Injecting BGP RIBs into Dynagen networks

I’ve been playing with Dynagen this week to build a copy of part of our network, so I can test some config changes safely. One of the things is to figure out if we have enough resources to run full BGP views on one of the routers, so I’ve been trying to figure out a nice way to take MTR RIB dumps from routeviews.org, and inject them into my emulated network.

So far I have a perl script that uses Net::BGP to act as a BGP peer, and another bit of perl to read the MTR-format dumps. You can then use Loopback interfaces in Windows to make an interface on one of the routers appear as a ‘real’ interface on the host PC. Finally, I should be able to get the perl BGP speaker to talk to the virtual Cisco, and pass in my RIB.

At the moment, something funny is happening, and the peer is never established. I don’t know yet if it’s perl on Windows, the loopback interface or the emulation though. Net::BGP will talk to a real router, because I do that already for something else, but on a BSD system. TCPView says that perl isn’t listening on any port, and the router is complaining about connections being refused, but I can’t see why. Ping works, and I can also access the web interface on the router, so I know it’s roughly right.

I’ll be fiddling with this some more on Monday, because it seems like a useful thing to me.