Specifications
Implementing BGP on Cisco IOS XR Software
Information About Implementing BGP on Cisco IOS XR Software
RC-13
Cisco IOS XR Routing Configuration Guide
3. Otherwise, if the neighbor uses a neighbor group and does not use a session group or address family
group, the configuration value can be obtained from the neighbor group either directly or through
inheritance. In the example that follows, the advertisement interval from the neighbor group is used
because it is not configured directly on the neighbor and no session group is used:
RP/0/RP0/CPU0:router(config)# router bgp 150
RP/0/RP0/CPU0:router(config-bgp)# session-group AS_2
RP/0/RP0/CPU0:router(config-bgp-sngrp)# advertisement-interval 20
RP/0/RP0/CPU0:router(config-bgp-sngrp)# exit
RP/0/RP0/CPU0:router(config-bgp)# neighbor-group AS_1
RP/0/RP0/CPU0:router(config-bgp-nbrgrp)# advertisement-interval 15
RP/0/RP0/CPU0:router(config-bgp-nbrgrp)# exit
RP/0/RP0/CPU0:router(config-bgp)# neighbor 192.168.1.1
RP/0/RP0/CPU0:router(config-bgp-nbr)# remote-as 1
RP/0/RP0/CPU0:router(config-bgp-nbr)# use neighbor-group AS_1
The following output from the show bgp neighbors command shows that the advertisement interval
used is 15 seconds:
RP/0/RP0/CPU0:router# show bgp neighbors 192.168.1.1
BGP neighbor is 192.168.2.2, remote AS 1, local AS 140, external link
Remote router ID 0.0.0.0
BGP state = Idle
Last read 00:00:00, hold time is 180, keepalive interval is 60 seconds
Received 0 messages, 0 notifications, 0 in queue
Sent 0 messages, 0 notifications, 0 in queue
Minimum time between advertisement runs is 15 seconds
For Address Family: IPv4 Unicast
BGP neighbor version 0
Update group: 0.1
eBGP neighbor with no outbound policy; defaults to 'drop'
Route refresh request: received 0, sent 0
Inbound path policy configured
Policy for incoming advertisements is POLICY_1
0 accepted prefixes
Prefix advertised 0, suppressed 0, withdrawn 0, maximum limit 524288
Threshold for warning message 75%
Connections established 0; dropped 0
Last reset 00:01:14, due to BGP neighbor initialized
External BGP neighbor not directly connected.
To illustrate the same rule, the following example shows how to set the advertisement interval to 15
(from the session group) and 25 (from the neighbor group). The advertisement interval set in the
session group overrides the one set in the neighbor group. The inbound policy is set to POLICY_1
from the neighbor group.
RP/0/RP0/CPU0:router(config)# router bgp 140
RP/0/RP0/CPU0:router(config-bgp)# session-group ADV
RP/0/RP0/CPU0:router(config-bgp-sngrp)# advertisement-interval 15
RP/0/RP0/CPU0:router(config-bgp-sngrp)# exit
RP/0/RP0/CPU0:router(config-bgp)# neighbor-group ADV_2
RP/0/RP0/CPU0:router(config-bgp-nbrgrp)# advertisement-interval 25
RP/0/RP0/CPU0:router(config-bgp-nbrgrp)# address-family ipv4 unicast
RP/0/RP0/CPU0:router(config-bgp-nbrgrp-af)# route-policy POLICY_1 in
RP/0/RP0/CPU0:router(config-bgp-nbrgrp-af)# exit
RP/0/RP0/CPU0:router(config-bgp-nbrgrp)# exit
RP/0/RP0/CPU0:router(config-bgp)# exit
RP/0/RP0/CPU0:router(config-bgp)# neighbor 192.168.2.2
RP/0/RP0/CPU0:router(config-bgp-nbr)# remote-as 1