Internet Engineering Task Force Alan Johnston Internet Draft WorldCom Document: draft-ietf-sip-service-examples-02.txt Robert Sparks Category: Informational Chris Cunningham June 2001 Steve Donovan Expires: December 2001 dynamicsoft Kevin Summers Sonus SIP 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 SIP (Session Initiation Protocol) 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 method and Replaces header. These features are not intented 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 June 2001 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..................6 2.1 Call Hold..................................................6 2.2 Consultation Hold.........................................16 2.3 Music On Hold.............................................30 2.4 Unattended Transfer.......................................37 2.5 Attended Transfer.........................................43 2.6 Call Forwarding Unconditional.............................54 2.7 Call Forwarding - Busy....................................59 2.8 Call Forwarding - No Answer...............................65 2.9 3-way Conference..........................................72 2.10 Single Line Extension.....................................72 2.11 Find-Me...................................................73 2.12 Call Management (Incoming Call Screening).................82 2.13 Call Management (Outgoing Call Screening).................86 2.14 Call Park.................................................89 2.15 Call Pickup...............................................97 3 References...............................................106 4 Author's Addresses.......................................107 Johnston, et al. Informational [Page 2]
Internet Draft SIP Service Examples June 2001 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 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 2543 [2] with some noted updates for RFC 2543bis. Note that this document is informational, and nothing stated here should be taken as normative. RFC 2543 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. These flows assume the functionality described in the SIP Call Flow Examples document [3], which explores basic behavior and PSTN internetworking. 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 Accept-Contact [6], and some of the concepts in the 3pcc (third party call control) document [7]. 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. 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 Johnston, et al. Informational [Page 3]
Internet Draft SIP Service Examples June 2001 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 since 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. 1.4 Changes since 01 Johnston, et al. Informational [Page 4]
Internet Draft SIP Service Examples June 2001 - 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. Johnston, et al. Informational [Page 5]
Internet Draft SIP Service Examples June 2001 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 (c=0) F10 |INVITE (c=0) 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 | Johnston, et al. Informational [Page 6]
Internet Draft SIP Service Examples June 2001 | 200 OK F25 |<-------------| |<---------------| | | | | 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 here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com> Call-ID: 12345601@here.com CSeq: 1 INVITE Contact: <sip:UserA@100.101.102.103> Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 100.101.102.103 t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F2 INVITE Proxy 1 -> B INVITE sip:UserB@110.111.112.113 SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 Via: SIP/2.0/UDP here.com:5060 Record-Route: <sip:UserB@there.com;maddr=ss1.wcom.com> From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com> Call-ID: 12345601@here.com CSeq: 1 INVITE Contact: <sip:UserA@100.101.102.103> Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com Johnston, et al. Informational [Page 7]
Internet Draft SIP Service Examples June 2001 s=Session SDP c=IN IP4 100.101.102.103 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 here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com> 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=83749.1 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=314159 Call-ID: 12345601@here.com CSeq: 1 INVITE Content Length:0 F5 180 Ringing Proxy 1 -> A SIP/2.0 180 Ringing Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=314159 Call-ID: 12345601@here.com CSeq: 1 INVITE Content Length: 0 F6 200 OK B -> Proxy 1 SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 Via: SIP/2.0/UDP here.com:5060 Record-Route: <sip:UserB@there.com;maddr=ss1.wcom.com> From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=314159 Call-ID: 12345601@here.com CSeq: 1 INVITE Johnston, et al. Informational [Page 8]
Internet Draft SIP Service Examples June 2001 Contact: <sip:UserB@110.111.112.113> Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844527 2890844527 IN IP4 client.there.com s=Session SDP c=IN IP4 110.111.112.113 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 here.com:5060 Record-Route: <sip:UserB@there.com;maddr=ss1.wcom.com> From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=314159 Call-ID: 12345601@here.com CSeq: 1 INVITE Contact: <sip:UserB@110.111.112.113> Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844527 2890844527 IN IP4 client.there.com s=Session SDP c=IN IP4 110.111.112.113 t=3034423619 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F8 ACK A -> Proxy 1 ACK sip:UserB@there.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 Route: <sip:UserB@110.111.112.113> From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=314159 Call-ID: 12345601@here.com CSeq: 1 ACK Content-Length: 0 F9 ACK Proxy 1 -> B ACK sip:UserB@110.111.112.113 SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 Johnston, et al. Informational [Page 9]
Internet Draft SIP Service Examples June 2001 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;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@here.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 Route: <sip:UserA@100.101.102.103> From: LittleGuy <sip:UserB@there.com>;tag=314159 To: BigGuy <sip:UserA@here.com>;tag=1234567 Call-ID: 12345601@here.com CSeq: 1 INVITE Contact: <sip:UserB@110.111.112.113> Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844528 2890844528 IN IP4 client.there.com s=Session SDP c=IN IP4 0.0.0.0 t=3034423619 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F11 INVITE Proxy 1 -> A INVITE sip:UserA@100.101.102.103 SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 Via: SIP/2.0/UDP there.com:5060 Record-Route: <sip:UserA@here.com;maddr=ss1.wcom.com> From: LittleGuy <sip:UserB@there.com>;tag=314159 To: BigGuy <sip:UserA@here.com>;tag=1234567 Call-ID: 12345601@here.com CSeq: 1 INVITE Contact: <sip:UserB@110.111.112.113> Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844528 2890844528 IN IP4 client.there.com s=Session SDP c=IN IP4 0.0.0.0 Johnston, et al. Informational [Page 10]
Internet Draft SIP Service Examples June 2001 t=3034423619 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 /* 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=83749.1 Via: SIP/2.0/UDP there.com:5060 Record-Route: <sip:UserA@here.com;maddr=ss1.wcom.com> From: LittleGuy <sip:UserB@there.com>;tag=314159 To: BigGuy <sip:UserA@here.com>;tag=1234567 Call-ID: 12345601@here.com CSeq: 1 INVITE Contact: <sip:UserA@100.101.102.103> Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 100.101.102.103 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 there.com:5060 Record-Route: <sip:UserA@here.com;maddr=ss1.wcom.com> From: LittleGuy <sip:UserB@there.com>;tag=314159 To: BigGuy <sip:UserA@here.com>;tag=1234567 Call-ID: 12345601@here.com CSeq: 1 INVITE Contact: <sip:UserA@100.101.102.103> Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 100.101.102.103 t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 Johnston, et al. Informational [Page 11]
Internet Draft SIP Service Examples June 2001 F14 ACK B -> Proxy 1 ACK sip:UserA@here.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 Route: <sip:UserB@110.111.112.113> From: LittleGuy <sip:UserB@there.com>;tag=314159 To: BigGuy <sip:UserA@here.com>;tag=1234567 Call-ID: 12345601@here.com CSeq: 1 ACK Content-Length: 0 F15 ACK Proxy 1 -> A ACK sip:UserA@100.101.102.103 SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 Via: SIP/2.0/UDP there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=314159 To: BigGuy <sip:UserA@here.com>;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@here.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 Route: <sip:UserA@100.101.102.103> From: LittleGuy <sip:UserB@there.com>;tag=314159 To: BigGuy <sip:UserA@here.com>;tag=1234567 Call-ID: 12345601@here.com CSeq: 2 INVITE Contact: <sip:UserB@110.111.112.113> Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844529 2890844529 IN IP4 client.there.com s=Session SDP c=IN IP4 110.111.112.113 t=3034423619 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F17 INVITE Proxy 1 -> A Johnston, et al. Informational [Page 12]
Internet Draft SIP Service Examples June 2001 INVITE sip:UserA@100.101.102.103 SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 Via: SIP/2.0/UDP there.com:5060 Record-Route: <sip:UserA@here.com;maddr=ss1.wcom.com> From: LittleGuy <sip:UserB@there.com>;tag=314159 To: BigGuy <sip:UserA@here.com>;tag=1234567 Call-ID: 12345601@here.com CSeq: 2 INVITE Contact: <sip:UserB@110.111.112.113> Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844529 2890844529 IN IP4 client.there.com s=Session SDP c=IN IP4 110.111.112.113 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=83749.1 Via: SIP/2.0/UDP there.com:5060 Record-Route: <sip:UserA@here.com;maddr=ss1.wcom.com> From: LittleGuy <sip:UserB@there.com>;tag=314159 To: BigGuy <sip:UserA@here.com>;tag=1234567 Call-ID: 12345601@here.com CSeq: 2 INVITE Contact: <sip:UserA@100.101.102.103> Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 100.101.102.103 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 there.com:5060 Record-Route: <sip:UserA@here.com;maddr=ss1.wcom.com> From: LittleGuy <sip:UserB@there.com>;tag=314159 To: BigGuy <sip:UserA@here.com>;tag=1234567 Johnston, et al. Informational [Page 13]
Internet Draft SIP Service Examples June 2001 Call-ID: 12345601@here.com CSeq: 2 INVITE Contact: <sip:UserA@100.101.102.103> Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 100.101.102.103 t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F20 ACK B -> Proxy 1 ACK sip:UserA@here.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 Route: <sip:UserA@100.101.102.103> From: LittleGuy <sip:UserB@there.com>;tag=314159 To: BigGuy <sip:UserA@here.com>;tag=1234567 Call-ID: 12345601@here.com CSeq: 2 ACK Content-Length: 0 F21 ACK Proxy 1 -> A ACK sip:UserA@100.101.102.103 SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 Via: SIP/2.0/UDP there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=314159 To: BigGuy <sip:UserA@here.com>;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@there.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 Route: <sip:UserB@110.111.112.113> From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=314159 Call-ID: 12345601@here.com CSeq: 2 BYE Content-Length: 0 Johnston, et al. Informational [Page 14]
Internet Draft SIP Service Examples June 2001 F23 BYE Proxy 1 -> B BYE sip:UserB@110.111.112.113 SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;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=83749.1 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;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 here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=314159 Call-ID: 12345601@here.com CSeq: 2 BYE Content-Length: 0 Johnston, et al. Informational [Page 15]
Internet Draft SIP Service Examples June 2001 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 (c=0) F10 | |INVITE (c=0) 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 | | |--------------------------------->| Johnston, et al. Informational [Page 16]
Internet Draft SIP Service Examples June 2001 | | Both way RTP Established | | | |<=================>| | | 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 here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com> Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: <sip:UserA@100.101.102.103> Content-Type: application/sdp Content-Length: ... v=0 Johnston, et al. Informational [Page 17]
