asterisk users - Mar 2006 - Asterisk in production as a fax server, anyone?

Greetings, All-Knowing Asterisk Users List,

	My company needs to build a reliable fax server that can handle at 
least 30 simultaneous incoming faxes from the PSTN, using PRI.  We 
realize that this can be solved in any number of ways using a Linux box, 
but since IVR is also a must, Asterisk popped up as the most promising 
solution.

	After combing these lists for clues, we began experimenting extensively 
with Asterisk and its software DSP and fax capabilities in most of their 
incarnations, such as Rxfax or Iaxmodem/Hylafax, together with Digium's 
E1 cards in server-grade Intel motherboards, all in a dedicated test 
environment.

	Unfortunately, though, we have yet to achieve reliable and satisfactory 
results, even with only 1 fax call at a time.  I won't go into the 
details because we don't need technical support, given that this is, as 
of yet, a very loosely defined test.  What we want is is merely a 
pointer in the right direction. So here it comes:

	Has anybody ever achieved, or know of someone who has, reliable 30 
simultaneous PRI fax calls using Asterisk and Asterisk-compatible 
hardware and software?

	We are hardware agnostic, so if you say Sangoma's cards do it better 
than Digium's, or that Eicon Diva cards' hardware DSP and chan_capi are 
the only solution, we have no problem going there.  I would be most 
thankful, however, for detailed explanations of successful scenarios, 
including such things as motherboard make and model, processor speed, 
Linux distribution and version, and anything else you decide to be even 
marginally pertinent.

	Thank you very much,
	Adolfo R. Brandes

Hi Adolfo,

I have done this and it works.  I have maxed out an E1 with 30 concurrent 
calls of which at least 25 would have been fax.

Hardware is nothing special, Dell Poweredge 750, 512mb ram, single SATA 
drive with either of a TE410p or TE110p card.  OS is FC2 with kernel 2.6.9 
I expect the server would handle 60 concurrent calls.  Asterisk is 1.0.10 
with spandsp 0.0.2pre25 and libtiff 3.5.7

Email me privately if you want more details.

Craig

----- Original Message ----- 
From: "Adolfo R. Brandes" <arbrandes@instant.com.br>
To: <asterisk-users@lists.digium.com>
Sent: Thursday, March 30, 2006 10:20 PM
Subject: [Asterisk-Users] Asterisk in production as a fax server, anyone?

> Greetings, All-Knowing Asterisk Users List,
>
> My company needs to build a reliable fax server that can handle at least 
> 30 simultaneous incoming faxes from the PSTN, using PRI.  We realize that 
> this can be solved in any number of ways using a Linux box, but since IVR 
> is also a must, Asterisk popped up as the most promising solution.
>
> After combing these lists for clues, we began experimenting extensively 
> with Asterisk and its software DSP and fax capabilities in most of their 
> incarnations, such as Rxfax or Iaxmodem/Hylafax, together with Digium's
E1
> cards in server-grade Intel motherboards, all in a dedicated test 
> environment.
>
> Unfortunately, though, we have yet to achieve reliable and satisfactory 
> results, even with only 1 fax call at a time.  I won't go into the
details
> because we don't need technical support, given that this is, as of yet,
a
> very loosely defined test.  What we want is is merely a pointer in the 
> right direction. So here it comes:
>
> Has anybody ever achieved, or know of someone who has, reliable 30 
> simultaneous PRI fax calls using Asterisk and Asterisk-compatible hardware 
> and software?
>
> We are hardware agnostic, so if you say Sangoma's cards do it better
than
> Digium's, or that Eicon Diva cards' hardware DSP and chan_capi are
the
> only solution, we have no problem going there.  I would be most thankful, 
> however, for detailed explanations of successful scenarios, including such 
> things as motherboard make and model, processor speed, Linux distribution 
> and version, and anything else you decide to be even marginally pertinent.
>
> Thank you very much,
> Adolfo R. Brandes
>
> _______________________________________________
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>
> Asterisk-Users mailing list
> To UNSUBSCRIBE or update options visit:
>   http://lists.digium.com/mailman/listinfo/asterisk-users

Adolfo R. Brandes wrote:
>     After combing these lists for clues, we began experimenting 
> extensively with Asterisk and its software DSP and fax capabilities in 
> most of their incarnations, such as Rxfax or Iaxmodem/Hylafax, 
> together with Digium's E1 cards in server-grade Intel motherboards, 
> all in a dedicated test environment.
>
>     Unfortunately, though, we have yet to achieve reliable and 
> satisfactory results, even with only 1 fax call at a time.

Well, if you weren't just trying to test you could send some logs to an 
appropriate mailing list (like iaxmodem-users or whatever would be most 
appropriate), and you'd probably get a very quick indication as to why.

