Admittedly, I am not a routing guru. However, I have to get some redundancy built in to our existing Internet infrastructure. The proposed setup is pretty simple; 2 sites w/ different ISPs and a total of 4 routers, switches, and firewalls. Please visitto see the logical diagram (for anonymity I have used someone else's external IP blocks). Anyway, if you look at the diagram you will see that we have routers A and C and routers B and D connected over some high speed metro Ethernet links.
We are peering with Time Warner in Austin, and SBC in Taylor. Within our network we want all four routers to peer with each other over iBGP. For our IGP, we will use OSPF. My understanding is the BGP will not advertise routes learned via another iBGP neighbor unless that route is known by an IGP (in this case OSPF).
What we want is simple, if Time Warner dies, SBC needs to be able to handle routes to and from the 220.127.116.11 /24 block, and if SBC dies, Time Warner needs to be able to handle routers to and from the 18.104.22.168 /24 block. Also, any router and switch failures should be relatively transparent to our Internal and External users.
My question is this; should all four routers be a member of Area 0, or should we have disparate areas between sites? The reason I ask is because when we brought this topology up last night, we established BGP peering just fine. The problem was that as the BGP routes were being propagated between iBGP peers, they would climb up to 156,000, and then suddenly drop to roughly 4000. They would then slowly creep back up, only to plummet again. This, of course, made for a very unstable network. We were forced to remove the secondary routers for the time being to stabilize the network.
Sorry to ramble, but if anyone has any suggestions on how to configure this in a highly available and stable manner PLEASE make a suggestion. Thanks in advance for the help.