Cloud Router documentation
Cloud Router enables you to dynamically exchange routes between your Virtual Private Cloud (VPC) and peer network by using Border Gateway Protocol (BGP).
For example, if you use a Cloud VPN tunnel to connect your networks, you can use Cloud Router to establish a BGP session with a router in your peer network over a Cloud VPN tunnel. The peer network can be an on-premises network, multicloud network, or another VPC network. Cloud Router automatically learns new subnet IP address ranges in your VPC network and can announce them to your peer network.