Internet Draft SIP Service Examples June 2001 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 100.101.102.103 t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F2 INVITE Proxy 1 -> B INVITE sip:UserB@110.111.112.113 SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 Via: SIP/2.0/UDP here.com:5060 Record-Route: <sip:UserB@there.com;maddr=ss1.wcom.com> From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com> Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: <sip:UserA@100.101.102.103> Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 100.101.102.103 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 here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com> 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=83749.1 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=314159 Call-ID: 12345600@here.com CSeq: 1 INVITE Johnston, et al. Informational [Page 18]
Internet Draft SIP Service Examples June 2001 Content Length:0 F5 180 Ringing Proxy 1 -> A SIP/2.0 180 Ringing Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=314159 Call-ID: 12345600@here.com CSeq: 1 INVITE Content Length: 0 F6 200 OK B -> Proxy 1 SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 Via: SIP/2.0/UDP here.com:5060 Record-Route: <sip:UserB@there.com;maddr=ss1.wcom.com> From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=314159 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: <sip:UserB@110.111.112.113> Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844527 2890844527 IN IP4 client.there.com s=Session SDP c=IN IP4 110.111.112.113 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 here.com:5060 Record-Route: <sip:UserB@there.com;maddr=ss1.wcom.com> From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=314159 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: <sip:UserB@110.111.112.113> Content-Type: application/sdp Content-Length: ... v=0 Johnston, et al. Informational [Page 19]
Internet Draft SIP Service Examples June 2001 o=UserB 2890844527 2890844527 IN IP4 client.there.com s=Session SDP c=IN IP4 110.111.112.113 t=3034423619 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F8 ACK A -> Proxy 1 ACK sip:UserB@there.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 Route: <sip:UserB@110.111.112.113> From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=314159 Call-ID: 12345600@here.com CSeq: 1 ACK Content-Length: 0 F9 ACK Proxy 1 -> B ACK sip:UserB@110.111.112.113 SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;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@here.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 Route: <sip:UserA@100.101.102.103> From: LittleGuy <sip:UserB@there.com>;tag=314159 To: BigGuy <sip:UserA@here.com>;tag=1234567 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: <sip:UserB@110.111.112.113> Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844528 2890844528 IN IP4 client.there.com s=Session SDP c=IN IP4 0.0.0.0 Johnston, et al. Informational [Page 20]
Internet Draft SIP Service Examples June 2001 t=3034423619 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F11 INVITE Proxy 1 -> A INVITE sip:UserA@100.101.102.103 SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 Via: SIP/2.0/UDP there.com:5060 Record-Route: <sip:UserA@here.com;maddr=ss1.wcom.com> From: LittleGuy <sip:UserB@there.com>;tag=314159 To: BigGuy <sip:UserA@here.com>;tag=1234567 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: <sip:UserB@110.111.112.113> Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844528 2890844528 IN IP4 client.there.com s=Session SDP c=IN IP4 0.0.0.0 t=3034423619 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F12 200 OK A -> Proxy 1 SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 Via: SIP/2.0/UDP there.com:5060 Record-Route: <sip:UserA@here.com;maddr=ss1.wcom.com> From: LittleGuy <sip:UserB@there.com>;tag=314159 To: BigGuy <sip:UserA@here.com>;tag=1234567 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: <sip:UserA@100.101.102.103> Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 100.101.102.103 t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 Johnston, et al. Informational [Page 21]
Internet Draft SIP Service Examples June 2001 F13 200 OK Proxy 1 -> B SIP/2.0 200 OK Via: SIP/2.0/UDP there.com:5060 Record-Route: <sip:UserA@here.com;maddr=ss1.wcom.com> From: LittleGuy <sip:UserB@there.com>;tag=314159 To: BigGuy <sip:UserA@here.com>;tag=1234567 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: <sip:UserA@100.101.102.103> Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 100.101.102.103 t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F14 ACK B -> Proxy 1 ACK sip:UserA@here.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 Route: <sip:UserA@100.101.102.103> From: LittleGuy <sip:UserB@there.com>;tag=314159 To: BigGuy <sip:UserA@here.com>;tag=1234567 Call-ID: 12345600@here.com CSeq: 1 ACK Content-Length: 0 F15 ACK Proxy 1 -> A ACK sip:UserA@100.101.102.103 SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 Via: SIP/2.0/UDP there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=314159 To: BigGuy <sip:UserA@here.com>;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 there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=8675309 Johnston, et al. Informational [Page 22]
Internet Draft SIP Service Examples June 2001 To: OtherGuy <sip:UserC@anywhere.com> Call-ID: 9876543210@there.com CSeq: 1 INVITE Contact: <sip:UserB@110.111.112.113> Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844526 2890844526 IN IP4 client.there.com s=Session SDP c=IN IP4 110.111.112.113 t=3034423619 0 m=audio 50170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F17 INVITE Proxy 1 -> C INVITE sip:UserC@120.121.122.123 SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 Via: SIP/2.0/UDP there.com:5060 Record-Route: <sip:UserC@anywhere.com;maddr=ss1.wcom.com> From: LittleGuy <sip:UserB@there.com>;tag=8675309 To: OtherGuy <sip:UserC@anywhere.com> Call-ID: 9876543210@there.com CSeq: 1 INVITE Contact: <sip:UserB@110.111.112.113> Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844526 2890844526 IN IP4 client.there.com s=Session SDP c=IN IP4 110.111.112.113 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 there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=8675309 To: OtherGuy <sip:UserC@anywhere.com> Call-ID: 9876543210@there.com CSeq: 1 INVITE Content-Length: 0 F19 180 Ringing C -> Proxy 1 Johnston, et al. Informational [Page 23]
Internet Draft SIP Service Examples June 2001 SIP/2.0 180 Ringing Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 Via: SIP/2.0/UDP there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=8675309 To: OtherGuy <sip:UserC@anywhere.com>;tag=456654 Call-ID: 9876543210@here.com CSeq: 1 INVITE Content Length:0 F20 180 Ringing Proxy 1 -> B SIP/2.0 180 Ringing Via: SIP/2.0/UDP there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=8675309 To: OtherGuy <sip:UserC@anywhere.com>;tag=456654 Call-ID: 9876543210@there.com CSeq: 1 INVITE Content Length: 0 F21 200 OK C -> Proxy 1 SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 Via: SIP/2.0/UDP there.com:5060 Record-Route: <sip:UserC@anywhere.com;maddr=ss1.wcom.com> From: LittleGuy <sip:UserB@there.com>;tag=8675309 To: OtherGuy <sip:UserC@anywhere.com>;tag=456654 Call-ID: 9876543210@there.com CSeq: 1 INVITE Contact: <sip:UserC@120.121.122.123> Content-Type: application/sdp Content-Length: ... v=0 o=UserC 2890844527 2890844527 IN IP4 client.anywhere.com s=Session SDP c=IN IP4 120.121.122.123 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 there.com:5060 Record-Route: <sip:UserC@anywhere.com;maddr=ss1.wcom.com> From: LittleGuy <sip:UserB@there.com>;tag=8675309 Johnston, et al. Informational [Page 24]
Internet Draft SIP Service Examples June 2001 To: OtherGuy <sip:UserC@anywhere.com>;tag=456654 Call-ID: 9876543210@there.com CSeq: 1 INVITE Contact: <sip:UserC@120.121.122.123> Content-Type: application/sdp Content-Length: ... v=0 o=UserC 2890844527 2890844527 IN IP4 client.anywhere.com s=Session SDP c=IN IP4 120.121.122.123 t=3034423619 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F23 ACK B -> Proxy 1 ACK sip:UserC@anywhere.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 Route: <sip:UserC@120.121.122.123> From: LittleGuy <sip:UserB@there.com>;tag=8675309 To: OtherGuy <sip:UserC@anywhere.com>;tag=456654 Call-ID: 9876543210@there.com CSeq: 1 ACK Content-Length: 0 F24 ACK Proxy 1 -> C ACK sip:UserC@120.121.122.123 SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 Via: SIP/2.0/UDP there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=8675309 To: OtherGuy <sip:UserC@anywhere.com>;tag=456654 Call-ID: 9876543210@there.com CSeq: 1 ACK Content-Length: 0 F25 BYE B -> Proxy 1 BYE sip:UserC@anywhere.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 Route: <sip:UserC@120.121.122.123> From: LittleGuy <sip:UserB@there.com>;tag=8675309 To: OtherGuy <sip:UserC@anywhere.com>;tag=456654 Call-ID: 9876543210@there.com CSeq: 2 BYE Content-Length: 0 Johnston, et al. Informational [Page 25]
Internet Draft SIP Service Examples June 2001 F26 BYE Proxy 1 -> C BYE sip:UserC@120.121.122.123 SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 Via: SIP/2.0/UDP there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=8675309 To: OtherGuy <sip:UserC@anywhere.com>;tag=456654 Call-ID: 9876543210@there.com CSeq: 2 BYE Content-Length: 0 F27 200 OK C -> Proxy 1 SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 Via: SIP/2.0/UDP there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=8675309 To: OtherGuy <sip:UserC@anywhere.com>;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 there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=8675309 To: OtherGuy <sip:UserC@anywhere.com>;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@here.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 Route: <sip:UserA@100.101.102.103> From: LittleGuy <sip:UserB@there.com>;tag=314159 To: BigGuy <sip:UserA@here.com>;tag=1234567 Call-ID: 12345600@here.com CSeq: 2 INVITE Contact: <sip:UserB@110.111.112.113> Content-Type: application/sdp Content-Length: ... Johnston, et al. Informational [Page 26]
Internet Draft SIP Service Examples June 2001 v=0 o=UserB 2890844529 2890844529 IN IP4 client.there.com s=Session SDP c=IN IP4 110.111.112.113 t=3034423619 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F30 INVITE Proxy 1 -> A INVITE sip:UserA@100.101.102.103 SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 Via: SIP/2.0/UDP there.com:5060 Record-Route: <sip:UserA@here.com;maddr=ss1.wcom.com> From: LittleGuy <sip:UserB@there.com>;tag=314159 To: BigGuy <sip:UserA@here.com>;tag=1234567 Call-ID: 12345600@here.com CSeq: 2 INVITE Contact: <sip:UserB@110.111.112.113> Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844529 2890844529 IN IP4 client.there.com s=Session SDP c=IN IP4 110.111.112.113 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=83749.1 Via: SIP/2.0/UDP there.com:5060 Record-Route: <sip:UserA@here.com;maddr=ss1.wcom.com> From: LittleGuy <sip:UserB@there.com>;tag=314159 To: BigGuy <sip:UserA@here.com>;tag=1234567 Call-ID: 12345600@here.com CSeq: 2 INVITE Contact: <sip:UserA@100.101.102.103> Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 100.101.102.103 t=3034423619 0 Johnston, et al. Informational [Page 27]
Internet Draft SIP Service Examples June 2001 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 there.com:5060 Record-Route: <sip:UserA@here.com;maddr=ss1.wcom.com> From: LittleGuy <sip:UserB@there.com>;tag=314159 To: BigGuy <sip:UserA@here.com>;tag=1234567 Call-ID: 12345600@here.com CSeq: 2 INVITE Contact: <sip:UserA@100.101.102.103> Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 100.101.102.103 t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F33 ACK B -> Proxy 1 ACK sip:UserA@here.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 Route: <sip:UserA@100.101.102.103> From: LittleGuy <sip:UserB@there.com>;tag=314159 To: BigGuy <sip:UserA@here.com>;tag=1234567 Call-ID: 12345600@here.com CSeq: 2 ACK Content-Length: 0 F34 ACK Proxy 1 -> A ACK sip:UserA@100.101.102.103 SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 Via: SIP/2.0/UDP there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=314159 To: BigGuy <sip:UserA@here.com>;tag=1234567 Call-ID: 12345600@here.com CSeq: 2 ACK Content-Length: 0 F35 BYE A -> Proxy 1 Johnston, et al. Informational [Page 28]
