Cloud Router uses Border Gateway Protocol (BGP) to exchange routes between your Virtual Private Cloud (VPC) network and your on-premises network. On Cloud Router, you configure an interface and a BGP peer for your on-premises router. The interface and BGP peer configuration together form a BGP session.
Within Google Cloud, a Cloud Router interface connects to exactly one of the following Google Cloud resources:
- A Classic VPN tunnel using dynamic routing
- An HA VPN tunnel (using dynamic routing as required)
- A VLAN attachment for Dedicated Interconnect
- A VLAN attachment for Partner Interconnect
- A router appliance instance
Cloud Routers support multiple interfaces each. You don't need to create a separate Cloud Router for each Cloud VPN tunnel or VLAN attachment. However, each Cloud Router uses the same ASN for all its BGP sessions. Because Partner Interconnect requires a public ASN, and all other types of interface require private ASNs, a Cloud Router that manages BGP sessions for a VLAN attachment on Partner Interconnect cannot manage BGP sessions for any other type of interface.
The following sections provide links that describe how to configure BGP sessions for each type of interface.
- For HA VPN tunnels, see Creating an HA VPN to a peer VPN gateway or Creating an HA VPN to another HA VPN gateway.
- For Classic VPN tunnels with dynamic routing, see Creating Cloud VPN tunnels with dynamic routes.
- For Dedicated Interconnect, see Creating VLAN attachments (dedicated).
- For Partner Interconnect, see Creating VLAN attachments (partner).
- For router appliance instances, see Setting up a Cloud Router in the Network Connectivity Center documentation.
To update the base advertised route priority to change route metrics, see Updating the base advertised route priority.
To disable or end a BGP session, see Disabling or removing BGP sessions.