Express Route Global Reach

Raviraj Velankar 86 Reputation points
2024-01-16T06:23:44.58+00:00

Hello Team,Following is the scenario There are two Azure Regions - (Region-A & Region-B) and in each Azure region has AVS (Azure VMware Solution - Private Cloud) instance. Each Azure region has Express Route to On-premise Network and 'Express Route Global Reach' feature is configured between Onprem ER Circuit and AVS ER Circuit. This way Onprem IP prefixes are learned into respective region AVS instance There is replication requirement between two AVS instances. As per Azure documentation 'Global Reach' can be configured between two AVS - Express Route Circuits to enable this communication and it can leverage Microsoft backbone network. However both Azure regions are connected to each other using MPLS-WAN Network. If we enable 'Global Reach' between two AVS managed Express Circuit then there will be possibility of sub-optimal routing. Onprem IP prefixes learned by Region-A will be forwarded to Region-B through 'Global Reach' between two AVS managed Express Circuit and it can take that path instead of taking direct path available via Onprem Express Route Circuit in Region. Would like to know whether it is feasible to apply route filtering in 'Global Reach' in order to advertise only specific routes or is there any alternate way possible to have replication between two Azure region AVS instances

Azure ExpressRoute
Azure ExpressRoute
An Azure service that provides private connections between Azure datacenters and infrastructure, either on premises or in a colocation environment.
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  1. ChaitanyaNaykodi-MSFT 24,231 Reputation points Microsoft Employee
    2024-01-18T03:21:22.2833333+00:00

    @Raviraj Velankar

    Thank you for reaching out.

    Can you please share a rough network diagram of your network and plot the sub-optimal path the traffic can take?

    Meanwhile based on my understanding of your question above. Based on the FAQ here The current behavior is to prefer the ExpressRoute circuit path over hub-to-hub for VNet-to-VNet connectivity. The express route circuit path will preferred over MPLS-WAN Network between the two regions.

    You can also go through this documentation to understand how to prevent sub-optimal routing in Azure Express Route https://video2.skills-academy.com/en-us/azure/expressroute/expressroute-optimize-routing

    Thank you!

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