Teleworker Phones With No Audio

[BobbyMitel]

Hi All -

We are deploying teleworker phones out in the field and noticing a lot of problems with calls not connecting.  Phone rings, staff answer and it's dead air on both ends.  Doesn't matter what time of day, any teleworker phone and any location.  Our support blamed it on the firewall but we showed them that it's not.  Then they blamed the carrier and they reported back that it's not them.  We see errors in the teleworker servers that say "One-Way Audio"...  Can anyone point us in the right direction to get this fixed?  We have been waiting on our support way too long and would rather fix it ourselves if possible.  Thanks!

[ralph]

What kind of trunks?
Does this happen with every call?
Or does it work for a while and then stop working and maybe a reboot fixes it?


Ralph

[acejavelin]

Teleworker phones? Meaning you have MiVoice Border Gateway?

[BobbyMitel]

Hey guys -

We have a PRI and MPLS.  We do have a MiVoice Border Gateway and the phones connect in via a public IP.  This does not happen on every call....I would say it happens 15-20% of my personal calls everyday.  Sometimes when calling someone, I have to call 3 times in order for it to work.  We have never had to reboot to fix it.  Below is an example of the errors that we see on the server:

http://imgur.com/a/zhJcF

Thanks for your help!

[ralph]

This isn't going to be a TW server issue.
Where it says "From SS" means it wasn't receiving audio from the "Set Side".
In other words something block the audio stream from the phones from getting to the server.

Ralph

[acejavelin]

This isn't going to be a TW server issue.
Where it says "From SS" means it wasn't receiving audio from the "Set Side".
In other words something block the audio stream from the phones from getting to the server.

Ralph

Agreed, this is a remote (set side) onsite issue if the MBG is on the network edge... most likely firewall misconfiguration, SPI is turned on, or some similar "on the fly" real-time traffic shaping or packet inspection is stopping the traffic. SonicWalls were notorious for this issue a few years back, used to cuss them up and down with ESI installs, but I digress.

Look into the network setup at the remote phone site, you will likely find something causing the problem.

[BobbyMitel]

Ralph and Ace -

Huge help! Thank you.  I took this information to my coworker who handles the firewalls and he would like more information.  Do you guys have a manual for Teleworker guidelines and requirements? 

[ralph]

Sent you a PM.

Ralph

[VinceWhirlwind]

Your coworker should look at his logs and filter it to the relevant subnets to see which packets are being dropped.
 
The first thing I would do though, is implement a
<IP handset subnet> to <MBG Server> on <any port UDP & TCP>
AND
<MBG Server> to <IP handset subnet> on <any port UDP & TCP>
 
I'd probably try MBG Server <--> ICP : any as well.

If the problem goes away, then I would know I need to fiddle with the firewall. If it doesn't, I would know I need to look somewhere else along the path.