- Purple, 4500 points or more
I'm having a hard time understanding the "no synchronization" line in bgp.
The link shows a topology where an IGP is running between router, but iBGP is running between the two routers.
If I understand correctly, synchronization requires the IGP to know about the route before BGP will redistribute it to other neighbors. (Right?) If that's the case, if I were to look on RouterB's (the far side of iBGP) routing table, wouldn't I see a route point to the network that IGP doesn't know about, to RouterA as the next hop?
So, I envision RouterA knowing about 188.8.131.52, and it doesn't get redistributed into IGP when it hits router A, but instead gets propagated to it's iBGP peer (RouterB). Wouldn't RouterB have an entry in its routing table like:
B 184.108.40.206 [20/0] via 220.127.116.11
Does sync or "no sync" allow for router B to propagate this route to RouterD? I would think "no sync" if I'm trying to keep BGP from requiring the IGP knowing aobut the 18.104.22.168 subnet.
I may have just talked myself through it. =)
Don't forget the rule. The router will not modify the next-hop when it sends routes via iBGP. That's why RouterB will see 22.214.171.124 as the next-hop.
RouterB may think about how to get there via IGP. Or you may use the nexthop-self command on the RouterA for some reason.
To be honest this document is good but for this part of your question it doesn't give you more configuration.