Nokia Certified Network Associate (NCNA) — Question 53

Using Q-in-Q Virtual Local Area Network (VLAN) stacking, how does a carrier differentiate one customers traffic from that of another?

Answer options

• A. The provider edge (PE) switch adds an additional field called a PE tag to the customers Layer 2 data.
• B. The PE switch replaces the customers VLAN tag with a carrier-assigned tag.
• C. The PE switch adds a second VLAN tag to identify the customers traffic on the carriers network.
• D. The PE switch assigns a customer-specific priority label to the customers traffic.

Correct answer: C

Explanation

The correct answer is C because Q-in-Q VLAN stacking allows the PE switch to add an additional VLAN tag to the customer's traffic, thus enabling the differentiation of multiple customer VLANs within the carrier's network. Option A is incorrect as it mentions a PE tag, which is not part of the Q-in-Q process, while option B incorrectly describes replacing the VLAN tag rather than adding to it. Option D is also wrong as priority labels do not serve the purpose of traffic differentiation in this context.