Internet Engineering Task Force Alan Johnston Internet Draft WorldCom Document: draft-ietf-sipping-service-examples-03.txt Robert Sparks Category: Informational Chris Cunningham November 2002 Steve Donovan Expires: May 2003 dynamicsoft Kevin Summers Sonus Session Initiation Protocol Service Examples Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026[1]. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet- Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. Abstract This informational document gives examples of Session Initiation Protocol (SIP) services. This covers most features offered in so- called Centrex offerings from local exchange carriers and PBX (Private Branch Exchange) features. Most of the services shown in this document are implemented in the SIP User Agents, although some require the assistance of a SIP Proxy. Some require some extensions to SIP including the REFER, SUBSCRIBE, and NOTIFY methods and the Replaces and Join headers. These features are not intended to be an exhaustive set, but rather show implementations of common features likely to be implemented on SIP IP telephones in a business environment. Johnston, et al. [Page 1] Internet Draft SIP Service Examples November 2002 Table of Contents 1 Overview...................................................3 1.1 Legend for Message Flows...................................4 1.2 Document History...........................................4 2 IP Telephony Services Features Call Flows..................8 2.1 Call Hold..................................................8 2.2 Consultation Hold.........................................19 2.3 Music On Hold.............................................34 2.4 Unattended Transfer.......................................41 2.5 Attended Transfer.........................................48 2.6 Call Forwarding Unconditional.............................59 2.7 Call Forwarding - Busy....................................64 2.8 Call Forwarding - No Answer...............................71 2.9 3-way Conference û Third Party is Added...................79 2.10 3-way Conference û Third Party Joins......................84 2.11 Single Line Extension.....................................89 2.12 Find-Me..................................................105 2.13 Call Management (Incoming Call Screening)................115 2.14 Call Management (Outgoing Call Screening)................119 2.15 Call Park................................................122 2.16 Call Pickup..............................................131 2.17 Automatic Redial.........................................138 3 Security Considerations..................................144 4 IANA Considerations......................................145 5 Acknowledgements.........................................146 6 References...............................................147 7 Author's Addresses.......................................148 Johnston, et al. Informational [Page 2] Internet Draft SIP Service Examples November 2002 1 Overview This informational document provides call flows detailing a SIP implementation of the following traditional telephony services: Call Hold Music on Hold Unattended Transfer Consultation Hold Unconditional Call Forwarding Attended Transfer No Answer Call Forwarding Busy Call Forwarding Single-Line Extension 3-way Call Incoming Call Screening Find-Me Call Pickup Call Park Outgoing Call Screening Automatic Redial It is the hope of the authors that this document will be useful for SIP implementors, users, designers, and protocol researchers alike and will help further the goal of a standard SIP implementation for IP Telephony. It is envisioned that as changes to the standard and additional RFCs are added that this document will reflect those changes and represent the current state of a standard SIP IP Telephony implementation. These flows use SIP as defined by RFC 3261 [2] and SDP usage defined by RFC 3264 [8]. Note that this document is informational, and nothing stated here should be taken as normative. The SIP specification and the other referenced documents are definitive as far as protocol issues are concerned. Also, these flows do not represent the only way to implement these services - other approaches such as 3pcc (Third Party Call Control) or Back-to-Back User Agents (B2BUA) may be more appropriate in some circumstances. The design and principles of these service examples are described in the the Multiparty Framework document [12]. These flows assume the functionality described in the SIP Basic Call Flow Examples document [3], which explores basic behavior. Some of the scenarios described herein make use of the SIP method extension REFER [4] and the SIP header extension Replaces [5], the SIP header extension Join [6], and some of the concepts in the 3pcc (third party call control) document [7]. The SIP Events document [11] describes the use of SUBSCRIBE and NOTIFY while the SIP Call Package document [10] describes the dialog event package. These flows were prepared assuming a network of proxies, registrars, PSTN gateways, and other SIP servers that have a pre-established trust relationship with each other, secured through other means than SIP. User agents wishing to use the services in this network are required to authenticate themselves with an edge proxy using SIP Digest. To improve the clarity of this document, authentication of User Agents is not explicitly shown in all flows, except where authentication directly relates to the service example. Johnston, et al. Informational [Page 3] Internet Draft SIP Service Examples November 2002 Each call flow is presented with a textual description of the scenario, a message flow diagram showing the messages exchanged between separate network elements, and the detailed contents of each message shown in the diagram. 1.1 Legend for Message Flows Dashed lines (---) represent control messages that are mandatory to the call scenario. These control messages can be SIP or PSTN signaling. Double dashed lines (===) represent media paths between network elements. Messages with parenthesis around name represent optional control messages. Messages are identified in the Figures as F1, F2, etc. This references the message details in the table that follows the Figure. Comments in the message details are shown in the following form: /* Comments. */ 1.2 Document History The first version of this document was the Internet-Draft "draft-sparks-sip-service-examples.txt" October 1999. The next version was combined with the SIP Telephony Call Flows document into the "draft-ietf-sip-call-flows-00.txt" April 2000. This version is based on Section 7 of that document with many of the examples extensively rewritten using the REFER method. 1.3 Changes to 00 - Moddified all REFER flows to include 202 Accepted and NOTIFY result message. - Removed "Telephony" from title of document. - Added note on 2.9 on use of REFER to exit 3-way conference. - Modified Music on Hold/Call Park flow (2.2). - Modified order of messages in transfers (2.4 and 2.5) to more closely resemble PSTN experience. - Added Call Pickup flow (2.13). - Added editorial notes on usefulness of Replaces header. Johnston, et al. Informational [Page 4] Internet Draft SIP Service Examples November 2002 1.4 Changes to 01 - Added Replaces header to flows. - Changed handling of call hold. - Added Contact and Referred-By headers and ref parameters to REFER messages. - Changed some Contacts, Routes, and Request-URIs to IP addresses. - Incremented o= line when SDP is updated with hold. - Added From tags throughout. - Renamed Music On Hold/Call Park to Call Park and added new Music On Hold call flow using 3pcc. 1.5 Changes to 02 - Changed call hold flows to show sendonly attribute based on [8]. - Removed ref parameter from the Referred-By headers since it is now just a generic paramter in the latest draft [4]. (Note that if the ref parameter stays, additional characters such as "<", "@", and ">" must be escaped.) - Removed tags in CANCEL requests and responses. 1.6 Changes to sipping-00 - Added Max-Forwards - Added branch parm and received param to Vias - Changed Record-Route and Route behavior to show loose routing. - Added Record-Route and Contact to 18x responses - Changed Call Pickup to show Replaces with an early dialog - Changed description of Single Line Extension service - Changed Call Park and Pickup flow to show a different user picking up the call. - Added Allow and Supported headers to REFER and replaces flows. 1.7 Changes to -01 Johnston, et al. Informational [Page 5] Internet Draft SIP Service Examples November 2002 - Added SIP Events and dialog event package to Call Pickup flow. - Added Auto Redial call flows - Updated based on new Replaces draft with 481 behavior instead of using Accept-Contact in attended transfer. - Added Single Line Extension call flow. - Added Error-Info in call screening flows. 1.8 Changes to -02 - Added 3-way call flows showing transition from 2 party call. 1.9 Changes to -03 - Fixed owner/version SDP errors in hold SDP. - Add Notification of remote-URI in Call Pickup scenario - Updated 3-way conference flows to show just internal User Agent mixing - Added FQDNs in Contacts and SDP, changed example addresses - Replaced use of Accept-Contact header with Contact URI - Updated for refer-06 changes Johnston, et al. Informational [Page 6] Internet Draft SIP Service Examples November 2002 Johnston, et al. Informational [Page 7] Internet Draft SIP Service Examples November 2002 2 IP Telephony Services Features Call Flows These call flows show how a number of standard telephony features can be implemented using SIP. They are not meant to represent a complete set. Some calls make use of SIP extensions. 