sundance-communications.com/forum Forums VOIP Phones & IP PBX VoIP & Cloud Phones, Hosted PBX, General IP Phones Voice breakups

Alright VOIP gurus, I need help BIGTIME!!

I have installed an Asterisk (trixbox 2.2.9) for a client. VERY small and simple configuration. I have 3 Polycom IP-320 phones and a Grandstream GXW-4104 FXO gateway. I am simply using 3 PSTN lines into the gateway. I have configured the phones and the Grandstream with the G711Ulaw codecs.

about 1/3 of the calls in and out of the system result in the distant party's voice unintelligible from breaking up. The client is ready to throw me and our system in the street AFTER we install a legacy TDM system for them!!!

HELP!!!!

Ed

If they have three lines and 1/3 of the calls sound bad, are the bad calls hitting the same line each time?

No, I have certified the bad calls on every port, and I also went right on the trunks with my butt set and have NO problem with any call.

You are leaving key information out of your cry for help.

Is everything on the same local LAN or going across Internet?

If it's going across Internet, what is your internet connection speed?

But if you want some immediate feedback, I can take a stab in the dark and say that it's probably one of two things. 1) Your grandstream gateway, or 2) The computer the trixbox is running on is not powerful enough.

The second one is easy to answer, what are the spec's of the server the trixbox is running on?

As far as figuring out the first one, here's a little scenario to walk through. The polycom phones are the only thing i'm willing to use as a known good in your configuration, so lets work backwards. If you call from 1 polycom to another, do you hear any voice breaking up, chops, audio issue, devil with horns talking dirty to you, weasels? Try a dozen times or so with call lengths that you know have produced the problem before. If you cant reproduce the issue phone to phone, then we step backwards again, and add the grandstream gateway into the mix. Same testing procedure, same methodology. If you now have issues, the problem is either between your trixbox and the grandstream or the grandstream itself.

Why do I suspect the grandstream? Because they are the cheapest hardware out there, and not just because they are a smart manufacturer. Their phones and ATA's are notorious for being flaky. Since a SIP Gateway is just an ATA with more then 2 ports I cant imagine they are any better.

Anyways, good luck, and keep (atleast me) posted.

Kumba, thanks, you are always VERY helpful.

Ok...let's look at this stuff, one at a time. Everything is on the same local LAN, that being said, so is a lot of other stuff. The customer is a local restaurant and they have video feeds, cameras etc, set up all over the restaurant...I think about 6 cams, and they all run on the same network. The server is a P4 with a 40 Gig HD and 512M memory (utilization runs about 45%). The Grandstream appears to work just fine when I bring it back to the office and set it up on my lab system, which is configured the same as the one at the client site. In addition, I replaced it with a Multitech gateway and had the same issue so I put the Grandstream back in. Relative to testing, I have no problems with station to station calling.

oops, more info...I thought perhaps there is a network device causing my issue so I was contemplating putting all my stuff on a separate switch and moving away from all of the other devices, however, I still need to get to the internet for things like upgrades and the date and time on the phones....there is only one DSL out there so I am kind of stuck with the other gear being on the network since all of that stuff needs the internet too.

Ed-

What kind of switch do you have on the network? Depending on age, speed, utilization, etc., it may be that the switch is a bit overloaded (although after reading things again, I doubt this since phone to phone calls are fine).

Are you allowing reinvites between the phones and the Grandstream gateway, or is the machine running Trixbox sitting in the middle of everything during calls?

Your server sounds fine for your setup, but utilization seems a bit high for just VoIP - are you running anything else on the machine?

If you need any additional help, I'm in the area and so is djweis.

Trixbox sits in the middle of everything. The switch is new (45 days old) and (it was installed by someone else) it will do up to gigabit switching.

Trixbox is the only thing on the server.

Is it a SMC switch perhaps? I'm thinking it is either an issue with the server that was installed or the gateways. I've only had experience with Linksys SPA series getways, however.

Server utilization does seem high. I normally like to see it in the sub-30% range. This has to do with load-spikes that asterisk can cause. The higher the average load the higher the chance Asterisk runs of maxing the CPU resulting in lost audio, audio de-sync, etc.

If phone to phone works flawlessly, but phone to gateway causes echo, then we need to focus on the link between those two. The interesting thing is you said you put a multitech gateway in place of the grandstream and it worked flawlessly. Is the data path between the grandstream and server the same as the data path between the server and phones? I.E. it's not daisy chained down a few hubs? How far is the run from the grandstream to the server? Does the grandstream have jitter-buffer and is it enabled on both it and the server? Have you tried different port on the network switch for the grandstream?

Just for my own entertainment, what model grandstream is it? I might take a stab at the spec's see if there's something that sticks out.