Cloud Router

Google Cloud Router is a fully managed dynamic routing service that enables dynamic route exchange between your VPC networks and on-premises networks using Border Gateway Protocol (BGP). It works with Cloud VPN and Cloud Interconnect to provide dynamic routing.

Key Features:

1. Dynamic routing - Automatically propagates route changes using BGP without manual configuration.

2. Regional and global routing - Regional routing advertises subnet routes within a region; global routing advertises all subnets across all regions.

3. Works with Cloud VPN and Interconnect - Required for dynamic routing with HA VPN and Cloud Interconnect.

4. Custom route advertisements - Advertise specific IP ranges to on-premises networks.

5. BFD support - Bidirectional Forwarding Detection for fast failure detection.

The below example shows how to create a Cloud Router and configure BGP using gcloud.

It gives the following output,

Created router [my-cloud-router].
Router Status:
  name: my-cloud-router
  network: my-vpc
  region: us-central1
  bgpPeers:
  - name: peer-to-onprem
    peerAsn: 65002
    status: UP
    advertisedRoutes: 3

Regional vs Global Routing Mode:

Regional routing - Cloud Router only advertises subnets in its own region to the BGP peer. Default mode.

Global routing - Cloud Router advertises all subnets in all regions across the VPC to the BGP peer. Enables multi-region connectivity via a single Interconnect or VPN.