BGP Local Preference (Local_Pref)
BGP Local preference (Local_Pref) Path attribute gives the router inside a single autonomous system a value that they can set per-route and advertise to all iBGP routers inside the autonomous system, so that all routers in the autonomous system agree about which routers is the best exit point for packet destined for that prefix.
Path with highest preference value is more desirable, by default Local_pref value is 100 and the range is 0 through 4,294,967,295. Local preference is well-known, discretionary attribute. It is advertised only to iBGP neighbors within an autonomous system.
Topology:
