[asterisk-users] OT - "T.38 unreliable on a LAN" : truth or obscurantism ?

[James Sharp]

On 02/15/2012 03:03 PM, Olivier wrote:
> Hi,
>
> When someone says "T.38 is not reliable on a (normally loaded and
> managed) LAN", would you rather agree or disagree ?
> In this case, fax calls are coming in through an analog gateway,
> passing trough Asterisk and then going out to ISDN through a digital
> gateway.
>
> Comments ?

While I can't speak for Asterisk's T.38 performance (it was barely past 
the point of "okay, it compiles" at the time of this datapoint), T.38 in 
general can handle nasty network conditions without a problem as long 
you enable some sort of error correction (either FEC or packet 
redundancy).  Case in point, I ran several hundred SIP-based T.38 calls 
a month over VSAT links.  The links ran anywhere from 550 to 750ms 
latency and would average around 1-2% packet loss (averaged over a 5 
minute period).  Those were with a Quintum ASG400 at the far end and a 
Quintum CMS960 going into PRIs at the VSAT hub.

So if T.38 can handle that, it can handle just about anything.