Skype For Business What is Enterprise Voice ?

Enterprise Voice is simply connecting Skype For Business to other telephony systems.
Enterprise Skype Voice For Business allows you to:

  • Implement other Skype for Business features such as Response Group, Call Park, Unassigned Numbers, Call via Work, and Group Call Park.
  • Connect with other existing PBXs (Cloud or On-Premise).

To install it you must have a minus:

  • A Skype for Business server
  • A Mediation server
  • A Trunk SIP to connect with other third party systems.

Skype For Business Enterprise Voice

The previous figure describes the Enterprise Voice flow.
The user connects to the SFB Front End server.
The SFB Front End server is connected to a Mediation server.
The Mediation server manages communication with third-party systems through a SIP trunk, PBX or Gateway.
The Mediation server: “Media” as its name indicates it manages the media between the SFB environment and the third systems. It converts media from one format to another. To be more precise, it converts traffic from the codec used by SFB to a standard codec used by third-party systems.
SIP: This is an XML-based protocol used in telephony systems. It controls the media whether it is Audio or Video. It allows you to make a call, pick up or hang up.

Call Flow:

SIP actually does much more. Every time you send an instant message to a coworker, that whole conversation happens solely using the SIP protocol.
Media is the voice or video portion of the call. The SIP protocol is used to negotiate the type of media to be used. But once that is done, media can go its own way.

Skype For Business CallFlow
Skype For Business Call Flow


The Trunk is the object to connect the Mediation server with a Gateway. The path that will be taken by a call when it arrives at the Mediation server. This is the point of exit from a call to the external telephone system.

Dial Plan:

A dial plan is used to control the numbers entered by a Skype For Business user. It makes it possible to standardize the numbers transmitted to Skype For Business so that the choice of route to take is easily taken.
Generally it is advisable to standardize all numbers in E164 format. Thus the management of Enterprise Voice will be much simplified.

Voice Policies:

Voice policies define user permissions. They control which features users are allowed to use. For example, can user X make calls? Can he use the Call Park?
The voice Policy work with two other bricks:

  • PSTN Usage
  • Routes

These are used to define how a user can make calls. Can he make international calls? Is he allowed to call mobile numbers?


As previously described, routes are used by Voice policies to define a user’s permissions to make calls.
Primarily, a route consists of two parts:

  • A rule to check if a number can be called (mobile number, international, national …)
  • The Trunk to use to make the call

PSTN usage:

PSTN usage is used to link the voice Policy (What a user can do) with the routes (How the user can make calls).