Question

Your company connects an on-premises data center to a Google Cloud VPC using two HA VPN tunnels terminating on a single Cloud Router in region us-central1. Both tunnels advertise the same on-premises prefix 10.50.0.0/16 via BGP. You want tunnel-1 to be the active path and tunnel-2 to serve only as a backup, becoming active automatically if tunnel-1 fails. Which configuration achieves this?

Accepted Answer

Configure the on-premises router to advertise 10.50.0.0/16 to Cloud Router with a lower MED value on tunnel-1 than on tunnel-2.

Answer

Configure the on-premises router to advertise 10.50.0.0/16 with a lower AS-path prepend on tunnel-1, and rely on the VPC's default route priority of 1000 for both tunnels.

Answer

Set a lower Cloud Router advertised route priority (MED) on the BGP session for tunnel-1 than on tunnel-2 so that Google Cloud prefers the tunnel-1-learned route.

Answer

Create a custom static route to 10.50.0.0/16 with priority 100 pointing at tunnel-1 and priority 200 pointing at tunnel-2.