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.
Prerequisites for L2CP Tunneling
A Cisco IOS XR Software that supports Layer 2 Control Protocol Tunneling must be installed previously on the router.