Before BGP can be implemented, the following entities must be configured:
The autonomous system (AS) number for the router
An AS number is a globally unique value which associates a router to a specific autonomous system. This number is used to exchange exterior routing information with neighboring ASs and as an identifier of the AS itself. Each router participating in BGP must have an AS number specified.
To implement BGP, the AS number must be specified in the config>router context.
Router ID
The router ID is the IP address of the local router. The router ID identifies a packet’s origin. The router ID must be a valid host address.