What are MPLS L2 & L3 VPNs ?

Layer3 MPLS VPNs are characterized by fully meshed architectures that enable, for instance, multicast conferencing in support of projects involving a dispersed work group. Layer2 MPLS technology is limited in this area because it does not scale as well as Layer3.

Some businesses like the Layer3 options that are available now because the service provider takes over all the WAN routing, whereas with a Layer2 WAN, such as MPLS-based virtual private LAN services (VPLS), businesses would have to handle the routing themselves, customers noted.

Outsourcing of routing tables is also seen as a weakness of Layer3 VPN services because many corporations don't want to relinquish control or even share their routing schemes with anyone, not even their service provider. They prefer Layer2 network services, such as frame relay or ATM, that are simpler in architecture and that allow customers to retain control of their own routing tables.

Businesses considering MPLS VPN services should factor these differences and opt for the one that best fits their own needs, and remember that once they are tied into the network, they will have the option for either.