Summary

The central point in this chapter is that the concepts and solutions of broadband access to MPLS VPN are, in fact, relatively generic and apply for other forms of IP VPN. To show this, the chapter introduced network-based VPNs using GRE and IPSec tunnels, with passing reference to the topic of virtual routers and how they can be emulated using per-VRF functions. You could just as easily substitute another tunneling protocol that transports IP, for example L2TPv3.

The examples in this chapter illustrated how to use different routing protocols between VRFs connected by either 802.1q or GRE tunnels. The first design simulated a simple campus environment with route distribution to every router. Using VRFs in this way is gaining popularity as a way to segment campus environments without running VLANs across the network. The second design showed a service provider deploying network-based IP VPNs over an IP core. The example used RIP between PEs, more for simplicity than as an actual endorsement of this protocol in live networks. The third case study added BGP and touched on route redistribution in VRF-Lite scenarios, which is useful when the CE-PE routing protocol is different from the PE-PE routing protocol.