Incoming Callers Hear Choppy Audio

[neronut]

Hello all,

I've recently set myself up with an ATA (SPA122) and FPL. It is working great and the quality is awesome, so awesome that most people think I'm using a landline! I have started noticing an interesting problem. When I make calls the audio both ways is fine. When my family is using the Internet and uploading and downloading the only slight side effect I see is there is delay in the outgoing audio momentary, but nothing to cause concern. However, if I get an incoming call there is a much different story. The incoming audio is great, I don't notice any problems, but the outgoing audio is horrible! My callers report that it is all choppy and they can't understand a word I am saying.

I called it from my cellphone and noticed when my upload is in use that my audio does, indeed, become incomprehensible. I'm trying to find a solution. I have made sure that my router (WRT-54GS) is port forwarding to the ATA, it's IP address is static and incoming calls come in without a hitch. I even tried changing the codec to G.729a.

Does anyone know of a way to limit this effect on incoming calls?

Thanks,

[dibsmft]

Most high speed internet provides fast downloads and much lower upload speeds. When the only thing on the network is voip it should work well and you may be able to have two or three conversations at the same time but if anything else is using the same internet then the sound quality will rapidly worsen. SIP/voip, by default, uses UDP to send the adudio packets and the packets are not normally error check to keep tranmission delay as low as possible and lost packets are not resent and may arrive in the wrong order if the bandwidth is to low. A great way to demonstrate this effect is to try running torrents at the same time that you make a voip/SIP phone call.
Yor router can apply a form of priority/QOS to connected services so you should try that to see if it cures your problems. In my experience it can annoy other users (bittorrent) of the network but your voip should be OK - what fun!.
Have a look at eg.
http://www.dslreports.com/forum/remark,11539265

[bridonca]

I have had a poor experience with QOS, so I would be hard pressed to offer it as a solution, because it is so hard to configure correctly, and the results are still not very good, especially if the ISP is causing the problem, like doing traffic shaping.

If you are using bit torrent, you probably should not. If you still need to use it, limit the upload slots to 2. You torrents will not be much slower, but you will get better throughput overall.

My fix to the bit torrent problem was to rent a VPS for less than $5 a month, and torrent from there, then download the completed torrents. Much faster, and much easier on the bandwidth. and I am not uploading!

[neronut]

I tried QoS and it did squat. Outgoing calls seem to work fine, but Incoming ones seem to have the biggest issue. If someone uploads a picture, or something then the audio for that period of time is lost. I also can't seem to control the incoming audio codec, it always seems to settle on G.711. If I can get it to G.729 then maybe the lower bandwidth call will be less effected.

[dibsmft]

One thing that you can try is to plug the ethernet cable to the computer running the torrent into the ethernet port (LAN port) of the ATA and let it control the QOS. If it works like my 3102 it should almost stop the bittorrent while on a call.
Even if you can control the codec it may not help as torrents and uploads will still cause problems the voice packets do need to be passed without delay. THis probably means that you plug the ATA into your modem directly and your router into the ATA LAN port.

[neronut]

THe computer making traffic is on Wireless, does that make a difference? Also the traffic is HTTP, not BT.

[dibsmft]

Any traffic that uses upload bandwidth will give you problems with voip. My download speed is currently 6.74 Mb/s and upload is 0.52 Mb/s which is pretty normal for my connection. Check yours at http://www.speedtest.net and I would gues that yours should be significantly faster download but probably not upload. One way to slow down the wireless connection might be to to cover the antenna with tinfoil............. just joking... perhaps turn the antenna so that it is less effiicient. I suppose you really could pulg the ATA directly into the modem and then plug the router into the ATA lan port if nothing else helps. My main phone is a Yealink desk phone that connects to my internet and my computer is connected to the second ethernet port on the phone so it is similar to what you would have.

[Funkytown]

THe computer making traffic is on Wireless, does that make a difference? Also the traffic is HTTP, not BT.

I think what you should do is more like this, place your modem then your voip ata device and after your wireless router.

[neronut]

THe computer making traffic is on Wireless, does that make a difference? Also the traffic is HTTP, not BT.

I think what you should do is more like this, place your modem then your voip ata device and after your wireless router.

Then I have a double NAT Which will screw over other stuff...

[dibsmft]

Double NAT can be a problem but if everything is configured OK it should not be a problem. I used the modem -> ATA (as router) -> router for a while with 4 users without any problem. Mind you the internet connection that I had at the time was pretty slow but voip/SIP still worked. Again, what connection speed (upload/download) do you have and what modem do you have? You may already be double natted.

[Funkytown]

Just curious any progress?

[neronut]

Just curious any progress?

I have not made any progress with this, the solution, for now, seems to be the traffic gets lost in high bandwidth traffic because the system doesn't know that it is suppose to be Real-time and have the most priority. I tried QoS on my router but that did nothing at all, the weird thing still is that outgoing calls have better audio quality than incoming calls.

I will try some more ideas and post back, but it won't be for a little bit.

[TheHardy]

This phenomenon is not really that odd at all --- I use the PC softphone straight into my laptop which has an internet stick (ie no router or anything at all). Incoming calls are HORRID and usually require a call back (which is why I am still pissed off that the FPL softphone does not have working Caller ID! -- I have to read the LOG....). If I call right back to the same number, literally within seconds of the failed/crappy incoming call, I have decent enough sound quality! So it is not really ODD, just a fact of how things seem to work ...

Again for me, it is just via the PC softphone app, not via an ATA or anything else, but in and of itself, that says a lot too ...

[dibsmft]

On the other hand, if you are using an ATA and DSL calls should be possible, even more than one at a time. You need to discipline other users of the network or via router or a network server take control of the network. When I had 3 other users on my network (and they were torrent users) I simple assigned enough bandwith to voip and left the rest to other network use and it worked OK for years. I guess you can't have your cake and eat it. You might find that you can get FibreOp which (at least in NL) offers the same speed up and down (eg. 15 Mbits/sec up and down) which would solve the problems.