Internet Engineering Task Force Robert Sparks Internet Draft Chris Cunningham draft-sparks-sip-service-examples-00 Alan Johnston October 1999 Steve Donovan Kevin Summers MCI WorldCom SIP Telephony Service Examples With Call Flows 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 is an informational draft showing one implementation of a set of traditional telephony services using the Session Initiation Protocol. Diagrams of the SIP conversations and the complete SIP messages are provided. Sparks, et. al. [Page 1]
Internet Draft Service Examples October 1999 Table of Contents: 1 Overview:.........................................................3 2 Call Flows - IP Desktop Services Features.........................4 2.1 Call Hold.......................................................4 2.2 Consultation Hold..............................................16 2.3 Unattended Transfer............................................32 2.4 Attended Transfer..............................................48 2.5 Call Forwarding Unconditional..................................48 2.6 Call Forwarding - Busy.........................................54 2.7 Call Forwarding û No Answer....................................61 2.8 3-way Call.....................................................67 2.9 Single Line Extension..........................................67 2.10 Find-Me.......................................................68 2.11 Call Management (Incoming Call Screening).....................77 2.12 Call Management (Outgoing Call Screening).....................80 3 Author's Addresses...............................................83 4 Acknowledgments..................................................83 5 References.......................................................84 MCI WorldCom [Page 2]
Internet Draft Service Examples October 1999 1 Overview: This document provides call flows detailing a SIP implementation of the following traditional telephony services: Call Hold Consultation Hold Unattended Transfer Attended Transfer Unconditional Call Forwarding Busy Call Forwarding No Answer Call Forwarding 3-way Call Single-Line Extension Find-Me Incoming Call Screening 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 assume the functionality described in "SIP Telephony Call Flow Examples" [2], which explores basic behavior and PSTN internetworking. Some of the scenarios described herein make use of "SIP Call Control Services" [3]. 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. All communication between these user agents and the remaining network elements MUST occur through the edge proxy. To improve the clarity of this document, this authentication step is not explicitly shown in all flows. These flows use SIP as defined by RFC2543 [4] with the following changes/extensions assumed throughout: A Contact header is included with every INVITE and 200 OK. A Content-Length header is present in every message, set to zero if there is no message body. The final entry in a Route header is always the Contact information obtained from the INVITE or 200 OK messages. Each call flow is presented with a textual description of the scenario, a message flow diagram showing the messages exchanged between separate network elements, and the detailed contents of each message shown in the diagram. MCI WorldCom [Page 3]
Internet Draft Service Examples October 1999 Legend for Message Flows: Dashed lines represent SIP messages. Optional messages have their labels surrounded with parenthesis. The direction of the message is indicated with < or >. Example: Invite ------------> Media paths are denoted with alternating dashes and ms. Direction is indicated as above. Example: Both way RTP established <-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-> 2 Call Flows - IP Desktop Services Features 2.1 Call Hold User A calls User B, User B places call on hold. User B then takes call off hold. User A hangs up call. User A Proxy User B | | | | INVITE F1 | | |--------------->| | | | | | 407 Proxy Authorization F2 | |<---------------| | | | | | ACK F3 | | |--------------->| | | | | | INVITE F4 | | |--------------->| | | | INVITE F5 | |(100 Trying) F6 |------------->| |<---------------| | | |180 Ringing F7| | 180 Ringing F8 |<-------------| |<---------------| | | | 200 OK F9 | | 200 OK F10 |<-------------| |<---------------| | | | | MCI WorldCom [Page 4]
