route reflector
also: BGP route reflector, RR
A BGP router that re-advertises (reflects) route announcements from one set of BGP peers to another, reducing the need for a full mesh of BGP connections in large networks.
A route reflector is a BGP (Border Gateway Protocol) router that acts as a central hub for route distribution within an autonomous system. Instead of requiring every internal BGP router to maintain direct connections with every other internal router (a full mesh topology), a route reflector receives route announcements from client routers and reflects them to other clients, simplifying network scaling.
When an internal BGP router advertises a route to the route reflector, the reflector re-announces that route to its other BGP clients. This breaks the normal BGP rule that a router won't advertise routes received from one iBGP peer to another iBGP peer. The route reflector is configured with special cluster rules to prevent routing loops.
Example: In a data center with 20 internal routers, instead of each router maintaining 19 BGP connections (190 total connections), you can use 2-3 route reflectors where each router connects only to the reflectors, reducing connections to roughly 40-60 and improving convergence time during network changes.