Practical BGP

Route Reflectors

From the preceding sections on full mesh iBGP cores, and the scaling implications of iBGP cores, it's obvious that we should look for some way to eliminate the need for a full mesh among iBGP speakers in the same autonomous system. How could this be accomplished given the possibility of routing loops or reachability problems if we don't maintain a full mesh of connectivity? One possibility is route reflection, which reorganizes the iBGP core into a hierarchy and relaxes the iBGP route advertisement rules. Route reflection introduces the notion of reflected routes, which allows BGP speakers to break the rule of never advertising a route learned through iBGP to another iBGP peer in specific circumstances.

Route Reflection is described ...