Cisco 3845 Software Guide - Page 613

Chapter 29 Configuring IP Unicast Routing Configuring BGP 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 Appendix C, "Unsupported Commands in Cisco IOS Release 12.2(52)EY," for a list of BGP commands that are visible but not supported by the switch. Managing Routing Policy Changes 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. The switch supports a soft reset without any prior configuration when both BGP peers support the soft route refresh capability, which is advertised in the OPEN message sent when the peers establish a TCP session. A soft reset allows the dynamic exchange of route refresh requests and routing information between BGP routers and the subsequent re-advertisement of the respective outbound routing table. • When soft reset generates inbound updates from a neighbor, it is called dynamic inbound soft reset. • When soft reset sends a set of updates to a neighbor, it is called outbound soft reset. OL-23400-01 Cisco ME 3800X and 3600X Switch Software Configuration Guide 29-47