Connecting two POPs - which IGP, other info?

[randal]

OK, right now we are setup as described in currentwan.gif. 7206 BGP'd to two peers, works great. Very easy.

We are planning on opening a pop up north, where we will be purchasing all of our bandwidth. We will be maintaining connectivity on the southern side for failover, just in case our oc-3 fails.

I would like to connect the two POPs so that every client in both locations gets the benefit of every connected provider. Also, if the northern uplinks fail, things will failover to the southern link, and vice versa.

How do I connect routerA and routerB to make this work? I am leaning towards iBGP, but I'm pretty sure OSPF or EIGRP would work as well. These are all customer networks, we have our own /24 and that's it, so this is oriented towards public access. Is there a standard way of setting up such a scenario? Do I have to worry about crazy route redistribution? Any other advice would be appreciated.

Thanks,

randal

[thisisshanky]

IBGP is the right way to go, so that you manipulate BGP attributes across both routers and have traffic (inbound and outbound) follow a particular path. For BGP to exist and propagate routes, you do need a IGP or some sort such as OSPF and EIGRP. (No sync command should solve the issue of advertising routes to external ISPs).

[randal]

Hmm, maybe I'm missing something. With two directly connected routers, I still have to run an IGP in addition to iBGP? I find that a little odd; I thought iBGP would handle moving all the routes as appropriate, considering that we don't have any `internal` routes to speak of as everything is internet-facing?

[tahequivoice]

I believe you need eigrp so that your internal network is distributed between all routers as well. The iBGP only distributes external routes between the routers. the two should never cross paths unless you redistribute eigrp into BGP. In that case you would need to add route-maps to filter unwanted networks from being distributed through BGP.