Azure Express Route

Tim Unterberger 1 Reputation point

We currently have Express Route deployed and we have a vNet that is connected to the Express route and we have another existing vNet peered to the vNet that is connected to Express Route, and that is all working fine. We want to add another vNet and peer that vNet with the vNet that is connected to the Express Route. So we have Express Route vNet acting as a hub to the rest of our Azure environment.

The question is if we use Transit Gateway on the "hub" vNet do we need to publish routes across BGP for the on-premise infrastructure or will the Transit Gateway essentially publish the routes?

Thank you,

Azure Virtual Network
Azure Virtual Network
An Azure networking service that is used to provision private networks and optionally to connect to on-premises datacenters.
2,122 questions
Azure ExpressRoute
Azure ExpressRoute
An Azure service that provides private connections between Azure datacenters and infrastructure, either on premises or in a colocation environment.
320 questions
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  1. ChaitanyaNaykodi-MSFT 22,061 Reputation points Microsoft Employee

    Hello anonymous user, Welcome to the Microsoft Q&A platform.

    As per this common design principle guide In order to allow the ExpressRoute virtual gateway to advertise routes from Hub to Spoke, you must select the “Allow Gateway Transit” option in the VNet peering panel of the Hub. And then to allow the Spoke VNet routes to transit out of the ExpressRoute gateway, you must select the “Use Remote Gateway” option in the VNet peering panel of the Spoke. Once complete, all on-prem BGP routes advertised through ExpressRoute will be visible in the Hub and all participating Spokes, and vise-versa. You can also go through this FAQ documentation for additional details.

    Hope this helps. Please let me know if you have any additional questions. Thank you!

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