multiexit discriminator
In BGP, an arbitrary rating number that the PortMaster can use to enforce the use of preferred exit and entry points when multiple connections exist between its autonomous system and another. The PortMaster assigns the multiexit discriminator to any route that it advertises to its external peers, and forwards any multiexit discriminator it learns from its external peers on to its internal peers. A lower number indicates a greater preference for a route when more than one exists to a destination through multiple peers within the same neighboring autonomous system. You can use a routing policy rule to override this value and assign your own multiexit discriminator to a route that you learn or advertise.