2.1 Call Hold User A Proxy User B | | | | INVITE F1 | | |--------------->| | | | INVITE F2 | |(100 Trying) F3 |------------->| |<---------------| | | |180 Ringing F4| | 180 Ringing F5 |<-------------| |<---------------| | | | 200 OK F6 | | 200 OK F7 |<-------------| |<---------------| | | ACK F8 | | |--------------->| ACK F9 | | |------------->| | Both way RTP Established | |<=============================>| | |INVITE(hold) F10 |INVITE(hold) F11|<-------------| |<---------------| | | 200 OK F12 | | |--------------->| 200 OK F13 | | |------------->| | | ACK F14 | | ACK F15 |<-------------| |<---------------| | | No RTP Sent! | | | INVITE F16 | | INVITE F17 |<-------------| |<---------------| | | 200 OK F18 | | |--------------->| 200 OK F19 | | |------------->| | | ACK F20 | | ACK F21 |<-------------| |<---------------| | | Both way RTP Established | |<=============================>| | BYE F22 | | |--------------->| BYE F23 | | |------------->| | | 200 OK F24 | | 200 OK F25 |<-------------| Johnston, et al. Informational [Page 8] Internet Draft SIP Service Examples November 2002 |<---------------| | | | | User A calls User B, User B places call on hold. User B then takes call off hold. User A hangs up call. Hold is unidirectional in nature. However, a UA that places the other party on hold will generally also stop sending media, resulting in no media exchange between the UAs. Message Details F1 INVITE A -> Proxy 1 INVITE sip:UserB@there.com SIP/2.0 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 Max-Forwards: 70 From: BigGuy ;tag=1234567 To: LittleGuy Call-ID: 12345601@here.com CSeq: 1 INVITE Contact: Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 client.here.com t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F2 INVITE Proxy 1 -> B INVITE sip:UserB@client.there.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 Record-Route: Max-Forwards: 69 From: BigGuy ;tag=1234567 To: LittleGuy Call-ID: 12345601@here.com CSeq: 1 INVITE Contact: Content-Type: application/sdp Content-Length: ... v=0 Johnston, et al. Informational [Page 9] Internet Draft SIP Service Examples November 2002 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 client.here.com t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F3 (100 Trying) Proxy 1 -> A SIP/2.0 100 Trying Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 From: BigGuy ;tag=1234567 To: LittleGuy Call-ID: 12345601@here.com CSeq: 1 INVITE Content-Length: 0 F4 180 Ringing B -> Proxy 1 SIP/2.0 180 Ringing Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 ;received=192.0.2.54 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 Record-Route: From: BigGuy ;tag=1234567 To: LittleGuy ;tag=314159 Call-ID: 12345601@here.com CSeq: 1 INVITE Contact: Content Length:0 F5 180 Ringing Proxy 1 -> A SIP/2.0 180 Ringing Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 Record-Route: From: BigGuy ;tag=1234567 To: LittleGuy ;tag=314159 Call-ID: 12345601@here.com CSeq: 1 INVITE Contact: Content Length: 0 F6 200 OK B -> Proxy 1 Johnston, et al. Informational [Page 10] Internet Draft SIP Service Examples November 2002 SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 ;received=192.0.2.54 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 Record-Route: From: BigGuy ;tag=1234567 To: LittleGuy ;tag=314159 Call-ID: 12345601@here.com CSeq: 1 INVITE Contact: Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844527 2890844527 IN IP4 client.there.com s=Session SDP c=IN IP4 client.there.com t=3034423619 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F7 200 OK Proxy 1 -> A SIP/2.0 200 OK Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 Record-Route: From: BigGuy ;tag=1234567 To: LittleGuy ;tag=314159 Call-ID: 12345601@here.com CSeq: 1 INVITE Contact: Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844527 2890844527 IN IP4 client.there.com s=Session SDP c=IN IP4 client.there.com t=3034423619 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F8 ACK A -> Proxy 1 ACK sip:UserB@client.there.com SIP/2.0 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 Route: Max-Forwards: 70 Johnston, et al. Informational [Page 11] Internet Draft SIP Service Examples November 2002 From: BigGuy ;tag=1234567 To: LittleGuy ;tag=314159 Call-ID: 12345601@here.com CSeq: 1 ACK Content-Length: 0 F9 ACK Proxy 1 -> B ACK sip:UserB@client.there.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 Max-Forwards: 69 From: BigGuy ;tag=1234567 To: LittleGuy ;tag=314159 Call-ID: 12345601@here.com CSeq: 1 ACK Content-Length: 0 /* User B places User A on hold. Note that the version is incremented in the o= field of the SDP */ F10 INVITE B -> Proxy 1 INVITE sip:UserA@client.here.com SIP/2.0 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 Route: Max-Forwards: 70 From: LittleGuy ;tag=314159 To: BigGuy ;tag=1234567 Call-ID: 12345601@here.com CSeq: 1 INVITE Contact: Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844527 2890844528 IN IP4 client.there.com s=Session SDP c=IN IP4 client.there.com t=3034423619 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 a=sendonly F11 INVITE Proxy 1 -> A INVITE sip:UserA@client.here.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 Johnston, et al. Informational [Page 12] Internet Draft SIP Service Examples November 2002 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 ;received=192.0.2.105 Record-Route: Max-Forwards: 69 From: LittleGuy ;tag=314159 To: BigGuy ;tag=1234567 Call-ID: 12345601@here.com CSeq: 1 INVITE Contact: Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844527 2890844528 IN IP4 client.there.com s=Session SDP c=IN IP4 client.there.com t=3034423619 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 a=sendonly /* A replies with normal SDP */ F12 200 OK A -> Proxy 1 SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 ;received=192.0.2.54 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 ;received=192.0.2.105 Record-Route: From: LittleGuy ;tag=314159 To: BigGuy ;tag=1234567 Call-ID: 12345601@here.com CSeq: 1 INVITE Contact: Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 client.here.com t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F13 200 OK Proxy 1 -> B SIP/2.0 200 OK Johnston, et al. Informational [Page 13] Internet Draft SIP Service Examples November 2002 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 ;received=192.0.2.105 Record-Route: From: LittleGuy ;tag=314159 To: BigGuy ;tag=1234567 Call-ID: 12345601@here.com CSeq: 1 INVITE Contact: Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 client.here.com t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F14 ACK B -> Proxy 1 ACK sip:UserA@client.here.com SIP/2.0 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 Route: Max-Forwards: 70 From: LittleGuy ;tag=314159 To: BigGuy ;tag=1234567 Call-ID: 12345601@here.com CSeq: 1 ACK Content-Length: 0 F15 ACK Proxy 1 -> A ACK sip:UserA@client.here.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 ;received=192.0.2.105 Max-Forwards: 69 From: LittleGuy ;tag=314159 To: BigGuy ;tag=1234567 Call-ID: 12345601@here.com CSeq: 1 ACK Content-Length: 0 /* User B takes the call off hold */ F16 INVITE B -> Proxy 1 INVITE sip:UserA@client.here.com SIP/2.0 Johnston, et al. Informational [Page 14] Internet Draft SIP Service Examples November 2002 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 Route: Max-Forwards: 70 From: LittleGuy ;tag=314159 To: BigGuy ;tag=1234567 Call-ID: 12345601@here.com CSeq: 2 INVITE Contact: Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844527 2890844529 IN IP4 client.there.com s=Session SDP c=IN IP4 client.there.com t=3034423619 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F17 INVITE Proxy 1 -> A INVITE sip:UserA@client.here.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 ;received=192.0.2.105 Record-Route: Max-Forwards: 69 From: LittleGuy ;tag=314159 To: BigGuy ;tag=1234567 Call-ID: 12345601@here.com CSeq: 2 INVITE Contact: Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844527 2890844529 IN IP4 client.there.com s=Session SDP c=IN IP4 client.there.com t=3034423619 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F18 200 OK A -> Proxy 1 SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 ;received=192.0.2.54 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 ;received=192.0.2.105 Johnston, et al. Informational [Page 15] Internet Draft SIP Service Examples November 2002 Record-Route: From: LittleGuy ;tag=314159 To: BigGuy ;tag=1234567 Call-ID: 12345601@here.com CSeq: 2 INVITE Contact: Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 client.here.com t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F19 200 OK Proxy 1 -> B SIP/2.0 200 OK Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 ;received=192.0.2.105 Record-Route: From: LittleGuy ;tag=314159 To: BigGuy ;tag=1234567 Call-ID: 12345601@here.com CSeq: 2 INVITE Contact: Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 client.here.com t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F20 ACK B -> Proxy 1 ACK sip:UserA@client.here.com SIP/2.0 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 Route: Max-Forwards: 70 From: LittleGuy ;tag=314159 To: BigGuy ;tag=1234567 Call-ID: 12345601@here.com CSeq: 2 ACK Content-Length: 0 Johnston, et al. Informational [Page 16] Internet Draft SIP Service Examples November 2002 F21 ACK Proxy 1 -> A ACK sip:UserA@client.here.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 ;received=192.0.2.105 Max-Forwards: 69 From: LittleGuy ;tag=314159 To: BigGuy ;tag=1234567 Call-ID: 12345601@here.com CSeq: 2 ACK Content-Length: 0 /* RTP Media stream re-established. User A disconnects. */ F22 BYE A -> Proxy 1 BYE sip:UserB@client.there.com SIP/2.0 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 Route: Max-Forwards: 70 From: BigGuy ;tag=1234567 To: LittleGuy ;tag=314159 Call-ID: 12345601@here.com CSeq: 2 BYE Content-Length: 0 F23 BYE Proxy 1 -> B BYE sip:UserB@client.there.