Should Have Gone With Cisco

This is a continuation from Part I of the MPLS worklog

PE-CE routing with BGP

I wanted to touch a little bit more on the subject of using BGP as a PE-CE routing protocol. In most cases, you probably won’t be using BGP as the routing protocol between the CE and PE routers (in terms of site-to-site VPN usage). In some cases, your sites may need to rely on BGP for internet routing and therefore we probably want to use an IGP protocol for route sharing between our VPN sites (especially if our sites use private IPv4 addressing). Don’t forget that our CE routers can only run one instance of BGP (only 1 BGP AS per router). Unless we are using static routing for internet access, we probably don’t want to waste our only instance of BGP for routing between our PE-CE routers. Now in some cases, our provider could import all routes from its global routing table into our vrf table—from the research I’ve done, this is very bad. Adding Internet access really introduces a lot of possibilities for how we can do things. I will cover more on Internet access later. Let’s get back on track here and take a look at the diagram below.

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