asterisk users - Jun 2017 - asterisk 13.16 / pjsip / t.38: res_pjsip_t38.c:207 t38_automatic_reject: Automatically rejecting T.38 request on channel 'PJSIP/91-00000007'

On Fri, Jun 16, 2017, at 02:13 AM, Michael Maier wrote:
> Has anybody any idea why asterisk drops the media stream in the 200 OK? 
> The channel has been T38_ENABLED before! Or is it necessary to add more 
> debug code? Who does the negotiating? 
> Only asterisk or is pjsip doing some parts, too?
Asterisk does the T.38 negotiation and produces the answer SDP, PJSIP
does the SDP negotiation. It's likely in the realm of Asterisk where it
is doing that.

-- 
Joshua Colp
Digium, Inc. | Senior Software Developer
445 Jan Davis Drive NW - Huntsville, AL 35806 - US
Check us out at: www.digium.com & www.asterisk.org

Am 16.06.2017 um 11:12 schrieb Joshua Colp:
> On Fri, Jun 16, 2017, at 02:13 AM, Michael Maier wrote:
> 
>> Has anybody any idea why asterisk drops the media stream in the 200 OK?
>> The channel has been T38_ENABLED before! Or is it necessary to add more
>> debug code? Who does the negotiating?
>> Only asterisk or is pjsip doing some parts, too?
> 
> Asterisk does the T.38 negotiation and produces the answer SDP, PJSIP
> does the SDP negotiation. It's likely in the realm of Asterisk where it
> is doing that.
> 
t38modem and asterisk are using

m=image 35622 udptl t38
               ^^^^^

Provider uses

m=image 35622 UDPTL t38
               ^^^^^

Could this be a problem? If I'm sending internal only, it's always 
lowercase.

On Fri, Jun 16, 2017, at 10:49 AM, Michael Maier wrote:

<snip>
> 
> t38modem and asterisk are using
> 
> m=image 35622 udptl t38
>                ^^^^^
> 
> Provider uses
> 
> m=image 35622 UDPTL t38
>                ^^^^^
> 
> Could this be a problem? If I'm sending internal only, it's always 
> lowercase.
Looking at the tests we have we only use 'udptl' as the transport.
Without diving deep into the SDP negotiator it is possible that it gets
upset at that, as we would only produce 'udptl'. If the SDP negotiator
in PJSIP is case sensitive then you'd get a declined stream like you
see. Looking at the T.38 examples from the ITU doc also shows it in
lowercase, so uppercase is probably not commonly used.

-- 
Joshua Colp
Digium, Inc. | Senior Software Developer
445 Jan Davis Drive NW - Huntsville, AL 35806 - US
Check us out at: www.digium.com & www.asterisk.org