[j-nsp] BGP route-reflection question

[Dmitri Kalintsev]

Hi All,

Let's imagine that I have two straight ipv4 BGP route reflectors in the same
cluster, say R1 and RR2. Now imagine that I have a reflector client, which
is:

a) Connected to both of them via dedicated point to point links;
b) Advertising the same routes to both of them.

Now imagine that one of the point to point links (say client to RR1) has
failed. Client would still advertise it's routes to the RR2, and RR2 would
readvertise them to RR1.

The experience that I had with other vendor's equipment is that RR1 would
not accept the client route advertisements from RR2, because it would reject
them having seen it's own cluster ID in these. The only way to make this
work was to remove the cluster ID (cluster list is used instead to prevent
routing loops).

In JunOS, it is a prerequisite and the only way to configure route reflector
client by setting the cluster ID in the bgp group to which the client
belongs.

http://www.juniper.net/techpubs/software/junos/junos57/swconfig57-routing/html/bgp-config37.html#1015846

states:

"By default, the BGP route reflector performs intracluster reflection
because it assumes that all the client peers are not fully meshed."

Could anybody please clarify to me how this is implemented in JunOS and this
"intracluster reflection" is?

SY,
-- 
D.K.