HA-VPN

[fmugambi]

Hello FAM!,
hope you are well.

I have a desired topology as attached,

I have peered the gcp <>on-prem via BGP. On the gcp end can i use MED values to influence which tunnel carries active traffic at a time to avoid route-asymmetric issues?

[vishnuramac]

Hello @fmugambi ,

Welcome to Google Cloud Community!

On cloud routers/BGP sessions you can define a base advertised priority that is used as a value for the BGP MED attribute. Base priorities let you specify which Cloud VPN tunnels or Cloud Interconnect VLAN attachments on-premises systems to use to send packets to your VPC network. You can create active-active, active-passive, or a custom combination of these topologies by using the base priority to influence how packets are sent to your VPC network. For an example using HA VPN tunnels, see Active-active and active-passive routing options for HA VPN in the Cloud VPN documentation.

Please note that the "Base advertised priority (MED)" set on the GCP side is for the routes it advertise and not for the routes it learns. If you want to make sure a particular tunnel is also preferred from the GCP end for the traffic to on-prem, you would need to adjust and advertise the MED from on-prem side accordingly.

I hope that help clarify your question.