802.1Q Tunneling (Q-in-Q) Configuration Example

Hello Gregory

First of all, I think the command you’re looking for is l2protocol-tunnel cdp. This command will cause an interface to encapsulate any received CDP messages within the QinQ tunnel. In other words, it won’t receive them and process them as if the interface itself is the intended destination, but it will encapsulate them and tunnel them through without processing them as CDP messages.

If you configure the no cdp enable command on that same interface, it will not cause any conflict in operation. This command tells the interface not to participate in any CDP communication. So it won’t generate any CDP messages, and it won’t process any messages it may receive.

If CDP messages are tunneled, then it won’t process any CDP messages anyway since all received CDP messages are encapsulated in the tunnel and sent along their way.

So these two commands are not incompatible. Looking at the lesson, the no cdp enable command was not actually used anywhere. Where did you encounter it?

You can find out more info about how to tunnel CDP and other Layer 2 protocols in such a scenario, take a look at this Cisco command reference:

I hope this has been helpful!

Laz