BGP PIC (Prefix Independent Convergence) Core & Edge

Hello Dominique

The specific example was within the BGP PIC Core section, which means that we are attempting to decrease convergence time in the event that a core router (P router) fails. Because the PE routers are those that are on the edge of the BGP AS, and they contain the routes to the prefixes at each customer, it is these routers that require the hierarchical FIB enabled. The P routers simply interconnect the PE routers and do not need to know about the multiple prefixes that exist at the customers. So in the event of a core failure, the remaining functioning core routers will not have many prefixes to reconverge. The edge routers however will have many (millions?) of prefixes to reconverge. So although you can apply it to a core router, such a command would only beneficial to edge and not core routers.

I hope this has been helpful!

Laz

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