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 Max-Forwards: 69 From: BigGuy ;tag=1234567 To: LittleGuy ;tag=314159 Call-ID: 12345601@here.com CSeq: 2 BYE Content-Length: 0 F24 200 OK B -> Proxy 1 SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 ;received=192.0.2.54 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 Johnston, et al. Informational [Page 17] Internet Draft SIP Service Examples November 2002 From: BigGuy ;tag=1234567 To: LittleGuy ;tag=314159 Call-ID: 12345601@here.com CSeq: 2 BYE Content-Length: 0 F25 200 OK Proxy 1 -> A SIP/2.0 200 OK Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 From: BigGuy ;tag=1234567 To: LittleGuy ;tag=314159 Call-ID: 12345601@here.com CSeq: 2 BYE Content-Length: 0 Johnston, et al. Informational [Page 18] Internet Draft SIP Service Examples November 2002 2.2 Consultation Hold User A Proxy User B User C | | | | | INVITE F1 | | | |--------------->| INVITE F2 | | | |------------->| | |(100 Trying) F3 | | | |<---------------|180 Ringing F4| | | |<-------------| | | 180 Ringing F5 | | | |<---------------| 200 OK F6 | | | |<-------------| | | 200 OK F7 | | | |<---------------| | | | ACK F8 | | | |--------------->| ACK F9 | | | |------------->| | | Both way RTP Established | | |<=============================>| | | |INVITE(hold) F10 | |INVITE(hold) F11|<-------------| | |<---------------| | | | 200 OK F12 | | | |--------------->| 200 OK F13 | | | |------------->| | | | ACK F14 | | | |<-------------| | | ACK F15 | | | |<---------------| | | | No RTP Sent! | | | | INVITE F16 | | | |<-------------| | | | | INVITE F17 | | |--------------------------------->| | |(100 Trying) F18 | | |------------->| | | | | 180 Ringing F19 | | |<---------------------------------| | | 180 Ringing F20 | | |------------->| | | | | 200 OK F21 | | |<---------------------------------| | | 200 OK F22 | | | |------------->| | | | ACK F23 | | | |<-------------| | | | | ACK F24 | | |--------------------------------->| | | Both way RTP Established | Johnston, et al. Informational [Page 19] Internet Draft SIP Service Examples November 2002 | | |<=================>| | | BYE F25 | | | |<-------------| | | | | BYE F26 | | |--------------------------------->| | | | 200 OK F27 | | |<---------------------------------| | | 200 OK F28 | | | |------------->| | | | INVITE F29 | | | INVITE F30 |<-------------| | |<---------------| | | | 200 OK F31 | | | |--------------->| 200 OK F32 | | | |------------->| | | | ACK F33 | | | |<-------------| | | ACK F34 | | | |<---------------| | | | Both way RTP Established | | |<=============================>| | | BYE F35 | | | |--------------->| BYE F36 | | | |------------->| | | | 200 OK F37 | | | |<-------------| | | 200 OK F38 | | | |<---------------| | | | | | | User A calls user B. User B places call on hold. User B calls User C. User B then disconnects with C, then takes the call with User A off hold. The call ends with B hangs up. Message Details F1 INVITE A -> Proxy 1 INVITE sip:UserB@there.com SIP/2.0 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 Max-Forwards: 70 From: BigGuy ;tag=1234567 To: LittleGuy Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com Johnston, et al. Informational [Page 20] Internet Draft SIP Service Examples November 2002 s=Session SDP c=IN IP4 client.here.com t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F2 INVITE Proxy 1 -> B INVITE sip:UserB@client.there.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 Record-Route: Max-Forwards: 69 From: BigGuy ;tag=1234567 To: LittleGuy Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 client.here.com t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F3(100 Trying) Proxy 1 -> A SIP/2.0 100 Trying Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 From: BigGuy ;tag=1234567 To: LittleGuy Call-ID: 12345600@here.com CSeq: 1 INVITE Content-Length: 0 F4 180 Ringing B -> Proxy 1 SIP/2.0 180 Ringing Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 ;received=192.0.2.54 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 Record-Route: Johnston, et al. Informational [Page 21] Internet Draft SIP Service Examples November 2002 From: BigGuy ;tag=1234567 To: LittleGuy ;tag=314159 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: Content Length:0 F5 180 Ringing Proxy 1 -> A SIP/2.0 180 Ringing Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 Record-Route: From: BigGuy ;tag=1234567 To: LittleGuy ;tag=314159 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: Content Length: 0 F6 200 OK B -> Proxy 1 SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 ;received=192.0.2.54 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 Record-Route: From: BigGuy ;tag=1234567 To: LittleGuy ;tag=314159 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844527 2890844527 IN IP4 client.there.com s=Session SDP c=IN IP4 client.there.com t=3034423619 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F7 200 OK Proxy 1 -> A SIP/2.0 200 OK Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 Johnston, et al. Informational [Page 22] Internet Draft SIP Service Examples November 2002 Record-Route: From: BigGuy ;tag=1234567 To: LittleGuy ;tag=314159 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844527 2890844527 IN IP4 client.there.com s=Session SDP c=IN IP4 client.there.com t=3034423619 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F8 ACK A -> Proxy 1 ACK sip:UserB@client.there.com SIP/2.0 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 Route: Max-Forwards: 70 From: BigGuy ;tag=1234567 To: LittleGuy ;tag=314159 Call-ID: 12345600@here.com CSeq: 1 ACK Content-Length: 0 F9 ACK Proxy 1 -> B ACK sip:UserB@client.there.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 Max-Forwards: 69 From: BigGuy ;tag=1234567 To: LittleGuy ;tag=314159 Call-ID: 12345600@here.com CSeq: 1 ACK Content-Length: 0 /* User B places User A on hold. */ F10 INVITE B -> Proxy 1 INVITE sip:UserA@client.here.com SIP/2.0 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 Route: Johnston, et al. Informational [Page 23] Internet Draft SIP Service Examples November 2002 Max-Forwards: 70 From: LittleGuy ;tag=314159 To: BigGuy ;tag=1234567 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844527 2890844528 IN IP4 client.there.com s=Session SDP c=IN IP4 client.there.com t=3034423619 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 a=sendonly F11 INVITE Proxy 1 -> A INVITE sip:UserA@client.here.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 ;received=192.0.2.105 Record-Route: Max-Forwards: 69 From: LittleGuy ;tag=314159 To: BigGuy ;tag=1234567 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844527 2890844528 IN IP4 client.there.com s=Session SDP c=IN IP4 client.there.com t=3034423619 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 a=sendonly F12 200 OK A -> Proxy 1 SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 ;received=192.0.2.54 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 ;received=192.0.2.105 Johnston, et al. Informational [Page 24] Internet Draft SIP Service Examples November 2002 Record-Route: From: LittleGuy ;tag=314159 To: BigGuy ;tag=1234567 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 client.here.com t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F13 200 OK Proxy 1 -> B SIP/2.0 200 OK Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 ;received=192.0.2.105 Record-Route: From: LittleGuy ;tag=314159 To: BigGuy ;tag=1234567 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 client.here.com t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F14 ACK B -> Proxy 1 ACK sip:UserA@client.here.com SIP/2.0 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 Route: Max-Forwards: 70 From: LittleGuy ;tag=314159 To: BigGuy ;tag=1234567 Call-ID: 12345600@here.com CSeq: 1 ACK Content-Length: 0 Johnston, et al. Informational [Page 25] Internet Draft SIP Service Examples November 2002 F15 ACK Proxy 1 -> A ACK sip:UserA@client.here.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 ;received=192.0.2.105 Max-Forwards: 69 From: LittleGuy ;tag=314159 To: BigGuy ;tag=1234567 Call-ID: 12345600@here.com CSeq: 1 ACK Content-Length: 0 F16 INVITE B -> Proxy 1 INVITE sip:UserC@anywhere.com SIP/2.0 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 Max-Forwards: 70 From: LittleGuy ;tag=8675309 To: OtherGuy Call-ID: 9876543210@there.com CSeq: 1 INVITE Contact: Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844834 2890844834 IN IP4 client.there.com s=Session SDP c=IN IP4 client.there.com t=3034423619 0 m=audio 50170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F17 INVITE Proxy 1 -> C INVITE sip:UserC@client.anywhere.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 ;received=192.0.2.105 Record-Route: Max-Forwards: 69 From: LittleGuy ;tag=8675309 To: OtherGuy Call-ID: 9876543210@there.com CSeq: 1 INVITE Contact: Content-Type: application/sdp Johnston, et al. Informational [Page 26] Internet Draft SIP Service Examples November 2002 Content-Length: ... v=0 o=UserB 2890844834 2890844834 IN IP4 client.there.com s=Session SDP c=IN IP4 client.there.com t=3034423619 0 m=audio 50170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F18 (100 Trying) Proxy 1 -> B SIP/2.0 100 Trying Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 ;received=192.0.2.105 From: LittleGuy ;tag=8675309 To: OtherGuy Call-ID: 9876543210@there.com CSeq: 1 INVITE Content-Length: 0 F19 180 Ringing C -> Proxy 1 SIP/2.0 180 Ringing Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 ;received=192.0.2.54 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 ;received=192.0.2.105 Record-Route: From: LittleGuy ;tag=8675309 To: OtherGuy ;tag=456654 Call-ID: 9876543210@here.com CSeq: 1 INVITE Contact: Content Length:0 F20 180 Ringing Proxy 1 -> B SIP/2.0 180 Ringing Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 ;received=client.anywhere.com Record-Route: From: LittleGuy ;tag=8675309 To: OtherGuy ;tag=456654 Call-ID: 9876543210@there.com CSeq: 1 INVITE Contact: Content Length: 0 Johnston, et al. Informational [Page 27] Internet Draft SIP Service Examples November 2002 F21 200 OK C -> Proxy 1 SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 ;received=192.0.2.54 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 ;received=192.0.2.105 Record-Route: From: LittleGuy ;tag=8675309 To: OtherGuy ;tag=456654 Call-ID: 9876543210@there.com CSeq: 1 INVITE Contact: Content-Type: application/sdp Content-Length: ... v=0 o=UserC 2890844922 2890844922 IN IP4 client.anywhere.com s=Session SDP c=IN IP4 client.anywhere.com t=3034423619 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F22 200 OK Proxy 1 -> B SIP/2.0 200 OK Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 ;received=192.0.2.105 Record-Route: From: LittleGuy ;tag=8675309 To: OtherGuy ;tag=456654 Call-ID: 9876543210@there.com CSeq: 1 INVITE Contact: Content-Type: application/sdp Content-Length: ... v=0 o=UserC 2890844922 2890844922 IN IP4 client.anywhere.com s=Session SDP c=IN IP4 client.anywhere.com t=3034423619 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F23 ACK B -> Proxy 1 ACK sip:UserC@client.anywhere.com SIP/2.0 Johnston, et al. Informational [Page 28] Internet Draft SIP Service Examples November 2002 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 Route: Max-Forwards: 70 From: LittleGuy ;tag=8675309 To: OtherGuy ;tag=456654 Call-ID: 9876543210@there.com CSeq: 1 ACK Content-Length: 0 F24 ACK Proxy 1 -> C ACK sip:UserC@client.anywhere.