In Microsoft Lync Server 2010 the Mediation Server is now able to control multiple PSTN gateways. How does this impact outbound routing of calls?
Imagine a scenario as in the figure below.
We have two sites A and B each with a SE server, a co-located MS and a PSTN gateway. In the topology the PSTN gateways depends on their local MS, i.e. have them as the next hop. We have a route describing that calls to Denmark (+45) should be sent to PSTNGateway1.
Alice wants to call a number in Denmark. Since the Mediation Server can control multiple PSTN gateways will the call go via MS1 or MS2? The outbound routing component on SE2 will send the call to the MS on which the PSTN gateway depends. In this case MS1.
Imagine we change the scenario slightly as in the figure below.
We now add PSTNGateway2 to the route for Denmark. What will happen when Alice wants to call a number in Denmark? The outbound routing component on SE2 will round-robin over the two PSTN gateways, so the call will either go via MS1 or MS2.