Confused between when to use dot1-Q tunnels or l2protocol-tunnel

Hi All,

 

Can anyone tell me what I should be looking for when deciding when to pick one or the other? Specifically, I cannot see the difference between WB 3 Lab 10 task 2.3 and WB 2 Lab 7 task 1.1?

 

I get that if one of the 'customer edge' ports had tagged subinterfaces then this would make the desicion to use dot1-q but it seems in both of these tasks that this is not the case but one has dot1-q as the answer and the other has l2protocol-tunnel.

 

I can configure them both fine, but am just afraid of doing the wrong one during the exam if I'm not understanding something that should be a sign to use one or the other if there's an option.

 

Thanks,

Gavin

Comments

  • Hi Gavin,

    l2protocol tunnel is used when you have a single vlan and the port that connects the ce is an access port.

    dot1q tunnel is usually used when you have more than one vlan on your site and you need to transport them transparently through the service provider cloud; it adds and additional 4 byte tag (outer tag), which is stripped later on * increase system mtu on transit switches to support extra tag.

    you can use l2protocol with dot1q tunnel to trasport stp,cdp and/or pagp

    HTH

    Good luck!

     

  • I get that if one of the 'customer edge' ports had tagged subinterfaces then this would make the desicion to use dot1-q but it seems in both of these tasks that this is not the case but one has dot1-q as the answer and the other has l2protocol-tunnel.

    If we are meeting up the requirement of the task without breaking any lab rule we are fine with it. In some of the task i have also noticed that dotq tunnel is being used even though the same task could be solved by just using l2protocol-tunnel.

  • Not everone knows that you can tunnel CDP etc without using the dot1q tunnel functionality so they always configure it. For a lab task I would look for something saying, port to customer must support multiple VLANs or backbone should carry all customer VLANs with a single VLAN or something like that. Otherwise it should be fine to use whatever.

  • Thanks guys, makes me feel a bit better. I'll watch out for the wording and hopefully it won't catch me out.

     

    Gavin

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