Steve Totaro wrote:
On Tue, Aug 9, 2011 at 7:22 PM, Lee Howard <[email protected]> wrote:
Ryan McGuire wrote:
Unless your network is under load and you are seeing dropped packets
and high jitter, I would absolutely not do T.38. The cheapest and
easiest approach that I have found is to buy yourself an FXS gateway
and just make sure you are using ulaw.
As SIP is usually running over UDP/IP it doesn't take much to produce
dropped packets. Dropped packets mean lost audio which means lost data and
possible demodulation difficulties for the modems. If you're in an
environment where dropped UDP packets don't occur you're in a very rare
scenario.
I suppose you are talking about from the provider and not on the LAN?
You certainly can (and usually will) have UDP packet loss on an
uncontrolled LAN.
At Equinix in Ashburn VA, I have never had a dropped packet via the
crossconnect from our cage to Level3's cage. Sub ms pings. Putting
the primary PBX in Equinix and a 100meg speed for all VoIP calls in
our out. 100meg DIA and 100meg layer 2 fiber to corporate.
I have no reason to doubt your claims, but if this is true, then your
arrangement there clearly mitigates the likelihood of UDP packet loss.
Nevertheless, this arrangement is not something that the typical user
who asks "how do I fax over SIP/VoIP" is going to have. Without being
very clear about the environment and explaining the pitfalls of not
following your example exactly, you're not doing them any favors by
encouraging them to attempt it in their environment.
For every one user who I've ever heard from saying that they have
reliable G.711 faxing over their SIP channels I've heard from a dozen
who don't.
Thanks,
Lee.
--
_____________________________________________________________________
-- Bandwidth and Colocation Provided by http://www.api-digital.com --
New to Asterisk? Join us for a live introductory webinar every Thurs:
http://www.asterisk.org/hello
asterisk-users mailing list
To UNSUBSCRIBE or update options visit:
http://lists.digium.com/mailman/listinfo/asterisk-users