Internet Draft SIP Service Examples June 2001 BYE sip:UserB@there.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 Route: <sip:UserB@110.111.112.113> From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=314159 Call-ID: 12345600@here.com CSeq: 2 BYE Content-Length: 0 F36 BYE Proxy 1 -> B BYE sip:UserB@110.111.112.113 SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;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=83749.1 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;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 here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=314159 Call-ID: 12345600@here.com CSeq: 2 BYE Content-Length: 0 Johnston, et al. Informational [Page 29]
Internet Draft SIP Service Examples June 2001 2.3 Music On Hold User A User B Music Server | | | | INVITE F1 | | |--------------->| | |(100 Trying) F2 | | |<---------------| | | 180 Ringing F3 | | |<---------------| | | 200 OK F4 | | |<---------------| | | ACK F5 | | |--------------->| | | RTP | | |<==============>| | | | | | B places A on hold with music | | | | | | INVITE no sdp F6 | |------------->| | |200 OK sdpM F7| | |<-------------| | INVITE c=0 F7 | | |<---------------| | | 200 OK sdpA F9 | | |--------------->| | | ACK F10 | | |<---------------| | | | ACK sdpA F11 | | |------------->| | RTP | |<==============================| | | | | B Picks up the Call | | | BYE F12 | | |------------->| | | 200 OK F13 | | |<-------------| | INVITE F14 | | |<---------------| | | 200 OK F15 | | |--------------->| | | ACK F16 | | |<---------------| | | RTP | | |<==============>| | Johnston, et al. Informational [Page 30]
Internet Draft SIP Service Examples June 2001 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 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 (c=0) 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 here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com> Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: <sip:UserA@100.101.102.103> Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 100.101.102.103 t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F2 (100 Trying B -> A) SIP/2.0 100 Trying Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com> Call-ID: 12345600@here.com CSeq: 1 INVITE Content-Length: 0 F3 180 Ringing B -> A SIP/2.0 180 Ringing Johnston, et al. Informational [Page 31]
Internet Draft SIP Service Examples June 2001 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=23431 Call-ID: 12345600@here.com CSeq: 1 INVITE Content-Length: 0 F4 200 OK B -> A SIP/2.0 200 OK Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=23431 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: <sip:UserB@110.111.112.113> Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844527 2890844527 IN IP4 client.there.com s=Session SDP c=IN IP4 110.111.112.113 t=3034423619 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F5 ACK A -> B ACK sip:UserB@there.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;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 */ F6 INVITE B -> Music Server INVITE sip:music@server.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=8675309 To: Music <sip:music@server.com> Call-ID: sdjfdjfskdf@there.com CSeq: 1 INVITE Johnston, et al. Informational [Page 32]
Internet Draft SIP Service Examples June 2001 Contact: <sip:UserB@110.111.112.113> Content-Length: 0 F7 200 OK C -> B SIP/2.0 200 OK Via: SIP/2.0/UDP there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=8675309 To: Music <sip:music@server.com>;tag=90210 Call-ID: sdjfdjfskdf@there.com CSeq: 1 INVITE Contact: <sip:music@server.com> Content-Type: application/sdp Content-Length: ... v=0 o=MusicServer 2890844576 2890844576 IN IP4 music.server.com s=Session SDP c=IN IP4 50.60.70.80 t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 /* B re-INVITEs A on hold */ F8 INVITE B -> A INVITE sip:UserA@here.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 To: BigGuy <sip:UserA@here.com>;tag=1234567 From: LittleGuy <sip:UserB@there.com>;tag=23431 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: <sip:UserB@110.111.112.113> Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844528 2890844528 IN IP4 client.there.com s=Session SDP c=IN IP4 0.0.0.0 t=3034423619 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 /* A responds with normal SDP */ F9 200 OK A -> B Johnston, et al. Informational [Page 33]
Internet Draft SIP Service Examples June 2001 SIP/2.0 200 OK Via: SIP/2.0/UDP here.com:5060 To: BigGuy <sip:UserA@here.com>;tag=1234567 From: LittleGuy <sip:UserB@there.com>;tag=23431 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: <sip:UserB@100.101.102.103> Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 100.101.102.103 t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F10 ACK B -> A ACK sip:UserA@here.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 To: BigGuy <sip:UserA@here.com>;tag=1234567 From: LittleGuy <sip:UserB@there.com>;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 */ F11 ACK B -> Music Server ACK sip:music@server.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=8675309 To: Music <sip:music@server.com>;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 100.101.102.103 t=3034423619 0 m=audio 49170 RTP/AVP 0 Johnston, et al. Informational [Page 34]
Internet Draft SIP Service Examples June 2001 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 */ F12 BYE B -> Music Server BYE sip:music@server.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=8675309 To: Music <sip:music@server.com>;tag=90210 Call-ID: sdjfdjfskdf@there.com CSeq: 2 BYE Content-Length: 0 F13 200 OK Music Server -> B SIP/2.0 200 OK Via: SIP/2.0/UDP there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=8675309 To: Music <sip:music@server.com>;tag=90210 Call-ID: sdjfdjfskdf@there.com CSeq: 2 BYE Content-Length:0 /* B re-INVITEs taking A off hold */ F14 INVITE B -> A INVITE sip:UserB@there.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 To: BigGuy <sip:UserA@here.com>;tag=1234567 From: LittleGuy <sip:UserB@there.com>;tag=23431 Call-ID: 12345600@here.com CSeq: 2 INVITE Contact: <sip:UserB@110.111.112.113> Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844527 2890844527 IN IP4 client.there.com s=Session SDP c=IN IP4 110.111.112.113 t=3034423619 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 Johnston, et al. Informational [Page 35]
Internet Draft SIP Service Examples June 2001 F15 200 OK A -> B SIP/2.0 200 OK Via: SIP/2.0/UDP here.com:5060 To: BigGuy <sip:UserA@here.com>;tag=1234567 From: LittleGuy <sip:UserB@there.com>;tag=23431 Call-ID: 12345600@here.com CSeq: 2 INVITE Contact: <sip:UserB@100.101.102.103> Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 100.101.102.103 t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F16 ACK B -> A ACK sip:UserB@there.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 To: BigGuy <sip:UserA@here.com>;tag=1234567 From: LittleGuy <sip:UserB@there.com>;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 36]
Internet Draft SIP Service Examples June 2001 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 | | |<-------------------| | | BYE F7 | | |------------------->| | | 200 OK F8 | | |<-------------------| | | No RTP Session | INVITE Referred-By: A F9 | |------------------->| | | 180 Ringing F10 | | |<-------------------| | | 200 OK F11 | | |<-------------------| | | ACK F12 | | |------------------->| | | RTP | | |<==================>| | NOTIFY F13 | | |<-------------------| | | 200 OK F14 | | |------------------->| | | | | 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 37]
Internet Draft SIP Service Examples June 2001 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 there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=314159 To: BigGuy <sip:UserA@here.com> Call-ID: 12345601@here.com CSeq: 1 INVITE Contact: <sip:UserB@110.111.112.113> Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844527 2890844527 IN IP4 client.there.com s=Session SDP c=IN IP4 110.111.112.113 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 there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=314159 To: BigGuy <sip:UserA@here.com>;tag=1234567 Call-ID: 12345601@here.com CSeq: 1 INVITE Content-Length: 0 F3 200 OK A -> B SIP/2.0 200 OK Via: SIP/2.0/UDP there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=314159 To: BigGuy <sip:UserA@here.com>;tag=1234567 Call-ID: 12345601@here.com CSeq: 1 INVITE Contact: <sip:UserA@100.101.102.103> Content-Type: application/sdp Content-Length: ... Johnston, et al. Informational [Page 38]
Internet Draft SIP Service Examples June 2001 v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 100.101.102.103 t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F4 ACK B -> A ACK sip:UserA@here.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=314159 To: BigGuy <sip:UserA@here.com>;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@there.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=314159 Call-ID: 12345601@here.com CSeq: 2 REFER Refer-To: <sip:UserC@anywhere.com> Referred-By: <UserA@here.com>;ref=<sip:UserC@anywhere.com> Contact: <sip:UserA@100.101.102.103> Content-Length: 0 F6 202 Accepted B -> A SIP/2.0 202 Accepted Via: SIP/2.0/UDP there.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=314159 Call-ID: 12345601@here.com CSeq: 2 REFER Content-Length: 0 /* A now disconnects with B */ Johnston, et al. Informational [Page 39]
Internet Draft SIP Service Examples June 2001 F7 BYE A -> B BYE sip:UserA@here.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=314159 Call-ID: 12345601@here.com CSeq: 3 BYE Content-Length: 0 F8 200 OK B -> A SIP/2.0 200 OK Via: SIP/2.0/UDP there.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=314159 Call-ID: 12345601@here.com CSeq: 3 BYE Content-Length: 0 /* B attempts the transfer to C */ F9 INVITE B -> C INVITE sip:UserC@anywhere.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=8675309 To: OtherGuy <sip:UserC@anywhere.com> Call-ID: 7436222@here.com CSeq: 1 INVITE Contact: <sip:UserB@110.111.112.113> Referred-By: <UserA@here.com> Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844539 2890844539 IN IP4 client.there.com s=Session SDP c=IN IP4 110.111.112.113 t=3034423821 0 m=audio 3458 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F10 180 Ringing C -> B SIP/2.0 180 Ringing Via: SIP/2.0/UDP there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=8675309 Johnston, et al. Informational [Page 40]
Internet Draft SIP Service Examples June 2001 To: OtherGuy <sip:UserC@anywhere.com>;tag=928287 Call-ID: 7436222@here.com CSeq: 1 INVITE F11 200 OK C -> B SIP/2.0 200 OK Via: SIP/2.0/UDP there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=8675309 To: OtherGuy <sip:UserC@anywhere.com>;tag=928287 Call-ID: 7436222@here.com CSeq: 1 INVITE Contact: <sip:UserC@120.121.122.123> Content-Type: application/sdp Content-Length: ... v=0 o=UserC 2890844527 2890844527 IN IP4 client.anywhere.com s=Session SDP c=IN IP4 120.121.122.123 t=3034423619 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F12 ACK B -> C ACK sip:UserC@anywhere.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=8675309 To: OtherGuy <sip:UserC@anywhere.com>;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. */ F13 NOTIFY B -> A NOTIFY sip:UserA@here.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=314159 To: BigGuy <sip:UserA@here.com>;tag=1234567 Call-ID: 12345601@here.com CSeq: 2 NOTIFY Event: refer Content-Type: application/sip Content-Length: ... Johnston, et al. Informational [Page 41]
Internet Draft SIP Service Examples June 2001 SIP/2.0 200 OK Via: SIP/2.0/UDP there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=8675309 To: OtherGuy <sip:UserC@anywhere.com>;tag=928287 Call-ID: 7436222@here.com CSeq: 1 INVITE Contact: <sip:UserC@120.121.122.123> Content-Type: application/sdp Content-Length: ... F14 200 OK A -> B SIP/2.0 200 OK Via: SIP/2.0/UDP there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=314159 To: BigGuy <sip:UserA@here.com>;tag=1234567 Call-ID: 12345601@here.com CSeq: 2 NOTIFY Content-Length: 0 Johnston, et al. Informational [Page 42]
