Hello,

Recently I tested a SIP Federation trunk between Lync Server 2013 and non-Lync Client.

In this scenario the Lync Client 2013 support SIP Reverse Negotiation, by other words if SIP Invite without SDP it's sent to Lync Client 2013 it will be accepted by any configuration option?

With the default settings seams that it's not supported with error reason "Error parsing body"

Trace-Correlation-Id: 3549384327
Instance-Id: 4C9
Direction: outgoing
Peer: lynctest.domain.com:2138
Message-Type: response
Start-Line: SIP/2.0 488 Not Acceptable Here
From: "User4" <sip:User4@domain.test>;tag=3794445243
To: <sip:vsc@domain.local>;epid=abad235729;tag=a130a7e357
Call-ID: 17dfe5addf23550195a5000c296451a6@172.16.3.51
CSeq: 12784624 INVITE
Via: SIP/2.0/TLS 172.16.3.51:5065;branch=z9hG4bK-5765F571;rport;alias;received=172.16.3.51;ms-received-port=2138;ms-received-cid=1200
Content-Length: 0
ms-client-diagnostics: 52009;reason="Error parsing body"

Regards,

Claudio

Hi,

" if SIP Invite without SDP it's sent to Lync Client 2013 it will be accepted by any configuration option?"

Answer as far as I know is "No" (anyone feel free to correct me if i'm wrong)

the SDP Body is used to give description of the INVITE coming "what kind of Media?, path?, Network information...etc., so if Lync cannot understand what kind of media this INVITE request is sent for, it will not be accepted

Thank you for the answer,

Make sense the answer, would be necessary to the Lync Client to send an answer with a SDP body that contains all the media types and network info to all possible scenarios and this would be quite huge SDP.

My next finding will be if the Edge Server can handle this Invite without SDP in behalf of the Lync client and generate a local SDP offer to the Lync client, similar to what Mediation Server can do.

Claudio

Lync supports "Early Offer" which is basically where SDP is sent with the Invite.  Delayed offer may work, but there have been issues, I can't speak to them because this gets deep into custom development.  It's going to be rough to get this to work without custom coding to play nice with Microsoft, but perhaps it's possible.

I agree with Anthony, out of the box, would be hard to achieve what you want, but using custom developed application it might be possible https://msdn.microsoft.com/en-us/office/dn820099.aspx

Hello All,

After some analysis I got the following conclusions.

Lync PC Client doesn't accept initial Invite without SDP ( Delayed Offer ).

However our goal was to test the SIP Reverse Media Negotiation mechanism, so we sent initially a dummy SDP for the initial invite and after the connect send a SIP INVITE without SDP and for my surprise the Lync Client accepted and sent his own SDP on the 200 OK and we sent the new SDP offer in the ACK.

However the result was no Audio, and Lync Client kept sending the Audio to the initial INVITE SDP and ignored the new SDP offered in the ACK message.

So my conclusion it's that LYNC Client doesn't support SIP Reverse Media Negotiation (Delayed Offer) at all since it ignores the new SDP offered in the ACK message for the mid call media renegotiation attempt with SIP INVITE without SDP.

Traces:

INVITE sip:172.16.1.87:64425;transport=tls;ms-opaque=a3edae884b;ms-received-cid=1F9C00;grid SIP/2.0
Record-Route: <sip:LYNC2013-FE.domain.sifi:5061;transport=tls;opaque=state:F:Ci.R1f9c00;lr;ms-route-sig=aaCRxLomQ6J6ATKjSZx4vJQ22miSAfUAExqMcDvEWyHdss4x_99VHTLQAA>;tag=C161B833E3EAA57C26010E775AC607C8
Via: SIP/2.0/TLS 172.16.0.37:5061;branch=z9hG4bK97FD40ED.FD1FE32C7CB76CCD;branched=FALSE;ms-internal-info="bb0yvN-Txta-aXcfTMPmVSdyK0kBz7b-pamgWfOIbn8vks4x_9o9kUwQAA"
Via: SIP/2.0/TLS 172.16.13.192:5065;branch=z9hG4bK-57656CED;rport;alias;received=172.16.13.192;ms-received-port=2051;ms-received-cid=1D0800
Proxy-Authentication-Info: Kerberos qop="auth", opaque="D83CD7C8", srand="F5054EF3", snum="104", rspauth="040401ffffffffff0000000000000000e9693240576b479326af5617", targetname="sip/LYNC2013-FE.domain.sifi", realm="SIP Communications Service", version=4
Max-Forwards: 56
From: "" <sip:cantest@domain.test>;tag=3691888833
To: <sip:can@domain.sifi>;epid=8a34f77d58;tag=4066ac742a
Call-ID: 6eb67bc63a3155016d89000c296451a6@172.16.13.192
CSeq: 12046301 INVITE
Contact: <sip:cantest@172.16.13.192:5065;transport=TLS>
Allow: REGISTER,SUBSCRIBE,NOTIFY,INVITE,ACK,PRACK,OPTIONS,BYE,CANCEL,REFER,INFO,UPDATE,PUBLISH
Content-Length: 0
Require: 100rel
Supported: 100rel,replaces,privacy,timer,from-change,histinfo,answermode
User-Agent: (Virtual Appliance)
P-Asserted-Identity: "" <sip:cantest@domain.test>
Session-Expires: 720;refresher=uac
P-Sig-Options: Sending-Complete


