Together with the proliferation of the communication platforms like Microsoft Teams, the problem of the emergency call management in this context has come up. Those platforms deal with “fixed and nomadic” users, namely users normally calling from predefined places like homes, offices, smart working, and so on (fixed) but capable of moving by using telephonic applications installed on PC’s/smartphones/tablets and so on (nomadic). Especially in those cases where the Direct Routing service vs Microsoft Teams is offered by a Telephone Service Provider to third party like enterprises, for example, the Provider itself shall guarantee the offer of a solution of emergency calls in this context.
The features of:
- Emergency 911 (E911)
- Emergency Location Identification Number (ELIN)
are the answers of Microsoft to this need.
Management of emergency calls with specialized operators
The E911 feature, mainly used in North America, enriches the SIP signalling of an emergency call originated by a Microsoft Teams user with information allowing specialized operators, named Emergency Service Providers or Screening Centre Operators, to correctly handle emergency calls by forwarding them to the proper listening points (Police, Fire Dept and so on).
In this context, the Session Border Controller that puts in communication the Microsoft platform with that type of specialized operators shall be “transparent” as per that information and shall skip the licensing and bandwidth controls, with the aim of guaranteeing the emergency call management in a “preferential” way.
Management of emergency calls without specialized operators
When there is no specialized operator to consume/manage that type of native information coming from Microsoft platform (like in Italy and Europe) the Session Border Controller shall be capable of filtering that information.
The NetMatch-S Cloud Inside is now certified to accomplish this task.
The key role of ELIN
The E911 feature is propaedeutic to the second feature named ELIN. ELIN feature further enriches the information present in the SIP signalling, in the cases of emergency calls originated by Microsoft Teams users, with an Emergency Location Identification Number (precisely ELIN)
ELIN is a pool of telephone numbers associated to a particular enterprise branch and not assigned and serves a dual purpose:
- allowing the correct emergency originated call routing towards the emergency service (Police, Fire Dept, and so on) geographically co-located with the calling party.
- enabling the emergency service operator to call back a user after an emergency call drop.
Geographical location of the caller
Microsoft Teams platform characterizes each user moving to a particular branch with the ELIN information of that branch. This way ELIN guarantees the emergency calls are managed with geographical characterization, even though the users are “nomadic” (i.e. move from one branch to the other one, keeping their own native telephone numbers).
In order to enable this scenario, the Session Border Controller interconnecting Microsoft platform to a Service Provider forwarding emergency calls to an “ad hoc” management point shall be able to:
- replace with ELIN the native calling party number.
- save the association calling party number / ELIN for 30 minutes.
- In case of call back by the operator (following an emergency call drop, it shall be able to forward that call to the original calling party, by using the saved ELIN association.
The NetMatch-S Cloud Inside, after the certification, is now able to accomplish even this “delicate” task.
