MULTI_EXIT_DISC

When there are multiple entry or exit points for the same neighboring AS, the MULTI_EXIT_DISCRIMINATOR is used to distinguish between them. It is not propagated when the routing information is passed on to outside ASs. A lower MULTI_EXIT_DISC is given precedence over a higher one.

B sets the MULTI_EXIT_DISCRIMINATOR to 5 on one link and 10 on the other link when sending routing information to C. In this way, B can suggest an entry point for C to take when routing through B.