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 ;received=192.0.2.105 Max-Forwards: 69 From: LittleGuy ;tag=8675309 To: OtherGuy ;tag=456654 Call-ID: 9876543210@there.com CSeq: 1 ACK Content-Length: 0 F25 BYE B -> Proxy 1 BYE sip:UserC@client.anywhere.com SIP/2.0 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 Route: Max-Forwards: 70 From: LittleGuy ;tag=8675309 To: OtherGuy ;tag=456654 Call-ID: 9876543210@there.com CSeq: 2 BYE Content-Length: 0 F26 BYE Proxy 1 -> C BYE sip:UserC@client.anywhere.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 ;received=192.0.2.105 Max-Forwards: 69 From: LittleGuy ;tag=8675309 To: OtherGuy ;tag=456654 Call-ID: 9876543210@there.com CSeq: 2 BYE Content-Length: 0 F27 200 OK C -> Proxy 1 Johnston, et al. Informational [Page 29] Internet Draft SIP Service Examples November 2002 SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 ;received=192.0.2.54 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 ;received=192.0.2.105 From: LittleGuy ;tag=8675309 To: OtherGuy ;tag=456654 Call-ID: 9876543210@there.com CSeq: 2 BYE Content-Length: 0 F28 200 OK Proxy 1 -> B SIP/2.0 200 OK Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 ;received=192.0.2.105 From: LittleGuy ;tag=8675309 To: OtherGuy ;tag=456654 Call-ID: 9876543210@there.com CSeq: 2 BYE Content-Length: 0 /* User B takes the call off hold */ F29 INVITE B -> Proxy 1 INVITE sip:UserA@client.here.com SIP/2.0 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 Route: Max-Forwards: 70 From: LittleGuy ;tag=314159 To: BigGuy ;tag=1234567 Call-ID: 12345600@here.com CSeq: 2 INVITE Contact: Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844527 2890844529 IN IP4 client.there.com s=Session SDP c=IN IP4 client.there.com t=3034423619 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F30 INVITE Proxy 1 -> A Johnston, et al. Informational [Page 30] Internet Draft SIP Service Examples November 2002 INVITE sip:UserA@client.here.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 ;received=192.0.2.105 Record-Route: Max-Forwards: 69 From: LittleGuy ;tag=314159 To: BigGuy ;tag=1234567 Call-ID: 12345600@here.com CSeq: 2 INVITE Contact: Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844527 2890844529 IN IP4 client.there.com s=Session SDP c=IN IP4 client.there.com t=3034423619 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F31 200 OK A -> Proxy 1 SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 ;received=192.0.2.54 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 ;received=192.0.2.105 Record-Route: From: LittleGuy ;tag=314159 To: BigGuy ;tag=1234567 Call-ID: 12345600@here.com CSeq: 2 INVITE Contact: Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 client.here.com t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F32 200 OK Proxy 1 -> B SIP/2.0 200 OK Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 Johnston, et al. Informational [Page 31] Internet Draft SIP Service Examples November 2002 ;received=192.0.2.105 Record-Route: From: LittleGuy ;tag=314159 To: BigGuy ;tag=1234567 Call-ID: 12345600@here.com CSeq: 2 INVITE Contact: Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 client.here.com t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F33 ACK B -> Proxy 1 ACK sip:UserA@client.here.com SIP/2.0 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 Route: Max-Forwards: 70 From: LittleGuy ;tag=314159 To: BigGuy ;tag=1234567 Call-ID: 12345600@here.com CSeq: 2 ACK Content-Length: 0 F34 ACK Proxy 1 -> A ACK sip:UserA@client.here.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 ;received=192.0.2.105 Max-Forwards: 69 From: LittleGuy ;tag=314159 To: BigGuy ;tag=1234567 Call-ID: 12345600@here.com CSeq: 2 ACK Content-Length: 0 F35 BYE A -> Proxy 1 BYE sip:UserB@client.there.com SIP/2.0 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 Route: Max-Forwards: 70 Johnston, et al. Informational [Page 32] Internet Draft SIP Service Examples November 2002 From: BigGuy ;tag=1234567 To: LittleGuy ;tag=314159 Call-ID: 12345600@here.com CSeq: 2 BYE Content-Length: 0 F36 BYE Proxy 1 -> B BYE sip:UserB@client.there.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 Max-Forwards: 69 From: BigGuy ;tag=1234567 To: LittleGuy ;tag=314159 Call-ID: 12345600@here.com CSeq: 2 BYE Content-Length: 0 F37 200 OK B -> Proxy 1 SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 ;received=192.0.2.54 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 From: BigGuy ;tag=1234567 To: LittleGuy ;tag=314159 Call-ID: 12345600@here.com CSeq: 2 BYE Content-Length: 0 F38 200 OK Proxy 1 -> A SIP/2.0 200 OK Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 From: BigGuy ;tag=1234567 To: LittleGuy ;tag=314159 Call-ID: 12345600@here.com CSeq: 2 BYE Content-Length: 0 Johnston, et al. Informational [Page 33] Internet Draft SIP Service Examples November 2002 2.3 Music On Hold User A User B Music Server | | | | INVITE F1 | | |--------------->| | | 180 Ringing F2 | | |<---------------| | | 200 OK F3 | | |<---------------| | | ACK F4 | | |--------------->| | | RTP | | |<==============>| | | | | | B places A on hold with music | | | | | | INVITE no sdp F5 | |------------->| | |200 OK sdpM F6| | |<-------------| |INVITE (hold) F7| | |<---------------| | | 200 OK sdpA F8 | | |--------------->| | | ACK F9 | | |<---------------| | | | ACK sdpA F10 | | |------------->| | RTP | |<==============================| | | | | B Picks up the Call | | | BYE F11 | | |------------->| | | 200 OK F12 | | |<-------------| | INVITE F13 | | |<---------------| | | 200 OK F14 | | |--------------->| | | ACK F15 | | |<---------------| | | RTP | | |<==============>| | In this flow,B places A on hold with music. This is performed by B acting as a B2BUA (Back-to-Back User Agent) using 3pcc (third party call control) [7] to INVITE a Music Server into the session, which Johnston, et al. Informational [Page 34] Internet Draft SIP Service Examples November 2002 sends RTP music to A. B picks the call up from hold by sending a BYE to the music server and taking A off of hold. Note that if A responds to the INVITE with hold SDP with hold SDP in the 200 OK, this call flow will not work properly. Note also that A will receive RTP packets from two different IP addresses during this call flow. Message Details F1 INVITE A -> B INVITE sip:UserB@there.com SIP/2.0 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 Max-Forwards: 70 From: BigGuy ;tag=1234567 To: LittleGuy Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 client.here.com t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F2 180 Ringing B -> A SIP/2.0 180 Ringing Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 From: BigGuy ;tag=1234567 To: LittleGuy ;tag=23431 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: Content-Length: 0 F3 200 OK B -> A SIP/2.0 200 OK Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 Johnston, et al. Informational [Page 35] Internet Draft SIP Service Examples November 2002 ;received=192.0.2.103 From: BigGuy ;tag=1234567 To: LittleGuy ;tag=23431 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844527 2890844527 IN IP4 client.there.com s=Session SDP c=IN IP4 client.there.com t=3034423619 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F4 ACK A -> B ACK sip:UserB@client.there.com SIP/2.0 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 Max-Forwards: 70 From: BigGuy ;tag=1234567 To: LittleGuy ;tag=23431 Call-ID: 12345600@here.com CSeq: 1 ACK Content-Length: 0 /* User B places A on hold with music by acting as a B2BUA and sending an INVITE to the Music Server */ F5 INVITE B -> Music Server INVITE sip:music@server.com SIP/2.0 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 Max-Forwards: 70 From: LittleGuy ;tag=8675309 To: Music Call-ID: sdjfdjfskdf@there.com CSeq: 1 INVITE Contact: Content-Length: 0 F6 200 OK C -> B SIP/2.0 200 OK Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 ;received=192.0.2.105 From: LittleGuy ;tag=8675309 Johnston, et al. Informational [Page 36] Internet Draft SIP Service Examples November 2002 To: Music ;tag=90210 Call-ID: sdjfdjfskdf@there.com CSeq: 1 INVITE Contact: Content-Type: application/sdp Content-Length: ... v=0 o=MusicServer 2890844576 2890844577 IN IP4 music.server.com s=Session SDP c=IN IP4 music.server.com t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 a=sendonly /* B re-INVITEs A on hold */ F7 INVITE B -> A INVITE sip:UserA@client.here.com SIP/2.0 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 To: BigGuy ;tag=1234567 Max-Forwards: 70 From: LittleGuy ;tag=23431 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844527 