Internet Draft Service Examples October 1999 | ACK F11 | | |--------------->| ACK F12 | | |------------->| | | | | Both way RTP Established | |<-m-m-m-m-m-m-m-m-m-m-m-m-m-m->| | | | | |INVITE (c=0) F13 |INVITE (c=0) F14|<-------------| |<---------------| | | | | | 200 OK F15 | | |--------------->| 200 OK F16 | | |------------->| | | | | | ACK F17 | | ACK F18 |<-------------| |<---------------| | | | | | No RTP Sent! | | | | | | INVITE F19 | | INVITE F20 |<-------------| |<---------------| | | | | | 200 OK F21 | | |--------------->| 200 OK F22 | | |------------->| | | | | | ACK F23 | | ACK F24 |<-------------| |<---------------| | | | | | Both way RTP Established | |<-m-m-m-m-m-m-m-m-m-m-m-m-m-m->| | | | | BYE F25 | | |--------------->| BYE F26 | | |------------->| | | | | | 200 OK F27 | | 200 OK F28 |<-------------| |<---------------| | | | | F1 Invite A->Proxy1 MCI WorldCom [Page 5]
Internet Draft Service Examples October 1999 INVITE sip:UserB@ss1.wcom.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com> Call-Id: 12345600@here.com CSeq: 1 INVITE Contact: TheBigGuy <sip:UserA@here.com> 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 /* Proxy 1 challenges User A for authentication */ 407 Proxy Authorization Required Proxy 1 -> A SIP/2.0 407 Proxy Authorization Required Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com> Call-Id: 12345600@here.com CSeq: 1 INVITE Proxy-Authenticate: Digest realm="MCI WorldCom SIP", domain="wcom.com", nonce="ea9c8e88df84f1cec4341ae6cbe5a359", opaque="", stale="FALSE", algorithm="MD5" Content-Length: 0 F3 ACK A -> Proxy 1 ACK sip:UserB@ss1.wcom.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com> Call-Id: 12345600@here.com CSeq: 1 ACK Content-Length:0 MCI WorldCom [Page 6]
Internet Draft Service Examples October 1999 F4 /* User A responds be re-sending the INVITE with authentication credentials in it. */ Invite A -> Proxy 1 INVITE sip:UserB@ss1.wcom.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com> Call-Id: 12345601@here.com CSeq: 1 INVITE Contact: TheBigGuy <sip:UserA@here.com> Proxy-Authorization: DIGEST username="UserA", realm="MCI WorldCom SIP", nonce="ea9c8e88df84f1cec4341ae6cbe5a359", opaque="", uri="sip:ss1.wcom.com", response="dfe56131d1958046689cd83306477ecc" 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 /* Proxy 1 accepts the credentials and forwards the INVITE User B. Client for A prepares to receive data on port 49170 from the network. */ Invite Proxy 1 -> B INVITE sip:UserB@there.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP here.com:5060 Record-Route: <sip:ss1.wcom.com> From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com> Call-Id: 12345601@here.com CSeq: 1 INVITE Contact: TheBigGuy <sip:UserA@here.com> 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 MCI WorldCom [Page 7]
Internet Draft Service Examples October 1999 t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F6 (100 Trying) Proxy 1-> A SIP/2.0 100 Trying Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com> Call-Id: 12345601@here.com CSeq: 1 INVITE Content-Length: 0 F7 180 Ringing B->Proxy 1 SIP/2.0 180 Ringing Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=314159 Call-Id: 12345601@here.com CSeq: 1 INVITE Content Length:0 F8 180 Ringing Proxy 1->A SIP/2.0 180 Ringing Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=314159 Call-Id: 12345601@here.com CSeq: 1 INVITE Content Length: 0 F9 200 OK B->Proxy 1 SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP here.com:5060 MCI WorldCom [Page 8]
Internet Draft Service Examples October 1999 Record-Route: <sip:ss1.wcom.com> From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=314159 Call-Id: 12345601@here.com CSeq: 1 INVITE Contact: TheLittleGuy <sip:UserB@there.com> 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 F10 200 OK Proxy 1-> A SIP/2.0 200 OK Via: SIP/2.0/UDP here.com:5060 Record-Route: <sip:ss1.wcom.com> From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=314159 Call-Id: 12345601@here.com CSeq: 1 INVITE Contact: TheLittleGuy <sip:UserB@there.com> 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 F11 ACK A->Proxy 1 ACK sip:UserB@ss1.wcom.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 Route: <sip:UserB@there.com> From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=314159 MCI WorldCom [Page 9]
Internet Draft Service Examples October 1999 Call-Id: 12345601@here.com CSeq: 1 ACK Content-Length:0 F12 ACK Proxy 1->B ACK sip: UserB@there.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=314159 Call-Id: 12345601@here.com CSeq: 1 ACK Content-Length:0 F13 /* User B places User A on hold. */ INVITE B -> Proxy 1 INVITE sip:UserA@ss1.wcom.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 Route: <sip:UserA@here.com> From: TheLittleGuy <sip:UserB@there.com>;tag=314159 To: TheBigGuy <sip:UserA@here.com> Call-Id: 12345601@here.com CSeq: 1 INVITE Contact: TheLittleGuy <sip:UserB@there.com> Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844527 2890844527 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 F14 INVITE Proxy 1 -> A INVITE sip:UserA@here.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP there.com:5060 MCI WorldCom [Page 10]
