E-VPLS vs. MPLS IP VPN

Both MPLS IP VPN and VPLS are high quality service delivery platforms. But there are a couple of major differences that carriers need to know prior to the decision to go with MPLS VPN or conversely a VPLS network.

The MPLS IP VPN network is a managed Layer 3 network controlled by the service provider while the VPLS network is a customer controlled and managed Layer 3 network. Using VPLS the Customer operates their own layer 3 network on top of the Layer 2 network.

An MPLS IP VPN is also called a Layer 3 VPN (L3VPN). A L3VPN requires the service provider to do all the heavy lifting to keep track of all the Layer 3 routing tables to keep track of and manage a BPG / OSPF / ISIS / EIGRP / RIP network for the customer. The customer can sit back and let their service provider do most of the routing work. The L3VPN also requires the service provider to manage, feed and control IP addressing to the different locations. Obviously, this level of management has a higher operating cost.

Incidentally the additional services that a service provider can offer are superior on the E-VPLS network versus the L3VPN network. With the E-VPLS network, the carrier can create a VLAN off on his PE on ingress to the network, and then pipe that VLAN over to a service router that can provide the Enterprise anything from VoIP, Internet, Data Backup, Firewall Service, Video etc.

• Migration path from an existing WAN is easier. Compared to ATM, frame relay or point- to- point, E-VPLS architectures are a logical replacement that requires less re-architecture than IP VPN.
• Transparently extend subnets between physical locations. Business will move a server from one location to another. Difficult with IP VPN but trivial with E-VPLS.
• Segmentation and isolation. When using VLANs on top of an E-VPLS service, a company can create a large number of virtual WANs. Often used by IT staffs to securely segment different types of traffic over the WAN or to give a number of different divisions their own WAN with full layer 2 control. A complex exercise with IP VPN and requires significant coordination with the service provider.
• Non-IP traffic. This is a huge headache with IP VPNs requiring GRE tunneling. With E-VPLS, if your traffic can be encapsulated as Ethernet you don't need to tunnel.
• QoS management. QoS management is a fundamental requirement of any customer converged network that carries voice, video and data over IP. E-VPLS networks use the tunneling technique, and the QoS function offers a flexible framework in which to convey customers’ traffic with corresponding service level agreement information over a carrier network with the QoS policy set. Service providers can leverage class-of-service technology to provide priority services and leverage rich QoS signaling protocols with bandwidth reservation technology providing connection-oriented paths for voice, video, and other mission-critical traffic over their networks.