SIP/2.0 100 Trying
Via: SIP/2.0/TLS 172.16.0.37:5061;branch=z9hG4bK97FD40ED.FD1FE32C7CB76CCD;branched=FALSE;ms-internal-info="bb0yvN-Txta-aXcfTMPmVSdyK0kBz7b-pamgWfOIbn8vks4x_9o9kUwQAA"
Via: SIP/2.0/TLS 172.16.13.192:5065;branch=z9hG4bK-57656CED;rport;alias;received=172.16.13.192;ms-received-port=2051;ms-received-cid=1D0800
From: "" <sip:cantest@domain.test>;tag=3691888833
To: <sip:can@domain.sifi>;epid=8a34f77d58;tag=4066ac742a
Call-ID: 6eb67bc63a3155016d89000c296451a6@172.16.13.192
CSeq: 12046301 INVITE
User-Agent: UCCAPI/15.0.4701.1000 OC/15.0.4701.1000 (Microsoft Lync)
Proxy-Authorization: Kerberos qop="auth", realm="SIP Communications Service", opaque="D83CD7C8", targetname="sip/LYNC2013-FE.domain.sifi", crand="785246a1", cnum="92", response="040400ffffffffff000000000000000000b60640ac2c60c49bc1b427"
Content-Length: 0

SIP/2.0 200 OK
Via: SIP/2.0/TLS 172.16.0.37:5061;branch=z9hG4bK97FD40ED.FD1FE32C7CB76CCD;branched=FALSE;ms-internal-info="bb0yvN-Txta-aXcfTMPmVSdyK0kBz7b-pamgWfOIbn8vks4x_9o9kUwQAA"
Via: SIP/2.0/TLS 172.16.13.192:5065;branch=z9hG4bK-57656CED;rport;alias;received=172.16.13.192;ms-received-port=2051;ms-received-cid=1D0800
From: "" <sip:cantest@domain.test>;tag=3691888833
To: <sip:can@domain.sifi>;epid=8a34f77d58;tag=4066ac742a
Call-ID: 6eb67bc63a3155016d89000c296451a6@172.16.13.192
CSeq: 12046301 INVITE
Record-Route: <sip:LYNC2013-FE.domain.sifi:5061;transport=tls;opaque=state:F:Ci.R1f9c00;lr;ms-route-sig=aaCRxLomQ6J6ATKjSZx4vJQ22miSAfUAExqMcDvEWyHdss4x_99VHTLQAA>;tag=C161B833E3EAA57C26010E775AC607C8
Contact: <sip:can@domain.sifi;opaque=user:epid:wc5Y6-kDo16CxuVbyxqk9gAA;gruu>
User-Agent: UCCAPI/15.0.4701.1000 OC/15.0.4701.1000 (Microsoft Lync)
Supported: histinfo
Supported: ms-safe-transfer
Supported: ms-dialog-route-set-update
Proxy-Authorization: Kerberos qop="auth", realm="SIP Communications Service", opaque="D83CD7C8", targetname="sip/LYNC2013-FE.domain.sifi", crand="e903d142", cnum="93", response="040400ffffffffff0000000000000000dbe0e9524a1031ef81a19d2f"
Content-Type: application/sdp
Content-Length: 354
v=0
o=- 0 1 IN IP4 172.16.1.87
s=session
c=IN IP4 172.16.1.87
b=CT:99980
t=0 0
m=audio 12530 RTP/SAVP 8 0 13 101
a=crypto:1 AES_CM_128_HMAC_SHA1_80 inline:mIMHiJBpn4ZRZfg2VXYSTdQfS4wyJ0x57QQ0q4kU|2^31
a=maxptime:200
a=rtpmap:8 PCMA/8000
a=rtpmap:0 PCMU/8000
a=rtpmap:13 CN/8000
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-16
a=ptime:20


ACK sip:172.16.1.87:64425;transport=tls;ms-opaque=a3edae884b;ms-received-cid=1F9C00;grid SIP/2.0
Via: SIP/2.0/TLS 172.16.0.37:5061;branch=z9hG4bK301D467E.2E943CC97CBC4CCD;branched=FALSE
Via: SIP/2.0/TLS 172.16.13.192:5065;branch=z9hG4bK-57656CEE;rport;received=172.16.13.192;ms-received-port=2051;ms-received-cid=1D0800
Proxy-Authentication-Info: Kerberos qop="auth", opaque="D83CD7C8", srand="B8AB5336", snum="105", rspauth="040401ffffffffff0000000000000000de85d6c7415302c9b7535777", targetname="sip/LYNC2013-FE.domain.sifi", realm="SIP Communications Service", version=4
Max-Forwards: 69
From: "" <sip:cantest@domain.test>;tag=3691888833
To: <sip:can@domain.sifi>;epid=8a34f77d58;tag=4066ac742a
Call-ID: 6eb67bc63a3155016d89000c296451a6@172.16.13.192
CSeq: 12046301 ACK
Contact: <sip:cantest@172.16.13.192:5065;transport=TLS>
Content-Length: 326
Content-Type: application/sdp
v=0
o=- 262 2 IN IP4 172.16.13.192
s=session
t=0 0
m=audio 16392 RTP/SAVP 8 101 13
c=IN IP4 172.16.13.191
a=rtpmap:8 PCMA/8000
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-15
a=ptime:20
a=silenceSupp:off - - - -
a=sendrecv
a=crypto:1 AES_CM_128_HMAC_SHA1_80 inline:X0rDwl9KxCJfSsRaX0rEkl9KxNJfSsUCX0rFOtIK|2^31