L2CP Tunneling MEF

This chapter introduces you to L2 Control Protocols (L2CP) tunneling to help initiate control packets from a local (customer-edge) CE device to a remote CE device.

L2CP Tunneling

The system supports the following tunnel protocols:

  • Link Layer Discovery Protocol (LLDP)

  • Link Aggregation Control Protocol (LACP)

  • Operation, Administration, Management (OAM)

  • Ethernet Local Management Interface (ELMI)

  • Cisco Discovery Protocol (CDP)

On a subinterface, when control packets such as LLDP and LACP are tunneled, the system tunnels the same control packets to the main interface.

The LACP packet for VPLS also known as E-LAN service either gets peered or dropped. LACP tunneling is not supported for VPLS service. Tunneling of LACP packets is supported only for VPWS and EVPN-VPWS services.

The router allows to tunnel layer 2 packets between CEs. The following figure depicts Layer 2 Protocol Tunneling. The layer 2 traffic is sent through the S-network, and the S-network switches the traffic from end-to-end. Third-party PE forwards S-tagged frames and peers untagged frames.

Figure 1. L2CP Tunneling

Prerequisites for L2CP Tunneling

A Cisco IOS XR Software that supports Layer 2 Control Protocol Tunneling must be installed previously on the router.

Configure L2CP Tunneling

You do not need to configure L2CP tunneling explicitly. L2CP packets are tunneled over Layer 2 tunnel by default.

Protocol

Packet Type

Action

CDP

Untagged

Peer

LACP

Untagged

Peer

LLDP

Untagged

Peer else Tunnelled

STP

Untagged

Peer

VTP

Untagged

Peer

OAM

Untagged

Peer

BPDU

Untagged

Tunnelled

UDLD

Untagged

Peer

CDP

Tagged

Tunnelled

LACP

Tagged

Tunnelled

LLDP

Tagged

Tunnelled

STP

Tagged

Tunnelled

VTP

Tagged

Tunnelled

BPDU

Tagged

Tunnelled

OAM

Tagged

Tunnelled

ELMI

Tagged

Tunnelled

UDLD

Tagged

Peer