Layer 2 Protocol to be Tunneled
To configure Layer 2 protocol tunneling, you must specify the protocol that is to be tunneled using the Layer 2 tunnel:
- cdp—Cisco Discovery Protocol.
- stp—All versions of the spanning-tree protocol.
- vtp—Tunnel the VLAN trunk protocol.
For each protocol specified, a static destination MAC address corresponding to the protocol being tunneled is installed in the MAC table.
To specify the protocol that will be tunneled by the Layer 2 protocol tunneling, you can include the protocol (cdp | stp | vtp) statement at the following hierarchy levels:
- [edit protocols layer2-control mac-rewrite interface ge-fpc/pic/port]
- [edit routing-instances routing-instance-name protocols layer2-control mac-rewrite interface ge-fpc/pic/port]
 | Note: When CDP, STP, or VTP is configured for tunneling on a customer-facing port in a provider bridge, the corresponding protocol should not be enabled for operation on that interface. |