2890844528 IN IP4 music.server.com s=Session SDP c=IN IP4 music.server.com t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 a=sendonly /* A responds with normal SDP */ F8 200 OK A -> B SIP/2.0 200 OK Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 To: BigGuy ;tag=1234567 From: LittleGuy ;tag=23431 Call-ID: 12345600@here.com CSeq: 1 INVITE Johnston, et al. Informational [Page 37] Internet Draft SIP Service Examples November 2002 Contact: Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 client.here.com t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F9 ACK B -> A ACK sip:UserA@client.here.com SIP/2.0 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 To: BigGuy ;tag=1234567 Max-Forwards: 70 From: LittleGuy ;tag=23431 Call-ID: 12345600@here.com CSeq: 1 ACK Content-Length: 0 /* B passes SDP of A to the Music Server to allow music to be sent from B to A */ F10 ACK B -> Music Server ACK sip:music@server.com SIP/2.0 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 Max-Forwards: 70 From: LittleGuy ;tag=8675309 To: Music ;tag=90210 Call-ID: sdjfdjfskdf@there.com CSeq: 1 ACK Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 client.here.com t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 /* RTP music is now sent from the Music Server to A */ /* B picks up the call from the Music Server */ Johnston, et al. Informational [Page 38] Internet Draft SIP Service Examples November 2002 F11 BYE B -> Music Server BYE sip:music@server.com SIP/2.0 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 Max-Forwards: 70 From: LittleGuy ;tag=8675309 To: Music ;tag=90210 Call-ID: sdjfdjfskdf@there.com CSeq: 2 BYE Content-Length: 0 F12 200 OK Music Server -> B SIP/2.0 200 OK Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 ;received=192.0.2.105 From: LittleGuy ;tag=8675309 To: Music ;tag=90210 Call-ID: sdjfdjfskdf@there.com CSeq: 2 BYE Content-Length:0 /* B re-INVITEs taking A off hold */ F13 INVITE B -> A INVITE sip:UserA@client.here.com SIP/2.0 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 To: BigGuy ;tag=1234567 Max-Forwards: 70 From: LittleGuy ;tag=23431 Call-ID: 12345600@here.com CSeq: 2 INVITE Contact: Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844527 2890844529 IN IP4 client.there.com s=Session SDP c=IN IP4 client.there.com t=3034423619 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F14 200 OK A -> B SIP/2.0 200 OK Johnston, et al. Informational [Page 39] Internet Draft SIP Service Examples November 2002 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 To: BigGuy ;tag=1234567 From: LittleGuy ;tag=23431 Call-ID: 12345600@here.com CSeq: 2 INVITE Contact: Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 client.here.com t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F15 ACK B -> A ACK sip:UserA@client.here.com SIP/2.0 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 To: BigGuy ;tag=1234567 Max-Forwards: 70 From: LittleGuy ;tag=23431 Call-ID: 12345600@here.com CSeq: 2 ACK Content-Length: 0 /* Normal media session between A and B is resumed */ Johnston, et al. Informational [Page 40] Internet Draft SIP Service Examples November 2002 2.4 Unattended Transfer User A User B User C | INVITE F1 | | |<-------------------| | | 180 Ringing F2 | | |------------------->| | | 200 OK F3 | | |------------------->| | | ACK F4 | | |<-------------------| | | RTP | | |<==================>| | | | | | A performs unattended transfer | | | | | REFER Refer-To:C F5| | |------------------->| | | 202 Accepted F6 | | |<-------------------| | | NOTIFY F7 | | |<-------------------| | | 200 OK F8 | | |------------------->| | | BYE F9 | | |------------------->| | | 200 OK F10 | | |<-------------------| | | No RTP Session | INVITE Referred-By: A F11 | |------------------->| | | 180 Ringing F12 | | |<-------------------| | | 200 OK F13 | | |<-------------------| | | ACK F14 | | |------------------->| | | RTP | | |<==================>| | NOTIFY F14 | | |<-------------------| | | 200 OK F15 | | |------------------->| | | | | User B call User A. User A then transfers User B to User C, then User A disconnects with User B. User B establishes the session to C then reports the success back to A in the NOTIFY. If the transfer fails, User B can send a new INVITE back to A to re-establish the session. Johnston, et al. Informational [Page 41] Internet Draft SIP Service Examples November 2002 Note that the BYE could be sent by A after the NOTIFY. Also, if A has flushed all state information, the NOTIFY may receive a 481 Call Leg Does Not Exist. Message Details F1 INVITE B -> A INVITE sip:UserA@here.com SIP/2.0 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 Max-Forwards: 70 From: LittleGuy ;tag=314159 To: BigGuy Call-ID: 12345601@here.com CSeq: 1 INVITE Contact: Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY Supported: replaces Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844527 2890844527 IN IP4 client.there.com s=Session SDP c=IN IP4 client.there.com t=3034423619 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F2 180 Ringing A -> B SIP/2.0 180 Ringing Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 ;received=192.0.2.113 From: LittleGuy ;tag=314159 To: BigGuy ;tag=1234567 Call-ID: 12345601@here.com CSeq: 1 INVITE Contact: Content-Length: 0 F3 200 OK A -> B SIP/2.0 200 OK Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 ;received=192.0.2.113 From: LittleGuy ;tag=314159 To: BigGuy ;tag=1234567 Johnston, et al. Informational [Page 42] Internet Draft SIP Service Examples November 2002 Call-ID: 12345601@here.com CSeq: 1 INVITE Contact: Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY Supported: replaces Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 client.here.com t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F4 ACK B -> A ACK sip:UserA@client.here.com SIP/2.0 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 Max-Forwards: 70 From: LittleGuy ;tag=314159 To: BigGuy ;tag=1234567 Call-ID: 12345601@here.com CSeq: 1 ACK Content-Length: 0 /* Session is established between A and B. */ /* A peforms unattended transfer of B to C */ F5 REFER A -> B REFER sip:UserB@client.there.com SIP/2.0 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 Max-Forwards: 70 From: BigGuy ;tag=1234567 To: LittleGuy ;tag=314159 Call-ID: 12345601@here.com CSeq: 2 REFER Refer-To: Referred-By: Contact: Content-Length: 0 F6 202 Accepted B -> A SIP/2.0 202 Accepted Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 Johnston, et al. Informational [Page 43] Internet Draft SIP Service Examples November 2002 ;received=192.0.2.113 From: BigGuy ;tag=1234567 To: LittleGuy ;tag=314159 Call-ID: 12345601@here.com CSeq: 2 REFER Content-Length: 0 F7 NOTIFY B -> A NOTIFY sip:UserA@client.here.com SIP/2.0 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 Max-Forwards: 70 From: LittleGuy ;tag=314159 To: BigGuy ;tag=1234567 Call-ID: 12345601@here.com CSeq: 2 NOTIFY Event: refer Subscription-State: active;expires=60 Content-Type: message/sipfrag Content-Length: ... SIP/2.0 100 Trying F8 200 OK A -> B SIP/2.0 200 OK Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 ;received=192.0.2.113 From: LittleGuy ;tag=314159 To: BigGuy ;tag=1234567 Call-ID: 12345601@here.com CSeq: 2 NOTIFY Content-Length: 0 /* A now disconnects with B */ F9 BYE A -> B BYE sip:UserB@client.there.com SIP/2.0 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 Max-Forwards: 70 From: BigGuy ;tag=1234567 To: LittleGuy ;tag=314159 Call-ID: 12345601@here.com CSeq: 3 BYE Content-Length: 0 Johnston, et al. Informational [Page 44] Internet Draft SIP Service Examples November 2002 F10 200 OK B -> A SIP/2.0 200 OK Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 ;received=192.0.2.105 From: BigGuy ;tag=1234567 To: LittleGuy ;tag=314159 Call-ID: 12345601@here.com CSeq: 3 BYE Content-Length: 0 /* B attempts the transfer to C */ F11 INVITE B -> C INVITE sip:UserC@anywhere.com SIP/2.0 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 Max-Forwards: 70 From: LittleGuy ;tag=8675309 To: OtherGuy Call-ID: 7436222@here.com CSeq: 1 INVITE Contact: Referred-By: Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY Supported: replaces Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844539 2890844539 IN IP4 client.there.com s=Session SDP c=IN IP4 client.there.com t=3034423821 0 m=audio 3458 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F12 180 Ringing C -> B SIP/2.0 180 Ringing Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 ;received=192.0.2.113 From: LittleGuy ;tag=8675309 To: OtherGuy ;tag=928287 Call-ID: 7436222@here.com CSeq: 1 INVITE Contact: Content-Length: 0 Johnston, et al. Informational [Page 45] Internet Draft SIP Service Examples November 2002 F13 200 OK C -> B SIP/2.0 200 OK Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 ;received=192.0.2.113 From: LittleGuy ;tag=8675309 To: OtherGuy ;tag=928287 Call-ID: 7436222@here.com CSeq: 1 INVITE Contact: Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY Supported: replaces Content-Type: application/sdp Content-Length: ... v=0 o=UserC 2890844527 2890844527 IN IP4 client.anywhere.com s=Session SDP c=IN IP4 client.anywhere.com t=3034423619 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F14 ACK B -> C ACK sip:UserC@client.anywhere.com SIP/2.0 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 Max-Forwards: 70 From: LittleGuy ;tag=8675309 To: OtherGuy ;tag=928287 Call-ID: 7436222@here.com CSeq: 1 ACK Content-Length: 0 /* B and C now have established a session. B reports success to A which A probably ignores. */ F15 NOTIFY B -> A NOTIFY sip:UserA@client.here.com SIP/2.0 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 Max-Forwards: 70 From: LittleGuy ;tag=314159 To: BigGuy ;tag=1234567 Call-ID: 12345601@here.com CSeq: 3 NOTIFY Event: refer Subscription-State: terminated;reason=noresource Content-Type: message/sipfrag Content-Length: ... Johnston, et al. Informational [Page 46] Internet Draft SIP Service Examples November 2002 SIP/2.0 200 OK Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 ;received=192.0.2.113 From: LittleGuy ;tag=8675309 To: OtherGuy ;tag=928287 Call-ID: 7436222@here.com CSeq: 1 INVITE Contact: Content-Type: application/sdp Content-Length: ... F16 200 OK A -> B SIP/2.0 200 OK Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 ;received=192.0.2.113 From: LittleGuy ;tag=314159 To: BigGuy ;tag=1234567 Call-ID: 12345601@here.com CSeq: 3 NOTIFY Content-Length: 0 Johnston, et al. Informational [Page 47] Internet Draft SIP Service Examples November 2002 2.5 Attended Transfer User A User B User C | | | | INVITE F1 | | |--------------->| | | 180 Ringing F2 | | |<---------------| | | 200 OK F3 | | |<---------------| | | ACK F4 | | |--------------->| | | RTP | | |<==============>| | |INVITE (hold) F5| | |<---------------| | | 200 OK F6 | | |--------------->| | | ACK F7 | | |<---------------| | | No RTP | | | | INVITE F8 | | |------------->| | | 180 Ringing F9 | |<-------------| | | 200 OK F10 | | |<-------------| | | ACK F11 | | |------------->| | | RTP | | |<============>| | |INVITE (hold) F12 | |------------->| | | 200 OK F13 | | |<-------------| | | ACK F14 | | |------------->| | | No RTP | | REFER Refer-To: C F15 | |<---------------| | |202 Accepted F16| | |--------------->| | | NOTIFY F17 | | |--------------->| | | 200 OK F18 | | |<---------------| | | INVITE Replaces: B F19 | |------------------------------>| | 200 OK F20 | |<------------------------------| | ACK F21 | Johnston, et al. Informational [Page 48] Internet Draft SIP Service Examples November 2002 |------------------------------>| | RTP | |<=============================>| | | BYE F22 | | |<-------------| | | 200 OK F23 | | |------------->| | NOTIFY F24 | | |--------------->| | | 200 OK F25 | | |<---------------| | | BYE F26 | | |<---------------| | | 200 OK F27 | | |--------------->| | User A calls User B. User B puts User A on hold then calls User C to announce transfer, then places C on hold. User B transfers User A to User C which replaces the session between B and C. C then disconnects session with B. A reports success of transfer to B, who then disconnects with A. In this example, the Replaces header [5] is inserted into the Refer-To URL by B. Note that the Refer-To URI is the Contact URI returned by C in the 200 OK response F10. This ensures that only the correct instance of User C is reached. If the triggered INVITE had failed, B would have retried the REFER with a Refer-To URI of the URI used to reach User C but with a Require: replaces header escaped in the Refer-To header field, as discussed in [9]. Message Details F1 INVITE A -> B INVITE sip:UserB@there.com SIP/2.0 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 Max-Forwards: 70 From: BigGuy ;tag=1234567 To: LittleGuy Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY Supported: replaces Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 client.here.com t=3034423619 0 Johnston, et al. Informational [Page 49] Internet Draft SIP Service Examples November 2002 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F2 180 Ringing B -> A SIP/2.0 180 Ringing Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 From: BigGuy ;tag=1234567 To: LittleGuy ;tag=23431 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: Content-Length: 0 F3 200 OK B -> A SIP/2.0 200 OK Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 From: BigGuy ;tag=1234567 To: LittleGuy ;tag=23431 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY Supported: replaces Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844527 2890844527 IN IP4 client.there.com s=Session SDP c=IN IP4 client.there.com t=3034423619 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F4 ACK A -> B ACK sip:UserB@client.there.com SIP/2.0 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 Max-Forwards: 70 From: BigGuy ;tag=1234567 To: LittleGuy ;tag=23431 Call-ID: 12345600@here.com CSeq: 1 ACK Content-Length: 0 Johnston, et al. Informational [Page 50] Internet Draft SIP Service Examples November 2002 /* User A and User B have established a session. User B puts User A on Hold */ F5 INVITE B -> A INVITE sip:UserA@client.here.com SIP/2.0 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 Max-Forwards: 70 From: LittleGuy ;tag=23431 To: BigGuy ;tag=1234567 Call-ID: 12345600@here.com CSeq: 1024 INVITE Contact: Content-Type: application/sdp Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY Supported: replaces Content-Length: ... v=0 o=UserB 2890844527 2890844528 IN IP4 client.there.com s=Session SDP c=IN IP4 client.there.com t=3034423619 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 a=sendonly F6 200 OK A -> B SIP/2.0 200 OK Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 ;received=192.0.2.113 From: LittleGuy ;tag=23431 To: BigGuy ;tag=1234567 Call-ID: 12345600@here.com CSeq: 1024 INVITE Contact: Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY Supported: replaces Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 client.here.com t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 Johnston, et al. Informational [Page 51] Internet Draft SIP Service Examples November 2002 F7 ACK B -> A ACK sip:UserA@client.here.com SIP/2.0 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 Max-Forwards: 70 From: LittleGuy ;tag=23431 To: BigGuy ;tag=1234567 Call-ID: 12345600@here.com CSeq: 1024 ACK Content-Length: 0 /* User B calls User C */ F8 INVITE B -> C INVITE sip:UserC@anywhere.com SIP/2.0 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 Max-Forwards: 70 From: LittleGuy ;tag=8675309 To: OtherGuy Call-ID: sdjfdjfskdf@there.com CSeq: 42 INVITE Contact: Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY Supported: replaces Content-Type: application/sdp Content-Length: ... v=0 o=UserB 28908445834 2890844834 IN IP4 client.there.com s=Session SDP c=IN IP4 client.there.com t=3034423645 0 m=audio 3458 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F9 180 Ringing C -> B SIP/2.0 180 Ringing Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 ;received=192.0.2.113 From: LittleGuy ;tag=8675309 To: OtherGuy ;tag=5f35a3 Call-ID: sdjfdjfskdf@there.com CSeq: 42 INVITE Contact: Content-Length: 0 Johnston, et al. Informational [Page 52] Internet Draft SIP Service Examples November 2002 F10 200 OK C -> B SIP/2.0 200 OK Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 ;received=192.0.2.113 From: LittleGuy ;tag=8675309 To: OtherGuy ;tag=5f35a3 Call-ID: sdjfdjfskdf@there.com CSeq: 42 INVITE Contact: Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY Supported: replaces Content-Type: application/sdp Content-Length: ... v=0 o=UserC 2890844922 2890844922 IN IP4 client.anywhere.com s=Session SDP c=IN IP4 client.anywhere.com t=3034423619 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F11 ACK B -> C ACK sip:UserC@client.anywhere.com SIP/2.0 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 Max-Forwards: 70 From: LittleGuy ;tag=8675309 To: OtherGuy ;tag=5f35a3 Call-ID: sdjfdjfskdf@there.com CSeq: 42 ACK Content-Length: 0 /* User B puts User C on hold */ F12 INVITE B -> C INVITE sip:UserC@client.anywhere.com SIP/2.0 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 Max-Forwards: 70 From: LittleGuy ;tag=8675309 To: OtherGuy ;tag=5f35a3 Call-ID: sdjfdjfskdf@there.com CSeq: 43 INVITE Contact: Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY Supported: replaces Content-Type: application/sdp Content-Length: ... Johnston, et al. Informational [Page 53] Internet Draft SIP Service Examples November 2002 v=0 o=UserB 289084834 2890844835 IN IP4 client.there.com s=Session SDP c=IN IP4 client.there.com t=3034423645 0 m=audio 3458 RTP/AVP 0 a=rtpmap:0 PCMU/8000 a=sendonly F13 200 OK C -> B SIP/2.0 200 OK Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 ;received=192.0.2.113 From: LittleGuy ;tag=8675309 To: OtherGuy ;tag=5f35a3 Call-ID: sdjfdjfskdf@there.com CSeq: 43 INVITE Contact: Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY Supported: replaces Content-Type: application/sdp Content-Length: ... v=0 o=UserC 2890844922 2890844922 IN IP4 client.anywhere.com s=Session SDP c=IN IP4 client.anywhere.com t=3034423619 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F14 ACK B -> C ACK sip:UserC@client.anywhere.com SIP/2.0 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 Max-Forwards: 70 From: LittleGuy ;tag=8675309 To: OtherGuy ;tag=5f35a3 Call-ID: sdjfdjfskdf@there.com CSeq: 43 ACK Content-Length: 0 /* User B Transfers User A to User C. */ F15 REFER B -> A REFER sip:UserA@client.here.com SIP/2.0 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 Johnston, et al. Informational [Page 54] Internet Draft SIP Service Examples November 2002 Max-Forwards: 70 From: LittleGuy ;tag=23431 To: BigGuy ;tag=1234567 Call-ID: 12345678900@here.com CSeq: 1025 REFER Refer-To: Referred-By: Contact: Content-Length: 0 F16 202 Accepted A -> B SIP/2.0 202 Accepted Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 ;received=192.0.2.113 From: LittleGuy ;tag=1234567 To: BigGuy ;tag=23431 Call-ID: 12345678900@here.com CSeq: 1025 REFER Content-Length: 0 F17 NOTIFY A -> B NOTIFY sip:UserB@client.there.com SIP/2.0 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 Max-Forwards: 70 From: BigGuy ;tag=1234567 To: LittleGuy ;tag=23431 Call-ID: 12345678900@here.com CSeq: 2 NOTIFY Event: refer Subscription-State: active;expires=60 Content-Type: message/sipfrag Content-Length: ... SIP/2.0 100 Trying F18 200 OK B -> C SIP/2.0 200 OK Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 To: LittleGuy ;tag=1234567 From: OtherGuy ;tag=5f35a3 Call-ID: 12345678900@here.com CSeq: 2 NOTIFY Content-Length: 0 Johnston, et al. Informational [Page 55] Internet Draft SIP Service Examples November 2002 /* User A establishes session with User C which replaces the session between User B and User C */ F19 INVITE A -> C INVITE