Internet Draft SIP Service Examples June 2001 2.5 Attended Transfer User A User B User C | | | | INVITE F1 | | |--------------->| | |(100 Trying) F2 | | |<---------------| | | 180 Ringing F3 | | |<---------------| | | 200 OK F4 | | |<---------------| | | ACK F5 | | |--------------->| | | RTP | | |<==============>| | | INVITE c=0 F6 | | |<---------------| | | 200 OK F7 | | |--------------->| | | ACK F8 | | |<---------------| | | No RTP | | | | INVITE F9 | | |------------->| | |(100 Trying) F10 | |<-------------| | | 180 Ringing F11 | |<-------------| | | 200 OK F12 | | |<-------------| | | ACK F13 | | |------------->| | | RTP | | |<============>| | |INVITE c=0 F14| | |------------->| | | 200 OK F15 | | |<-------------| | | ACK F16 | | |------------->| | | No RTP | | REFER Refer-To: C F17 | |<---------------| | |202 Accepted F18| | |--------------->| | | INVITE Replaces: B F19 | |------------------------------>| | 200 OK F20 | |<------------------------------| Johnston, et al. Informational [Page 43]
Internet Draft SIP Service Examples June 2001 | ACK F21 | |------------------------------>| | 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. The Accept-Contact header [6] is also used to ensure that the triggered INVITE reaches the same instance of the User C. Message Details F1 INVITE A -> B INVITE sip:UserB@there.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com> Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: <sip:UserA@100.101.102.103> Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 100.101.102.103 t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 Johnston, et al. Informational [Page 44]
Internet Draft SIP Service Examples June 2001 F2 (100 Trying B -> A) SIP/2.0 100 Trying Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com> Call-ID: 12345600@here.com CSeq: 1 INVITE Content-Length: 0 F3 180 Ringing B -> A SIP/2.0 180 Ringing Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=23431 Call-ID: 12345600@here.com CSeq: 1 INVITE Content-Length: 0 F4 200 OK B -> A SIP/2.0 200 OK Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=23431 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: <sip:UserB@110.111.112.113> Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844527 2890844527 IN IP4 client.there.com s=Session SDP c=IN IP4 110.111.112.113 t=3034423619 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F5 ACK A -> B ACK sip:UserB@there.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=23431 Call-ID: 12345600@here.com CSeq: 1 ACK Johnston, et al. Informational [Page 45]
Internet Draft SIP Service Examples June 2001 Content-Length: 0 /* User A and User B have established a session. User B puts User A on Hold */ F6 INVITE B -> A INVITE sip:UserA@here.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=23431 To: BigGuy <sip:UserA@here.com>;tag=1234567 Call-ID: 12345600@here.com CSeq: 1024 INVITE Contact: <sip:UserB@110.111.112.113> Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844528 2890844528 IN IP4 client.there.com s=Session SDP c=IN IP4 0.0.0.0 t=3034423619 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F7 200 OK A -> B SIP/2.0 200 OK Via: SIP/2.0/UDP there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=23431 To: BigGuy <sip:UserA@here.com>;tag=1234567 Call-ID: 12345600@here.com CSeq: 1024 INVITE Contact: <sip:UserA@100.101.102.103> Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 100.101.102.103 t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F8 ACK B -> A ACK sip:UserA@here.com SIP/2.0 Johnston, et al. Informational [Page 46]
Internet Draft SIP Service Examples June 2001 Via: SIP/2.0/UDP there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=23431 To: BigGuy <sip:UserA@here.com>;tag=1234567 Call-ID: 12345600@here.com CSeq: 1024 ACK Content-Length: 0 /* User B calls User C */ F9 INVITE B -> C INVITE sip:UserC@anywhere.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=8675309 To: OtherGuy <sip:UserC@anywhere.com> Call-ID: sdjfdjfskdf@there.com CSeq: 42 INVITE Contact: <sip:UserB@110.111.112.113> Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844528 2890844528 IN IP4 client.there.com s=Session SDP c=IN IP4 110.111.112.113 t=3034423645 0 m=audio 3458 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F10 (100 Trying C -> B) SIP/2.0 100 Trying Via: SIP/2.0/UDP there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=8675309 To: OtherGuy <sip:UserC@anywhere.com> Call-ID: sdjfdjfskdf@there.com CSeq: 42 INVITE Content-Length: 0 F11 180 Ringing C -> B SIP/2.0 180 Ringing Via: SIP/2.0/UDP there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=8675309 To: OtherGuy <sip:UserC@anywhere.com>;tag=5f35a3 Call-ID: sdjfdjfskdf@there.com CSeq: 42 INVITE Content-Length: 0 Johnston, et al. Informational [Page 47]
Internet Draft SIP Service Examples June 2001 F12 200 OK C -> B SIP/2.0 200 OK Via: SIP/2.0/UDP there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=8675309 To: OtherGuy <sip:UserC@anywhere.com>;tag=5f35a3 Call-ID: sdjfdjfskdf@there.com CSeq: 42 INVITE Contact: <sip:UserC@120.121.122.123> Content-Type: application/sdp Content-Length: ... v=0 o=UserC 2890844527 2890844527 IN IP4 client.anywhere.com s=Session SDP c=IN IP4 120.121.122.123 t=3034423619 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F13 ACK B -> C ACK sip:UserC@anywhere.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=8675309 To: OtherGuy <sip:UserC@anywhere.com>;tag=5f35a3 Call-ID: sdjfdjfskdf@there.com CSeq: 42 ACK Content-Length: 0 /* User B puts User C on hold */ F14 INVITE B -> C INVITE sip:UserC@anywhere.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=8675309 To: OtherGuy <sip:UserC@anywhere.com>;tag=5f35a3 Call-ID: sdjfdjfskdf@there.com CSeq: 43 INVITE Contact: <sip:UserB@110.111.112.113> Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844529 2890844529 IN IP4 client.there.com s=Session SDP Johnston, et al. Informational [Page 48]
Internet Draft SIP Service Examples June 2001 c=IN IP4 0.0.0.0 t=3034423645 0 m=audio 3458 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F15 200 OK C -> B SIP/2.0 200 OK Via: SIP/2.0/UDP there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=8675309 To: OtherGuy <sip:UserC@anywhere.com>;tag=5f35a3 Call-ID: sdjfdjfskdf@there.com CSeq: 43 INVITE Contact: <sip:UserC@120.121.122.123> Content-Type: application/sdp Content-Length: ... v=0 o=UserC 2890844527 2890844527 IN IP4 client.anywhere.com s=Session SDP c=IN IP4 120.121.122.123 t=3034423619 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F16 ACK B -> C ACK sip:UserC@anywhere.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=8675309 To: OtherGuy <sip:UserC@anywhere.com>;tag=5f35a3 Call-ID: sdjfdjfskdf@there.com CSeq: 43 ACK Content-Length: 0 /* User B Transfers User A to User C. */ F17 REFER B -> A REFER sip:UserA@here.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=23431 To: BigGuy <sip:UserA@here.com>;tag=1234567 Call-ID: 12345678900@here.com CSeq: 1025 REFER Refer-To: <sip:UserC@anywhere.com?Replaces= sdjfdjfskdf@there.com%3Bto-tag%3D5f35a3%3Bfrom-tag%3D8675309&Accept- Contact=%3Csip%3AUserC@120.121.122.123%3C%3Bonly%3Dtrue> Referred-By: <sip:UserB@there.com>;ref= Johnston, et al. Informational [Page 49]
Internet Draft SIP Service Examples June 2001 <sip:UserC@anywhere.com?Replaces= sdjfdjfskdf@there.com%3Bto-tag%3D5f35a3%3Bfrom-tag%3D8675309&Accept- Contact=%3Csip%3AUserC@120.121.122.123%3C%3Bonly%3Dtrue> Contact: <sip:UserB@110.111.112.113> Content-Length: 0 F18 202 Accepted A -> B SIP/2.0 202 Accepted Via: SIP/2.0/UDP there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=1234567 To: BigGuy <sip:UserA@here.com>;tag=23431 Call-ID: 12345678900@here.com CSeq: 1025 REFER Content-Length: 0 /* User A establishes session with User C which replaces the session between User B and User C */ F19 INVITE A -> C INVITE sip:UserA@here.com SIP/2.0 Via: SIP/2.0/UDP anywhere.com:5060 To: OtherGuy <sip:UserC@anywhere.com> From: BigGuy <sip:UserA@here.com>;tag=3461 Call-ID: 9435674543@here.com CSeq: 1 INVITE Referred-By: <sip:UserB@there.com>; ref=<sip:UserC@anywhere.com?Replaces= sdjfdjfskdf@there.com%3Bto-tag%3D5f35a3%3Bfrom-tag%3D8675309&Accept- Contact=%3Csip%3AUserC@120.121.122.123%3C%3Bonly%3Dtrue> Accept-Contact: <sip:UserC@120.121.122.123>;only=true Replaces: 12345600@here.com;to-tag=23431;from-tag=8675309 Contact: <sip:UserC@120.121.122.123> Content-Type: application/sdp Content-Length: ... v=0 o=UserC 2890844529 2890844529 IN IP4 client.anywhere.com s=Session SDP c=IN IP4 120.121.122.123 t=3034423643 0 m=audio 3458 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F20 200 OK C -> A SIP/2.0 200 OK Johnston, et al. Informational [Page 50]
Internet Draft SIP Service Examples June 2001 Via: SIP/2.0/UDP anywhere.com:5060 To: OtherGuy <sip:UserC@anywhere.com>;tag=ff3a From: BigGuy <sip:UserA@here.com>;tag=3461 Call-ID: 9435674543@here.com CSeq: 1 INVITE Contact: <sip:UserA@100.101.102.103> Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844538 2890844538 IN IP4 client.here.com s=Session SDP c=IN IP4 100.101.102.103 t=3034423452 0 m=audio 49172 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F21 ACK A -> C ACK sip:UserC@anywhere.com SIP/2.0 Via: SIP/2.0/UDP anywhere.com:5060 To: OtherGuy <sip:UserC@anywhere.com>;tag=ff3a From: BigGuy <sip:UserA@here.com>;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@there.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 To: LittleGuy <sip:UserB@there.com>;tag=8675309 From: OtherGuy <sip:UserC@anywhere.com>;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 here.com:5060 To: LittleGuy <sip:UserB@there.com>;tag=8675309 From: OtherGuy <sip:UserC@anywhere.com>;tag=5f35a3 Call-ID: sdjfdjfskdf@there.com CSeq: 1 BYE Content-Length: 0 Johnston, et al. Informational [Page 51]
Internet Draft SIP Service Examples June 2001 /* User A tells User B that the call has been successfully transferred */ F24 NOTIFY A -> B NOTIFY sip:UserB@there.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=23431 Call-ID: 12345678900@here.com CSeq: 2 NOTIFY Content-Type: application/sdp Content-Length: ... SIP/2.0 200 OK Via: SIP/2.0/UDP anywhere.com:5060 From: OtherGuy <sip:UserC@anywhere.com>;tag=ff3a To: BigGuy <sip:UserA@here.com>;tag=3461 Call-ID: 9435674543@anywhere.com CSeq: 1 INVITE Contact: <sip:UserA@100.101.102.103> F25 200 OK B -> C SIP/2.0 200 OK Via: SIP/2.0/UDP here.com:5060 To: LittleGuy <sip:UserB@there.com>;tag=1234567 From: OtherGuy <sip:UserC@anywhere.com>;tag=5f35a3 Call-ID: 12345678900@here.com CSeq: 2 NOTIFY Content-Length: 0 /* User B disconnects with User A */ F26 BYE B -> A BYE sip:UserA@here.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=23431 To: BigGuy <sip:UserA@here.com>;tag=1234567 Call-ID: 12345678900@here.com CSeq: 1026 BYE Content-Length: 0 F27 200 OK A -> B Johnston, et al. Informational [Page 52]
Internet Draft SIP Service Examples June 2001 SIP/2.0 200 OK Via: SIP/2.0/UDP there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=23431 To: BigGuy <sip:UserA@here.com>;tag=1234567 Call-ID: 12345678900@here.com CSeq: 1026 BYE Content-Length: 0 Johnston, et al. Informational [Page 53]
Internet Draft SIP Service Examples June 2001 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 here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com> Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: <sip:UserA@100.101.102.103> Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 100.101.102.103 t=3034423619 0 Johnston, et al. Informational [Page 54]
Internet Draft SIP Service Examples June 2001 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=83749.1 Via: SIP/2.0/UDP here.com:5060 Record-Route: <sip:UserB@there.com;maddr=ss1.wcom.com> From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com> Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: <sip:UserA@100.101.102.103> Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 100.101.102.103 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 here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com> 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=83749.1 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=314159 Call-ID: 12345600@here.com CSeq: 1 INVITE Content Length:0 Johnston, et al. Informational [Page 55]
