[Freeswitch-users] Faxing problems if B leg offers T.38

[Peter Steinbach]

I have opened a JIRA for this: FS-5577



On 06/30/13 20:36, Peter Steinbach wrote:
> I have the same problem with a freeswitch GIT version ~ 1 week old.
> A leg is a Patton resp. Hylafax via tty modem, B-leg is another Patton.
>
> When the B leg offers T.38 by a reinvite:
>
>   * Freeswitch sends a "trying"
>   * the Freeswitch console shows the B leg's SDP with T.38
>   * Then  nothing happens for ~30 sec
>   * Then the B-leg cancels the request and the call is terminated.
>
> Grepping the network traffic I can see that Freeswitch will never
> answer the Reinvite request. This also happens if a leg is T.30
> (hylafax tty modem), so this is not a behaviour of forwarding the t.38
> SDP to the A-leg and waiting for an answer.
>
> I saw a similar behaviour in http://jira.freeswitch.org/browse/FS-5181
> but the solution there was to fallback to T.30.
>
> Is there any solution so far or any hint how to overcome this?
>
> Best regards
> Peter
>
>
>
> On 06/02/11 19:57, Anthony Minessale wrote:
>> start by proving them and post them in a jira with full console traces
>> with sofia global siptrace on and pcaps etc
>>
>> then wait for us to get to them or email consulting at freeswitch.org for
>> expedition
>>
>> On Wed, May 25, 2011 at 11:56 AM, Rob Morin <rmorin at blie-ent.com> wrote:
>>> Thank you.
>>>
>>>
>>>
>>> So, I believe that there are two potential problems, fixing either of which
>>> will allow me to send faxes.
>>>
>>>
>>>
>>> 1.       When T.38 is enabled in passthrough mode and the B leg offers T.38,
>>> Freeswitch needs to forward the invite and the responses. Currently it isn’t
>>> forwarding the response back to the B leg.
>>>
>>> 2.       When T.38 is not enabled and the B leg offers T.38, Freeswitch
>>> needs to respond with a 488 indicating T.38 is not acceptable.  Currently it
>>> doesn’t respond at all.
>>>
>>>
>>>
>>> How would I go about making or requesting these fixes?
>>>
>>> Thank you,
>>> Rob
>>>
>>>
>>>
>>> From: David Ponzone [mailto:david.ponzone at ipeva.fr]
>>> Sent: Wednesday, May 25, 2011 11:11 AM
>>>
>>> To: FreeSWITCH Users Help
>>> Subject: Re: [Freeswitch-users] Faxing problems if B leg offers T.38
>>>
>>>
>>>
>>> Rob,
>>>
>>>
>>>
>>> On my test box, I run a GIT from 05-02, and I don't have any issue.
>>>
>>> But I just did the test, and the call flow is different from yours.
>>>
>>>
>>>
>>> When I send a fax with my endpoint (Zoiper Softphone), I got the remote fax
>>> tone, and then my Zoiper sends the T38-REINVITE, not the remote gateway.
>>>
>>> So I guess there are 2 possible call flows, because I remember in some
>>> circumstances, the remote sends the RE-INVITE.
>>>
>>>
>>>
>>> David Ponzone  Direction Technique
>>>
>>> email: david.ponzone at ipeva.fr
>>>
>>> tel:      01 74 03 18 97
>>>
>>> gsm:   06 66 98 76 34
>>>
>>>
>>>
>>> Service Client IPeva
>>>
>>> tel:      0811 46 26 26
>>>
>>> www.ipeva.fr  -   www.ipeva-studio.com
>>>
>>>
>>>
>>> Ce message et toutes les pièces jointes sont confidentiels et établis à
>>> l'intention exclusive de ses destinataires. Toute utilisation ou diffusion
>>> non autorisée est interdite. Tout message électronique est susceptible
>>> d'altération. IPeva décline toute responsabilité au titre de ce message s'il
>>> a été altéré, déformé ou falsifié. Si vous n'êtes pas destinataire de ce
>>> message, merci de le détruire immédiatement et d'avertir l'expéditeur.
>>>
>>>
>>>
>>>
>>>
>>> Le 25/05/2011 à 13:18, Rob Morin a écrit :
>>>
>>> Is the fact that I was previously running the snapshot from 25 March
>>> adequate to meet this test?
>>>
>>>
>>>
>>> From: Rob Morin [mailto:rmorin at blie-ent.com]
