[Asterisk-Dev] T.38 pass-through / T.38 support

Steve Underwood steveu at coppice.org
Tue Jun 7 06:13:36 MST 2005


Hi,

I see no sign of T.38 succeeding. I see the Azacall200 box try to switch 
to T.38 over UDPTL. I see Asterisk reject this. I see the two parties 
agree to use ulaw. Seems like the FAXes are transferred by ulaw. Can you 
try an ethereal trace, and see if you see any UDPTL? It looks like you 
won't.

Regards,
Steve


Matthew Boehm wrote:

>Kevin P. Fleming wrote:
>
>  
>
>>I too am wondering just how Matthew Boehm's system is working; as of
>>this point, a T.38 call of any form (RTP or UDPTL) can't be handled by
>>chan_sip, and an existing call can't turn into T.38 either.
>>    
>>
>
>OK. Test call. This call came from PSTN -> PRI -> Cisco 5300
>(22.22.22.22) -> Asterisk (33.33.33.33) -> ATA (44.44.44.44 NAT'd to
>192.168.0.20)
>
>cisco> show call active voice compact
>G148A  ANS     T29    t38         TELE  P2819870065
>G148A  ORG     T29    t38         VOIP  P2815692770    33.33.33.33:18056
>
>A very very very very long SIP debug of the entire call:
>
>    http://www.cytelcom.net/drmac/fax_trace.txt
>
>Here is the short version:
>
>    -- Executing Goto("SIP/22.22.22.22-4080d3e0","5000008|2815692770|1") in
>new stack
>    -- Goto (5000008,2815692770,1)
>    -- Executing Goto("SIP/22.22.22.22-4080d3e0", "20|1") in new stack
>    -- Goto (5000008,20,1)
>    -- Executing Dial("SIP/22.22.22.22-4080d3e0", "SIP/TEI20|15") in new
>stack
>    -- Called TEI20
>    -- SIP/TEI20-5556 is ringing
>    -- SIP/TEI20-5556 answered SIP/22.22.22.22-4080d3e0
>    -- Attempting native bridge of SIP/22.22.22.22-4080d3e0 and
>SIP/TEI20-5556
>Jun  6 10:09:40 WARNING[14277]: chan_sip.c:3063 process_sdp: Unknown SDP
>media type in offer: image 49170 udptl t38
>Jun  6 10:09:40 WARNING[14277]: chan_sip.c:3063 process_sdp: Unknown SDP
>media type in offer: image 49170 udptl t38
>Jun  6 10:09:41 WARNING[14277]: chan_sip.c:3063 process_sdp: Unknown SDP
>media type in offer: image 49170 udptl t38
>Jun  6 10:09:41 WARNING[14277]: chan_sip.c:3063 process_sdp: Unknown SDP
>media type in offer: image 49170 udptl t38
>Jun  6 10:09:42 WARNING[14277]: chan_sip.c:3063 process_sdp: Unknown SDP
>media type in offer: image 49170 udptl t38
>Jun  6 10:09:42 WARNING[14277]: chan_sip.c:3063 process_sdp: Unknown SDP
>media type in offer: image 49170 udptl t38
>Jun  6 10:09:43 WARNING[14277]: chan_sip.c:3063 process_sdp: Unknown SDP
>media type in offer: image 49170 udptl t38
>Jun  6 10:09:43 WARNING[14277]: chan_sip.c:3063 process_sdp: Unknown SDP
>media type in offer: image 49170 udptl t38
>Jun  6 10:09:44 WARNING[14277]: chan_sip.c:3063 process_sdp: Unknown SDP
>media type in offer: image 49170 udptl t38
>Jun  6 10:09:44 WARNING[14277]: chan_sip.c:3063 process_sdp: Unknown SDP
>media type in offer: image 49170 udptl t38
>Jun  6 10:09:45 WARNING[14277]: chan_sip.c:3063 process_sdp: Unknown SDP
>media type in offer: image 49170 udptl t38
>Jun  6 10:09:45 WARNING[14277]: chan_sip.c:3063 process_sdp: Unknown SDP
>media type in offer: image 49170 udptl t38
>Jun  6 10:09:46 WARNING[14277]: chan_sip.c:3063 process_sdp: Unknown SDP
>media type in offer: image 49170 udptl t38
>Jun  6 10:09:47 WARNING[14277]: chan_sip.c:3063 process_sdp: Unknown SDP
>media type in offer: image 49170 udptl t38
>Jun  6 10:09:47 WARNING[14277]: chan_sip.c:3063 process_sdp: Unknown SDP
>media type in offer: image 49170 udptl t38
>Jun  6 10:09:48 WARNING[14277]: chan_sip.c:3063 process_sdp: Unknown SDP
>media type in offer: image 49170 udptl t38
>Jun  6 10:09:48 WARNING[14277]: chan_sip.c:3063 process_sdp: Unknown SDP
>media type in offer: image 49170 udptl t38
>Jun  6 10:09:49 WARNING[14277]: chan_sip.c:3063 process_sdp: Unknown SDP