Internet Draft SIP Service Examples June 2001 F5 180 Ringing Proxy -> A SIP/2.0 180 Ringing Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=314159 Call-ID: 12345600@here.com CSeq: 1 INVITE Content Length: 0 F6 200 OK Gateway -> Proxy SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 Via: SIP/2.0/UDP here.com:5060 Record-Route: <sip:UserB@there.com;maddr=ss1.wcom.com> From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=314159 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: <sip:+19727293660@gw1.wcom.com;user=phone> 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 here.com:5060 Record-Route: <sip:UserB@there.com;maddr=ss1.wcom.com> From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=314159 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: <sip:+19727293660@gw1.wcom.com;user=phone> Content-Type: application/sdp Content-Length: ... v=0 o=GATEWAY1 2890844527 2890844527 IN IP4 gatewayone.wcom.com s=Session SDP Johnston, et al. Informational [Page 56]
Internet Draft SIP Service Examples June 2001 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 here.com:5060 Route: <sip:+19727293660@gw1.wcom.com;user=phone> From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;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=83749.1 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;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 here.com:5060 Route: <sip:+19727293660@gw1.wcom.com;user=phone> From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;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=83749.1 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=314159 Call-ID: 12345600@here.com CSeq: 2 BYE Johnston, et al. Informational [Page 57]
Internet Draft SIP Service Examples June 2001 Content-Length: 0 F12 200 OK Gateway -> Proxy 1 SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;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 here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=314159 Call-ID: 12345600@here.com CSeq: 2 BYE Content-Length: 0 Johnston, et al. Informational [Page 58]
Internet Draft SIP Service Examples June 2001 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 here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com> Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: <sip:UserA@100.101.102.103> Johnston, et al. Informational [Page 59]
Internet Draft SIP Service Examples June 2001 Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 100.101.102.103 t=0 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F2 INVITE Proxy -> B1 INVITE sip:UserB@110.111.112.113 SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 Via: SIP/2.0/UDP here.com:5060 Record-Route: <sip:UserB@there.com;maddr=ss1.wcom.com> From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com> Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: <sip:UserA@100.101.102.103> Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 100.101.102.103 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 here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com> Call-ID: 12345600@here.com CSeq: 1 INVITE Content-Length: 0 F4 486 Busy Here B1 -> Proxy SIP/2.0 486 Busy Here Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 Via: SIP/2.0/UDP here.com:5060 Johnston, et al. Informational [Page 60]
Internet Draft SIP Service Examples June 2001 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=765432 Call-ID: 12345600@here.com CSeq: 1 INVITE Content-Length: 0 F5 ACK Proxy -> B1 ACK sip:UserB@110.111.112.113 SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;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@there.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.2 Via: SIP/2.0/UDP here.com:5060 Record-Route: <sip:UserB@there.com;maddr=ss1.wcom.com> From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com> Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: <sip:UserA@100.101.102.103> Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 100.101.102.103 t=0 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F7 180 Ringing B2 -> Proxy SIP/2.0 180 Ringing Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.2 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=7654321 Call-ID: 12345600@here.com Johnston, et al. Informational [Page 61]
Internet Draft SIP Service Examples June 2001 CSeq: 1 INVITE Content-Length: 0 F8 180 Ringing Proxy -> A SIP/2.0 180 Ringing Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=7654321 Call-ID: 12345600@here.com CSeq: 1 INVITE Content-Length: 0 F9 200 OK B2 -> Proxy SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.2 Via: SIP/2.0/UDP here.com:5060 Record-Route: <sip:UserB@there.com;maddr=ss1.wcom.com> From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=7654321 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: <sip:UserB2@110.111.112.114> Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844527 2890844527 IN IP4 client2.there.com s=Session SDP c=IN IP4 110.111.112.114 t=0 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F10 200 OK Proxy -> A SIP/2.0 200 OK Via: SIP/2.0/UDP here.com:5060 Record-Route: <sip:UserB@there.com;maddr=ss1.wcom.com> From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=7654321 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: <sip:UserB2@110.111.112.114> Content-Type: application/sdp Content-Length: ... Johnston, et al. Informational [Page 62]
Internet Draft SIP Service Examples June 2001 v=0 o=UserB 2890844527 2890844527 IN IP4 client2.there.com s=Session SDP c=IN IP4 110.111.112.114 t=0 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F11 ACK A -> Proxy ACK sip:UserB2@there.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 Route: <sip:UserB2@110.111.112.114> From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=7654321 Call-ID: 12345600@here.com CSeq: 1 ACK Content-Length: 0 F12 ACK Proxy -> B2 ACK sip:UserB2@110.111.112.114 SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=7654321 Call-ID: 12345600@here.com CSeq: 1 ACK Content-Length: 0 /* RTP streams are established between A and B2 */ /* User A eventually hangs up with User B2. */ F13 BYE A -> Proxy BYE sip:UserB2@there.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 Route: <sip:UserB2@110.111.112.114> From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=7654321 Call-ID: 12345600@here.com CSeq: 2 BYE Content-Length: 0 F14 BYE Proxy -> B2 Johnston, et al. Informational [Page 63]
Internet Draft SIP Service Examples June 2001 BYE sip:UserB2@110.111.112.114 SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;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=83749.1 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;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 here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=7654321 Call-ID: 12345600@here.com CSeq: 2 BYE Content-Length: 0 Johnston, et al. Informational [Page 64]
Internet Draft SIP Service Examples June 2001 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 Johnston, et al. Informational [Page 65]
Internet Draft SIP Service Examples June 2001 INVITE sip:UserB@there.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com> Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: <sip:UserA@100.101.102.103> Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 100.101.102.103 t=0 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F2 INVITE Proxy -> B1 INVITE sip:UserB1@110.111.112.113 SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 Via: SIP/2.0/UDP here.com:5060 Record-Route: <sip:UserB@there.com;maddr=ss1.wcom.com> From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com> Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: <sip:UserA@100.101.102.103> Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 100.101.102.103 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 here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com> Call-ID: 12345600@here.com CSeq: 1 INVITE Content-Length: 0 Johnston, et al. Informational [Page 66]
Internet Draft SIP Service Examples June 2001 F4 180 Ringing B1 -> Proxy SIP/2.0 180 Ringing Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=3145678 Call-ID: 12345600@here.com CSeq: 1 INVITE Content-Length: 0 F5 180 Ringing Proxy -> A SIP/2.0 180 Ringing Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=3145678 Call-ID: 12345600@here.com CSeq: 1 INVITE 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@110.111.112.113 SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com> Call-ID: 12345600@here.com CSeq: 1 CANCEL Content-Length: 0 F7 200 OK B1 -> Proxy SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com> Call-ID: 12345600@here.com CSeq: 1 CANCEL Content-Length: 0 F8 487 Request Terminated B1 -> Proxy Johnston, et al. Informational [Page 67]
Internet Draft SIP Service Examples June 2001 SIP/2.0 487 Request Terminated Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=3145678 Call-ID: 12345600@here.com CSeq: 1 INVITE Content-Length: 0 F9 ACK Proxy -> B1 ACK sip:UserB@110.111.112.113 SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=3145678 Call-ID: 12345600@here.com CSeq: 1 ACK Content-Length: 0 F10 INVITE Proxy -> B2 INVITE sip:UserB4@110.111.112.114 SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.2 Via: SIP/2.0/UDP here.com:5060 Record-Route: <sip:UserB@there.com;maddr=ss1.wcom.com> From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com> Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: <sip:UserA@100.101.102.103> Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 100.101.102.103 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=83749.2 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 Johnston, et al. Informational [Page 68]
Internet Draft SIP Service Examples June 2001 To: LittleGuy <sip:UserB@there.com>;tag=765432 Call-ID: 12345600@here.com CSeq: 1 INVITE Content-Length: 0 F12 180 Proxy -> A SIP/2.0 180 Ringing Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=765432 Call-ID: 12345600@here.com CSeq: 1 INVITE Content-Length: 0 F13 200 OK B2 -> Proxy SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.2 Via: SIP/2.0/UDP here.com:5060 Record-Route: <sip:UserB@there.com;maddr=ss1.wcom.com> From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=765432 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: <sip:UserB2@110.111.112.114> Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844527 2890844527 IN IP4 client2.there.com s=Session SDP c=IN IP4 110.111.112.114 t=0 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F14 200 OK Proxy -> A SIP/2.0 200 OK Via: SIP/2.0/UDP here.com:5060 Record-Route: <sip:UserB@there.com;maddr=ss1.wcom.com> From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=765432 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: <sip:UserB2@110.111.112.114> Content-Type: application/sdp Johnston, et al. Informational [Page 69]
Internet Draft SIP Service Examples June 2001 Content-Length: ... v=0 o=UserB 2890844527 2890844527 IN IP4 client2.there.com s=Session SDP c=IN IP4 110.111.112.114 t=0 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F15 ACK A -> Proxy ACK sip:UserB2@there.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 Route: <sip:UserB@110.111.112.114> From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=765432 Call-ID: 12345600@here.com CSeq: 1 ACK Content-Length: 0 F16 ACK Proxy -> B2 ACK sip:UserB2@110.111.112.114 SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=765432 Call-ID: 12345600@here.com CSeq: 1 ACK Content-Length: 0 /* RTP streams are established between A and B2. User A Hangs Up with User B2. */ F17 BYE A -> Proxy BYE sip:UserB2@there.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 Route: <sip:UserB@110.111.112.114> From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=765432 Call-ID: 12345600@here.com CSeq: 2 BYE Content-Length: 0 F18 BYE Proxy -> B2 Johnston, et al. Informational [Page 70]
Internet Draft SIP Service Examples June 2001 BYE sip:UserB2@there.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=765432 Call-ID: 12345600@here.com CSeq: 2 BYE Content-Length: 0 F19 200 OK B2 -> Proxy SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=765432 Call-ID: 12345600@here.com CSeq: 2 BYE Content-Length: 0 F20 200 OK Proxy -> A SIP/2.0 200 OK Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=765432 Call-ID: 12345600@here.com CSeq: 2 BYE Content-Length: 0 Johnston, et al. Informational [Page 71]
