A Deep Dive into MPLS L2VPN

Introduction to MPLS L2VPN

Multiprotocol Label Switching (MPLS) Layer 2 Virtual Private Network (L2VPN) is a technology for providing Layer 2 VPN services over an MPLS network. It is a highly scalable and flexible technology that is used by service providers to provide Layer 2 VPN services to their customers.

This article will provide a technical deep dive into MPLS L2VPN, exploring the different types of MPLS L2VPNs, their architecture, and how they work.

Types of MPLS L2VPNs

There are two main types of MPLS L2VPNs:

Virtual Private Wire Service (VPWS): VPWS is a point-to-point L2VPN service. It is used to connect two customer sites together as if they were connected by a dedicated Layer 2 circuit.
Virtual Private LAN Service (VPLS): VPLS is a multipoint-to-multipoint L2VPN service. It is used to connect multiple customer sites together as if they were all connected to the same Ethernet LAN.

VPWS Architecture and Operation

The VPWS architecture is made up of a number of different components:

Customer Edge (CE) Router: The CE router is a router that is located at the customer’s site. It is connected to the provider edge (PE) router.
Provider Edge (PE) Router: The PE router is a router that is located at the edge of the service provider’s network. It is connected to the CE router and to the provider (P) routers.
Provider (P) Router: The P router is a router that is located in the core of the service provider’s network. It is responsible for forwarding traffic between the PE routers.

VPWS works by creating a pseudowire between two PE routers. A pseudowire is a virtual connection that emulates a physical wire. The pseudowire is used to carry the customer’s Layer 2 traffic between the two sites.

VPLS Architecture and Operation

The VPLS architecture is made up of the same components as the VPWS architecture. However, in a VPLS network, the PE routers are fully meshed. This means that each PE router has a pseudowire to every other PE router in the VPLS instance.

VPLS works by creating a virtual switch instance (VSI) on each PE router. The VSI is a virtual switch that is used to switch the customer’s Layer 2 traffic between the different sites.

When a PE router receives a Layer 2 frame from a CE router, it performs a lookup in the VSI to find the destination MAC address. If the destination MAC address is in the VSI, the PE router forwards the frame to the corresponding PE router over the pseudowire. If the destination MAC address is not in the VSI, the PE router floods the frame to all of the other PE routers in the VPLS instance.

Benefits of MPLS L2VPN

MPLS L2VPN provides a number of benefits, including:

Scalability: MPLS L2VPN is a very scalable technology. It can support thousands of customers and tens of thousands of sites.
Flexibility: MPLS L2VPN is a very flexible technology. It can be used to provide a wide range of Layer 2 VPN services.
Security: MPLS L2VPN is a very secure technology. It provides a high degree of isolation between the different customers.
Quality of Service (QoS): MPLS L2VPN can be used to provide QoS for the different customers.

Conclusion

MPLS L2VPN is a technology for providing Layer 2 VPN services over an MPLS network. It is a highly scalable, flexible, and secure technology that is used by service providers to provide Layer 2 VPN services to their customers. A deep understanding of MPLS L2VPN is essential for anyone who is responsible for managing a service provider network.