Re: [hylafax-users] Using a serial modem through a converter from ethernet to serial

["andrew rinaldi" <andrew.rinaldi@xxxxxxxxxxxx>]

This sort of detailed information is invaluable Rob, thank you very much !

 

Regards

 

ANDREW RINALDI

Mainpine Limited Support

USA +1 503 822 9944 | Asia/Europe +44 1225 869439  

andrew.rinaldi@xxxxxxxxxxxx | www.mainpine.com

---

From: Rob Rothberg [mailto:rrothberg@xxxxxxxxx]
Sent: 03 February 2007 18:24
To: andrew.rinaldi@xxxxxxxxxxxx
Cc: Mark; hylafax-users@xxxxxxxxxxx
Subject: Re: [hylafax-users] Using a serial modem through a converter from ethernet to serial

FWIW, we tried the VM route initially here.  I started small 
with a VM on an Intel Core 2 Duo system with a gig of memory.  This system 
did nothing but run the VM.
On the VM I installed Asterisk, HylaFAX and 
integrated the two with IAXmodems (actually I should say Lee Howard did this for 
me).  First I tried faxing over VoIP.  Broadvoice failed 100% of the 
time. 
I then tried Vitelity, that worked occasioanlly.  Clearly VoIP 
was not the answer, so II interfaced Asterisk to 4 PSTN lines with an 
SPA-400.  This failed because of volume level issues most likely as a 
result of the SPA-400. 

Next I installed Hylafax on a dedicated box and 
purchased a Mainpine Rockforce Quattro+ and this worked very successfully, but 
it wasn't enough to meet my needs.

I then had a T-1 installed with 11 PRI 
channels and purchased a RedFone FoneBridge2.  I still had Asterisk running 
in a VM working as our production PBX at this point, so I interfaced the VM 
Asterisk install 
with the FoneBridge.  Initially the two pieces of 
hardware had a Cisco layer 2 switch between them and timings between the two 
pieces of hardware weren't good enough for 100% reliability.  I then 
plugged them into 
a dedicated switch, some improvement but still not good 
enough.  RedFone told me I needed a dedicated NIC on the server and to plug 
the FoneBridge into it directly.  The VM was just introducing too 
much
latency.  I finally just installed Asterisk on the dedicated 
Hylafax server with two NICs, and plugged in the FoneBridge2 directly.  Lee 
set up 11 IAXmodems interfaced to Asterisk.  No more issues.  We've 
been sending around 500 pages a day reliably with this config (reliably in the 
sense all the telecomm stuff is working great, there are other unrelated issues 
but they're being worked out). 

The lesson I learned here was that while 
it might be POSSIBLE to get a VM working reliably (probably not the free 
version, you'd probably need to play with the $$$ version and tweak performance 
parameters and memory allocation), it's not worth the time and effort, and I 
don't know how long it would take before I trusted it for faxing.  It was 
fine for voice but faxing is a different story.

On 2/3/07, andrew rinaldi <andrew.rinaldi@xxxxxxxxxxxx> wrote:

Hi Mark,

'Speed' is not the issue here... With Ethernet it's what happens when you
get large packet loss (which equates to lost 'audio' in our case)... And
with virtualisation it's the loss of deterministic behaviour (which degrades
low level timing)... In both cases some systems will work and some won't...
And the 'working' systems can almost always be broken by heavy work load on
the network or system.

A good example of what happens with Ethernet packet loss is to run a VoIP
call across a busy network and listen to the call quality degrade.... In fax
this quickly equates to a failed call.

Have you ever stress tested your setup ?  How many fax's do you send/receive
in a typical day ?  In our lab we've been able to break most (maybe all)
virtual servers that we have tested for use with fax servers.

Ultimately, I'm trying to encourage people to keep it simple because in my
experience that always works out for the best.

Regards

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

-----Original Message-----
From: hylafax-users-bounce@xxxxxxxxxxx
[mailto:hylafax-users-bounce@xxxxxxxxxxx ] On Behalf Of Mark
Sent: 03 February 2007 16:44
To: hylafax-users@xxxxxxxxxxx
Subject: Re: [hylafax-users] Using a serial modem through a converter from
ethernet to serial

andrew rinaldi <andrew.rinaldi <at> mainpine.com> writes:

>
> Hi Davide,

< snip >
< snip >

> > Hi Davide,
> >
> > I suspect that this will never work reliably.... Firstly, running
HylaFAX on
> > a virtual server removes the tight timing and control needed between the
> > protocol engine and the fax hardware, and secondly, the Ethernet to
serial
> > converter does the same thing but with even less control of the timing.

Andrew,

Do you not believe that the use of good quality network-serial adapters, and
virtual servers - if they are VERY FAST, would work reliably?  I believe
that
many virtual servers out there are over-powered and under-utilized.  At
least in
my case I have been experimenting with VMware Server (free version) on my
personal Acer Aspire 3000LMi laptop, and am using with it an ESP-2MI serial
adapter with a good serial modem - it receives and sends faxes just fine.

Mark




____________________ HylaFAX(tm) Users Mailing List _______________________
  To subscribe/unsubscribe, click http://lists.hylafax.org/cgi-bin/lsg2.cgi
On UNIX: mail -s unsubscribe hylafax-users-request@xxxxxxxxxxx < /dev/null
  *To learn about commercial HylaFAX(tm) support, mail sales@xxxxxxxxx*




____________________ HylaFAX(tm) Users Mailing List _______________________
  To subscribe/unsubscribe, click http://lists.hylafax.org/cgi-bin/lsg2.cgi
On UNIX: mail -s unsubscribe hylafax-users-request@xxxxxxxxxxx < /dev/null
  *To learn about commercial HylaFAX(tm) support, mail sales@xxxxxxxxx*