Azure ER peering location and Azure Region

Question

Hello Experts,

Are there any latency considerations when choosing an azure ER peering location and mapping that to an Azure Region?

So for instance if I'm setting up an Azure infrastructure in Canada Central, is the latency significantly reduced if the peering location is in Toronto and not Quebec?

Answer 1

Hello anonymous user ,

Azure regions are global datacenters where Azure compute, networking and storage resources are located. When creating an Azure resource, a customer needs to select a resource location. The resource location determines which Azure datacenter (or availability zone) the resource is created in.

ExpressRoute locations (sometimes referred to as peering locations) are co-location facilities where Microsoft Enterprise Edge (MSEE) devices are located. ExpressRoute locations are the entry point to Microsoft's network – and are globally distributed, providing customers the opportunity to connect to Microsoft's network around the world. These locations are where ExpressRoute partners and ExpressRoute Direct customers issue cross connections to Microsoft's network.

In general, the ExpressRoute location does not need to match the Azure region. For example, a customer can create an ExpressRoute circuit with the resource location East US, in the Seattle Peering location.

While they are not related, it is a good practice to choose a Network Resource Provider geographically close to the Peering Location of the circuit.

We have seen latency/bandwidth issues when the Azure ER peering location and Azure Region differs. You can refer the below article to see such an example of West US 2 Azure region where the latency to Seattle Peering location is less compared to regions such as West US or Central US (NOTE : Seattle peering location is located in West US 2 Azure region):

https://learn.microsoft.com/en-us/azure/expressroute/expressroute-troubleshooting-network-performance#latencybandwidth-expectations

Hence, it would be a good idea to choose peering location Toronto and not Quebec if you are setting up an Azure infrastructure in Canada Central to ensure reduced latency. But as I mentioned before, the ExpressRoute location does not necessarily need to match the Azure region.

Kindly let us know if the above helps or you need further assistance on this issue.

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Answer 2

Hello @GitaraniSharma-MSFT ,

Thanks for your insight above, very informative!

How do I programmatically (using Azure API/Python SDK) list the compatible Azure Regions in order from the closest to the furthest when selecting a Peering Location? And vice versa.

For example:

1. If I select Toronto, the API/Python SDK would return a list starting with Canada Central, Canada East, Central US, etc...
2. If I select Canada Central, the API/Python SDK would return a list starting with Toronto, Toronto2, Montreal, etc..

Source:

ExpressRoute locations
Atlanta, Chicago, Chicago2, Dallas, Denver, Las Vegas, Los Angeles, Los Angeles2, Miami, Minneapolis, Montreal, New York, Phoenix, Quebec City, Queretaro(Mexico), Quincy, San Antonio, Seattle, Silicon Valley, Silicon Valley2, Toronto, Toronto2, Vancouver, Washington DC, Washington DC2

Azure regions
East US, West US, East US 2, West US 2, West US 3, Central US, South Central US, North Central US, West Central US, Canada Central, Canada East

Thanks & Regards,
Romain