Router ID

If multiple routes to the same destination are available, BGP preferentially selects the route advertised by the device with the smallest 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 { ipv4-address | vpn-instance auto-select } command. If no router ID is configured in the BGP view, BGP selects a router ID configured in the system view. For details on how a router ID configured in the system view is selected.
Run the router-id (BGP) { ipv4-address | auto-select } command in the BGP VPN instance IPv4/IPv6 address family view. The router-id (BGP VPN instance IPv4/IPv6 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.