Microsoft PSTN gateways are the servers that sit at the edge of the Microsoft Teams cloud service and route calls between Direct Routing services and the Microsoft platform

It is important to factor in the locations of the Microsoft PSTN gateways for decisions regarding data sovereignty and privacy management. Since there are a limited number of gateways it is possible that the voice traffic for customers will cross international boundaries on its journey across the Microsoft network.

Network routing generally means that from a customer service location (sip trunk or PBX), the voice traffic will take the shortest route onto the Microsoft network, and will then transit to the nearest designated PSTN gateway. The benefit of this is that the voice traffic is safely within the Microsoft cloud and quality and performance is optimised., 

For example, a call from customer in Canada will transit to the USA before ingress to the Microsoft Teams PSTN gateway, although the actual data traffic may hop-on to the Microsoft network within Canada as shown in the diagram below:

Location of gateways

This is the current list of Microsoft PSTN gateways as published on this page at microsoft.com    Washington US West    Virginia US East    Amsterdam Netherlands    Dublin Ireland        Hong Kong    Singapore    Sydney Australia    Melbourne Australia    Osaka Japan    Tokyo Japan

The service gateways are provisioned to be adjacent to these Microsoft gateways, within the Microsoft Azure cloud so it is aligned to Microsoft's approach to global voice routing


Customers looking at data management and sovereignty should factor-in Microsoft's regional approach used by both the service and Microsoft; customer voice traffic may cross international boundaries to reach the Microsoft Teams service.