Internet Draft SIP Service Examples June 2001 2.9 3-way Conference User A calls User B, User B then invites user C to a 3-way call. User B will mix the audio streams (act as the conference bridge). If user B drops out of the call then the entire call is dropped. This is not a fully meshed conference, and does not make use of the concepts in the call control draft. The signaling for this scenario is as follows: User A calls User B, this establishes the call between A and B. User B calls User C, this establishes the call between B and C. User B will mix the audio streams, sending media originating at A to C, and media originating at C to A. There is no SIP signaling relationship between User A and User C. The REFER method with the Replaces header could be used by User B to drop out of the call without disconnecting A and C. 2.10 Single Line Extension Single Line Extension (Sequential, First Wins implementation), a call will ring several extensions in sequence. The extension to answer the call becomes the active set, no other sets may join the call. The signaling is described in Section 2.11 of this document. It is anticipated that Single Line Extension will be associated with help desk/call center applications rather then individual users. The signaling for this implementation of Single Line Extension and Find- Me is the same, the difference may be in the provisioning of the service. Note that the call flows for a Home Extension have not yet been designed. Johnston, et al. Informational [Page 72]
Internet Draft SIP Service Examples June 2001 2.11 Find-Me User A Proxy User User User User B1 B2 B3 B4 | | | | | | | INVITE F1 | | | | | |--------------->| INVITE F2 | | | | | |------------->| | | | |(100 Trying) F3 | | | | | |<---------------|180 Ringing F4| | | | | |<-------------| | | | | 180 Ringing F5 | | | | | |<---------------| | | | | | | Timeout | | | | | | | | | | | | CANCEL F6 | | | | | |------------->| | | | | | 200 OK F7 | | | | | |<-------------| | | | | | 487 F8 | | | | | |<-------------| | | | | | ACK F9 | | | | | |------------->| | | | | | INVITE F10 | | | | |-------------------->| | | | |480 Not Logged In F11| | | | |<--------------------| | | | | ACK F12| | | | |-------------------->| | | | | INVITE F13 | | | |--------------------------->| | | | 486 Busy Here F14 | | | |<---------------------------| | | | ACK F15 | | | |--------------------------->| | | | INVITE F16 | | |---------------------------------->| | | 180 Ringing F17 | | 180 F18 |<----------------------------------| |<---------------| 200 OK F19 | | 200 OK F20 |<----------------------------------| |<---------------| | | ACK F21 | | |--------------->| ACK F22 | | |---------------------------------->| | Both way RTP Established | |<==================================================>| | | BYE F23 | | BYE F24 |<----------------------------------| |<---------------| | Johnston, et al. Informational [Page 73]
Internet Draft SIP Service Examples June 2001 | 200 OK F25 | | |--------------->| 200 OK F26 | | |---------------------------------->| | | | A call to a user will attempt to locate that user by calling locations from a list of contacts. The location to answer the call becomes the active set, no other sets may join the call. It is anticipated that the Find-me feature will be associated with individual users. The signaling for the implementation of Single Line Extension and Find-Me is the same, the difference may be in the provisioning of the service. Message Details F1 INVITE A -> Proxy INVITE sip:UserB@there.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com> Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: <sip:UserA@100.101.102.103> Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 100.101.102.103 t= 0 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F2 INVITE Proxy -> B1 INVITE sip:UserB@110.111.112.113 SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 Via: SIP/2.0/UDP here.com:5060 Record-Route: <sip:UserB@there.com;maddr=ss1.wcom.com> From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com> Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: <sip:UserA@100.101.102.103> Content-Type: application/sdp Johnston, et al. Informational [Page 74]
Internet Draft SIP Service Examples June 2001 Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 100.101.102.103 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 here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com> Call-ID: 12345600@here.com 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=83749.1 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=765432 Call-ID: 12345600@here.com CSeq: 1 INVITE Content-Length: 0 F5 180 Ringing Proxy -> A SIP/2.0 180 Ringing Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=765432 Call-ID: 12345600@here.com CSeq: 1 INVITE Content-Length: 0 /* B1 rings for until a configurable timer in the Proxy expires. The Proxy then sends Cancel and proceeds down the list of routes. */ F6 CANCEL Proxy -> B1 CANCEL sip:UserB@110.111.112.113 SIP/2.0 Johnston, et al. Informational [Page 75]
Internet Draft SIP Service Examples June 2001 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com> Call-ID: 12345600@here.com CSeq: 1 CANCEL Content-Length: 0 F7 200 OK B1 -> Proxy SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com> 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=83749.1 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=765432 Call-ID: 12345600@here.com CSeq: 1 INVITE Content-Length: 0 F9 ACK Proxy -> B1 ACK sip:UserB@110.111.112.113 SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=765432 Call-ID: 12345600@here.com CSeq: 1 ACK Content-Length: 0 F10 INVITE Proxy -> B2 INVITE sip:UserB2@110.111.112.114 SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.2 Via: SIP/2.0/UDP here.com:5060 Record-Route: <sip:UserB@there.com;maddr=ss1.wcom.com> From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com> Call-ID: 12345600@here.com Johnston, et al. Informational [Page 76]
Internet Draft SIP Service Examples June 2001 CSeq: 1 INVITE Contact: <sip:UserA@100.101.102.103> Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 100.101.102.103 t=0 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F11 480 Not Logged In B2 -> Proxy SIP/2.0 480 Not Logged In Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.2 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=314756 Call-ID: 12345600@here.com CSeq: 1 INVITE Content-Length: 0 F12 ACK Proxy -> B2 ACK sip:UserB2@110.111.112.114 SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.2 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=314756 Call-ID: 12345600@here.com CSeq: 1 ACK Content-Length: 0 F13 INVITE Proxy -> B3 INVITE sip:UserB3@110.111.112.115 SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.3 Via: SIP/2.0/UDP here.com:5060 Record-Route: <sip:UserB@there.com;maddr=ss1.wcom.com> From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com> Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: <sip:UserA@100.101.102.103> Content-Type: application/sdp Content-Length: ... Johnston, et al. Informational [Page 77]
Internet Draft SIP Service Examples June 2001 v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 100.101.102.103 t=0 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F14 486 Busy Here B3 -> Proxy SIP/2.0 486 Busy Here Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.3 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=7654321 Call-ID: 12345600@here.com CSeq: 1 INVITE Content-Length: 0 F15 ACK Proxy -> B3 ACK sip:UserB3@110.111.112.115 SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.3 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=7654321 Call-ID: 12345600@here.com CSeq: 1 ACK Content-Length: 0 F16 INVITE Proxy -> B4 INVITE sip:UserB4@110.111.112.116 SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.4 Via: SIP/2.0/UDP here.com:5060 Record-Route: <sip:UserB@there.com;maddr=ss1.wcom.com> From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com> Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: <sip:UserA@100.101.102.103> Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 100.101.102.103 t=0 0 m=audio 49170 RTP/AVP 0 Johnston, et al. Informational [Page 78]
Internet Draft SIP Service Examples June 2001 a=rtpmap:0 PCMU/8000 F17 180 Ringing B4 -> Proxy SIP/2.0 180 Ringing Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.4 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=7137136 Call-ID: 12345600@here.com CSeq: 1 INVITE Content-Length: 0 F18 180 Ringing B4 -> Proxy SIP/2.0 180 Ringing Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=7137136 Call-ID: 12345600@here.com CSeq: 1 INVITE Content-Length: 0 F19 200 OK B4 -> Proxy SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.4 Via: SIP/2.0/UDP here.com:5060 Record-Route: <sip:UserB@there.com;maddr=ss1.wcom.com> From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=7137136 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: <sip:UserB4@110.111.112.116> Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844527 2890844527 IN IP4 client4.there.com s=Session SDP c=IN IP4 110.111.112.116 t=0 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F20 200 OK Proxy -> A Johnston, et al. Informational [Page 79]
Internet Draft SIP Service Examples June 2001 SIP/2.0 200 OK Via: SIP/2.0/UDP here.com:5060 Record-Route: <sip:UserB@there.com;maddr=ss1.wcom.com> From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=7137136 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: <sip:UserB4@110.111.112.113.116> Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844527 2890844527 IN IP4 client4.there.com s=Session SDP c=IN IP4 110.111.112.116 t=0 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F21 ACK A -> Proxy ACK sip:UserB@there.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 Route: <sip:UserB4@110.111.112.116> From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=7137136 Call-ID: 12345600@here.com CSeq: 1 ACK Content-Length: 0 F22 ACK Proxy -> B4 ACK sip:UserB4@110.111.112.116 SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=7137136 Call-ID: 12345600@here.com CSeq: 1 ACK Content-Length: 0 /* RTP streams are established between A and B4*/ /* User B4 Hangs Up with User A. */ F23 BYE B4 -> Proxy BYE sip:UserA@here.com SIP/2.0 Johnston, et al. Informational [Page 80]
Internet Draft SIP Service Examples June 2001 Via: SIP/2.0/UDP there.com:5060 Route: <sip:UserA@100.101.102.103> From: LittleGuy <sip:UserB@there.com>;tag=7137136 To: BigGuy <sip:UserA@here.com>;tag=1234567 Call-ID: 12345600@here.com CSeq: 1 BYE Content-Length: 0 F24 BYE Proxy -> A BYE sip:UserA@100.101.102.103 SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 Via: SIP/2.0/UDP there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=7137136 To: BigGuy <sip:UserA@here.com>;tag=1234567 Call-ID: 12345600@here.com CSeq: 1 BYE Content-Length: 0 F25 200 OK A -> Proxy SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 Via: SIP/2.0/UDP there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=7137136 To: BigGuy <sip:UserA@here.com>;tag=1234567 Call-ID: 12345600@here.com CSeq: 1 BYE Content-Length: 0 F26 200 OK Proxy -> B4 SIP/2.0 200 OK Via: SIP/2.0/UDP there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=7137136 To: BigGuy <sip:UserA@here.com>;tag=1234567 Call-ID: 12345600@here.com CSeq: 1 BYE Content-Length: 0 Johnston, et al. Informational [Page 81]
Internet Draft SIP Service Examples June 2001 2.12 Call Management (Incoming Call Screening) User A Proxy User B | | | | INVITE F1 | | |------------------------------>| | 305 Use Proxy F2 | |<------------------------------| | ACK F3 | | |------------------------------>| | INVITE F4 | | |--------------->| | | 407 Proxy Authorization F5 | |<---------------| | | ACK F6 | | |--------------->| | | INVITE F7 | | |--------------->| | | 403 Screening Failure (Terminating) F8 |<---------------| | | ACK F9 | | |--------------->| | | | | User B has an incoming call screening list, User A is included on the list of addresses User B will not accept calls from. User A attempts to call user B. Messages F1, F2, and F3 are included to show that User B does not accept INVITEs that have not been screened by the proxy. Message Details F1 INVITE A -> B INVITE sip:UserB@there.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com> Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: <sip:UserA@100.101.102.103> Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 100.101.102.103 t=3034423619 0 Johnston, et al. Informational [Page 82]
