Cisco Systems 3130 User Manual

Router B:

Switch(config)# router bgp 200

Switch(config-router)# neighbor 129.213.1.2 remote-as 100

Switch(config-router)# neighbor 175.220.1.2 remote-as 200

Router C:

Switch(config)# router bgp 200

Switch(config-router)# neighbor 175.220.212.1 remote-as 200

Switch(config-router)# neighbor 192.208.10.1 remote-as 300

Router D:

Switch(config)# router bgp 300

Switch(config-router)# neighbor 192.208.10.2 remote-as 200

To verify that BGP peers are running, use the show ip bgp neighbors privileged EXEC command. This 
is the output of this command on Router A:

Switch# show ip bgp neighbors

BGP neighbor is 129.213.1.1, remote AS 200, external link

 BGP version 4, remote router ID 175.220.212.1

 BGP state = established, table version = 3, up for 0:10:59

 Last read 0:00:29, hold time is 180, keepalive interval is 60 seconds

 Minimum time between advertisement runs is 30 seconds

 Received 2828 messages, 0 notifications, 0 in queue

 Sent 2826 messages, 0 notifications, 0 in queue

 Connections established 11; dropped 10

Anything other than state = established means that the peers are not running. The remote router ID is 
the highest IP address on that router (or the highest loopback interface). Each time the table is updated 
with new information, the table version number increments. A table version number that continually 
increments means that a route is flapping, causing continual routing updates.

For exterior protocols, a reference to an IP network from the network router configuration command 
controls only which networks are advertised. This is in contrast to Interior Gateway Protocols (IGPs), 
such as EIGRP, which also use the network command to specify where to send updates.

For detailed descriptions of BGP configuration, see the “IP Routing Protocols” part of the Cisco IOS IP 
Configuration Guide, Release 12.2. For details about specific commands, see the Cisco IOS IP 
Command Reference, Volume 2 of 3: Routing Protocols, Release 12.2. See 

 for a list of BGP commands that are visible but not 

supported by the switch.

Routing policies for a peer include all the configurations that might affect inbound or outbound routing 
table updates. When you have defined two routers as BGP neighbors, they form a BGP connection and 
exchange routing information. If you later change a BGP filter, weight, distance, version, or timer, or 
make a similar configuration change, you must reset the BGP sessions so that the configuration changes 
take effect. 

There are two types of reset, hard reset and soft reset. Cisco IOS Releases 12.1 and later support a soft 
reset without any prior configuration. To use a soft reset without preconfiguration, both BGP peers must 
support the soft route refresh capability, which is advertised in the OPEN message sent when the peers