Exam Professional Cloud Network Engineer topic 1 question 39 discussion

A is the right answer. VPC peering is not transitive. If you want any VPC to any VPC connection, you need to connect all VPCs in a full mesh manner.

A would appear to be correct as per the following link: https://cloud.google.com/vpc/docs/using-vpc-peering

The correct answer is A. Explanation: In the current configuration, you have VPC peering between Sales and Finance, and Marketing and Finance, but this does not allow for full connectivity between all three VPCs (Sales ↔ Marketing). To achieve connectivity between all three VPCs, you need to configure VPC peering in a full mesh, meaning you need to establish VPC peering connections between all three VPCs: Sales ↔ Finance, Marketing ↔ Finance, and Sales ↔ Marketing. This ensures that traffic can flow between all VPCs.

Create a Full Messh Peering to achieve the connectivity between all the VPC, as peering is not transitive.

Full Mesh VPC Peering: VPC peering in a full mesh means establishing direct peering connections between all pairs of VPCs (Sales, Marketing, and Finance). In a full mesh topology, all VPCs are interconnected, allowing traffic to flow seamlessly between any pair of VPCs. Routing Considerations: Ensure that the routing tables in each VPC are appropriately configured to handle traffic between all the VPCs in the full mesh. VPC peering generally allows transitive routing, meaning if VPC A is peered with VPC B and VPC B is peered with VPC C, then VPC A can communicate with VPC C.

A: As soon as the peering moves to an ACTIVE state, subnet routes and custom routes are exchanged. The following traffic flows are set up: • Between VM instances in the peered networks: Full mesh connectivity.

A is right Only directly peered networks can communicate. Transitive peering is not supported. In other words, if VPC network N1 is peered with N2 and N3, but N2 and N3 are not directly connected, VPC network N2 cannot communicate with VPC network N3 over VPC Network Peering. https://cloud.google.com/vpc/docs/vpc-peering

Because VPC peering is not transitive we MUST connect ALL the VPC's. A=>B,A=>C,B=>A,B=>C,C=>A,C=>B

This question is BS. VPC Peering is NOT transitive, none of these answers are valid. https://cloud.google.com/vpc/docs/vpc-peering "Only directly peered networks can communicate. Transitive peering is not supported. In other words, if VPC network N1 is peered with N2 and N3, but N2 and N3 are not directly connected, VPC network N2 cannot communicate with VPC network N3 over VPC Network Peering." "Because VPC Network Peering isn't transitive, VM instances in network-a and network-c cannot communicate with each other unless you also peer network network-a with network-c."

Answer is : A