11.2 BGP router

First of all you must configure BGP router with router bgp command. To configure BGP router, you need AS number. AS number is an identification of autonomous system. BGP protocol uses the AS number for detecting whether the BGP connection is internal one or external one.

Command: router bgp asn

Enable a BGP protocol process with the specified asn. After this statement you can input any BGP Commands. You can not create different BGP process under different asn without specifying multiple-instance (see Multiple instance).

Command: no router bgp asn

Destroy a BGP protocol process with the specified asn.

BGP: bgp router-id A.B.C.D

This command specifies the router-ID. If bgpd connects to zebra it gets interface and address information. In that case default router ID value is selected as the largest IP Address of the interfaces. When router zebra is not enabled bgpd can’t get interface information so router-id is set to 0.0.0.0. So please set router-id by hand.