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New Member

dot1q trunk with a service provider


We have 100mbps trunk link between two of our data centers through a local service provider. We have configured the switch port on both the ends with a dot1q trunk, but VTP information is not being shared. When I run "sh cdp neigh" the switches don't see each other - our switches are 6513 on both ends.

one of the switches on both the ends is configured in server mode and the other as a client in the same domain - rest of the vtp related information has been applied and verified several times with no result.

Are there any more configurations required to be set.

Any support will be appreciated.


Hall of Fame Super Gold

Re: dot1q trunk with a service provider


likey the SP doesn't pass CDP nor VTP frames, as these are not ARP nor IP.

Either you get the SP to do that, or live without the services. If would be then good enough if they pass dot1q frames.

Hope this helps,please rate post if it does!

New Member

Re: dot1q trunk with a service provider

Thanks for the info. Can you forward a link where I can go through some more technical details about what you stated.

Or what could be the alternative solution so that both the switches can talk to each other or share vlan information.

YOu kind help is appreciated.


Re: dot1q trunk with a service provider


As Paolo stated the provider by default won't pass layer2 protocols, but you can arrange with them passing VTP, CDP and STP (l2protocol-tunneling), no extra config required from your side, we do this for our customers.


Mohammed Mahmoud.

New Member

Re: dot1q trunk with a service provider

Thanks a lot, I appreciate your support - I'll contact the SP to confirm whether they allow l2 protocols to pass or not.



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