BGP Router ID

A router ID uniquely identifies a router in an AS, and the router ID can be configured as follows:

Run the router-id(BGP) { ipv4-address | vpn-instance auto-select } command. If no router ID is configured in the BGP view, BGP selects the global router ID. For details on how a global router ID is selected, see router-id.
Run the router-id (BGP-VPN Instance IPv4 Address Family View) { ipv4-address | auto-select } command in the BGP VPN instance IPv4 address family view. The router-id (BGP-VPN Instance IPv4 Address Family View) command takes precedence over the router-id(BGP) command.

If each route carries an Originator_ID, the Originator_IDs rather than router IDs are compared during route selection. The route with the smallest Originator_ID is preferred. By default, Cluster_List takes precedence over Originator_ID during BGP route selection. To enable Originator_ID to take precedence over Cluster_List during BGP route selection, run the bestroute router id-prior-clusterlist command.

For more router ID-based route selection examples, see Local_Pref, Origin, and MED.