[asterisk-users] T.38 passthru on 1.8.5

Fabian Borot fborot at hotmail.com
Tue Aug 30 12:53:25 CDT 2011


txs a lot for your explanation steve
so, it should work w/o spandsp fairly fine if we do not have a bad connection. I see that this version has a lot of fixes related to t.38
 but is the implementation already mature enough to guarantee a decent success rate with fax calls?


 

From: fborot at hotmail.com
To: asterisk-users at lists.digium.com
Subject: RE: T.38 passthru on 1.8.5
Date: Tue, 30 Aug 2011 13:15:19 -0400








will installing spandsp help with t.38 pass-through?


 

From: fborot at hotmail.com
To: asterisk-users at lists.digium.com
Subject: RE: T.38 passthru on 1.8.5
Date: Tue, 30 Aug 2011 11:42:41 -0400








both endpoints use public Ips, I just changed the real ones for the privates ones to protect our ips but made a mistake and left the dest as a pub and the orig as private, my bad.
but for the record, both are public IPs, there is no nat and iptables is off

 also, I see that the quintum sends a lot of these packages but asterisk sends only 1 or 2 to the other side.




 

From: fborot at hotmail.com
To: asterisk-users at lists.digium.com
Subject: T.38 passthru on 1.8.5
Date: Tue, 30 Aug 2011 09:44:15 -0400










 Hello
We want to implement T.38 passthru with asterisk 1.8.5 [Asterisk 1.8.5.0 built by root @ asterisk1-8.labdomain.com on a x86_64 running Linux on 2011-08-26 21:31:22 UTC]

The call flow is:
quintum gateway --> asterisk --> Dialogic IMG 1010

the call starts as a voice call, the remote fax picks up and we hear the fax tone, the we see the re-invite from the IMG asking for t.38, the RE-Invite is passed back to the user side [quintum gateway] whcih reply with 200 OK with t.38 and the nothing else happens. After 20 secs of "inactivity" the quintum sends another Invite with voice only and then a BYE.

We do see that the quintum sends a lot of messages like this from the quintum's IP [192.168.1.18] but we do not see that asterisk sends the packages to the destination

UDPTL (SIP/2345850624337933): packet to 192.30.189.146:12020 (type 0, seq 0, len 6)
 UDPTL (SIP/): packet from 192.168.1.18:10260 (type 0, seq 0, len 6)
 UDPTL (SIP/): packet from 192.168.1.18:10260 (type 0, seq 0, len 6)
 UDPTL (SIP/): packet from 192.168.1.18:10260 (type 0, seq 0, len 6)
 UDPTL (SIP/): packet from 192.168.1.18:10260 (type 0, seq 0, len 6)
 UDPTL (SIP/): packet from 192.168.1.18:10260 (type 0, seq 0, len 6)
 UDPTL (SIP/): packet from 192.168.1.18:10260 (type 0, seq 0, len 6)
 UDPTL (SIP/): packet from 192.168.1.18:10260 (type 0, seq 0, len 6)
 UDPTL (SIP/): packet from 192.168.1.18:10260 (type 0, seq 0, len 6)
 UDPTL (SIP/): packet from 192.168.1.18:10260 (type 0, seq 0, len 6)
 UDPTL (SIP/): packet from 192.168.1.18:10260 (type 0, seq 0, len 6)
 UDPTL (SIP/): packet from 192.168.1.18:10260 (type 0, seq 0, len 6)
 UDPTL (SIP/): packet from 192.168.1.18:10260 (type 0, seq 0, len 6)
 UDPTL (SIP/): packet from 192.168.1.18:10260 (type 0, seq 0, len 6)
 UDPTL (SIP/): packet from 192.168.1.18:10260 (type 0, seq 0, len 6)
 UDPTL (SIP/): packet from 192.168.1.18:10260 (type 0, seq 0, len 6)
 UDPTL (SIP/): packet from 192.168.1.18:10260 (type 0, seq 0, len 6)
 UDPTL (SIP/): packet from 192.168.1.18:10260 (type 0, seq 0, len 6)

we have this settings on sip.conf
faxdetect = yes
t38pt_udptl = yes,maxdatagram=400 [I have tested with several combinations t38pt_udptl = yes;t38pt_udptl = yes,fec etc]

When we send the fax from the quintum to the Dialogic IMG the fax works 100% of the times.
I enabled fax set debug on and udptl set debug on but the console does not show almost anything but the udptl packets shown above.
What else should I do?Any ideas/help is greatly appreciated

txs a lot
fborot

 		 	   		   		 	   		   		 	   		   		 	   		  
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