AI, ML, Development + Cisco Learning Blog Learning about Machine Learning, Artificial Intelligence, related devlopment topics and formerly Routing and Switching, Datacenter, Security and other topics, CCIE #23664, Frank Wagner

In this example there are

• Route Reflectors
• Route Reflecor Clients
• Non Clients to Route Reflectors

In a normal enviroment all iBGP neighbors must be fully meshed. There are two exeptions to this rule.

1. Route-Reflection
2. Confederation

iBGP neigbors do not advertise routes learned from another iBGP neighbor to prevent loops. Therefore it is needed, that all iBGP neighbors are full meshed.

A route reflector will pass prefixes learned from BGP neighbors to

Advertisement is as follows:

if a client is an EBGP neighbor, all prefixes learned from the peer, will be advertised to all other peers

if a route is received from a client peer, the route is advertised to all client peers

if a route is received from a non-client peer, it is candidate to be advertised on all client peers. Sometime the route will not be advertised, when for example the route is not the „best“ path, or the route is part of a community not to be advertised.

to be continued….