802.1Q Tunneling (Q-in-Q)

interface FastEthernet0/1
 switchport access vlan 100
 switchport mode dot1q-tunnel
 l2protocol-tunnel cdp
 no cdp enable

The access VLAN which is here called Tunnel-Tag, must exist in the transit path.

In a scenario where EtherChannel is implemented between two 802.1q customers and there are more than 1 switch in the transit path, and each CE switch has for example 3 different links to CE node, each PE-to-CE should be assigned to a different VLAN.

Also, the transit path should be in form of TRUNK links, and informed of the Tunnel-Tag VLANs.

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Author: Mo Moghaddas

Traveler. Casual investor. Hobbyist landscape photographer loving Networks. Blockchain/Cryptocurrency enthusiast. Internet citizen!

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