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? 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. Works like a charm. > > For the most part people who claim success when faxing over SIP G.711 are > being rescued by ECM (error correction) within the fax protocol. There are > very, very few who really have mitigated UDP packet loss. > > That said, all T.38 systems are not equal. Certainly, the reliability of > your T.38 provider may not be any better than that of G.711 fax over the SIP > UDP. > > I only recommend faxing over TDM everything else is at your own risk. All faxing in Asterisk is at your own risk. It is not reliable. > > 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