Internet Draft SIP Service Examples June 2001 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 /* User B only accepts INVITEs that have been screened by the proxy */ F2 305 Use Proxy B -> A SIP/2.0 305 Use Proxy Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=342123 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: <sip:ss1.wcom.com> Content-Length: 0 F3 ACK A -> B ACK sip:UserB@there.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=342123 Call-ID: 12345600@here.com CSeq: 1 ACK Content-Length: 0 /* A retries the call through the proxy */ F4 INVITE A -> Proxy 1 INVITE sip:UserB@there.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com> Call-ID: 12345600@here.com CSeq: 2 INVITE Contact: <sip:UserA@100.101.102.103> Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 100.101.102.103 t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 Johnston, et al. Informational [Page 83]
Internet Draft SIP Service Examples June 2001 /* Proxy 1 challenges User A for authentication */ F5 407 Proxy Authorization Required Proxy 1 -> A SIP/2.0 407 Proxy Authorization Required Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=7886765 Call-ID: 12345600@here.com CSeq: 2 INVITE Proxy-Authenticate: Digest realm="MCI WorldCom SIP", domain="sip:ss1.wcom.com", nonce="ea9c8e88df84f1cec4341ae6cbe5a359", opaque="", stale=FALSE, algorithm=MD5 Content-Length: 0 F6 ACK A -> Proxy 1 ACK sip:UserB@there.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=7886765 Call-ID: 12345600@here.com CSeq: 2 ACK Content-Length: 0 /* User A responds by sending an INVITE with authentication credentials in it. */ F7 INVITE A -> Proxy 1 INVITE sip:UserB@there.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com> Call-ID: 12345600@here.com CSeq: 3 INVITE Contact: <sip:UserA@100.101.102.103> Proxy-Authorization: DIGEST username="UserA", realm="MCI WorldCom SIP", nonce="ae9137be1c87d175c2dd63302a0d6e0a", opaque="", uri="sip:ss1.wcom.com", response="bbaec39f943bdcb3620d90afc548a45c" Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP Johnston, et al. Informational [Page 84]
Internet Draft SIP Service Examples June 2001 c=IN IP4 100.101.102.103 t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F8 403 Screening Failure (Terminating) Proxy 1 -> A SIP/2.0 403 Screening Failure (Terminating) Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=ffe254 Call-ID: 12345600@here.com CSeq: 3 INVITE Content-Length: 0 F9 ACK A -> Proxy 1 ACK sip:UserB@there.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=ffe254 Call-ID: 12345600@here.com CSeq: 3 ACK Content-Length: 0 Johnston, et al. Informational [Page 85]
Internet Draft SIP Service Examples June 2001 2.13 Call Management (Outgoing Call Screening) User A Proxy User B | | | | INVITE F1 | | |--------------->| | | 407 Proxy Authorization F2 | |<---------------| | | ACK F3 | | |--------------->| | | INVITE F4 | | |--------------->| | | 403 Screening Failure (Originating) F5 |<---------------| | | ACK F6 | | |--------------->| | | | | User A has an outgoing call screening list, User B is included on the list of addresses User A will not be able to place a call to. User A attempts to call user B. Message Details F1 INVITE A -> Proxy 1 INVITE sip:UserB@there.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com> Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: <sip:UserA@100.101.102.103> Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 100.101.102.103 t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 /* Proxy 1 challenges User A for authentication */ F2 407 Proxy Authorization Required Proxy 1 -> A Johnston, et al. Informational [Page 86]
Internet Draft SIP Service Examples June 2001 SIP/2.0 407 Proxy Authorization Required Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=90210 Call-ID: 12345600@here.com CSeq: 1 INVITE Proxy-Authenticate: Digest realm="MCI WorldCom SIP", domain="sip:ss1.wcom.com", nonce="ea9c8e88df84f1cec4341ae6cbe5a359", opaque="", stale=FALSE, algorithm=MD5 Content-Length: 0 F3 ACK A -> Proxy 1 ACK sip:UserB@there.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=90210 Call-ID: 12345600@here.com CSeq: 1 ACK Content-Length: 0 /* User A responds be sending an INVITE with authentication credentials in it. */ F4 INVITE A -> Proxy 1 INVITE sip:UserB@there.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com> Call-ID: 12345600@here.com CSeq: 2 INVITE Contact: <sip:UserA@100.101.102.103> Proxy-Authorization: DIGEST username="UserA", realm="MCI WorldCom SIP", nonce="cb360afc54bbaec39f943bd820d9a45c", opaque="", uri="sip:ss1.wcom.com", response="b9d2e5bcdec9f69ab2a9b44f270285a6" Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 100.101.102.103 t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F5 403 Screening Failure (Originating) Proxy 1 -> A Johnston, et al. Informational [Page 87]
Internet Draft SIP Service Examples June 2001 SIP/2.0 403 Screening Failure (Originating) Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=18017 Call-ID: 12345600@here.com CSeq: 2 INVITE Content-Length: 0 F6 ACK A -> Proxy 1 ACK sip:UserB@there.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=18017 Call-ID: 12345600@here.com CSeq: 2 ACK Content-Length: 0 Johnston, et al. Informational [Page 88]
Internet Draft SIP Service Examples June 2001 2.14 Call Park User A User B Park Server | | | | INVITE F1 | | |------------->| | |180 Ringing F2| | |<-------------| | | 200 OK F3 | | |<-------------| | | ACK F4 | | |------------->| | | RTP Media | | |<============>| | | User B Parks Call | | | REFER Refer-To: A F5 | |------------->| | | 202 F6 | | |<-------------| | INVITE F7 Referred-By: B | |<----------------------------| | 200 OK F8 | |---------------------------->| | ACK F9 | |<----------------------------| | RTP Music | |<===========================>| | BYE F10 | | |------------->| NOTIFY F12 | | 200 OK F11 |<-------------| |<-------------| 200 OK F13 | | |------------->| | User B picks up the call | | | | | INVITE F14 | | |<-------------| | | 200 F15 | | |------------->| | | ACK F16 | | |<-------------| | | RTP Media | | |<============>| | | BYE F17 | |---------------------------->| | 200 OK F18 | |<----------------------------| | No more RTP Music | In this example, User A calls User B. User B then parks the call at the Park Server by sending a REFER to the Park Server. The server Johnston, et al. Informational [Page 89]
Internet Draft SIP Service Examples June 2001 sends an INVITE to A which replaces the session between A and B. The call is accepted by A and causes A to send a BYE to B. User B receives notification of the successful park, and also receives the Call-ID in the application/sip body of the NOTIFY response. When User B wishes to retrieve the call, a new INVITE is sent to A which replaces the session with the Park Server. User A accepts the call and sends a BYE to the Park Server. If someone besides User B retrieves the call, then this becomes Call Park and Pickup. Note that this call is a special case of call transfer. Note also that this flow could also be used for Music on Hold. Message Details. F1 INVITE A -> B INVITE sip:UserB@there.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com> Call-ID: 12345601@here.com CSeq: 1 INVITE Contact: <sip:UserA@100.101.102.103> Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 100.101.102.103 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 there.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=314159 Call-ID: 12345601@here.com CSeq: 1 INVITE Content-Length: 0 F3 200 OK B -> A Johnston, et al. Informational [Page 90]
Internet Draft SIP Service Examples June 2001 SIP/2.0 200 OK Via: SIP/2.0/UDP there.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=314159 Call-ID: 12345601@here.com CSeq: 1 INVITE Contact: <sip:UserB@110.111.112.113> Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844527 2890844527 IN IP4 client.there.com s=Session SDP c=IN IP4 110.111.112.113 t=3034423619 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F4 ACK A -> B ACK sip:UserB@there.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=314159 Call-ID: 12345601@here.com CSeq: 1 ACK Content-Length: 0 /* User B REFERs Park Server to establish session with A which replaces the established session between A and B. Note that there is no session established between B and the Park Server. */ F5 REFER B -> Park Server REFER sip:park@server.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=02134 To: Park Server <sip:park@server.com> Call-ID: 4802029847@there.com CSeq: 1 REFER Refer-To: <sip:UserA@here.com?Replaces= 12345601@here.com%3Bfrom-tag%3D314159%3Bto-tag%3D1234567&Accept- Contact=%3Csip%3AUserA@100.101.102.103%3C%3Bonly%3Dtrue> Referred-By: <sip:UserB@there.com> ;ref=<sip:UserA@here.com?Replaces= 12345601@here.com%3Bfrom-tag%3D314159%3Bto-tag%3D1234567&Accept- Contact=%3Csip%3AUserA@100.101.102.103%3C%3Bonly%3Dtrue> Contact: <sip:UserB@110.111.112.113> Content-Length: 0 Johnston, et al. Informational [Page 91]
Internet Draft SIP Service Examples June 2001 F6 202 Accepted Park Server -> B SIP/2.0 202 Accepted Via: SIP/2.0/UDP there.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=02134 To: Park Server <sip:park@server.com>;tag=56323 Call-ID: 4802029847@there.com CSeq: 1 REFER Content-Length: 0 /* Park Server places call to User A to replace session between A and B */ F7 INVITE Park Server -> A INVITE sip:UserA@100.101.102.103 SIP/2.0 Via: SIP/2.0/UDP server.com:5060 From: <sip:park@server.com>;tag=0111 To: <sip:UserA@100.101.102.103> Call-ID: a5-75-34-12-76@server.com CSeq: 1 INVITE Referred-By: <sip:UserB@there.com> ;ref=<sip:UserA@100.101.102.103?Replaces=12345601@here.com%3Bfrom- tag%3D314159%3Bto-tag%3D1234567> Contact: <sip:park@server.com> Replaces: 12345601@here.com;from-tag=314159;to-tag=1234567 Accept-Contact: <sip:UserA@100.101.102.103>;only=true Content-Type: application/sdp Content-Length: ... v=0 o=ParkServer 2890844576 2890844576 IN IP4 Park.server.com s=Session SDP c=IN IP4 50.60.70.80 t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F8 200 OK A-> Park Server SIP/2.0 200 OK Via: SIP/2.0/UDP server.com:5060 From: <sip:park@server.com>;tag=0111 To: BigGuy <sip:UserA@100.101.102.103>;tag=098594 Call-ID: a5-75-34-12-76@server.com CSeq: 1 INVITE Contact: <sip:UserA@100.101.102.103> Johnston, et al. Informational [Page 92]
Internet Draft SIP Service Examples June 2001 Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 100.101.102.103 t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 a=recvonly F9 ACK Park Server -> A ACK sip:UserA@100.101.102.103 SIP/2.0 Via: SIP/2.0/UDP server.com:5060 From: <sip:park@server.com>;tag=0111 To: BigGuy <sip:UserA@100.101.102.103>;tag=098594 Call-ID: a5-75-34-12-76@server.com CSeq: 1 ACK Content-Length: 0 F10 BYE A -> B ACK sip:UserB@there.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=314159 Call-ID: 12345601@here.com CSeq: 2 BYE Content-Length: 0 F11 200 OK B -> A SIP/2.0 200 OK Via: SIP/2.0/UDP there.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=314159 Call-ID: 12345601@here.com CSeq: 2 BYE Content-Length: 0 /* Park Server reports success back to B by returning all the SIP headers in 200 OK response */ F12 NOTIFY Park Server -> B Johnston, et al. Informational [Page 93]
Internet Draft SIP Service Examples June 2001 NOTIFY sip:UserB@there.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 To: LittleGuy <sip:UserB@there.com>;tag=02134 From: Park Server <sip:park@server.com>;tag=56323 Call-ID: 4802029847@there.com CSeq: 1 NOTIFY Event: refer Content-Type: application/sip Content-Length: ... SIP/2.0 200 OK Via: SIP/2.0/UDP server.com:5060 From: <sip:park@server.com>;tag=0111 To: BigGuy <sip:UserA@100.101.102.103>;tag=098594 Call-ID: a5-75-34-12-76@server.com CSeq: 1 INVITE Contact: <sip:UserA@100.101.102.103> F13 200 OK B -> Park Server SIP/2.0 200 OK Via: SIP/2.0/UDP here.com:5060 To: LittleGuy <sip:UserB@there.com>;tag=02134 From: Park Server <sip:park@server.com>;tag=56323 Call-ID: 4802029847@there.com CSeq: 1 NOTIFY Content-Length: 0 /* User A is now parked at the Park Server */ /* User B picks up the call by sending an INVITE to A which replaces the existing session with the Park/Park Server. Note that B knows the Call-ID of the existing session from the NOTIFY response. */ /* Another UA besides B can pickup the call as long as it can construct the appropriate Replaces header. */ F14 INVITE B -> A INVITE sip:UserA@there.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=5893461 To: BigGuy <sip:UserA@here.com> Call-ID: 6485356@here.com CSeq: 1 INVITE Contact: <sip:UserB@110.111.112.113> Replaces: a5-75-34-12-76@server.com;from-tag=098594;to-tag=0111 Content-Type: application/sdp Content-Length: ... Johnston, et al. Informational [Page 94]
