Question

A service provider runs IBGP with two route reflectors (RR1 and RR2) serving the same set of clients for redundancy. To avoid unnecessary route storage and ensure loop prevention within the redundant reflector design, both RRs are configured with the same cluster-id. A network engineer troubleshooting missing paths observes that when an RR receives a reflected route, it silently discards updates that contain its own cluster identifier. Which attribute is responsible for this loop-prevention behavior among route reflectors sharing a cluster-id?

Accepted Answer

The CLUSTER_LIST attribute, which the RR checks for its own CLUSTER_ID and discards the update if found

Answer

The ORIGINATOR_ID attribute, which lists every RR that reflected the route so duplicates are dropped

Answer

The AS_PATH attribute, which accumulates the cluster-id as if it were a private AS number

Answer

The ORIGIN attribute, which is set to incomplete when a route passes through a reflector cluster