Layer 2 tunneling can be used to extend a network to remote sites across a service provider network. These commands configure layer 2 tunneling on switch interfaces.
To configure L2 protocol tunneling on an interface, you configure it as 802.1ad network-to-network interface (NNI) or user- to-network interface (UNI). Then, you configure the action (tunnel, terminate, discard, or discard-shutdown) the interface takes when it receives a PDU with a specified combination of a destination reserved MAC address and a protocol ID. If the interface is configured to tunnel the protocol/MAC address PDUs, then it appropriately tags the packet with a service definition (S-tag) and optionally with the customer's VLAN ID (C-tag), and forwards it to the NNI port.
