Question 560
An ISP allocates several multicast group ranges for different tenants. Observed: One tenant receives another tenant's IPTV stream on a shared access segment. What operational check best guards against this problem returning?
Explanation
Correct Answer
This control asks for the same recovery evidence (Receivers obtain only their authorized groups and cross-tenant traffic ceases) and flags recurrence of the same failure (One tenant receives another tenant's IPTV stream on a shared access segment). It targets the underlying issue, multicast group isolation and igmp membership controls are not scoped by tenant, rather than a different service problem. The exact cadence must be agreed with operations.
Incorrect Answers
The proposed control is tied to the incoming interface differs from the preferred unicast reverse path to the source, typically observed when pIM RPF discards increase when routing chooses the other uplink. Here the target is multicast group isolation and igmp membership controls are not scoped by tenant; monitor receivers obtain only their authorized groups and cross-tenant traffic ceases.
This gate monitors a different failure, sources transmit packets but receivers see none until a static join is added. It would not detect the current problem: One tenant receives another tenant's IPTV stream on a shared access segment. The appropriate check requires receivers obtain only their authorized groups and cross-tenant traffic ceases.
It is valid for another service scenario but checks source registers continue to reach the old rp while receivers use the new rp. This case instead needs a gate for one tenant receives another tenant's iptv stream on a shared access segment and evidence that receivers obtain only their authorized groups and cross-tenant traffic ceases.