Route advertisement from vWan to ExpressRoute / VPN over BGP

Andy 1 Reputation point
2020-08-18T16:21:15.083+00:00

Hello Experts,

Would you help me understand what prefixes will be advertised out from the VPN connection or Express Route ( over BGP ) if we have vWAN deployed over three regions - East, East2 and West.

Should we expect only regional prefixes to be advertised ? ( e.g. EAST2 VPN or ER will advertise only prefixes of VNETs connected to EAST2 region ) or all prefixes ( east2+west+east) will be advertised over bgp ?

Thank you !

Azure Virtual WAN
Azure Virtual WAN
An Azure virtual networking service that provides optimized and automated branch-to-branch connectivity.
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Azure VPN Gateway
Azure VPN Gateway
An Azure service that enables the connection of on-premises networks to Azure through site-to-site virtual private networks.
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Azure ExpressRoute
Azure ExpressRoute
An Azure service that provides private connections between Azure datacenters and infrastructure, either on premises or in a colocation environment.
325 questions
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  1. GitaraniSharma-MSFT 47,696 Reputation points Microsoft Employee
    2020-08-19T11:46:39.093+00:00

    Hello anonymous user-2512 ,

    Azure VPN gateways support BGP transit routing with the exception that Azure VPN gateways will NOT advertise default routes to other BGP peers. To enable transit routing across multiple Azure VPN gateways, you must enable BGP on all intermediate VNet-to-VNet connections. For more information, see About BGP.

    So it depends on your network architecture. If you have enabled BGP on all the intermediate connections then all prefixes will be advertised.

    Kindly let us know if you need any further assistance on this issue from our end.

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