Administrator Guide

Layer 3 Routing Commands 1257
User Guidelines
BGP tracks the reachability of each internal peer’s IP address. If a peer
becomes unreachable (that is, the RIB no longer has a non-default route to
the peer’s IP address), BGP drops the adjacency.
Command History
Introduced in version 6.2.0.1 firmware.
Example
console(config-router)# bgp fast-internal-fallover
bgp listen
Use the bgp listen command to create an IPv4 listen range and associates it
with the specified peer template. The bgp listen command also activates the
IPv4 or IPv6 BGP dynamic neighbors feature. Use the no form of the
command to remove an IPv4 or IPv6 listen range.
Syntax
bgp listen { limit max-number | range network/length [ inherit peer peer-
template-name ] }
no bgp listen { limit | range network/length [ inherit peer peer-template-
name ] }
• limit max-number — Sets a maximum limit number of IPv4 BGP
dynamic subnet range neighbors. The number is from 1 to 100. Default is
20.
• range network/length — Specifies a listen subnet range that is to be
created. The IP prefix representing a subnet is specified by network, and
length is the subnet mask in bits. The network argument can be valid IPv4
prefix (BGP Router Configuration mode or IPv4 Address Family
Configuration mode) or an IPv6 prefix (IPv6 Address Family
Configuration mode).
• inherit peer peer-template-name — (Optional) Specifies a BGP peer
template name that is to be associated with the specified listen subnet
range and inherited with dynamically created neighbors.