You have two VPCs: VPC A in Project A and VPC B in Project B. The VPCs are peered, and each VPC has VM instances in four zones. You are using the Network Intelligence Center Performance Dashboard to investigate the packet loss for traffic flows that start in VPC A and terminate in VPC B. You need the reported packet loss metric to have at least a 90% confidence level. What should you do?
To achieve a reported packet loss metric with at least a 90% confidence level, it's important to ensure that each zone in each of the VPC networks has at least 10 compute instances. Packet loss metrics related to traffic flows that terminate in VPC B should be checked in Project B, as the metrics for packet loss are visible where the traffic terminates. Therefore, the correct approach is to ensure that each zone has the required number of compute instances and to look for the reported metrics in the destination project, Project B.
To achieve a reported packet loss metric with at least a 90% confidence level, you need to ensure that the sample size is adequate for statistical significance. In this case, the question mentions that the packet loss investigation is for traffic flows starting in VPC A and terminating in VPC B. Since the traffic is originating from VPC A and terminating in VPC B, you should look in Project B for the reported metric, as this is where the traffic terminates. This makes options A and C incorrect. Now, you need to ensure that each zone in each of the VPC networks has at least 9 compute instances to provide a sufficient sample size for statistical analysis with a 90% confidence level. Therefore, the correct answer is: B. Ensure that each zone in each of the VPC networks has at least 9 compute instances. Look in Project B for the reported metric.
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/network-intelligence-center/docs/performance-dashboard/concepts/overview
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.
"The metrics for the collector destination provides an aggregate view of all mirrored traffic that it collects. However, for the individual mirrored instances, you can view the number of mirrored packets that were dropped. Metrics for the collector destination don't include dropped packets." https://cloud.google.com/vpc/docs/monitoring-packet-mirroring
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
the destination a VPC B, so its either B or D
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.
2.5 x 4 zones = 9 VMs
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?
https://cloud.google.com/vpc/docs/monitoring-packet-mirroring
D only