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Passing a trunk through an access mode port


we have a scenario that consists of a Cisco 4507 series core switch with more than 20 vlans which is connected to a C2960G switch( in a nearby building)  using a trunk by a fiber connection. Up to this point everyhting is fine . VTP domain is configured on the core switch and we have all of the 20 vlans present  correctly on the edge 2960G wich is part of course of this same VTP domain.

the fiber connection goes from core switch to a  "in the middle location"  where we have a fiber patch panel that is connected in a jumper style to another fiber patch panel going to the destination building where the C2960G sits.

Now imagine that Fiber connection from this middle location to the destination C2960 edge switch is down for any possible reason meanwhile the fiber connection from Core switch 4507 to the middle location is still intact.

In the same time, in this middle location , we do have a wireless connection which links 1 Cisco 3750G switche ( a different infrastructure and different VTP domain) to another C3560G switch which sits on the same Room in the nearby destination  building where we have the edge C2960G, An idea came to me is

to connect one of the fiber port (core) in the intact fiber patch panel coming from Core switch 4507    TO  an access vlan configured switchport in the 3750G  switch ( this switchport will belong to a vlan designed only to trasmit the vlans on the trunk coming from 4507 core switch say VLAN 10)

then connect one VLAN 10 access switchport to the destination C2960 edge switch ( the switchport on the c2960G is still a trunk)

Will this solution work and all of the 20- 4507 core switch vlans arrive to the destination C2960G ?

Or we do need something that tags the 2 VLAN 10 switchports  like switchport dot1q tunnel like QinQ


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Passing a trunk through an access mode port

I would think that you need something like QinQ for this to work. I do not believe that there is any way to keep the port as an access port and still pass multiple VLANs through it.



Passing a trunk through an access mode port

Hi Ziad,

Rick and yourself have answered the question. Q-in-Q would be the right solution for you. AFAIK You cant have tagged frames going to a normal access vlan as they will be dropped., The port where the access vlan is configured has to be a dot1q tunnel port.



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