Some Outgoing Calls timeout

I was working on a strange issue at a customer regarding Enterprise Voice from Lync.
The issue:
Some calls fail before call setup completes…In my case it was mostly landline calls, cell calls worked fine.

A wireshark trace showed that Lync was “getting bored” waiting for a response from my SIP gateway. Then sends a CANCEL to which the gateway sends a SIP 487.

The Lync Mediation Server is sending a CANCEL on call setup, after a very short time (seemed like 8 seconds but must have been 10 seconds all up)

The culprit…
After the Lync 2010 CU4 update from Microsoft, Lync has become impatient  and if the remote party has not responded with more that “100 Trying” during 10 sec the Mediation Server sends a CANCEL ! 

This timer was earlier 30 – 40 seconds, but is now only 10 !!
The remote party can’t respond with more that “100 Trying”, until they have received anything from the Called Party.

The fix:

Configuring Parameters
Some of the above timeouts can be configured. The file which has the configurable parameters is ‘OutboundRouting.exe.config”  Use caution when changing these values, as a rule of thumb try not to increase or decrease the value by more than 25% of its original value.
From OutboundRouting.exe.config
       – The culprit
The FailOverTimeout should be increased to the desired time limit.
The file is found under 

C:Program FilesMicrosoftLync Server 2010ServerCore on the Lync 2010 FrontEnd Server.
C:Program FilesMicrosoftLync Server 2013ServerCore on the Lync 2013 FrontEnd Server.

Changing the value from 10000 (10 sec) to 15000 (15 sec) solved the issue.
After changing this value, it’s recommended to reboot the server. I tried restarting services but wasn’t successful.

Next time you run Lync updates this value may be reset to 10000 – Keep a record!
This one caught me out a second time after an update reset the timer to 10 seconds


About Paul B

My name is Paul Bloem and I am employed at Lexel Systems in New Zealand as a Principal Consultant for Unified Communications. I have been working on enterprise voice solutions for over 20 years. My first 10 years were spent working for a Telco in South Africa (Telcom SA). This is where all the groundwork happened as I was exposed to just about every aspect of telecommunication you could imagine. I develop an interest in PBX technologies and eventually became the go-to guy. Next, I had a 10 year run at Siemens South Africa, most of my time there was as a Technical Trainer. During this time VoIP hit the world stage, I had the privilege of introducing VoIP both as H.323 and later SIP across the Siemens HiPath 4000 solution stack. In 2008 I immigrated to New Zealand with my newly attained MCSE, I was ready to go where no PBX Techie had gone before. I was employed to explore OCS 2007 and that was pretty much the beginning of the end for me. I have been working on OCS and Lync ever since. My current role focuses exclusively on Lync and associated technologies.. That includes pre-sales, consulting, architecture and design, training and support. I even get to play in the development space from time to time - focus on play ;-) I was nominated as a Microsoft VTSP for Lync early in 2013 and also awarded Microsoft's MVP award for Lync in 2014.
This entry was posted in Call issues, Call Timeout, Known Issues, SIP 487, SIP Error 487, Some Outgoing Calls timeout. Bookmark the permalink.

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