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Very poor softphone voice quality even on LAN

Tags:
  • VPN
  • LAN
  • Windows 2000
  • Networking
Last response: in Networking
Anonymous
November 26, 2004 12:55:48 AM

Archived from groups: comp.dcom.voice-over-ip (More info?)

I'm experimenting with using SIP and softphones on our LAN (and eventually
WAN.)
I'm amazed at how variable the quality is even on a lightly-loaded LAN.
I have two test Windows 2000 machines connected to the same HP Procurve
4104GL switch (which is supposed to have QOS support enabled by default) at
100mbit with a softphone loaded on each.
Conversation is great until one of the machines does almost any kind of
network access. Then there is immediate "crunchiness" or skipping of audio.
I've tried a variety of softphones (eyeP media, SoftJoy SJPhone) and codecs
(G.729, G711ulaw) but all seem to have this problem.
Am I missing something with configuring QOS with Windows 2000 Professional
itself? I tried enabled 802.1p support on the NIC's but this didn't help
either.

More about : poor softphone voice quality lan

Anonymous
November 26, 2004 10:09:30 AM

Archived from groups: comp.dcom.voice-over-ip (More info?)

"Ed M" <LEAVESPAMMERSemaendel@frontiernet.net> wrote in
news:Exspd.5242$Oi2.2210@news01.roc.ny:

> Conversation is great until one of the machines does almost any kind
> of network access.

You must have some problem on your network. If a single VoIP call (in any
codec) doesn't have acceptable quality on such a simple setup, there's got
to be a problem. Especially if the problems are comparable between G.711
and G.729. What does the CPU load on the PC's show?

--
Andreas
Anonymous
November 26, 2004 11:24:07 AM

Archived from groups: comp.dcom.voice-over-ip (More info?)

In article <Q_Fpd.5282$ZS2.3281@news01.roc.ny> "Ed M"
<LEAVESPAMMERSemaendel@frontiernet.net> writes:


>I'm beginning to wonder whether softphones can really deliver "toll quality"
>voice. Its seems that almost ANY activity on the PC's (from what I can tell
>even ones not involving network access) causes some audio degradation.

That in itself could be a clue.
Check the NIC card configuration on the PC to make absolutely sure you are
configured (locked) for 100 megs and full duplex, not 10/100 and not half
duplex and not auto-negotiate. Also make sure that nothing is connected to
a HUB. Any HUB + VOIP = Misery.

What else is the PC doing? Can you arrange to halt all other PC activity
and run the softphone application by itself?

>I then I wonder whether other customers of the softphones I've been trying
>expect toll quality voice. Is it possible that some people's expectations
>have gone down in this age of cell phones with their highly compressed audio
>and free VOIP where people are happy to have free calling even if it isn't
>perfect? The application I'm working on is for a sales department where the
>audio quality needs to be as close to toll quality as possible.

Mitel's YA (Your Assistant) and YAPro softphones, at least in release 2.1
do not seem to have this problem. I'm running one on my AMD 2400 at home
over a Linksys BEFSR41 router and VPN back to the Mitel 3300 VOIP pbx at
the office and making both local and LD calls with no observed issues and
with what I would certainly describe as "toll quality". The lone exception
has been when listening to MOH you can hear occasional dropouts and
scratchiness, but live voice is fine.
Related resources
Anonymous
November 27, 2004 1:52:30 AM

Archived from groups: comp.dcom.voice-over-ip (More info?)

On Thu, 25 Nov 2004 21:55:48 GMT, "Ed M"
<LEAVESPAMMERSemaendel@frontiernet.net> wrote:

>I'm experimenting with using SIP and softphones on our LAN (and eventually
>WAN.)
>I'm amazed at how variable the quality is even on a lightly-loaded LAN.
>I have two test Windows 2000 machines connected to the same HP Procurve
>4104GL switch (which is supposed to have QOS support enabled by default) at
>100mbit with a softphone loaded on each.
>Conversation is great until one of the machines does almost any kind of
>network access. Then there is immediate "crunchiness" or skipping of audio.
>I've tried a variety of softphones (eyeP media, SoftJoy SJPhone) and codecs
>(G.729, G711ulaw) but all seem to have this problem.
>Am I missing something with configuring QOS with Windows 2000 Professional
>itself? I tried enabled 802.1p support on the NIC's but this didn't help
>either.
>
Sounds like you need better test tools. www.voiptroubleshooter.com
has a list of them.

If you're doing this on a limited budget, try using a third machine to
do the heavy network access. This will help you determine whether its
a network issue or an issue with your local machine (e.g. not enough
CPU to do both VoIP and the data stuff).

If it's a network issue, check out www.testyourvoip.com and try the
voice quality tests there.
Anonymous
November 27, 2004 4:05:11 PM

Archived from groups: comp.dcom.voice-over-ip (More info?)

I think I found the problem
The three different Dell PC's I tested (two Dimension desktops and a
Latitude laptop) must have very low-end sound cards built into them. Maybe
they are software based? I tested using a Dell Optiplex using the same
softphone on the same network and the sound was perfect.

Then I tested using a USB headset adaptor from GN Netcom (GN8110 USB) on the
PC's that had trouble before and using that the quality is great.
Apparently there is a DSP built into the cord that offloads the processing
from the PC. So it looks like all along my problems were caused by the
Softphones trying to use the low-end built-in sound cards. Strange that I
see no other newsgroup postings about this or any warnings from the
softphone vendors..... Everyone focuses on network QOS (which is very
important but not the whole story.)
Thanks for the input everyone!