>media type in offer: image 49170 udptl t38
>Jun  6 10:09:49 WARNING[14277]: chan_sip.c:3063 process_sdp: Unknown SDP
>media type in offer: image 49170 udptl t38
>Jun  6 10:09:50 WARNING[14277]: chan_sip.c:3063 process_sdp: Unknown SDP
>media type in offer: image 49170 udptl t38
>Jun  6 10:09:50 WARNING[14277]: chan_sip.c:3063 process_sdp: Unknown SDP
>media type in offer: image 49170 udptl t38
>Jun  6 10:09:51 WARNING[14277]: chan_sip.c:3063 process_sdp: Unknown SDP
>media type in offer: image 49170 udptl t38
>Jun  6 10:09:51 WARNING[14277]: chan_sip.c:3063 process_sdp: Unknown SDP
>media type in offer: image 16806 udptl t38
>Jun  6 10:09:51 WARNING[14277]: chan_sip.c:3063 process_sdp: Unknown SDP
>media type in offer: image 49170 udptl t38
>Jun  6 10:09:52 WARNING[14277]: chan_sip.c:3063 process_sdp: Unknown SDP
>media type in offer: image 49170 udptl t38
>Jun  6 10:09:52 WARNING[14277]: chan_sip.c:3063 process_sdp: Unknown SDP
>media type in offer: image 49170 udptl t38
>Jun  6 10:09:53 WARNING[14277]: chan_sip.c:3063 process_sdp: Unknown SDP
>media type in offer: image 49170 udptl t38
>Jun  6 10:09:53 WARNING[14277]: chan_sip.c:3063 process_sdp: Unknown SDP
>media type in offer: image 49170 udptl t38
>Jun  6 10:09:54 WARNING[14277]: chan_sip.c:3063 process_sdp: Unknown SDP
>media type in offer: image 49170 udptl t38
>Jun  6 10:09:54 WARNING[14277]: chan_sip.c:3063 process_sdp: Unknown SDP
>media type in offer: image 49170 udptl t38
>Jun  6 10:09:55 WARNING[14277]: chan_sip.c:3063 process_sdp: Unknown SDP
>media type in offer: image 49170 udptl t38
>Jun  6 10:09:55 WARNING[14277]: chan_sip.c:3063 process_sdp: Unknown SDP
>media type in offer: image 49170 udptl t38
>Jun  6 10:09:56 WARNING[14277]: chan_sip.c:3063 process_sdp: Unknown SDP
>media type in offer: image 49170 udptl t38
>Jun  6 10:09:56 WARNING[14277]: chan_sip.c:3063 process_sdp: Unknown SDP
>media type in offer: image 49170 udptl t38
>Jun  6 10:09:57 WARNING[14277]: chan_sip.c:3063 process_sdp: Unknown SDP
>media type in offer: image 49170 udptl t38
>Jun  6 10:09:57 WARNING[14277]: chan_sip.c:3063 process_sdp: Unknown SDP
>media type in offer: image 49170 udptl t38
>Jun  6 10:09:58 WARNING[14277]: chan_sip.c:3063 process_sdp: Unknown SDP
>media type in offer: image 49170 udptl t38
>Jun  6 10:09:58 WARNING[14277]: chan_sip.c:3063 process_sdp: Unknown SDP
>media type in offer: image 49170 udptl t38
>Jun  6 10:09:59 WARNING[14277]: chan_sip.c:3063 process_sdp: Unknown SDP
>media type in offer: image 49170 udptl t38
><*** call complete ***>
>cytrex*CLI> sip show channels
>Peer             User/ANR    Call ID      Seq (Tx/Rx)   Format  Last Msg
>192.168.0.20     (None)      1153024370@  00101/00138   unknow  Rx:
>REGISTER 192.168.0.20     TEI20       6eb51a3f676  00102/00076   ulaw
>(d)       Rx: ACK
>22.22.22.22      9792979098  166F146B-D5  00101/00103   ulaw  (d)
>Rx: ACK
>
>I think Steve will be interested in this part:
>
>INVITE sip:2819870065 at 33.33.33.33 SIP/2.0
>Via: SIP/2.0/UDP 192.168.0.20:5060;branch=z9hG4bK441433602
>From: <sip:TEI20 at 192.168.0.20:5060>;tag=2311634843
>To: "2819870065" <sip:2819870065 at 33.33.33.33>;tag=as40e02db9
>Call-ID: 74839a6a27d23cbf15e2441c677e51e4 at 33.33.33.33
>CSeq: 9 INVITE
>Contact: <sip:TEI20 at 192.168.0.20:5060>
>max-forwards: 70
>user-agent: Azacall200 V1.5.7-RC14
>Allow: INVITE, ACK, OPTIONS, CANCEL, BYE
>Content-Type: application/sdp
>Content-Length:   258
>
>v=0
>o=- 108 3480 IN IP4 192.168.0.20
>s=-
>c=IN IP4 192.168.0.20
>t=0 0
>m=image 49170 udptl t38
>a=T38FaxVersion:0
>a=T38MaxBitRate:14400
>a=T38FaxRateManagement:transferredTCF
>a=T38FaxMaxBuffer:0
>a=T38FaxMaxDatagram:176
>a=T38FaxUdpEC:t38UDPRedundancy
>
>-Matthew
>  
>




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