IMS

INVITE - RCS 1to1 Chat

INVITE is a session initiation (session creation) process in SIP based communication. There are some SIP communication that does not require a session establishement (e.g, SMS over IMS or some other form of Short Message), but most of the IMS/SIP based communication (e.g, VoLTE, Video, File Transfer etc) are going on in a session.  Whenever the session needs to be established, it is done by INVITE process. The critical part of this process is 'INVITE' at the beginning and 200 OK at the end. But in reality, many other steps are going on between the INVITE and 200OK and the detailed sequences of messages between INVITE and 200 OK differs depending on what kind of session is to be established. (If you are not familiar with what Session means, refer to Session page)

The example in this page is the simplest form of INVITE being used in VoLTE. The example in this page focus only the INVITE and its corresponding 200 OK. If you want to know the detailed example of what is going on after this session creation, refer to RCS 1to1 Chat page.

(1) INVITE

INVITE sip:+14448880000@sharetechnote.com;user=phone SIP/2.0

Conversation-ID: 6b79b8bc937e4985b1dffd062b687bd7

Contribution-ID: d5e4121aeec2cc59546ebaef8966ef185a2f37f0

P-Preferred-Service: urn:urn-7:3gpp-service.ims.icsi.oma.cpm.session

P-Preferred-Identity: <sip:310410123456789@sharetechnote.com>

P-Early-Media: supported

Allow: INVITE,ACK,OPTIONS,CANCEL,BYE,UPDATE,INFO,REFER,NOTIFY,MESSAGE,PRACK

User-Agent: Samsung IMS 5.0

CSeq: 1 INVITE

Max-Forwards: 70

P-Access-Network-Info: 3GPP-E-UTRAN-FDD;utran-cell-id-3gpp=31041000010000000

Route: <sip:[2001:0:0:1::2]:5060;lr>

a: *;+g.3gpp.icsi-ref="urn%3Aurn-7%3A3gpp-service.ims.icsi.oma.cpm.session"

c: application/sdp

f: <sip:310410123456789@sharetechnote.com>;tag=284849603

i: 508868544@2001::1:4c16:9c0f:4986:9e6d

k: timer

l: 363

m: <sip:310410123456789@[2001::1:4c16:9c0f:4986:9e6d]:5060;transport=UDP>;+g.3gpp.icsi-ref="urn%3Aurn-7%3A3gpp-service.ims.icsi.oma.cpm.session"

t: <sip:+14448880000@sharetechnote.com;user=phone>

v: SIP/2.0/TCP [2001::1:4c16:9c0f:4986:9e6d]:5060;branch=z9hG4bK2563646430smg;transport=TCP

v=0

o=TEST-IMS-UE 1234562 0 IN IP6 2001::1:4c16:9c0f:4986:9e6d

s=SS VOIP

c=IN IP6 2001::1:4c16:9c0f:4986:9e6d

t=0 0

m=message 8880 TCP/MSRP *

a=accept-types:message/cpim application/im-iscomposing+xml

a=accept-wrapped-types:text/plain message/imdn+xml

a=setup:active

a=path:msrp://[2001::1:4c16:9c0f:4986:9e6d]:8880/FmnP;tcp

a=msrp-cema

a=sendrecv

(2) 100 Trying

SIP/2.0 100 Trying

Via: SIP/2.0/TCP [2001::1:4c16:9c0f:4986:9e6d]:5060;branch=z9hG4bK2563646430smg;transport=TCP

Max-Forwards: 70

From: <sip:310410123456789@sharetechnote.com>;tag=284849603

To: <sip:+14448880000@sharetechnote.com;user=phone>

Call-ID: 508868544@2001::1:4c16:9c0f:4986:9e6d

CSeq: 1 INVITE

Content-Length: 0

(3) 183 Session Progress

SIP/2.0 183 Session Progress

Max-Forwards: 70

Via: SIP/2.0/TCP [2001::1:4c16:9c0f:4986:9e6d]:5060;branch=z9hG4bK2563646430smg;transport=TCP

From: <sip:310410123456789@sharetechnote.com>;tag=284849603

To: <sip:+14448880000@sharetechnote.com;user=phone>;tag=b2fbe90a8c2e488ba04ad6d0c0956a6c

Call-ID: 508868544@2001::1:4c16:9c0f:4986:9e6d

CSeq: 1 INVITE

Contact: <sip:+14448880000@sharetechnote.com>

Record-Route: <sip:[2001:0:0:1::2]:5060;lr>

Content-Length: 0

(4) 200 OK

Via: SIP/2.0/TCP [2001::1:4c16:9c0f:4986:9e6d]:5060;branch=z9hG4bK2563646430smg;transport=TCP

From: <sip:310410123456789@sharetechnote.com>;tag=284849603

To: <sip:+14448880000@sharetechnote.com;user=phone>;tag=b2fbe90a8c2e488ba04ad6d0c0956a6c

Call-ID: 508868544@2001::1:4c16:9c0f:4986:9e6d

CSeq: 1 INVITE

Allow: INVITE, ACK, CANCEL, BYE, MESSAGE

Contact: <sip:[2001:0:0:1::2]:49466;transport=tcp>

Content-Type: application/sdp

Record-Route: <sip:[2001:0:0:1::2]:5060;lr>

Content-Length: 292

v=0

o=- 1192 5963 IN IP6 2001:0:0:1::2

s=-

c=IN IP6 2001:0:0:1::2

m=message 16000 TCP/MSRP *

a=accept-types:message/cpim application/im-iscomposing+xml

a=accept-wrapped-types:*

a=path:msrp://[2001:0000:0000:0001:0000:0000:0000:0002]:16000/558f02b9d0;tcp

a=msrp-cema

a=setup:passive

(5) ACK

SIP/2.0 200 OK

Max-Forwards: 70

ACK sip:[2001:0:0:1::2]:49466;transport=UDP SIP/2.0

CSeq: 1 ACK

Max-Forwards: 70

Route: <sip:[2001:0:0:1::2]:5060;lr>

f: <sip:310410123456789@sharetechnote.com>;tag=284849603

i: 508868544@2001::1:4c16:9c0f:4986:9e6d

l: 0

m: <sip:310410123456789@[2001::1:4c16:9c0f:4986:9e6d]:5060;transport=UDP>

t: <sip:+14448880000@sharetechnote.com;user=phone>;tag=b2fbe90a8c2e488ba04ad6d0c0956a6c

v: SIP/2.0/UDP [2001::1:4c16:9c0f:4986:9e6d]:5060;branch=z9hG4bK1597981393smg;transport=UDP