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why q in q over leased line ?

khaled alodat
Level 1
Level 1

hi ,


i know how q in q work but i don't understand why i need q in q when we have a leased line installed between two locations. 


we delivered a solution to one of our customer and the design is to install leased line between multiple office in hub and spoke design , and another service provide will configure q in q on top of that .


if both of them deliver a L2 functionality , why the Q in Q ? is it more secure ?






1 Reply 1

Mark Malone
VIP Alumni
VIP Alumni
Maybe to stop overlapping of vlan ids on the ISP network , thats one of the reasons ISPs use it

Q-in-Q Tunneling

Business customers of service providers often have specific requirements for VLAN IDs and the number of VLANs to be supported. The VLAN ranges required by different customers in the same service-provider network might overlap, and traffic of customers through the infrastructure might be mixed. Assigning a unique range of VLAN IDs to each customer would restrict customer configurations and could easily exceed the VLAN limit of 4096 of the 802.1Q specification.
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