sip:UserC@client.anywhere.com SIP/2.0 Via: SIP/2.0/UDP client.anywhere.com:5060;branch=z9hG4bKadfe4ko To: OtherGuy Max-Forwards: 70 From: BigGuy ;tag=3461 Call-ID: 9435674543@here.com CSeq: 1 INVITE Referred-By: Replaces: 12345600@here.com;to-tag=23431;from-tag=8675309 Contact: Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY Supported: replaces Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844989 2890844989 IN IP4 client.here.com s=Session SDP c=IN IP4 client.here.com t=3034423643 0 m=audio 3458 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F20 200 OK C -> A SIP/2.0 200 OK Via: SIP/2.0/UDP client.anywhere.com:5060;branch=z9hG4bKadfe4ko ;received=192.0.2.123 To: OtherGuy ;tag=ff3a From: BigGuy ;tag=3461 Call-ID: 9435674543@here.com CSeq: 1 INVITE Contact: Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY Supported: replaces Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844221 2890844221 IN IP4 client.anywhere.com s=Session SDP c=IN IP4 client.anywhere.com t=3034423452 0 m=audio 49172 RTP/AVP 0 a=rtpmap:0 PCMU/8000 Johnston, et al. Informational [Page 56] Internet Draft SIP Service Examples November 2002 F21 ACK A -> C ACK sip:UserC@client.anywhere.com SIP/2.0 Via: SIP/2.0/UDP client.anywhere.com:5060;branch=z9hG4bKadfe4ko To: OtherGuy ;tag=ff3a Max-Forwards: 70 From: BigGuy ;tag=3461 Call-ID: 9435674543@here.com CSeq: 1 INVITE Content-Length: 0 /* User C then disconnects from User B */ F22 BYE C -> B BYE sip:UserB@client.there.com SIP/2.0 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 To: LittleGuy ;tag=8675309 Max-Forwards: 70 From: OtherGuy ;tag=5f35a3 Call-ID: sdjfdjfskdf@there.com CSeq: 1 BYE Content-Length: 0 F23 200 OK B -> C SIP/2.0 200 OK Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 To: LittleGuy ;tag=8675309 From: OtherGuy ;tag=5f35a3 Call-ID: sdjfdjfskdf@there.com CSeq: 1 BYE Content-Length: 0 /* User A tells User B that the call has been successfully transferred */ F24 NOTIFY A -> B NOTIFY sip:UserB@client.there.com SIP/2.0 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 Max-Forwards: 70 From: BigGuy ;tag=1234567 To: LittleGuy ;tag=23431 Call-ID: 12345678900@here.com CSeq: 3 NOTIFY Johnston, et al. Informational [Page 57] Internet Draft SIP Service Examples November 2002 Event: refer Subscription-State: terminated;reason=noresource Content-Type: message/sipfrag Content-Length: ... SIP/2.0 200 OK Via: SIP/2.0/UDP client.anywhere.com:5060;branch=z9hG4bKadfe4ko ;received=192.0.2.123 From: OtherGuy ;tag=ff3a To: BigGuy ;tag=3461 Call-ID: 9435674543@anywhere.com CSeq: 1 INVITE Contact: F25 200 OK B -> C SIP/2.0 200 OK Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 To: LittleGuy ;tag=1234567 From: OtherGuy ;tag=5f35a3 Call-ID: 12345678900@here.com CSeq: 3 NOTIFY Content-Length: 0 /* User B disconnects with User A */ F26 BYE B -> A BYE sip:UserA@client.here.com SIP/2.0 Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 Max-Forwards: 70 From: LittleGuy ;tag=23431 To: BigGuy ;tag=1234567 Call-ID: 12345678900@here.com CSeq: 1026 BYE Content-Length: 0 F27 200 OK A -> B SIP/2.0 200 OK Via: SIP/2.0/UDP client.there.com:5060;branch=z9hG4bKnashds7 ;received=192.0.2.113 From: LittleGuy ;tag=23431 To: BigGuy ;tag=1234567 Call-ID: 12345678900@here.com CSeq: 1026 BYE Content-Length: 0 Johnston, et al. Informational [Page 58] Internet Draft SIP Service Examples November 2002 2.6 Call Forwarding Unconditional User A Proxy Gateway | | | | INVITE F1 | | |--------------->| INVITE F2 | |(100 Trying) F3 |------------->| |<---------------|180 Ringing F4| | 180 Ringing F5 |<-------------| |<---------------| 200 OK F6 | | 200 OK F7 |<-------------| |<---------------| | | ACK F8 | | |--------------->| ACK F9 | | |------------->| | Both way RTP Established | |<=============================>| | BYE F10 | | |--------------->| BYE F11 | | |------------->| | | 200 OK F12 | | 200 OK F13 |<-------------| |<---------------| | | | | User B wants all calls forwarded to the PSTN. User A calls User B. The Proxy server rewrites the request URI, and forwards the INVITE to a Gateway. Details of messaging behind the Gateway are not shown. Message Details F1 INVITE A -> Proxy INVITE sip:UserB@there.com SIP/2.0 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 Max-Forwards: 70 From: BigGuy ;tag=1234567 To: LittleGuy Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 client.here.com Johnston, et al. Informational [Page 59] Internet Draft SIP Service Examples November 2002 t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 /* Proxy forwards call by rewriting Request-URI */ F2 INVITE Proxy -> Gateway INVITE sip:+19727293660@gw1.wcom.com;user=phone SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 Record-Route: Max-Forwards: 69 From: BigGuy ;tag=1234567 To: LittleGuy Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 client.here.com t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F3 (100 Trying) Proxy -> A SIP/2.0 100 Trying Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 From: BigGuy ;tag=1234567 To: LittleGuy Call-ID: 12345600@here.com CSeq: 1 INVITE Content-Length: 0 F4 180 Ringing Gateway -> Proxy SIP/2.0 180 Ringing Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 ;received=192.0.2.54 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 Record-Route: Johnston, et al. Informational [Page 60] Internet Draft SIP Service Examples November 2002 From: BigGuy ;tag=1234567 To: LittleGuy ;tag=314159 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: Content Length:0 F5 180 Ringing Proxy -> A SIP/2.0 180 Ringing Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 Record-Route: From: BigGuy ;tag=1234567 To: LittleGuy ;tag=314159 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: Content Length: 0 F6 200 OK Gateway -> Proxy SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 ;received=192.0.2.54 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 Record-Route: From: BigGuy ;tag=1234567 To: LittleGuy ;tag=314159 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: Content-Type: application/sdp Content-Length: ... v=0 o=GATEWAY1 2890844527 2890844527 IN IP4 gatewayone.wcom.com s=Session SDP c=IN IP4 gatewayone.wcom.com t=0 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F7 200 OK Proxy -> A SIP/2.0 200 OK Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 Johnston, et al. Informational [Page 61] Internet Draft SIP Service Examples November 2002 Record-Route: From: BigGuy ;tag=1234567 To: LittleGuy ;tag=314159 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: Content-Type: application/sdp Content-Length: ... v=0 o=GATEWAY1 2890844527 2890844527 IN IP4 gatewayone.wcom.com s=Session SDP c=IN IP4 gatewayone.wcom.com t=0 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F8 ACK A -> Proxy ACK sip:+19727293660@gw1.wcom.com;user=phone SIP/2.0 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 Route: Max-Forwards: 70 From: BigGuy ;tag=1234567 To: LittleGuy ;tag=314159 Call-ID: 12345600@here.com CSeq: 1 ACK Content-Length: 0 F9 ACK Proxy -> Gateway ACK sip:+19727293660@gw1.wcom.com;user=phone SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 Max-Forwards: 69 From: BigGuy ;tag=1234567 To: LittleGuy ;tag=314159 Call-ID: 12345600@here.com CSeq: 1 ACK Content-Length: 0 F10 BYE A -> Proxy 1 BYE sip:+19727293660@gw1.wcom.com;user=phone SIP/2.0 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 Route: Max-Forwards: 70 From: BigGuy ;tag=1234567 Johnston, et al. Informational [Page 62] Internet Draft SIP Service Examples November 2002 To: LittleGuy ;tag=314159 Call-ID: 12345600@here.com CSeq: 2 BYE Content-Length: 0 F11 BYE Proxy 1 -> Gateway BYE sip:+19727293660@gw1.wcom.com;user=phone SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 Max-Forwards: 69 From: BigGuy ;tag=1234567 To: LittleGuy ;tag=314159 Call-ID: 12345600@here.com CSeq: 2 BYE Content-Length: 0 F12 200 OK Gateway -> Proxy 1 SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 ;received=192.0.2.54 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 From: BigGuy ;tag=1234567 To: LittleGuy ;tag=314159 Call-ID: 12345600@here.com CSeq: 2 BYE Content-Length: 0 F13 200 OK Proxy 1 -> A SIP/2.0 200 OK Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 From: BigGuy ;tag=1234567 To: LittleGuy ;tag=314159 Call-ID: 12345600@here.com CSeq: 2 BYE Content-Length: 0 Johnston, et al. Informational [Page 63] Internet Draft SIP Service Examples November 2002 2.7 Call Forwarding - Busy User A Proxy User B1 User B2 | | | | | INVITE F1 | | | |--------------->| INVITE F2 | | | |------------->| | |(100 Trying) F3 | | | |<---------------| 486 Busy F4 | | | |<-------------| | | | ACK F5 | | | |------------->| | | | | INVITE F6 | | |--------------------------------->| | | | 180 Ringing F7 | | |<---------------------------------| | 180 Ringing F8 | | | |<---------------| | 200 OK F9 | | |<---------------------------------| | 200 OK F10 | | | |<---------------| | | | ACK F11 | | | |--------------->| | ACK F12 | | |--------------------------------->| | Both way RTP Established | |<=================================================>| | BYE F13 | | | |--------------->| | BYE F14 | | |--------------------------------->| | | | 200 OK F15 | | 200 OK F16 |<---------------------------------| |<---------------| | | | | | | User B wants calls to B1 forwarded to B2 if B1 is busy (this information is known to the proxy). User A calls B1, B1 is busy, the proxy server places call to B2. Message Details F1 INVITE A -> Proxy INVITE sip:UserB@there.com SIP/2.0 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 Max-Forwards: 70 From: BigGuy ;tag=1234567 To: LittleGuy Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: Johnston, et al. Informational [Page 64] Internet Draft SIP Service Examples November 2002 Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 client.here.com t=0 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F2 INVITE Proxy -> B1 INVITE sip:UserB@client.there.