Exam Professional Cloud Network Engineer topic 1 question 171 discussion

D, as explained in https://cloud.google.com/network-intelligence-center/docs/performance-dashboard/concepts/metrics-views?hl=en#metric_availability_and_confidence_levels and https://cloud.google.com/network-intelligence-center/docs/performance-dashboard/concepts/metrics-views?hl=en#packet-loss "90% confidence 2.5 VMs multiplied by the number of zones in the project." Which in our case is 2.5 x 4 = 10. "If the peered networks are in different projects, packet loss is visible in the destination project." Which in this case is project B.

C is the answer. Why the Other Options Are Incorrect: A & D: Say “10 compute instances” — this is not required; 9 is sufficient for 90% confidence. B & D: Suggest looking in Project B, but the traffic starts in Project A, so metrics should be viewed there.

D only

For a 90% confidence, the required number of VMs in each zone is 2.5 VMs x the number of zones in the project, so 10 VMs per zone. Packet loss is visible in the destination project.

https://cloud.google.com/vpc/docs/monitoring-packet-mirroring

If it's 2.5 x 4 zones wouldn't that be 10? 2.25 x 4 zones equals 9 which is not what the link states. Are you factoring in the 90% to get to 9?

90% confidence 2.5 VMs x the number of zones in the project. For example, if you have 12 zones in your project, you must have 30 VMs in each zone.

Anything with VPC A as the destination is wrong: On the other hand, suppose that these two networks are not in the same project. That is, suppose network A is part of project A, and network M is part of project M. When the networks are peered, project M's Performance Dashboard shows packet loss data for situations where zone M is the destination zone. Conversely, when zone A is the destination zone, the packet loss data is visible only to project A