family. The default limits can be overridden
through configuration of the maximum-prefix limit command for the peer for the appropriate address
family. The following default limits are used if the user does not configure the maximum number of
prefixes for the address family:
◦
IPv4 Unicast: 1048576
◦
IPv4 Labeled-unicast: 131072
◦
IPv4 Tunnel: 1048576
◦
IPv6 Unicast: 524288
◦
IPv6 Labeled-unicast: 131072
◦
IPv4 Multicast: 131072
◦
IPv6 Multicast: 131072
◦
IPv4 MVPN: 2097152
◦
VPNv4 Unicast: 2097152
◦
IPv4 MDT: 131072
◦
VPNv6 Unicast: 1048576
◦
L2VPN EVPN: 2097152
A cease notification message is sent to the neighbor and the peering with the neighbor is terminated
when the number of prefixes received from the peer for a given address family exceeds the maximum
limit (either set by default or configured by the user) for that address family.
It is possible that the maximum number of prefixes for a neighbor for a given address family has been
configured after the peering with the neighbor has been established and a certain number of prefixes
have already been received from the neighbor for that address family. A cease notification message is
sent to the neighbor and peering with the neighbor is terminated immediately after the configuration if
Cisco ASR 9000 Series Aggregation Services Router Routing Configuration Guide, Release 5.1.x
OL-30423-03 11
Implementing BGP
BGP Default Limits

Cisco A9K-SIP-700 Specifications

General

Brand	Cisco
Model	A9K-SIP-700
Category	Network Router
Language	English