Hub-Spoke Connectivity in GCP: A Complete Guide to Network Connectivity Center

As organizations scale on Google Cloud Platform (GCP), network architectures often become complex. Enterprises may have multiple VPCs, on-premises data centers, branch offices, and partner networks that all require secure, reliable connectivity. Managing and troubleshooting this sprawl using point-to-point connections quickly becomes difficult.

Google Cloud Network Connectivity Center (NCC) is designed to address this challenge by serving as a centralized hub for managing hybrid and multi-network connectivity across GCP. In this blog, we’ll explore what NCC is, how it works, key components, use cases, and when you should consider using it.

What is the Network Connectivity Center?

The Network Connectivity Center is a hub-and-spoke connectivity service in GCP that simplifies connecting on-premises networks, branch offices, multiple VPC networks, and multi-cloud environments.

Instead of creating many direct connections between networks, NCC allows you to connect them through a central hub, improving scalability, visibility, and operational control. Think of NCC as a logical control plane that manages how different networks are interconnected using Google Cloud’s global infrastructure.

Why is the Network Connectivity Center Needed

Without NCC, organizations often face:

• Complex mesh networking
• Difficult route management
• Limited visibility across hybrid connectivity
• Scaling challenges as new sites or VPCs are added

NCC addresses these problems by:

• Centralizing connectivity management
• Reducing operational overhead
• Providing a consistent architecture for hybrid networks

Key Concepts and Components

1. Hub

The hub is the core of the Network Connectivity Center. It represents a global connectivity domain where all connected networks meet.

• Acts as a logical aggregation point
• Does not pass traffic itself, but manages connectivity

2. Spokes

The spoke represents the actual network attachments connected to the hub. Each spoke can be:

• VPC Spoke – Connects a VPC network
• Hybrid Spoke – Connects on-prem or branch networks using:
  • Cloud VPN
  • Dedicated Interconnect
  • Partner Interconnect

Spokes define how traffic enters or exits the hub.

3. Supported Connectivity Types

NCC works with existing GCP networking services:

• Cloud VPN (HA VPN)
• Cloud Interconnect
• VPC Networks
• Third-party Network Virtual Appliances

How the Network Connectivity Center Works

1. You create an NCC hub.
2. You attach multiple spokes (VPCs, VPNs, Interconnects).
3. NCC manages routing and connectivity relationships.
4. Traffic flows between spokes according to topology selection.

The following diagram shows star topology connectivity among four VPC spokes

Source: Preset connectivity topologies  |  Network Connectivity Center  |  Google Cloud Documentation

This hub-and-spoke design avoids the complexity of a full mesh and simplifies future expansion. The resources in the center group communicate with the resources in the centre group or the edge group. The edge group communicates with resources in the center group, but not with the other edge groups.

Common Use Cases

1. Hybrid Cloud Connectivity

Connect multiple on-premises data centers and branch offices to GCP using a single, centralized architecture.

2. Multi-VPC Architectures

Organizations with separate VPCs for dev, test, and prod can interconnect them securely without manual peering complexity.

3. Branch Office Connectivity

Retail stores or remote offices can connect via VPN or SD‑WAN to GCP and access shared services.

4. Centralized Security & Inspection

Route traffic through firewall or inspection appliances using router appliance spokes.

Preparing for Real-World GCP Networking Challenges

As organizations increasingly adopt hybrid and multi-cloud architectures, expertise in GCP networking has become a critical skill. Learning through Mastering Networking in Google Cloud 2.0 helps professionals understand real-world connectivity challenges, implement best practices, and stay ahead in cloud networking roles.

Simplifying GCP Connectivity

Google Cloud Network Connectivity Center is a powerful solution for enterprises looking to simplify and scale their network connectivity. By adopting a hub‑and‑spoke model, NCC reduces complexity, improves visibility, and provides a future-ready foundation for hybrid and multi-cloud networking.

If you are building large-scale or hybrid architectures on GCP, NCC is a service worth serious consideration.

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