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 Record-Route: Max-Forwards: 69 From: BigGuy ;tag=1234567 To: LittleGuy Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 client.here.com t=0 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F3 (100 Trying) Proxy -> A SIP/2.0 100 Trying Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 From: BigGuy ;tag=1234567 To: LittleGuy Call-ID: 12345600@here.com CSeq: 1 INVITE Content-Length: 0 F4 486 Busy Here B1 -> Proxy SIP/2.0 486 Busy Here Johnston, et al. Informational [Page 65] Internet Draft SIP Service Examples November 2002 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 ;received=192.0.2.54 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 From: BigGuy ;tag=1234567 To: LittleGuy ;tag=765432 Call-ID: 12345600@here.com CSeq: 1 INVITE Content-Length: 0 F5 ACK Proxy -> B1 ACK sip:UserB@client.there.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 Max-Forwards: 70 From: BigGuy ;tag=1234567 To: LittleGuy ;tag=765432 Call-ID: 12345600@here.com CSeq: 1 ACK Content-Length: 0 /* The proxy now forwards the call to B2 */ F6 INVITE Proxy -> B2 INVITE sip:UserB2@client2.there.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.2 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 Record-Route: Max-Forwards: 69 From: BigGuy ;tag=1234567 To: LittleGuy Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 client.here.com t=0 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F7 180 Ringing B2 -> Proxy Johnston, et al. Informational [Page 66] Internet Draft SIP Service Examples November 2002 SIP/2.0 180 Ringing Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.2 ;received=192.0.2.54 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 Record-Route: From: BigGuy ;tag=1234567 To: LittleGuy ;tag=7654321 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: Content-Length: 0 F8 180 Ringing Proxy -> A SIP/2.0 180 Ringing Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 Record-Route: From: BigGuy ;tag=1234567 To: LittleGuy ;tag=7654321 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: Content-Length: 0 F9 200 OK B2 -> Proxy SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.2 ;received=192.0.2.54 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 Record-Route: From: BigGuy ;tag=1234567 To: LittleGuy ;tag=7654321 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844527 2890844527 IN IP4 client2.there.com s=Session SDP c=IN IP4 client2.there.com t=0 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 Johnston, et al. Informational [Page 67] Internet Draft SIP Service Examples November 2002 F10 200 OK Proxy -> A SIP/2.0 200 OK Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 Record-Route: From: BigGuy ;tag=1234567 To: LittleGuy ;tag=7654321 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844527 2890844527 IN IP4 client2.there.com s=Session SDP c=IN IP4 client2.there.com t=0 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F11 ACK A -> Proxy ACK sip:UserB2@client2.there.com SIP/2.0 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 Route: Max-Forwards: 70 From: BigGuy ;tag=1234567 To: LittleGuy ;tag=7654321 Call-ID: 12345600@here.com CSeq: 1 ACK Content-Length: 0 F12 ACK Proxy -> B2 ACK sip:UserB2@client2.there.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 Max-Forwards: 69 From: BigGuy ;tag=1234567 To: LittleGuy ;tag=7654321 Call-ID: 12345600@here.com CSeq: 1 ACK Content-Length: 0 /* RTP streams are established between A and B2 */ Johnston, et al. Informational [Page 68] Internet Draft SIP Service Examples November 2002 /* User A eventually hangs up with User B2. */ F13 BYE A -> Proxy BYE sip:UserB2@client2.there.com SIP/2.0 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 Route: Max-Forwards: 70 From: BigGuy ;tag=1234567 To: LittleGuy ;tag=7654321 Call-ID: 12345600@here.com CSeq: 2 BYE Content-Length: 0 F14 BYE Proxy -> B2 BYE sip:UserB2@client2.there.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 Max-Forwards: 69 From: BigGuy ;tag=1234567 To: LittleGuy ;tag=7654321 Call-ID: 12345600@here.com CSeq: 2 BYE Content-Length: 0 F15 200 OK B2 -> Proxy SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 ;received=192.0.2.54 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 From: BigGuy ;tag=1234567 To: LittleGuy ;tag=7654321 Call-ID: 12345600@here.com CSeq: 2 BYE Content-Length: 0 F16 200 OK Proxy -> A SIP/2.0 200 OK Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 From: BigGuy ;tag=1234567 To: LittleGuy ;tag=7654321 Call-ID: 12345600@here.com Johnston, et al. Informational [Page 69] Internet Draft SIP Service Examples November 2002 CSeq: 2 BYE Content-Length: 0 Johnston, et al. Informational [Page 70] Internet Draft SIP Service Examples November 2002 2.8 Call Forwarding - No Answer User A Proxy User B1 User B2 | | | | | INVITE F1 | | | |--------------->| INVITE F2 | | |(100 Trying) F3 |------------->| | |<---------------|180 Ringing F4| | | 180 Ringing F5 |<-------------| | |<---------------| | | | Request Timeout | | | | | | | CANCEL F6 | | | |------------->| | | | 200 OK F7 | | | |<-------------| | | | 487 F8 | | | |<-------------| | | | ACK F9 | | | |------------->| | | | | INVITE F10 | | |--------------------------------->| | | | 180 Ringing F11 | | 180 Ringing F12|<---------------------------------| |<---------------| | 200 OK F13 | | |<---------------------------------| | 200 OK F14 | | | |<---------------| | | | ACK F15 | | | |--------------->| | ACK F16 | | |--------------------------------->| | Both way RTP Established | |<=================================================>| | BYE F17 | | | |--------------->| | BYE F18 | | |--------------------------------->| | | | 200 OK F19 | | 200 OK F20 |<---------------------------------| |<---------------| | | | | | | User B wants calls to B1 forwarded to B2 if B1 is not answered (information is known to the proxy server). User A calls B1 and no one answers. The proxy server then places the call to B2. Message Details F1 INVITE A -> Proxy INVITE sip:UserB@there.com SIP/2.0 Johnston, et al. Informational [Page 71] Internet Draft SIP Service Examples November 2002 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 Max-Forwards: 70 From: BigGuy ;tag=1234567 To: LittleGuy Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 client.here.com t=0 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F2 INVITE Proxy -> B1 INVITE sip:UserB1@client.there.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 Record-Route: Max-Forwards: 69 From: BigGuy ;tag=1234567 To: LittleGuy Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 client.here.com t=0 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F3 (100 Trying) Proxy -> A SIP/2.0 100 Trying Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 From: BigGuy ;tag=1234567 To: LittleGuy Call-ID: 12345600@here.com Johnston, et al. Informational [Page 72] Internet Draft SIP Service Examples November 2002 CSeq: 1 INVITE Content-Length: 0 F4 180 Ringing B1 -> Proxy SIP/2.0 180 Ringing Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 ;received=192.0.2.54 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 Record-Route: From: BigGuy ;tag=1234567 To: LittleGuy ;tag=3145678 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: Content-Length: 0 F5 180 Ringing Proxy -> A SIP/2.0 180 Ringing Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 Record-Route: From: BigGuy ;tag=1234567 To: LittleGuy ;tag=3145678 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: Content-Length: 0 /* B1 rings until a configurable timer expires in the Proxy. The Proxy sends Cancel and proceeds down the list of routes. */ F6 CANCEL Proxy -> B1 CANCEL sip:UserB1@client.there.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 Max-Forwards: 70 From: BigGuy To: LittleGuy Call-ID: 12345600@here.com CSeq: 1 CANCEL Content-Length: 0 F7 200 OK B1 -> Proxy SIP/2.0 200 OK Johnston, et al. Informational [Page 73] Internet Draft SIP Service Examples November 2002 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 ;received=192.0.2.54 From: BigGuy To: LittleGuy Call-ID: 12345600@here.com CSeq: 1 CANCEL Content-Length: 0 F8 487 Request Terminated B1 -> Proxy SIP/2.0 487 Request Terminated Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 ;received=192.0.2.54 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 From: BigGuy ;tag=1234567 To: LittleGuy ;tag=3145678 Call-ID: 12345600@here.com CSeq: 1 INVITE Content-Length: 0 F9 ACK Proxy -> B1 ACK sip:UserB@client.there.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.1 Max-Forwards: 70 From: BigGuy ;tag=1234567 To: LittleGuy ;tag=3145678 Call-ID: 12345600@here.com CSeq: 1 ACK Content-Length: 0 F10 INVITE Proxy -> B2 INVITE sip:UserB2@client2.there.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.2 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 Record-Route: Max-Forwards: 69 From: BigGuy ;tag=1234567 To: LittleGuy Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: Content-Type: application/sdp Content-Length: ... v=0 Johnston, et al. Informational [Page 74] Internet Draft SIP Service Examples November 2002 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 client.here.com t=0 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F11 180 Ringing B2 -> Proxy SIP/2.0 180 Ringing Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK83749.2 ;received=192.0.2.54 Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 Record-Route: From: BigGuy ;tag=1234567 To: LittleGuy ;tag=765432 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: Content-Length: 0 F12 180 Proxy -> A SIP/2.0 180 Ringing Via: SIP/2.0/UDP client.here.com:5060;branch=z9hG4bK74bf9 ;received=192.0.2.103 Record-Route: From: BigGuy ;tag=1234567 To: LittleGuy ;tag=765432 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: Content-Length: 0 F13 200 OK B2 -> Proxy SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=z9hG4bK