[Asterisk-code-review] res_pjsip_t38: T.38 error correction mode selection at 200 ok received (asterisk[13])

[Salah Ahmed]

Salah Ahmed has posted comments on this change. ( https://gerrit.asterisk.org/c/asterisk/+/13180 )

Change subject: res_pjsip_t38: T.38 error correction mode selection at 200 ok received
......................................................................


Patch Set 1:

> Patch Set 1: Code-Review-1
> 
> (3 comments)
> 
> I'm not sure about this. Is there an RFC someplace, or a known convention as to the expectations for negotiation of the 't38faxudpec attribute?
> 
> Reasonably, it seems like if one side doesn't allow EC then EC would not be included, or processed. I'm not sure about the other two modes.

Hello Kevin,

I think ITU-T Recommendation explain it as well.
https://www.itu.int/rec/dologin_pub.asp?lang=e&id=T-REC-T.38-201009-S!!PDF-E&type=items
In section, D.2.3.5 SDP parameter usage in SIP/SDP Offer/Answer negotiations, Table D.2 has those 3 cases explained as following,
t38UDPNoEC: No secondary IPF packets will be sent. The number of secondary messages is set
to zero in UDPTL.
t38UDPRedundancy: Only redundant error correction messages may be sent.
t38UDPFEC: The endpoints can use either redundancy or FEC error correction scheme. 

Thanks,
Salah


-- 
To view, visit https://gerrit.asterisk.org/c/asterisk/+/13180
To unsubscribe, or for help writing mail filters, visit https://gerrit.asterisk.org/settings

Gerrit-Project: asterisk
Gerrit-Branch: 13
Gerrit-Change-Id: I343c62253ea4c8b7ee17abbfb377a4d484a14b19
Gerrit-Change-Number: 13180
Gerrit-PatchSet: 1
Gerrit-Owner: Salah Ahmed <txrubel at gmail.com>
Gerrit-Reviewer: Friendly Automation
Gerrit-Reviewer: Kevin Harwell <kharwell at digium.com>
Gerrit-Comment-Date: Wed, 20 Nov 2019 15:23:52 +0000
Gerrit-HasComments: No
Gerrit-Has-Labels: No
Gerrit-MessageType: comment
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.digium.com/pipermail/asterisk-code-review/attachments/20191120/212297c1/attachment.html>