Prefixes Current: 1 1 (Consumes 52 bytes) Route refresh: advertised and received(old & new)Īddress family IPv4 Unicast: advertised and receivedĭefault minimum time between advertisement runs is 0 secondsīGP table version 3, neighbor version 3/0 Last read 00:00:58, last write 00:00:58, hold time is 180, keepalive interval is 60 seconds This is the basic principle of Route Reflection schemeīGP neighbor is 10.0.0.1, remote AS 65000, internal linkīGP version 4, remote router ID 208.209.251.213 This would eliminate the need for the IBGP session between RTR-A and RTR-B If this rule is relaxed and RTR-C is allowed to advertise IBGP learned routes to IBGP peers, then it could re-advertise (or reflect) the IBGP routes learned from RTR-A to RTR-B and vice versa. RTR-B and RTR-C (as IBGP speakers) will not re-advertise these IBGP learned routes to other IBGP speakers. With the existing BGP model, if RTR-A receives an external route and it is selected as the best path it must advertise the external route to both RTR-B and RTR-C. One of them is the use of “Route Reflectors”.In AS X there are three IBGP speakers (routers RTR-A, RTR-B and RTR-C). This scaling problem could be elevated in a couple of ways. This “full mesh” requirement clearly does not scale when there are a large number of IBGP speakers each exchanging a large volume of routing information, as is common in many of todays Internet. For n BGP speakers within an AS that requires to maintain n*(n-1)/2 unique IBGP sessions.

Currently in the Internet BGP deployments are configured such that that all BGP speakers within a single AS must be fully meshed so that any external routing information must be re-distributed to all other routers within that AS. The Border Gateway Protocol is an inter-autonomous system routing protocol designed for TCP/IP Internets.

Reflector 3 on cisco network