Mitel Telephony - Silent Call Issues

[choodmold]

Hello,

I’m hoping someone can shed some light on these silent calls issue that occurs globally through our contact centre, this has now been going on for just over 2 years with 3rd party venders getting involved, Mitel MSPs and internally reviewing our network and settings.

The sporadic issue we get (using the Micollab SIP application with the Ignite web dashboard open) the agent will accept calls and either the customer cannot hear the agent, or vice versa the agent cannot hear the customer. Below are several attempts at eliminating this issue but we are now clutching at straws.

• Replacement headsets/ different brands headsets (USB A&C)
  
  Made changes to user’s audio settings / preferences advised by MITEL MSP (exclusive mode/ hardware acceleration/audio enhancements)
  
  Installed all latest BIOS/Chipset software/ drivers
  
  Replaced laptop (tested with different brand laptop Dell/HP)
  
  Created isolated image with just Mitel software on (issue occurs on win10 & 11)
  
  Installed different audio drivers/software, including direct drivers for headsets being used, also any sound filter/processing tools to see if any difference
  
  Created new AD accounts/ Mitel accounts
  
  MIVB server has been rebooted – completed by MITEL MSP
  
  SIP MBG server has been rebooted - completed by MITEL MSP
  
  MITEL MSP hard coded system to G711 codec (it was suggested that they are seeing a lot of discarding RTP with unallowed codec)
  
  MiCC server upgrade 9.4.1 / Micollab software upgrade (9.8.112)
  
  Silent calls are replicable across office network and VPN
  
  Physical Mitel desk phones configured and tested (issues still occur)
  
  Multiple traces sent (Wireshark)and captured by MITEL MSP but cannot locate any example
  
  Our network MSP confirmed SIP AGL was disabled per Mitel MSP suggestion

The only unofficial fix we have is to completely remove any audio drivers and USB bus drivers and asking the user to reboot, although this is only bandage for some, the silent call issue can return on the next call or after several. - TO NOTE - out of curiosity if the agent receives a silent call if they make a call through MS TEAMS or other means the audio between both parties are fine. 
 

Any suggestions or input would highly be appreciated!!

[dilkie]

"Physical Mitel desk phones configured and tested (issues still occur)"

well, if that is the case, it's not a PC or s/w issue... so a physical phone connected to MBG also has instances of silence? Is this on trunk calls or internal calls?

[choodmold]

Correct, the official Mitel 6920 SIP phones are routing through the MiVB, We haven't been able to replicate the silence internally, only when an agent takes a call through the SIP trunks.

[dilkie]

response not clear...

can't repo on internal calls... good
agent calls via trunks.. failure

is agent using 6920 in this failure?
do 6920 trunks calls (non-agent) have issues?

[choodmold]

The company I work for is predominantly a hybrid workplace with agents using the Micollab SIP application to accept incoming calls or to make outbound calls, the 6920 SIP physical phones we setup were only used for trial, but with the issue is so sporadic some agents can have a good run whereby silent calls on either end don't occur for hours, possibly day/s which means we've not been able to accurately confirm if this replicable for "back office" users, however to confirm from your question; we have tried outbounding to our personal mobile numbers using a test Mitel account (using physical desk phones & Micollab SIP application) and haven't been able to replicate, but the issue is we wouldn't be able to test long enough to confirm, if that makes sense? 

[dilkie]

yup, it does.

Best I can offer is to look through the tug logs to see the rtp stats on the calls that have issues... if there are rtp stream issues, it WILL show up there. You can also set up a call recorder to see if the recording also shows a rtp loss (or silence)..

the issue boils down to one of:

• rtp not flowing in one direction
• rtp is flowing in both directions but audio itself is just "silence" packets

Curious, what is "Mitel MSP"?

[choodmold]

I refer to MITEL MSP (Managed Service Provider) a company that provides us with a SAAS contact centre platform.

Could you advise on how we can share these tug logs? it's something I'm not familiar with, are these to be pulled from the MiVB server?

[dilkie]

K, that's getting outside my knowledge of how customer are managed.

tug logs are on MBG... tug is the name of the linux process that does "all" the work (though my partner Mike would disagree)..

In MBG web interface, under "administration" on LH panel, go to "view log files".. you can download a single tug log file (ie. tug/tug.log) or rather them all (plus more) by selecting "collect log files and diag data".. that's called an "sosreport" file if you're ever ask to provide one.

I'm confused why this issue wasn't brought to mitel's PS attention and, if so, why it didn't get escalated enough that the logs would have been looked at to confirm what I posted earlier.