>>> Sent: Tuesday, May 24, 2011 10:50 AM
>>> To: 'FreeSWITCH Users Help'
>>> Subject: Re: [Freeswitch-users] Faxing problems if B leg offers T.38
>>>
>>>
>>>
>>> I can, if someone can tell me where to get the snapshot.  I looked
>>> at files.freeswitch.org and didn’t see one.
>>>
>>>
>>>
>>> Prior to updating to the 5-17 snapshot, I was having the same problems with
>>> the 3-25 snapshot that I was using.
>>>
>>>
>>>
>>> Thank you,
>>>
>>> Rob
>>>
>>>
>>>
>>> From: David Ponzone [mailto:david.ponzone at ipeva.fr]
>>> Sent: Tuesday, May 24, 2011 1:47 AM
>>> To: FreeSWITCH Users Help
>>> Subject: Re: [Freeswitch-users] Faxing problems if B leg offers T.38
>>>
>>>
>>>
>>> Rob,
>>>
>>>
>>>
>>> following Yehavi's comment, could you downgrade your GIT version to a
>>> previous version, like one month old ?
>>>
>>>
>>>
>>> David Ponzone  Direction Technique
>>>
>>> email: david.ponzone at ipeva.fr
>>>
>>> tel:      01 74 03 18 97
>>>
>>> gsm:   06 66 98 76 34
>>>
>>>
>>>
>>> Service Client IPeva
>>>
>>> tel:      0811 46 26 26
>>>
>>> www.ipeva.fr  -   www.ipeva-studio.com
>>>
>>>
>>>
>>> Ce message et toutes les pièces jointes sont confidentiels et établis à
>>> l'intention exclusive de ses destinataires. Toute utilisation ou diffusion
>>> non autorisée est interdite. Tout message électronique est susceptible
>>> d'altération. IPeva décline toute responsabilité au titre de ce message s'il
>>> a été altéré, déformé ou falsifié. Si vous n'êtes pas destinataire de ce
>>> message, merci de le détruire immédiatement et d'avertir l'expéditeur.
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> Le 24/05/2011 à 02:59, Rob Morin a écrit :
>>>
>>>
>>>
>>> David,
>>>
>>>
>>>
>>> It isn’t the ATA. I’ve tried both the Grandstream HandyTone 502 and
>>> Cisco/Linksys SPA 2102. Same story in both cases.
>>>
>>>
>>>
>>> I had my carrier help me troubleshoot and we can see the SIP request from
>>> the carrier come in. When T.38 is enabled, it is forwarded to the A leg, but
>>> the response from the A leg isn’t forwarded back to the B leg. I can produce
>>> traces that show this.
>>>
>>>
>>>
>>> When T.38 isn’t enabled, the B leg is sending a T.38 reinvite. FS doesn’t
>>> respond or forward it. So the connection dies.  I have every reason to
>>> believe that I’d be able to send the fax if FS would respond with a 488
>>> indicating T.38 is not acceptable. But instead, all I get is silence. Again,
>>> I can produce traces that demonstrate this.
>>>
>>>
>>>
>>> There’s another similar email  trail out
>>> there, http://freeswitch-users.2379917.n2.nabble.com/T-38-via-UPDATE-request-td3821994.html,
>>> but I’m not certain that they’re related.
>>>
>>>
>>>
>>> Thank you for your help!
>>> Rob
>>>
>>>
>>>
>>> From: David Ponzone [mailto:david.ponzone at ipeva.fr]
>>> Sent: Monday, May 23, 2011 6:11 PM
>>> To: FreeSWITCH Users Help
>>> Subject: Re: [Freeswitch-users] Faxing problems if B leg offers T.38
>>>
>>>
>>>
>>> Rob,
>>>
>>>
>>>
>>> perhaps you should not consider T38 is 100% interoperable.
>>>
>>> You may tell us what ATA is that, because some of them are nice piece of
>>> junk.
>>>
>>>
>>>
>>> David Ponzone  Direction Technique
>>>
>>> email: david.ponzone at ipeva.fr
>>>
>>> tel:      01 74 03 18 97
>>>
>>> gsm:   06 66 98 76 34
>>>
>>>
>>>
>>> Service Client IPeva
>>>
>>> tel:      0811 46 26 26
>>>
>>> www.ipeva.fr  -   www.ipeva-studio.com
>>>
>>>
>>>
>>> Ce message et toutes les pièces jointes sont confidentiels et établis à
>>> l'intention exclusive de ses destinataires. Toute utilisation ou diffusion
>>> non autorisée est interdite. Tout message électronique est susceptible
>>> d'altération. IPeva décline toute responsabilité au titre de ce message s'il
