Scenario:
* L2PT can be used to forward CDP/LACP/LLDP/VTP/STP/PVST+ packets.
Procedures:
1. For L2PT to function properly, QinQ must be enabled on the switch.
Console(config)#dot1q-tunnel system-tunnel-control
2. Configure Q-in-Q access port and L2PT on port 1 of 1-ECS4100 and 2-ECS4100. For example: LLDP
Console#configure Console(config)#interface ethernet 1/1 Console(config-if)#switchport dot1q-tunnel mode access Console(config-if)#switchport l2protocol-tunnel lldp
3. Configure Q-in-Q uplink port on port 48 of 1-ECS4100 and 2-ECS4100.
Console(config)#interface ethernet 1/48 Console(config-if)#switchport dot1q-tunnel mode uplink
4. Check the status on 1-ECS4100 and 2-ECS4100. Now the both switches will forward LLDP packets.
(receive LLDP packet on the port 1 and forward it to the port 48)
* The switch also replaces the destination MAC address by Tunnel MAC address.
By default, the L2PT MAC address is "01-12-CF-00-00-02" on Edge-corE Switch. Make sure "Tunnel MAC address" is the same on the both switches.
Console#show l2protocol-tunnel Layer 2 Protocol Tunnel Tunnel MAC Address : 01-12-CF-00-00-02 Interface Protocol ---------------------------------------------------------- Eth 1/1 LLDP
Console#show dot1q-tunnel 802.1Q Tunnel Status : Enabled 802.1Q Tunnel TPID : 8100 (Hex) Port Mode Priority Mapping -------- ------ ---------------- Eth 1/ 1 Access Disabled Eth 1/48 Uplink Disabled