VPC peering in GCP - Step-by-Step Execution

Process Flow - VPC peering

Create VPC Network A

↓

Request Peering from A to B

→Accept Peering in B

↓

Peering Connection Established

↓

Traffic Allowed Between A and B

This flow shows how two VPC networks request and accept peering to connect privately.

Execution Sample

GCP

gcloud compute networks peerings create peer-a-to-b \
  --network=vpc-a --peer-network=vpc-b

gcloud compute networks peerings create peer-b-to-a \
  --network=vpc-b --peer-network=vpc-a

Commands to create mutual VPC peering connections between two networks.

Process Table

Step	Action	Network A State	Network B State	Peering Status
1	Create VPC Network A	Exists, no peering	Not created	No peering
2	Create VPC Network B	Exists, no peering	Exists, no peering	No peering
3	Request peering from A to B	Peering request sent	No peering	Pending acceptance
4	Accept peering in B	Peering request sent	Peering accepted	Active
5	Create peering from B to A	Peering accepted	Peering request sent	Pending acceptance
6	Accept peering in A	Peering accepted	Peering accepted	Active
7	Peering connection established	Connected to B	Connected to A	Active
8	Traffic allowed between A and B	Can route to B	Can route to A	Active

💡 Peering is active after mutual acceptance, allowing private traffic.

Status Tracker

Variable	Start	After Step 3	After Step 4	After Step 5	After Step 6	Final
Network A Peering State	None	Request sent	Request sent	Accepted	Accepted	Active
Network B Peering State	None	None	Accepted	Request sent	Accepted	Active
Peering Status	No peering	Pending acceptance	Active	Pending acceptance	Active	Active

Key Moments - 3 Insights

Why do we need to create peering from both VPCs instead of just one?

Because VPC peering in GCP requires mutual peering connections for bidirectional communication, as shown in steps 3-6 in the execution_table.

What happens if one side does not accept the peering request?

The peering status remains pending and no traffic is allowed, as seen after step 3 before acceptance in step 4.

Does peering automatically allow all traffic between VPCs?

No, routing and firewall rules must allow traffic; peering only establishes the private connection, as implied after step 7 and 8.

Visual Quiz - 3 Questions

Look at the execution_table, what is the peering status after step 4?

A Pending acceptance

B No peering

C Active

D Disconnected

💡 Hint

Check the 'Peering Status' column at step 4 in the execution_table.

At which step do both networks have accepted peering requests?

A Step 6

B Step 3

C Step 5

D Step 7

💡 Hint

Look at 'Network A Peering State' and 'Network B Peering State' columns in execution_table.

If Network B never accepts the peering request, what will be the final peering status?

A Active

B Pending acceptance

C No peering

D Disconnected

💡 Hint

Refer to the state after step 3 and before step 4 in execution_table.

Concept Snapshot

VPC Peering in GCP:
- Create two VPC networks.
- Request peering from one to the other.
- Accept peering on the other side.
- Repeat for mutual peering.
- Once active, private traffic can flow between VPCs.
- Routing and firewall rules must allow traffic.

Full Transcript

VPC peering connects two separate virtual networks privately. First, you create two VPCs. Then, one network requests peering to the other. The other network must accept this request. For full communication, both sides create and accept peering connections. After mutual acceptance, the peering is active, allowing private traffic between the networks. However, routing and firewall rules must be configured to permit this traffic. If one side does not accept, the peering remains pending and no connection is established.