Internet Draft Service Examples October 1999 From: TheLittleGuy <sip:UserB@there.com>;tag=314159 To: TheBigGuy <sip:UserA@here.com> Call-Id: 12345601@here.com CSeq: 1 INVITE Contact: TheLittleGuy <sip:UserB@there.com> Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844527 2890844527 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 F15 200 OK A -> Proxy 1 SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP there.com:5060 From: TheLittleGuy <sip:UserB@there.com>;tag=314159 To: TheBigGuy <sip:UserA@here.com>;tag=1234567 Call-Id: 12345601@here.com CSeq: 1 INVITE Contact: TheBigGuy <sip:UserA@there.com> Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 0.0.0.0 t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F16 200 OK Proxy 1 -> B SIP/2.0 200 OK Via: SIP/2.0/UDP there.com:5060 From: TheLittleGuy <sip:UserB@there.com>;tag=314159 To: TheBigGuy <sip:UserA@here.com>;tag=1234567 Call-Id: 12345601@here.com CSeq: 1 INVITE MCI WorldCom [Page 11]
Internet Draft Service Examples October 1999 Contact: TheBigGuy <sip:UserA@there.com> Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 0.0.0.0 t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F17 ACK B-> Proxy 1 ACK sip:UserA@ss1.wcom.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 Route: <sip:UserB@there.com> From: TheLittleGuy <sip:UserB@there.com>;tag=314159 To: TheBigGuy <sip:UserA@here.com>;tag=1234567 Call-Id: 12345601@here.com CSeq: 1 ACK Content-Length: 0 F18 ACK Proxy 1 -> A ACK sip: UserA@here.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP there.com:5060 From: TheLittleGuy <sip:UserB@there.com>;tag=314159 To: TheBigGuy <sip:UserA@here.com>;tag=1234567 Call-Id: 12345601@here.com CSeq: 1 ACK Content-Length: 0 /* User B takes the call off hold */ F19 INVITE B -> Proxy 1 INVITE sip:UserA@ss1.wcom.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 Route: <sip:UserA@here.com> From: TheLittleGuy <sip:UserB@there.com>;tag=314159 To: TheBigGuy <sip:UserA@here.com>;tag=1234567 MCI WorldCom [Page 12]
Internet Draft Service Examples October 1999 Call-Id: 12345601@here.com CSeq: 2 INVITE Contact: TheLittleGuy <sip:UserB@there.com> 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 F20 INVITE Proxy 1 -> A INVITE sip:UserA@here.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP there.com:5060 From: TheLittleGuy <sip:UserB@there.com>;tag=314159 To: TheBigGuy <sip:UserA@here.com>;tag=1234567 Call-Id: 12345601@here.com CSeq: 2 INVITE Contact: TheLittleGuy <sip:UserB@there.com> 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 F21 200 OK A -> Proxy 1 SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP there.com:5060 From: TheLittleGuy <sip:UserB@there.com>;tag=314159 To: TheBigGuy <sip:UserA@here.com>;tag=1234567 Call-Id: 12345601@here.com CSeq: 2 INVITE Contact: TheBigGuy <sip:UserA@there.com> MCI WorldCom [Page 13]
Internet Draft Service Examples October 1999 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 F22 200 OK Proxy 1 -> B SIP/2.0 200 OK Via: SIP/2.0/UDP there.com:5060 From: TheLittleGuy <sip:UserB@there.com>;tag=314159 To: TheBigGuy <sip:UserA@here.com>;tag=1234567 Call-Id: 12345601@here.com CSeq: 2 INVITE Contact: TheBigGuy <sip:UserA@there.com> 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 F23 ACK B -> Proxy1 ACK sip:UserA@ss1.wcom.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 Route: <sip:UserA@here.com> From: TheLittleGuy <sip:UserB@there.com>;tag=314159 To: TheBigGuy <sip:UserA@here.com>;tag=1234567 Call-Id: 12345601@here.com CSeq: 2 ACK Content-Length: 0 F24 ACK Proxy 1 -> A MCI WorldCom [Page 14]
Internet Draft Service Examples October 1999 ACK sip: UserA@here.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP there.com:5060 From: TheLittleGuy <sip:UserB@there.com>;tag=314159 To: TheBigGuy <sip:UserA@here.com>;tag=1234567 Call-Id: 12345601@here.com CSeq: 2 ACK Content-Length: 0 F25 BYE A -> Proxy 1 BYE sip: UserB@ss1.wcom.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 Route: <sip:userB@there.com> From: TheBigGuy <sip:UserA@here.com>;tag=1234567 To: TheLittleGuy <sip:UserB@there.com>;tag=314159 Call-Id: 12345601@here.com CSeq: 2 BYE Content-Length: 0 F26 BYE Proxy 1 -> B BYE sip: UserB@there.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com>;tag=1234567 To: TheLittleGuy <sip:UserB@there.com>;tag=314159 Call-Id: 12345601@here.com CSeq: 2 BYE Content-Length: 0 F27 200 OK B -> Proxy 1 SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com>;tag=1234567 To: TheLittleGuy <sip:UserB@there.com>;tag=314159 Call-Id: 12345601@here.com CSeq: 2 BYE Content-Length: 0 MCI WorldCom [Page 15]
