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CFM Support for CCC Encapsulated Packets

IEEE 802.1ag CFM OAM Support for CCC Encapsulated Packets Overview

Layer 2 virtual private network (L2VPN) is a type of virtual private network service used to transport customer's private Layer 2 traffic (for example, Ethernet, ATM or Frame Relay) over the service provider's shared IP/MPLS infrastructure. The service provider edge (PE) router must have an interface with circuit cross-connect (CCC) encapsulation to switch the customer edge (CE) traffic to the public network.

The IEEE 802.1ag Ethernet Connectivity Fault Management (CFM) is an OAM standard used to perform fault detection, isolation, and verification on virtual bridge LANs. M120 and MX Series routers provide CFM support for bridge/VPLS/routed interfaces and support 802.1ag Ethernet OAM for CCC encapsulated packets.

CFM Features Supported on Layer 2 VPN Circuits

CFM features supported on L2VPN circuits are as follows:

  • Creation of up/down MEPs at any level on the CE-facing logical interfaces.

  • Creation of MIPs at any level on the CE-facing logical interfaces.

  • Support for continuity check, loopback, and linkrace protocol.

  • Support for the Y1731 Ethernet Delay measurement protocol.

  • Support for action profiles to bring the CE-facing logical interfaces down when loss of connectivity is detected.

Figure 1: Layer 2 VPN TopologyLayer 2 VPN Topology

To monitor the L2VPN circuit, a CFM up MEP (Level 6 in Figure 1) can be configured on the CE-facing logical interfaces of provider edge routers PE1 and PE2. To monitor the CE-PE attachment circuit, a CFM down MEP can be configured on the customer logical interfaces of CE1-PE1 and CE2-PE2 (Level 0 in Figure 1).

Configure CFM for CCC Encapsulated Packets

The only change from the existing CLI configuration is the introduction of a new command to create a MIP on the CE-facing interface of the PE router.