Location Based Routing (LBR) in Microsoft Teams

This post is about LBR – a planned feature – for calling or telephony with Microsoft Teams which might be released and available in Q4 2019.

Location Based Routing (LBR) allows basically to route and control voice calls depending on the location. In my opinion, this is very useful for deployments with roaming users especially regarding emergency calls or call restrictions.

Source: https://pixabay.com/de/illustrations/netzwerk-erde-blockchain-globus-3537401/

Why LBR?

There are some reasons to use LBR for managing and controlling your voice call flows:

  • Egress calls: Enforce outgoing calls to egress via local PSTN gateway, prevent PSTN toll bypass
  • Ingress calls: Prevent incoming PSTN calls via a NON-local PSTN gateway
  • Undefined location: Prevent PSTN calls to and from users in undefined locations

Let me describe a small (fictive) scenario where LBR could help:
Erik works for a special machinery engineering company.
Still, the company has decentralized PSTN connectivity.
Each location and site has a dedicated PSTN link and SBC.
Erik is a Teams user including calling capabilities.
He’s located and “homed” in Stuttgart, Germany.

Erik travels to another company site.
Erik needs to place an (emergency) call while being in another office in Berlin, Germany.


By default this (emergency) call would be routed via Stuttgart to the local emergency service answering point. However, that would be a very bad routing and in case of an emergency were every second counts this is not acceptable.It would be ok if Erik was really in Stuttgart and not Berlin.

By using LBR this (emergency) call would be routed locally and breakout to PSTN via the SBC in Berlin and land at the emergency service answering point in Berlin instead of Stuttgart. If Erik would have to call for emergency in the company site in Hamburg, Germany the call would be routed locally and breakout to PSTN via the SBC in Hamburg as well.

How does LBR work?

Usually you’ll have to define and save some of your network parameters (IP address ranges per site …) to define sites in the phone system. Afterwards you’ll have to define (LBR) voice routing for each site (e.g. LBR policies, voice route/s, policies …) so that calls are routed according to the location requirements and its configuration.

Conclusion, opinion and summary

This is subject to change or might be implemented different to what’s described above. This is just my personal assumption how it might look like. I’ve just assumed that it might be like that because of the approach which can be found in Skype for Business Server.

Additional resources