However, based on the comments you give I'd suspect that you're having 
what people seem to be calling "frame slipping".  There seem to be
some
motherboards that react poorly with Zap cards (or their respective 
drivers) and cause that.  Your zttest results should be revealing here.  
I don't know that anyone has yet proposed a conclusive solution to that 
matter other than to keep trying different motherboards until you find 
one that works.
> I won't go into the details because we don't need technical
support,
> given that this is, as of yet, a very loosely defined test.  What we 
> want is is merely a pointer in the right direction. So here it comes:
>
>     Has anybody ever achieved, or know of someone who has, reliable 30 
> simultaneous PRI fax calls using Asterisk and Asterisk-compatible 
> hardware and software?

Yes.  The concurrent calls really isn't that big of a deal, either, if 
those are your thoughts.  The bigger issue seems to be the quality of 
the audio as it is delivered to the fax application/modem.
>     We are hardware agnostic, so if you say Sangoma's cards do it 
> better than Digium's, or that Eicon Diva cards' hardware DSP and 
> chan_capi are the only solution, we have no problem going there.

In my experience Sangoma offers better (or maybe just more caring) 
post-sale support than does Digium, however, the "frame slipping"
issue
seems to happen with both sets of hardware.  Maybe that's because 
Sangomas partially use the zaptel driver as well as does the Digium 
hardware.  As for Eicon Divas being used for IVR, I've never used them 
that way.
> I would be most thankful, however, for detailed explanations of 
> successful scenarios, including such things as motherboard make and 
> model, processor speed, Linux distribution and version, and anything 
> else you decide to be even marginally pertinent. 

The most success I've seen has been to bridge the call through Asterisk 
to a T1 fax modem such as a Patton 2977 or an Eicon Diva Server with 
HylaFAX running the modems.  (So you put a crossover cable between the 
T1/E1 fax modem and one of the ports on your TE405P card and bridge the 
fax call, after IVR, to the fax port and let HylaFAX take it from there.)

That said, I see no reason why you couldn't have just as much success 
with iaxmodem-hylafax or even txfax/rxfax... I just haven't personally 
used either of those as much as I have the T1-faxmodem solution.

Lee.

Most of the problems like these for me are gone since I started using
iaxmodem+hylafax combination.

Hylafax has ECM capability which just tells the other side to resend the
affected frames (not the whole page).

With the latest 4.2.5.5 hylafax I even have color support :) Not that I
probably needed.

Give it a try.

Regards
> -----Original Message-----
> From: asterisk-users-bounces@lists.digium.com [mailto:asterisk-users-
> bounces@lists.digium.com] On Behalf Of Craig Guy
> Sent: Saturday, 1 July 2006 09:57
> To: Asterisk Users Mailing List - Non-Commercial Discussion
> Subject: Re: [Asterisk-Users] Re: Asterisk in production as a fax
> server,anyone?
> 
> In practice I've found that the fax receiving process is sensitive to
CPU
> load.  If the load jumps too high you will see half page fax pages or
> black
> streaky pages mixed with perfectly good pages in a multipage fax.
Things
> that can cause this include running agi scripts or rendering your tiff
to
> another format on your * server.
> 
> I render my faxes on the * server, however received tiffs are queued
so as
> to render them one at a time.  If you get page problems you could try
> rendering them on a dedicated server.
>

I have a worst issue for you... If your fax solution is ever going to 
receive fax in Brazil, how would you block collect calls?
I have made a fax server solution with cheap Digium hardware that works 
in Brazil (2 E1s).
--
Paulo

Adolfo R. Brandes escreveu:
>     Greetings, All-Knowing Asterisk Users List,
>
>     My company needs to build a reliable fax server that can handle at 
> least 30 simultaneous incoming faxes from the PSTN, using PRI.  We 
> realize that this can be solved in any number of ways using a Linux 
> box, but since IVR is also a must, Asterisk popped up as the most 
> promising solution.
>
>     After combing these lists for clues, we began experimenting 
> extensively with Asterisk and its software DSP and fax capabilities in 
> most of their incarnations, such as Rxfax or Iaxmodem/Hylafax, 
> together with Digium's E1 cards in server-grade Intel motherboards, 
> all in a dedicated test environment.
>
>     Unfortunately, though, we have yet to achieve reliable and 
> satisfactory results, even with only 1 fax call at a time.  I won't go 
> into the details because we don't need technical support, given that 
> this is, as of yet, a very loosely defined test.  What we want is is 
> merely a pointer in the right direction. So here it comes:
>
>     Has anybody ever achieved, or know of someone who has, reliable 30 
> simultaneous PRI fax calls using Asterisk and Asterisk-compatible 
> hardware and software?
>
>     We are hardware agnostic, so if you say Sangoma's cards do it 
> better than Digium's, or that Eicon Diva cards' hardware DSP and 
> chan_capi are the only solution, we have no problem going there.  I 
> would be most thankful, however, for detailed explanations of 
> successful scenarios, including such things as motherboard make and 
> model, processor speed, Linux distribution and version, and anything 
> else you decide to be even marginally pertinent.
>
>     Thank you very much,
>     Adolfo R. Brandes
>
> _______________________________________________
> --Bandwidth and Colocation provided by Easynews.com --
>
> Asterisk-Users mailing list
> To UNSUBSCRIBE or update options visit:
>   http://lists.digium.com/mailman/listinfo/asterisk-users
>