JN0-664: Service Provider Routing and Switching, Professional

A route reflector adds its cluster ID to the CLUSTER_LIST when reflecting client-learned routes, including advertisements to other clients. For an eBGP advertisement, the advertising BGP speaker sets itself as the NEXT_HOP. In contrast, iBGP route reflection preserves the next hop, and redundant reflectors that must reflect routes to other clusters require different cluster IDs.