>>> a été altéré, déformé ou falsifié. Si vous n'êtes pas destinataire de ce
>>> message, merci de le détruire immédiatement et d'avertir l'expéditeur.
>>>
>>>
>>>
>>>
>>>
>>>
>>> Le 23/05/2011 à 20:51, Rob Morin a écrit :
>>>
>>>
>>> I’m having problems faxing if the B leg offers T.38.  Several scenarios, but
>>> always the same result.
>>>
>>>
>>>
>>> First, the architecture
>>>
>>>
>>>
>>> FAX à ATA (T.38 optional) à FS à Carrier  à Destination (Possibly another
>>> carrier (PSTN) and the fax machine)
>>>
>>>
>>>
>>> On my ATA, T.38 is enabled (Auto Detect).
>>>
>>>
>>>
>>> If the destination supports T.38, the Carrier will offer it to Freeswitch.
>>> If the Destination doesn’t support T.38, the B leg doesn’t offer it and the
>>> faxes go through.
>>>
>>>
>>>
>>> I’ve set Freeswitch as:
>>>
>>>       <action application="set" data="fax_enable_t38=true"/>
>>>
>>>       <action application="export" data="t38_passthru=true"/>
>>>
>>> When that’s the case, and the B leg offers T.38, Freeswitch passes through
>>> the offer and the ATA responds, 3 times. But the response never gets sent to
>>> the B leg, so it terminates the call after about 30 seconds.
>>>
>>>
>>>
>>> When I set Freeswitch as:
>>>
>>>       <action application="set" data="fax_enable_t38=false"/>
>>>
>>> The B leg still offers T.38 if its other side is capable. Freeswitch doesn’t
>>> pass the offer through and the B leg terminates the call after about 30
>>> seconds.
>>>
>>>
>>>
>>> I’m running on a recent git ( FreeSWITCH Version 1.0.head (git-86d757d
>>> 2011-05-17 22-51-47 -0500) ).
>>>
>>>
>>>
>>> I’ve had no success attempting to configure FS as a gateway. Frankly, T.38
>>> “passthrough” has had the most success, mostly when the other ends aren’t
>>> T.38 capable and it stays in G711u.
>>>
>>>
>>>
>>> Is there something else I need to do to enable T.38 in passthrough mode?
>>>
>>>
>>>
>>> Thank you,
>>> Rob Morin
>>>
>>>
>>>
>>> PS – I can provide tcpdumps of this, or whatever else is necessary.
>>>
>>>
>>>
>>>
>>>
>>> _______________________________________________
>>> FreeSWITCH-users mailing list
>>> FreeSWITCH-users at lists.freeswitch.org
>>> http://lists.freeswitch.org/mailman/listinfo/freeswitch-users
>>> UNSUBSCRIBE:http://lists.freeswitch.org/mailman/options/freeswitch-users
>>> http://www.freeswitch.org
>>>
>>>
>>>
>>> _______________________________________________
>>> FreeSWITCH-users mailing list
>>> FreeSWITCH-users at lists.freeswitch.org
>>> http://lists.freeswitch.org/mailman/listinfo/freeswitch-users
>>> UNSUBSCRIBE:http://lists.freeswitch.org/mailman/options/freeswitch-users
>>> http://www.freeswitch.org
>>>
>>>
>>>
>>> _______________________________________________
>>> FreeSWITCH-users mailing list
>>> FreeSWITCH-users at lists.freeswitch.org
>>> http://lists.freeswitch.org/mailman/listinfo/freeswitch-users
>>> UNSUBSCRIBE:http://lists.freeswitch.org/mailman/options/freeswitch-users
>>> http://www.freeswitch.org
>>>
>>>
>>>
>>> _______________________________________________
>>> FreeSWITCH-users mailing list
>>> FreeSWITCH-users at lists.freeswitch.org
>>> http://lists.freeswitch.org/mailman/listinfo/freeswitch-users
>>> UNSUBSCRIBE:http://lists.freeswitch.org/mailman/options/freeswitch-users
>>> http://www.freeswitch.org
>>>
>>>
>>
>
>
> -- 
> With kind regards
> Peter Steinbach 
>
> Telefaks Services GmbH
> mailto:lists (att) telefaks.de
> Internet: www.telefaks.de
>


-- 
With kind regards
Peter Steinbach 

Telefaks Services GmbH
mailto:lists (att) telefaks.de
Internet: www.telefaks.de

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.freeswitch.org/pipermail/freeswitch-users/attachments/20130704/7fbb5c39/attachment.html