MPLS Layer 3 VPNs

This post is the continuation of the previous post I made on Basic MPLS. In this post, I will talk about the different steps in order to configure MPLS Layer 3 VPNs which include the PE-CE routing protocols configuration with RIP, EIGRP and OSPF. I will also talk about the different loop prevention rules used when using OSPF as a PE-CE routing protocol. Finally I will conclude this post by talking about OSPF Sham-link.

 In this topic, I will use the following topology:

Platform/IOS: Cisco 2691/12.4(15)T11 Adv IP services

 VRFs:

• Customer A: VRF A | IGP: RIP
• Customer B: VRF B | IGP: EIGRP
• Customer C: VRF C | IGP: OSPF 2 Area 0
• ISP: Core IGP: OSPF 1 Area 0 | MP-BGP AS 200

 Addressing: See topology. All the routers are configured with a Loopback IP and the format X.X.X.X /32 where X is the router number.