Re: O.T. - Shared Fax on Vonage problem

On 29 Jun, 23:50, Leythos <v...@xxxxxxxxxxx> wrote:
In article <1183155298.494635.311...@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>,
andrew.rina...@xxxxxxxxxxxx says...





On Jun 29, 10:05 pm, Leythos <v...@xxxxxxxxxxx> wrote:
In article <1183150131.012849.243...@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>,
andrew.rina...@xxxxxxxxxxxx says...

Our labs use over 50 different fax machines, MPP's, 100's of fax
machine emulations, and almost every fax modem on the market. Our
VoIP tests used many different ISP's, routers, and service suppliers,
in both the UK and US. Our motivation was to provide our customers
with advice regarding fax over VoIP.

I've done my best to pass on what we learned during that exercise, I
think all that's left is to wish you luck with your choice of VoIP
provider and router.

It would appear that you have a serious flaw in your testing methods. My
experience is that, all over the USA, different providers, different
devices, is that if the network capacity is available that all faxes
send/recv reliably.

--

Leythos
- Igitur qui desiderat pacem, praeparet bellum.
- Calling an illegal alien an "undocumented worker" is like calling a
drug dealer an "unlicensed pharmacist"
spam999f...@xxxxxxxxxx (remove 999 for proper email address)

Leythos,

Fax over VoIP has nothing to do with network capacity. What you fail
to understand is that fax cannot tolerate significant amounts of audio
loss because this is interpreted as 'silence' which is one of the
major components of the T.30 fax protocol. It doesn't matter how you
frame the packets... any lossy IP transport will corrupt the audio
it's transporting. Most IP based 'internet' connectivity is lossy by
its very nature and in most environments where DSL or Cable are used
as the transport this packet loss will be significant.

Well, it does have to do with network capacity - a lack of capacity will
cause loss of audio, we see this when we saturate the connection while
talking on the VOIP service also. So, you need to reconsider, as VOIP,
depending on the quality, requires about 90k for Best, 30k for poor
quality, and if you can't make that connection rate then your audio
drops out, it's that simple.

Given the perfect nature of your VoIP system I'm surprised the vendor
offers the following advice to their fax customers;

" If you are unable to send and or receive faxes try lowering the baud
rate on the fax machine to 9600. Also disable the ECM feature on the
fax machine if applicable."

When was the last time that a fax machine vendor told you to do that
on a POTS line ?

Hey, my ISP also tells me that there is no guarantee on performance
levels at any given time, but that doesn't mean that I'm getting crappy
service from them.

I don't think that my POTS vendor states anything about Fax service, so
what does that tell you?

So, again, your testing methods, while you've got a lot of data, appears
to be flawed because we're not seeing the same level of problem that you
describe - the difference could be that we have quality internet
connections where we don't experience any measurable loss to 99% of our
connections....

It's all about the connection quality, you appear to have a poor
connection quality for your testing.

--

Leythos
- Igitur qui desiderat pacem, praeparet bellum.
- Calling an illegal alien an "undocumented worker" is like calling a
drug dealer an "unlicensed pharmacist"
spam999f...@xxxxxxxxxx (remove 999 for proper email address)- Hide quoted text -

- Show quoted text -

Leythos,

Your POTS service provider has to meet agreed line 'quality'
standards. Please remember that fax is just audio and therefore the
POTS vendor does not need to differentiate between voice and fax
traffic.

The difference between voice and fax on a lossy (IP) transport is that
the human brain can tolerate small discrepancies in the audio stream
without it becoming problematic or even noticeable. Fax however,
cannot because it's a half-duplex mechanism on which one side is
always listening for 'silence' to indicate a change of state... it's
the false 'silence' that's introduced by a IP packet loss that upsets
the fax protocol. So, I hope you can see it's not bandwidth that's
important but packet loss and jitter.

I can see we are getting nowhere with this discussion and so, I'll
*** out and wish you luck.

Regards

ANDREW RINALDI
Mainpine Limited - Support
USA +1 503 822 9944 | Asia/Europe +44 1225 869439
andrew.rinaldi@xxxxxxxxxxxx | www.mainpine.com

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