Question

A service provider runs a single AS with 12 IBGP-speaking PE routers configured in a full mesh. The network team plans to grow to 40 PEs and wants to reduce IBGP peering overhead without splitting the AS or introducing loops. A senior engineer proposes deploying two route reflectors in the core. When a route reflector receives an IBGP prefix from one of its clients, how will it advertise that prefix, and what loop-prevention attribute is used?

Accepted Answer

It reflects the client route to all other clients and to non-client IBGP peers, and uses the ORIGINATOR_ID and CLUSTER_LIST attributes for loop prevention.

Answer

It reflects the client route only to non-client IBGP peers, relying on the AS_PATH prepend to prevent loops among clients.

Answer

It forwards the route only to its EBGP peers after resetting the NEXT_HOP, using the AS_PATH to detect loops within the cluster.

Answer

It reflects the route to all clients but not to non-client peers, using the LOCAL_PREF attribute to break potential routing loops.