That confirms what I was thinking. So "by default" my service provider for whatever reason it may be chooses to no to design/deploy a switching network that supports Q-in-Q out of the box for it's customers (me), I have to request it and then pay for it.
Typically they install a Cisco 2900XL-EN for the ME hand-off, when I expressed my network needs about 8 months ago they informed me I would need this Q-in-Q, gave me Cisco 3550 switches instead and tacked on some more charges.
This sort of behavior/approach normal for a provider?
The other part of the question: Q-in-Q would not be needed if I deploy routing at each of my locations instead of relying on switching?
Thanks
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by: donjohnstonPosted on 2009-08-07 at 05:17:03ID: 25041858
Q-in-Q tunneling is typically done by the provider. Usually, the client has no knowledge of it.
Here's the deal: You're a provider that offer Metro Ethernet through your switched network. You are going to separate your different customers data by putting each customer in a different VLAN. There's two ways that your can do this. The first is to put each customer facing port in their specific VLAN. But that will prevent them from establishing trunks between their sites.
That's where q-in-q tunneling comes in. If the customer decides that they need trunks between their sites, they can create a trunk. When you (the provider) receive the tagged frame, you ignore the existing tag and ADD another. You move that frame through your network (your switches look at the last tag added... which is the tag that you added) until it gets to the edge. Then your edge switch REMOVES your tag so that what is left is the tag the customer inserted.
The customer has no knowledge that q-in-q tunneling is being done.