CCIE Service Provider (legacy) — Question 10

Which action enables an IPv6 multicast router on a subnet with locally attached receivers to quickly determine if there is a need to send traffic for a certain multicast group out to that subnet?

Answer options

• A. Adjust the MLD report interval on the router.
• B. Activate IGPMv3 snooping and fast-leave.
• C. Enable the MLDv2 explicit-tracking feature.
• D. Decrease the ICMPv4 multicast query timer.

Correct answer: B

Explanation

The correct answer is B because IGMPv3 snooping with fast-leave allows the switch to quickly stop forwarding multicast traffic to ports that no longer have interested receivers. Option A modifies the report interval but does not directly influence traffic forwarding. Option C introduces explicit tracking, which is beneficial but not as immediate as fast-leave. Option D pertains to ICMPv4, which is not relevant for IPv6 multicast operations.