My recommendation would be for you to: o redistribute directly connected interfaces via a strict filter into BGP and use iBGP to carry it around the local AS or o use passive interfaces in IGPs to do the same Avoid having to run a topology computation everytime a T1/56k links drops. I prefer the first option to the second based on experience UUNET / Global Crossing has w/ option #1. - Serge Thus spake Mike Bernico (mbernico@illinois.net):
Hi,
I apologize if this has been asked before. I work for an ISP that started very small (hundreds of T1 and 56k customers) and has grown very large in the last few years (thousands of T1 customers, as well as DS3 customers and OC3 customers).
We currently use an IGP to route between our distribution routers and the CPE routers we manage. This has historically worked very well. We have recently begun running into scalability issues however. We have some distribution routers that have over 1000 T1 interfaces on them. This is causing some problems with stability in that edge IGP. Does any other service provider use an IGP all the way to the customer for non BGP customers or are we the only one? I have a feeling we maybe are.
If you do use an IGP, have you had any of the scalability issues we have had? How did you fix them?
If you use statics/BGP to CPE routers have you had any issues doing that? In particular I'm wondering about the thousands of lines of configuration used to make static routes work.
Thanks in advance for your advice.
Mike Bernico