Internet Draft SIP Service Examples June 2001 v=0 o=UserB 2890844528 2890844528 IN IP4 client.there.com s=Session SDP c=IN IP4 110.111.112.113 t=3034423619 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F15 200 OK A -> B SIP/2.0 200 OK Via: SIP/2.0/UDP here.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=5893461 To: BigGuy <sip:UserA@here.com>;tag=222 Call-ID: 6485356@here.com CSeq: 1 INVITE Contact: <sip:UserA@100.101.102.103> Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844527 2890844527 IN IP4 client.here.com s=Session SDP c=IN IP4 100.101.102.103 t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F16 ACK B -> A ACK sip:UserA@there.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 From: LittleGuy <sip:UserB@there.com>;tag=5893461 To: BigGuy <sip:UserA@here.com>;tag=222 Call-ID: 6485356@here.com CSeq: 1 ACK Content-Length: 0 /* A replaces the session to the Park Server with the new session and generates a BYE to disconnect the Park Server */ F17 BYE A -> Park Server BYE sip:park@server.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=098594 To: <sip:park@server.com>;tag=0111 Johnston, et al. Informational [Page 95]
Internet Draft SIP Service Examples June 2001 Call-ID: a5-75-34-12-76@server.com CSeq: 1 BYE Content-Length: 0 F18 200 OK Park Server -> A SIP/2.0 200 OK Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=098594 To: <sip:park@server.com>;tag=0111 Call-ID: a5-75-34-12-76@server.com CSeq: 1 BYE Content-Length: 0 Johnston, et al. Informational [Page 96]
Internet Draft SIP Service Examples June 2001 2.15 Call Pickup User A Proxy User B1 User B2 | | | | | INVITE F1 | | | |--------------->| INVITE F2 | | |(100 Trying) F3 |------------->| | |<---------------|180 Ringing F4| | | 180 Ringing F5 |<-------------| | |<---------------| | | | | | REGISTER F6 | | |<---------------------------------| | | | 200 OK F7 | | |--------------------------------->| | | | INVITE F8 | | |--------------------------------->| | | | 180 Ringing F9 | | 180 Ringing F10|<---------------------------------| |<---------------| | 200 OK F11 | | |<---------------------------------| | 200 OK F12 | CANCEL F13 | | |<---------------|------------->| | | ACK F15 | 200 OK F14 | | |--------------->|<-------------| | | | | ACK F16 | | |--------------------------------->| | | 487 F17 | | | |<-------------| | | | ACK F18 | | | |------------->| | | Both way RTP Established | |<=================================================>| | BYE F19 | | | |--------------->| | BYE F20 | | |--------------------------------->| | | | 200 OK F21 | | 200 OK F22 |<---------------------------------| |<---------------| | | | | | | User B1 and B2 are part of a work group that can pick up each others calls. User A calls B1 who does not answer. User B2 wishes to pick up the call and sends a REGISTER with Expires:0 to the proxy which recognizes this as a call pickup not a register based on the Request- URI. The proxy server then forks the INVITE by sending it to B2 who answers. The proxy then cancels the B1 fork of the INVITE. Message Details Johnston, et al. Informational [Page 97]
Internet Draft SIP Service Examples June 2001 F1 INVITE A -> Proxy INVITE sip:UserB@there.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com> Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: <sip:UserA@100.101.102.103> Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 100.101.102.103 t=0 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F2 INVITE Proxy -> B1 INVITE sip:UserB1@110.111.112.113 SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 Via: SIP/2.0/UDP here.com:5060 Record-Route: <sip:UserB@there.com;maddr=ss1.wcom.com> From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com> Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: <sip:UserA@100.101.102.103> Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 100.101.102.103 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 here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com> Call-ID: 12345600@here.com Johnston, et al. Informational [Page 98]
Internet Draft SIP Service Examples June 2001 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=83749.1 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=3145678 Call-ID: 12345600@here.com CSeq: 1 INVITE Content-Length: 0 F5 180 Ringing Proxy -> A SIP/2.0 180 Ringing Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=3145678 Call-ID: 12345600@here.com CSeq: 1 INVITE Content-Length: 0 /* User B2 decides to pick up the call */ F6 REGISTER B2 -> Proxy REGISTER sip:pickupgroup37.ss1.wcom.com SIP/2.0 Via: SIP/2.0/UDP b2.there.com:5060 From: LittleGuy <sip:UserB2@there.com>;tag=8675309 To: LittleGuy <sip:UserB2@there.com> Call-ID: 563456212@b2.there.com CSeq: 1 REGISTER Contact: <sip:UserB2@110.111.112.114> Expires: 0 Content-Length: 0 F7 200 OK Proxy -> B2 SIP/2.0 200 OK Via: SIP/2.0/UDP b2.there.com:5060 From: LittleGuy <sip:UserB2@there.com>;tag=8675309 To: LittleGuy <sip:UserB2@there.com>;tag=2913 Call-ID: 563456212@b2.there.com CSeq: 1 REGISTER Contact: <sip:UserB2@110.111.112.114> Johnston, et al. Informational [Page 99]
Internet Draft SIP Service Examples June 2001 Expires: 0 Content-Length: 0 /* Proxy recognizes the REGISTER directed at pickgroup37.ss1.wcom.com as being a call pickup attempt for the pending INVITE to B1. The proxy then forks the INVITE and sends it to B2. */ F8 INVITE Proxy -> B2 INVITE sip:UserB2@there.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.2 Via: SIP/2.0/UDP here.com:5060 Record-Route: <sip:UserB@there.com;maddr=ss1.wcom.com> From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com> Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: <sip:UserA@100.101.102.103> Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 100.101.102.103 t=0 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F9 180 Ringing B2 -> Proxy SIP/2.0 180 Ringing Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.2 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=765432 Call-ID: 12345600@here.com CSeq: 1 INVITE Content-Length: 0 F10 180 Proxy -> A SIP/2.0 180 Ringing Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=765432 Call-ID: 12345600@here.com CSeq: 1 INVITE Johnston, et al. Informational [Page 100]
Internet Draft SIP Service Examples June 2001 Content-Length: 0 F11 200 OK B2 -> Proxy SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.2 Via: SIP/2.0/UDP here.com:5060 Record-Route: <sip:UserB@there.com;maddr=ss1.wcom.com> From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=765432 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: <sip:UserB2@110.111.112.114> Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844527 2890844527 IN IP4 client2.there.com s=Session SDP c=IN IP4 110.111.112.114 t=0 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F12 200 OK Proxy -> A SIP/2.0 200 OK Via: SIP/2.0/UDP here.com:5060 Record-Route: <sip:UserB@there.com;maddr=ss1.wcom.com> From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=765432 Call-ID: 12345600@here.com CSeq: 1 INVITE Contact: <sip:UserB2@110.111.112.114> Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844527 2890844527 IN IP4 client2.there.com s=Session SDP c=IN IP4 110.111.112.114 t=0 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 /* The Proxy detects the answer by B2 and cancels the B1 branch */ F13 CANCEL Proxy -> B1 Johnston, et al. Informational [Page 101]
Internet Draft SIP Service Examples June 2001 CANCEL sip:UserB1@110.111.112.113 SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com> Call-ID: 12345600@here.com CSeq: 1 CANCEL Content-Length: 0 F14 200 OK B1 -> Proxy SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com> Call-ID: 12345600@here.com CSeq: 1 CANCEL Content-Length: 0 F15 ACK A -> Proxy ACK sip:UserB2@there.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 Route: <sip:UserB@110.111.112.114> From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=765432 Call-ID: 12345600@here.com CSeq: 1 ACK Content-Length: 0 F16 ACK Proxy -> B2 ACK sip:UserB2@110.111.112.114 SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com> To: LittleGuy <sip:UserB@there.com>;tag=765432 Call-ID: 12345600@here.com CSeq: 1 ACK Content-Length: 0 F17 487 Request Terminated B1 -> Proxy SIP/2.0 487 Request Terminated Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 Johnston, et al. Informational [Page 102]
Internet Draft SIP Service Examples June 2001 To: LittleGuy <sip:UserB@there.com>;tag=3145678 Call-ID: 12345600@here.com CSeq: 1 INVITE Content-Length: 0 F18 ACK Proxy -> B1 ACK sip:UserB1@110.111.112.113 SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=3145678 Call-ID: 12345600@here.com CSeq: 1 ACK Content-Length: 0 /* RTP streams are established between A and B2. User A Hangs Up with User B2. */ F19 BYE A -> Proxy BYE sip:UserB2@there.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 Route: <sip:UserB@110.111.112.114> From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=765432 Call-ID: 12345600@here.com CSeq: 2 BYE Content-Length: 0 F20 BYE Proxy -> B2 BYE sip:UserB2@there.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=765432 Call-ID: 12345600@here.com CSeq: 2 BYE Content-Length: 0 F21 200 OK B2 -> Proxy SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=83749.1 Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=765432 Johnston, et al. Informational [Page 103]
Internet Draft SIP Service Examples June 2001 Call-ID: 12345600@here.com CSeq: 2 BYE Content-Length: 0 F22 200 OK Proxy -> A SIP/2.0 200 OK Via: SIP/2.0/UDP here.com:5060 From: BigGuy <sip:UserA@here.com>;tag=1234567 To: LittleGuy <sip:UserB@there.com>;tag=765432 Call-ID: 12345600@here.com CSeq: 2 BYE Content-Length: 0 Johnston, et al. Informational [Page 104]
Internet Draft SIP Service Examples June 2001 Acknowledgements The authors wish to thank the following individuals for their assistance and review of this call flows document: Rohan Mahey, Jonathan Rosenberg, Hemant Agrawal, Henry Sinnreich, Dean Willis, David Devanatham, Joe Pizzimenti, Matt Cannon, John Hearty, the whole MCI WorldCom IPOP Design team, Scott Orton, Greg Osterhout, Pat Sollee, Doug Weisenberg, Danny Mistry, Steve McKinnon, and Denise Ingram, Denise Caballero, Tom Redman, Ilya Slain, Pat Sollee, John Truetken, and others from MCI WorldCom, 3Com, Cisco, Lucent and Nortel. Johnston, et al. Informational [Page 105]
Internet Draft SIP Service Examples June 2001 3 References [1] S. Bradner, "The Internet Standards Process -- Revision 3", BCP 9, RFC 2026, October 1996. [2] M. Handley, H. Schulzrinne, E. Schooler, and J. Rosenberg, "SIP: Session Initiation Protocol", RFC 2543, March 1999. [3] A. Johnston, S. Donovan, R. Sparks, C. Cunningham, D. Willis, J. Rosenberg, and H. Schulzrinne, "SIP Call Flow Examples", Internet Draft, Internet Engineering Task Force, June 2001, Work in Progress. [4] R. Sparks, "SIP Call Control Transfer", Internet Draft, Internet Engineering Task Force, February 2001, Work in Progress. [5] B. Biggs and R. Dean, "The SIP Replaces header," Internet Draft, Internet Engineering Task Force, November 2000, Work in Progress. [6] H. Schulzrinne and J. Rosenberg, "SIP Caller Preferences and Callee Capabilities," Internet Engineering Task Force, June 2001, Work in Progress. [7] J. Rosenberg, J. Peterson, H. Schulzrinne, and G. Camarillo, "Third Party Call Control in SIP," Internet Engineering Task Force, March 2001, Work in Progress. Johnston, et al. Informational [Page 106]
Internet Draft SIP Service Examples June 2001 4 Author's Addresses Alan Johnston Email: alan.johnston@wcom.com sip:alan.johnston@siptest.wcom.com Robert Sparks Email: rsparks@dynamicsoft.com Chris Cunningham Email: ccunningham@dynamicsoft.com Steve Donovan Email: sdonovan@dynamicsoft.com Kevin Summers Email: kevin.summers@sonusnet.com Copyright Notice "Copyright (C) The Internet Society 2001. All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Johnston, et al. Informational [Page 107]
