Restrictions For Configuring Mpls Vpns Over Ip Tunnels; Information About Mpls Vpns Over Ip Tunnels; Overview: Mpls Vpns Over Ip Tunnels - Cisco CRS Configuration Manual

Restrictions for Configuring MPLS VPNs over IP Tunnels

Restrictions for Configuring MPLS VPNs over IP Tunnels
The following restriction applies when you configure MPLS VPNs over IP tunnels:
• MPLS forwarding cannot be enabled on a provider edge (PE) router.

Information About MPLS VPNs over IP Tunnels

To implement MPLS VPNs over IP Tunnels, you must understand the following concepts:

Overview: MPLS VPNs over IP Tunnels

Traditionally, VPN services are deployed over IP core networks using MPLS, or L2TPv3 tunnels using
point-to-point links. However, an L2TPv3 multipoint tunnel network allows L3VPN services to be carried
through the core without the configuration of MPLS.
L2TPv3 multipoint tunneling supports multiple tunnel endpoints, which creates a full-mesh topology that
requires only one tunnel to be configured on each PE router. This permits VPN traffic to be carried from
enterprise networks across cooperating service provider core networks to remote sites.
The following figure below illustrates the topology used for the configuration steps.
Figure 10: Basic MPLS VPN over IP Topology
Cisco IOS XR Virtual Private Network Configuration Guide for the Cisco CRS Router, Release 6.1.x
36
◦ MPLS commands (generally)
◦ MPLS Layer 3 VPN commands
Implementing MPLS VPNs over IP Tunnels