You can troubleshoot network issues from the Mediation Server to the public switched telephone network (PSTN) as follows:
- Check the event log of the Mediation Server for error messages
related to connectivity or network problems. For details about
relevant Office Communications Server events, see
Enterprise Voice-Related Events.
- Ping the IP address of the PSTN gateway from the Mediation
Server to verify the network connectivity to the gateway.
- Start Performance Monitor, and then add the
Mediation Server – Outbound Callsobject so that you can view
the counter values for the Mediation Server. For details about
relevant Office Communications Server performance counters, see
Enterprise Voice-Related Performance Counters. For details
about using Performance Monitor, see
Perfmonon Microsoft TechNet at
- Record the current Mediation Server counter values. You will
use changes to these values to make decisions in the steps that
- Attempt a new outbound call to a PSTN number from an Office
- Look at the following Mediation Server current counter values:
Calls Attempted.If the Calls Attempted counter has not
changed, the call did not reach the Mediation Server. If the Calls
Attempted counter has incremented, the call reached the Mediation
Invites Forwarded to Gateway.If the Invites Forwarded to
Gateway counter has not changed, the Mediation Server could not
process the incoming call attempt from Office Communicator (that
is, through the Office Communications Server by proxy). Enable
Windows preprocessing (WPP) tracing on the Mediation Server for
session logging, and then reattempt the call. If the call fails
again, look at the trace output for information about why the
Mediation Server could not process the call. For details about WPP,
WPP Software Tracingon Microsoft MSDN at
If the Invites Forwarded to Gateway counter was incremented, check the Calls Established counter. If the Calls Established counter is not incremented, check the configuration and connectivity of the PSTN gateway.
Calls Established.If the Calls Established counter was
incremented, and the two parties could not talk, there is an issue
with audio. Check the endpoint device, ensure that the PSTN Gateway
has been configured for the correct G.711 variant for the locality
where it is installed, that the Mediation Server to MRAS handshake
is successful, and that you can successfully use the Media Relay
when the client and the Mediation Server are separated by network
address translations (NATs).
- Calls Attempted.If the Calls Attempted counter has not changed, the call did not reach the Mediation Server. If the Calls Attempted counter has incremented, the call reached the Mediation Server.
- Check the gateway logs to ensure that the PSTN gateway received
the call and was able to process it.