Network Peering

Google Cloud VPC Network Peering allows you to connect two Virtual Private Cloud (VPC) networks so that resources in each network can communicate using internal IP addresses. This works across projects and organizations without using external IPs or VPNs.

Key Features:

1. Private connectivity - Traffic stays within Google network and never traverses the public internet.

2. Cross-project/org - Peer VPCs across different GCP projects or organizations.

3. No bandwidth bottleneck - No single gateway or chokepoint; uses Google internal networking.

4. Non-transitive - If VPC A peers with VPC B and VPC B peers with VPC C, A cannot reach C directly.

5. MTU matching - Both VPCs must have the same MTU setting.

The below example shows how to set up VPC Network Peering using gcloud CLI.

It gives the following output,

NAME             NETWORK  PEER_PROJECT  PEER_NETWORK  STATE   STATE_DETAILS
peering-a-to-b   vpc-a    my-project    vpc-b         ACTIVE  Connected.

VPC Peering vs Cloud VPN vs Interconnect:

VPC Peering - Best for connecting GCP VPCs within the same or different projects. No extra cost, uses internal IPs, non-transitive.

Cloud VPN - Best for connecting GCP VPCs to on-premises networks over the internet with IPsec encryption.

Cloud Interconnect - Best for high-bandwidth, low-latency dedicated connections between on-premises and GCP.