Create Packet Mirroring Policies:

You need to create three packet mirroring policies, one for each zone (us-west2-a, us-west2-b, and us-west2-c). This ensures that each zone's traffic is mirrored appropriately without unnecessary cross-zone traffic.

Create Collector Instances:

Set up one group of collector instances for the us-west2 region. Having a single group of collector instances for the entire region minimizes the number of instances required and simplifies the management while keeping egress costs low since the collectors are within the same region.

Configuration of Policies:

Each packet mirroring policy should be configured to match traffic for its specific zone. Use instance-tags to identify and match the relevant instances within each zone. This helps in correctly capturing the traffic from the appropriate sources.

Filter for TCP Traffic:

Create a filter for TCP traffic (ports 80 and 443). This step ensures that only the relevant web application traffic is mirrored, reducing the amount of data processed and improving efficiency.

Cost Efficiency:

By having packet mirroring policies specific to each zone and a regional collector group, you reduce inter-zonal network egress costs. The data remains within the same region, avoiding extra charges associated with cross-zone traffic.