Layer 3 Virtual Private Networks

Layer 3 MPLS VPNs provide similar, complementary services to their L2 counterparts. While MPLS L3 VPNs use the same underlying MPLS control-plane, signalling, management and provisioning technologies, they further abstract the connectivity paradigm to the network layer.

In an MPLS L3VPN, each endpoint communicates routing reachability information with the VPN. Each LSR (label switch router) maintians a private routing table for the VPN, sharing that information amongst the LSRs in the MPLS domain, and with the end-site routers connected to each VPN drop port.

This type of VPN does include more complexiy for the end site, because proviciency with the Border Gateway Protocol (BPG) is required as the routing protocol of choice to use between the end-site and VPN cloud. There are some advantages to the L3VPN over L2VPNs:

• Completely Circuit Technology Agnostic. Because information is moved comletely at the network layer, access circuits may be any access technoloogy and do not need to be the same.
• Scales to Extremely Large Deployments. Since IP routing information is easily summarized, and BGP is designed to enable very large scale architectures, the L3VPN can scale to thousands of end-sites.
• Routed Boundaries. As all information is passed at the network layer, it is not possible to interface with an L3VPN at lower layers. This may be of advantage to enforce access policies for VPN participants.>/li>

If your site is interested in L3VPN services, Contact KanREN!