When a route to the same prefix can be reached through two or more paths, the BGP local-preference attribute can be used within an AS to favor a specified path based on highest local-preference value. The local-preference value is only applicable within the local AS.
Use the bgp local-pref command, in BGP configuration mode, to set the local-preference for advertised routes.
The following example sets the local-preference for advertised routes to 150:
System(su-config)->router bgp 65151 System(su-config-bgp)->bgp router-id 151.1.1.9 System(su-config-bgp)->bgp local-pref 150 System(su-config-bgp)->