Cisco ASR 9000 Series Routing Configuration Manual page 52

BGP Configuration
For Address Family: IPv4 Unicast
2 Otherwise, if an item is configured to be inherited from a session-group or neighbor-group and on the
neighbor directly, then the configuration on the neighbor is used. If a neighbor is configured to be inherited
from session-group or af-group, but no directly configured value, then the value in the session-group or
af-group is used. In the example that follows, the advertisement interval is configured on a neighbor group
and a session group and the advertisement interval value being used is from the session group:
RP/0/RSP0/CPU0:router(config)# router bgp 140
RP/0/RSP0/CPU0:router(config-bgp)# session-group AS_2
RP/0/RSP0/CPU0:router(config-bgp-sngrp)# advertisement-interval 15
RP/0/RSP0/CPU0:router(config-bgp-sngrp)# exit
RP/0/RSP0/CPU0:router(config-bgp)# neighbor-group AS_1
RP/0/RSP0/CPU0:router(config-bgp-nbrgrp)# advertisement-interval 20
RP/0/RSP0/CPU0:router(config-bgp-nbrgrp)# exit
RP/0/RSP0/CPU0:router(config-bgp)# neighbor 192.168.0.1
RP/0/RSP0/CPU0:router(config-bgp-nbr)# remote-as 1
RP/0/RSP0/CPU0:router(config-bgp-nbr)# use session-group AS_2
RP/0/RSP0/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/RSP0/CPU0:router# show bgp neighbors 192.168.0.1
BGP neighbor is 192.168.0.1, remote AS 1, local AS 140, external link
Remote router ID 0.0.0.0
For Address Family: IPv4 Unicast
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/RSP0/CPU0:router(config)# router bgp 150
RP/0/RSP0/CPU0:router(config-bgp)# session-group AS_2
RP/0/RSP0/CPU0:router(config-bgp-sngrp)# advertisement-interval 20
RP/0/RSP0/CPU0:router(config-bgp-sngrp)# exit
Cisco ASR 9000 Series Aggregation Services Router Routing Configuration Guide, Release 5.3.x
22
BGP neighbor version 0
Update group: 0.1
eBGP neighbor with no inbound or outbound policy; defaults to 'drop'
Route refresh request: received 0, sent 0
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Prefix advertised 0, suppressed 0, withdrawn 0, maximum limit 524288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 00:00:14, due to BGP neighbor initialized
External BGP neighbor not directly connected.
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
BGP neighbor version 0
Update group: 0.1
eBGP neighbor with no inbound or outbound policy; defaults to 'drop'
Route refresh request: received 0, sent 0
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 00:03:23, due to BGP neighbor initialized
External BGP neighbor not directly connected.
Implementing BGP