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Dot1q tunnel


I would like to be sure I understand Q-in-Q, and especially the configuration of this feature...

I understand that the ISP add a 802.1q tag for each customer. We can say that 1 customer = 1 vlan?

So when I configure the switch like this:

nterface FastEthernet1/0/3

description CustomerA=vlan103

switchport access vlan 103

switchport mode dot1q-tunnel

duplex full

speed 100

no mdix auto

is it correct to say that my custmer A = vlan 103?

I'm a little confused with my explanations..hope I'm right



Re: Dot1q tunnel

Hi Friend,

A customer can have two different offices located in a state. What happens in dot1q tunnel as when the traffic from the customers network hits the ISP switch interface it adds a Vlan ID to the customer traffic. Now the customer might be running 5 different vlans, they all will be tagged to only a single vlan as the traffic hits the ISP switch. The same tagged Vlan will be used to carry the customer's traffic across the ISP network. On the exit interface of the ISP's exit switch, the same vlan TAG will be mapped to all the vlans for which the traffic was carried over the ISP network.

This is basically used to minimize the number of vlan to carry the customers traffic across the ISP network.

HTH, Please rate if it does.

-amit singh

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