Extending VLAN through service provider.

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May 10th, 2007
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The scenario is, we extend some of our clients vlans from our core to the clients edge device through some service providers. This is done by having a interconnect and by running Q and Q trunking which extends our vlan to the place which we can?t reach.

At times while troubleshooting and liaising with other engineers (service providers) I often hear about mapping our vlan ID to some other vlan ID in their network. How its working ??

Can any help me to understand what is mapping and how its working. It will be very helpful if some one posts some link.



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kradjesh13 Thu, 05/10/2007 - 06:07
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No, this is just extending our ordinary VLAN as we do trunking between two switches.

Danilo Dy Thu, 05/10/2007 - 06:10
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In that case, it may be the one that John posted below.


Jon Marshall Thu, 05/10/2007 - 19:52
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Hi Rajesh

Apologies for the short answer before, i was in a bit of a rush.

With 802.1q tunneling the service provider takes your vlan tagged traffic and adds it's own vlan ID to the packet. Your vlan ID on the tagged traffic is not changed, it is just encapsulated in another tagged packet. When the traffic reaches the egress point of the Service provider network their tag is stripped leaving your original vlan ID's intact.

Hope this makes sense



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