Lync Enterprise Voice tips

Here you can find few tips about Lync Enterprise Voice and one possible way you can configure Lync Voice Policies, PSTN Usage Records, and Voice Routes for least cost routing.


  1. Did you know if you add more gateways to one Voice Route, the calls to the gateways will be evenly delivered. According my measures, if there are two gateways, maximum 3 consecutive calls goes to the same gateway, the 4th one goes to the other gateway.
  2. If you create two Routes with the same pattern to match and same PSTN Usage assigned, the one upper on the Route list will be always used, unless the gateway(s) assigned to the route is down. This can be used in fail-over situations.

Least cost routing plan


  • You sacrifice showing the right A number for outbound calls, unless your local operator lets you send any arbitrary number, even foreign ones.
  • Primarily for all international calls a dedicate SIP trunk is used.
  • Every user should be able to call every number in the country where company operates.
  • To make things more clear, one route has one associated PSTN usage.
  • PSTN usages are created based on the minute price of the calls, plus additional PSTN usages are created for the fail-over routes.

First of all, don’t let you get confused by the CSCP, where you cannot just create a single PSTN usage, but you have to create it from a Voice Policy configuration. Also when you check out a Route, the PSTN Usages are listed there with the associated Voice Policies, but right on the Route page you shouldn’t care about the Voice Policies associated.

  1. You should start with PSTN Usages, but you cannot. First you have to create Voice Policies.
  2. Create Voice Policy according to the user rights to place calls. e.g.
    • Limited User Policy
    • Normal User Policy
    • Advanced User Policy
  3. Now, you can define the PSTN usages and you should name them by the costs of the possible routes. This is the place where order really maters! Assign and create the PSTN Usages from cheap to expensive in each User Policy. For example you can create the next PSTN usages:
    • Free Calls (create in Limited User Policy assign to all other policies)
    • Low Cost Calls (create in Limited User Policy assign to all other policies)
    • Moderate Cost Calls  (create in Normal User Policy assign to Advanced User Policy)
    • High Cost Calls (create in Advanced User Policy)
    • Fail Over Route Calls 1 (create in Normal User Policy)
    • Fail Over Route Calls 2  (create in Advanced User Policy)
  4. Define routes through the gateways: Here you can define all the possible ways to reach different category numbers through all the gateways. Define the least expensive routes first and assign them the appropriate PSTN Usage.
    1. Define shortest, cheapest routes for all possible numbers you want to provide reach to: e.g.
      • London old PBX numbers through London gateway (categorized as Free Calls)
      • London area numbers through London gateway (categorized as Low Cost Calls)
      • UK numbers through London gateway (categorized as Moderate Cost Calls)
      • Helsinki old PBX numbers through Helsinki gateway (categorized as Free Calls)
      • Helsinki area numbers through Helsinki gateway (categorized as Low Cost Calls)
      • Finland numbers through Helsinki gateway (categorized as Moderate  Cost Calls)
      • International numbers through SIP trunk.  (categorized as High Cost Calls)
    2. Define alternative routes to provide fail over paths: e.g.
      • UK or Finland numbers through SIP trunk (categorized as Fail Over Route Calls 1) (this could be also categorized as Moderate Cost Calls, but then it wouldn’t be so easy to )
      • UK or Finland numbers through both gateways (categorized as Fail Over Route Calls 1) (this could be also categorized as Moderate Cost Calls, but then it wouldn’t be so easy to )
      • International numbers through both gateways.  (categorized as Fail Over Route Calls 1)