Troubleshooting intermittent echo issues can be a very daunting task with Microsoft Office Communication Server (OCS) 2007. An Enterprise Voice deployment has several pieces, sometimes involving multiple vendors. Troubleshooting any voice issues can seem overwhelming at first, until you have done it several times. Based on my experience with several customers, below is my best advice to those experiencing and trying to troubleshoot these issues or any issue regarding voice quality. We experienced this issue specifically with a customer using several different devices and a Dialogic 4000 Gateway.
Start with trying to narrow down the problem –
- Do the echo problems happen only on Voice calls to the PSTN (Public Switched Telephone Network)?
- Do the echo problems happen on Communicator to Communicator calls?
- Do the echo problems happen on both Communicator to Communicator calls and calls to the PSTN?
- Do the echo problems happen on all devices or only some (e.g. LG-Nortel 8501, 8502, 8540 devices or Bluetooth headsets) and not others?
Make Test Calls after Enterprise Voice has been enabled, checking for Echo and Delay -
- Make Calls to a company that you know has a digital circuit for Voice (T1 or ISDN PRI)
- Make calls to a known POTS line (Plain Old Telephone Service) – VERY IMPORTANT – Most Echo issue will be prevalent with this type of connection
Verify firmware is at the latest version –
- If using Tanjay (LG-Nortel IP 8540 and Polycom CX700 IP Phone) devices make sure latest firmware is installed via the OCS 2007 Update Server.
- If using Catalina (LG-Nortel 8501 and CX200) USB devices, make sure the serial number is later than 2007 Nov – there were voice issue with previous lots.
Verify your SIP Gateways firmware –
- Make sure you are running the latest firmware and SIP stacks on your gateways.
Run OCS BPA (Best Practice Analyzer) –
- Make sure all OCS servers have the latest Hotfixes and updates applied.
Keeps logs of calls that users complain has echo on them –
- Create and distribute a voice issues form in word to track the issues
- Track Time/Date of call
- Track type of call – PSTN , Communicator to Communicator Call
- Track flow of call – Incoming/outgoing
- Track the number Dialed or Caller ID of the Calls
- Track origin of problem – who hears echo, outside/inside party.
- Do the voice issues happen Internally (Campus only) and Externally (via Edge Server)
- Type of Connection – LAN, DSL , Cable etc…
- Do problems only happen on Local/Long Distance Calls
Install QOE Server (Quality of Experience Server) –
- A great tool for testing LAN/WAN voice Quality and obtaining MOSS scores
- Check Moss Scores referencing scores for logs on problematic calls
- Also able to Verify firmware versions for All Voice devices to help with Trouble shooting possible firmware issues
If using a Dialogic 4000 Hybrid gateway – obtain MLOG utility from Dialogic support – do the following if the problem can be reproduced:
- Save and extract the attached zip file, preferably to something like "c:\temp"
- Rename the extracted file "mlog.ex_" to "mlog.exe"
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Open a command prompt and change directory to c:\temp
Start the trace with the following command:
mlog -w40000 -l2200 -*ffffffff -$ffffffff
(Please leave the command prompt window open until all tests are complete)
Note: There is a small 'L' in '-l2200' and not '1' !!!
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Reproduce the problem
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Stop the mlog trace with the 'q' command in the command prompt window.
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Save the mlog output by running "mlog -rlog" in the command window, which will generate a "log.txt" file in the same folder as mlog.
- Send the mlog file to Dialogic support for Analysis.
Try Adjusting the Echo Cancellation setting on the SIP gateway. The following is an example of the setting on a Dialogic 4000 Series gateway:
Lastly these files may need to be replaced on a Dialogic 4000 series gateway. Dialogic support will send the updated files:
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Backup the files in \windows\system32\drivers\disdn (rename them)
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Copy these new files
- Reboot the gateway
Rob Ziolkowski
Voice Consultant
Project Leadership Associates
