Q-in-Q for MUX and 3560

Unanswered Question
Jun 28th, 2008

Dear Sir,

We have the following scenario...

1. One MUX (Megaplex 2100) with low speed module connect to SW1 (3560).

2. One MUX (Megaplex 2100) with low speed module connect to SW2 (3560).

3. SW1, SW2 and SW3 (all 3560), are connected in a ring with etherchannel on fiber ports.

4. Analog phones should be connected to MUX (Megaplex 2100).

The MUX vendor require us to have Q-in-Q support to let their VLANs communicate between two MUXs.

But, it seems 3560 does not support Q-in-Q feature.

Any suggestion on this case?

Many thanks!

I have this problem too.
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Giuseppe Larosa Sun, 06/29/2008 - 05:01

Hello Joseph I used the 802.1Q tunneling on C3550 so it should be supported also on c3560.

look at the following link


to see if it is supported go under an unused interface and try the following command:

switchport mode dot1q-tunnel

If it is not supported consider an IOS SW upgrade.

If the mux devices use only one vlan may be is enough to put all ports in SW1,SW2,SW3 on the same vlan to make them happy.

hope to help


josephschung Tue, 07/01/2008 - 23:21

Thanks Giuseppe, dot1q-tunnel works.

But we found that when we disconnect one link of the etherchannel (the channel has two links) between switches, the MUX reset its port and take a long time to resume the connection. Usually, for data traffic, one link disconnection has no downtime at all.

Any idea?



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