Hello,
On 2015-07-31 10:05, Tarun2 Gupta wrote:
Hi Nitin
This is a perfectly legal scenario, the 2nd ReINVITE is essentially a Stop Fax
/ Revert to Audio ReINVITE.
We have seen this behavior with many T.38 vendors.
Quite probably, but this does not make it legal. In the last re-INVITE
the media channel for T38 has been simply removed from SDP, while this
is against the protocol: media channels can be deactivated, but should
not be removed.
https://tools.ietf.org/html/rfc3264#page-14
Regards
Tarun Gupta
-----Original Message-----
From: sip-implementors-boun...@lists.cs.columbia.edu
[mailto:sip-implementors-boun...@lists.cs.columbia.edu] On Behalf Of NK
Sent: Friday, July 31, 2015 12:30 PM
To: Kumar, Puneet (Puneet)
Cc: sip-implementors@lists.cs.columbia.edu
Subject: Re: [Sip-implementors] SIP Reinvite after T38 Negotitaion
Hi Puneet,
Below is the SDP for Fax Re-invite from Vendor (UAS) after audio call
established with initial offer.
*T.38 RE INVITE SDP*
v=0
o=HuaweiSoftX3000 32970986 32970988 IN IP4 1.1.1.1 s=Sip Call c=IN IP4 1.1.1.1
t=0 0
m=image 41046 udptl t38
a=T38FaxVersion:0
a=T38MaxBitRate:14400
a=T38FaxRateManagement:transferredTCF
a=T38FaxUdpEC:t38UDPRedundancy
m=audio 41128 RTP/AVP 8 0 101
a=rtpmap:8 PCMA/8000
a=rtpmap:0 PCMU/8000
a=rtpmap:101 telephone-event/8000
a=ptime:20
a=silenceSupp:off - - - -
a=ecan:fb on -
a=fax
a=fmtp:101 0-15
*200 OK SDP for T.38 Re invite*
v=0
o=Sonus_UAC 10922 10626 IN IP4 1.1.1.1
s=-
c=IN IP4 1.1.1.1
t=0 0
m=image 6334 udptl t38
a=T38FaxVersion:0
a=T38MaxBitRate:14400
a=T38FaxRateManagement:transferredTCF
a=T38FaxMaxBuffer:262
a=T38FaxMaxDatagram:90
a=sendrecv
m=audio 0 RTP/AVP 8 0 101
a=rtpmap:8 PCMA/8000
a=rtpmap:0 PCMU/8000
a=rtpmap:101 telephone-event/8000
a=sendrecv
a=ptime:20
a=silenceSupp:off - - - -
*This is the Re-invite SDP after T38 Invite*
v=0
o=HuaweiSoftX3000 32970986 32970989 IN IP4 1.1.1.1 s=Sip Call c=IN IP4 1.1.1.1
t=0 0
m=audio 41046 RTP/AVP 18 101
a=rtpmap:18 G729/8000
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-15
a=fmtp:18 annexb=no
Regards,
Nitin Kapoor
On Fri, Jul 31, 2015 at 2:48 AM, Kumar, Puneet (Puneet) <pune...@avaya.com>
wrote:
Hi Nitin,
For reINVITE for fax, is far-end converting "m=audio" line to "m=image" ?
Can you share the SDP in both reINVITE's.
Thanks,
Puneet
-----Original Message-----
From: sip-implementors-boun...@lists.cs.columbia.edu [mailto:
sip-implementors-boun...@lists.cs.columbia.edu] On Behalf Of NK
Sent: Friday, July 31, 2015 11:32 AM
To: sip-implementors@lists.cs.columbia.edu
Subject: [Sip-implementors] SIP Reinvite after T38 Negotitaion
Dear All,
It is legal to send re-invite after sending T.38 when negotiation is
already done.
Below is the scenario.
UA ---------> INVITE
UA <------100 Trying
UA <------- 180 w/SDP
UA <------- 200 OK
UA ----------> (Re-invite for fax with T.38) UA <------100 Trying UA
<-----------200 OK *UA <---------- RE-INVITE wSDP G.729* *UA
---------> 488*
Now after this another re-invite is coming (in green) with G.729 Codec
and i am rejecting this with SIP 488.
Anyone observed this kind of scenario earlier?
Can you please advise and help on this.
Thank you in advance.
Regards
Nitin Kapoor
[]
--
Best regards,
Dmitry Akindinov
_______________________________________________
Sip-implementors mailing list
Sip-implementors@lists.cs.columbia.edu
https://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
