Determine difference between 2 BGP feeds

Hi, We receive a BGP feed from different providers on two different routers. While one seems to be a reasonable amount of feeds after reviewing the CIDR report, the other is anywhere from 3K to 10K more routes. Is there a utility that I can use that will pull the routes off each router (Foundry preferred), and then compare them as best it can to see why there is such a difference? I can understand a handful of routes over what CIDR says, but a minimum of 3K more? Thanks, Tuc/TBOH