Cisco SD-WAN 800v BGP peering with VWAN hub

Imroz Khan 0 Reputation points


I have 2 regions of Azure connected to each other via Azure VWAN hub. Also we have Azure express route from each Azure region landing into the on-prem DC.

We intend to manually deploy 2 x Cisco SD-WAN 8000v routers in each region and setup BGP peering with respective vhubs.

I wanted to know as part of BGP advertisement the 8000v routers will send BGP extended community Site-of-orignal (SOO) to the vhub. Will the vHub accept the extended community as part of BGP advertisement and send it to the on-prem routers within the BGP updates over the Express route links. We intend to use these community to enable routing loop prevention mechanism in the on-prem DC.    

Azure Virtual WAN
Azure Virtual WAN
An Azure virtual networking service that provides optimized and automated branch-to-branch connectivity.
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  1. KapilAnanth-MSFT 36,396 Reputation points Microsoft Employee

    @Imroz Khan


    Wrt, "can you advise if I configure my NVA's as Active-Active, how will the vhub understand that, and in case if it receives traffic from NVA-1, how to make sure the vhub will only forward the traffic to the required destination vnet and not send it back to NVA-2, which could be a routing issue."

    • Azure platform doesn’t guarantee symmetry - a single flow can have inbound come on instance0 and outbound return on instance1.  
    • For scenarios where the two NVA instances are advertising the same route with the same priority,
      • Make sure stateful inspection on the NVA or related firewalls is turned off or
        • Asymmetric forwarding is turned on. 
    • If stateful firewall is required consider active-passive set ups or having one nva instance advertise a route of higher priority for active-active purposes. 
      • i.e., you still get high availability but one NVA instance is preferred over the other unless this instance becomes unavailable.

    Hope this helps.



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