Introduction

Carrier Ethernet’s explosive adoption in the service provider networks is due, in part, to its inherent flexibility, reliability, and resiliency. Increasingly, Ethernet-based networks are being used for mission-critical metropolitan and wide-area services, including intra-site connectivity replacing legacy TDM infrastructure. Carrier Ethernet possesses vital capabilities to combine the transparency of circuit-switched time-domain multiplexing (TDM) with unsurpassed bandwidth, cost, and scalability metrics of Ethernet enabling next-generation Layer 2 Virtual Private Networks (L2VPNs).

This paper focuses on Carrier Ethernet L2VPNs, which are ideal for access and metro edge networks due to the ease of deployment and provisioning, true L2/L3 transparency, and support of superior Quality of Service (QoS) and Service Level Agreements (SLA).

The figure below illustrates the two primary service types provided by L2VPNs: Virtual Private Wire Service (VPWS) and Virtual Private LAN Service (VPLS).

Customer A has two locations and merely wants to interconnect the sites. Customer B has three (or more) locations and also wants complete connectivity. In both cases, the customers want the interconnectivity to appear as a single corporate network, as if all of the networked devices were on the same LAN.

The following figure shows a service provider network with connections to each customer location. L2VPNs maintain service separation so that customer traffic is only forwarded between the locations of each respective customer.

Continue

• Part 1:
  Introduction
• Part 2:
  Ethernet-based L2VPNs
• Part 3:
  L2VPN key Key Concepts
• Part 4:
  MPLS-based L2VPNs
• Part 5:
  VPN Standards Development
• Part 6:
  Layer 2 Control Frame Transport
• Part 7:
  L2VPN QoS and Management
• Part 8:
  Conclusion