Internet Draft Service Examples October 1999 F28 200 OK Proxy 1 -> A SIP/2.0 200 OK Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com>;tag=1234567 To: TheLittleGuy <sip:UserB@there.com>;tag=314159 Call-Id: 12345601@here.com CSeq: 2 BYE Content-Length: 0 2.2 Consultation Hold User A calls user B. User B places call on hold. User B calls User C, after that call is finished User B take the call with User A off 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 | | |<-m-m-m-m-m-m-m-m-m-m-m-m-m-m->| | | | | | | |INVITE (c=0) F10 | |INVITE (c=0) F11|<-------------| | |<---------------| | | | | | | | 200 OK F12 | | | |--------------->| | | MCI WorldCom [Page 16]
Internet Draft Service Examples October 1999 | | 200 OK F13 | | | |------------->| | | | | | | | ACK F14 | | | |<-------------| | | ACK F15 | | | |<---------------| | | | | | | | No RTP Sent! | | | | | | | | INVITE F16 | | | |<-------------| | | | | INVITE F17 | | |--------------------------------->| | | | | | |(100 Trying) F18 | | |------------->| | | | | 180 Ringing F19 | | |<---------------------------------| | | | | | | 180 Ringing F20 | | |------------->| | | | | 200 OK F21 | | |<---------------------------------| | | | | | | 200 OK F22 | | | |------------->| | | | | | | | ACK F23 | | | |<-------------| | | | | ACK F24 | | |--------------------------------->| | | | | | | Both way RTP Established | | | |<-m-m-m-m-m-m-m-m->| | | BYE F25 | | | |<-------------| | | | | BYE F26 | | |--------------------------------->| | | | | | | | 200 OK F27 | | |<---------------------------------| | | | | | | 200 OK F28 | | | |------------->| | | | | | | | INVITE F29 | | | INVITE F30 |<-------------| | |<---------------| | | MCI WorldCom [Page 17]
Internet Draft Service Examples October 1999 | | | | | 200 OK F31 | | | |--------------->| 200 OK F32 | | | |------------->| | | | | | | | ACK F33 | | | |<-------------| | | ACK F34 | | | |<---------------| | | | | | | | Both way RTP Established | | |<-m-m-m-m-m-m-m-m-m-m-m-m-m-m->| | | | | | | BYE F35 | | | |--------------->| BYE F36 | | | |------------->| | | | | | | | 200 OK F37 | | | |<-------------| | | 200 OK F38 | | | |<---------------| | | | | | | F1 Invite A -> Proxy 1 INVITE sip:UserB@ss1.wcom.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com> Call-Id: 12345600@here.com CSeq: 1 INVITE Contact: TheBigGuy <sip:UserA@here.com> Proxy-Authorization: DIGEST username="UserA", realm="MCI WorldCom SIP", nonce="ea9c8e88df84f1cec4341ae6cbe5a359", opaque="", uri="sip:ss1.wcom.com", response="dfe56131d1958046689cd83306477ecc" 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 MCI WorldCom [Page 18]
Internet Draft Service Examples October 1999 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F2 /* Proxy 1 accepts the credentials and forwards the INVITE User B. Client for A prepares to receive data on port 49170 from the network. */ Invite Proxy 1 -> B INVITE sip:UserB@there.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP here.com:5060 Record-Route: <sip:ss1.wcom.com> From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com> Call-Id: 12345600@here.com CSeq: 1 INVITE Contact: TheBigGuy <sip:UserA@here.com> 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: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <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 Via: SIP/2.0/UDP here.com:5060 MCI WorldCom [Page 19]
Internet Draft Service Examples October 1999 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=314159 Call-Id: 12345600@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: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <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 Via: SIP/2.0/UDP here.com:5060 Record-Route: <sip:ss1.wcom.com> From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=314159 Call-Id: 12345600@here.com CSeq: 1 INVITE Contact: TheLittleGuy <sip:UserB@there.com> 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:ss1.wcom.com> MCI WorldCom [Page 20]
Internet Draft Service Examples October 1999 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=314159 Call-Id: 12345600@here.com CSeq: 1 INVITE Contact: TheLittleGuy <sip:UserB@there.com> 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@ss1.wcom.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 Route: <sip:UserB@there.com> From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <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@there.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=314159 Call-Id: 12345600@here.com CSeq: 1 ACK Content-Length:0 F10 /* User B places User A on hold. */ INVITE B -> Proxy 1 INVITE sip:UserA@ss1.wcom.com SIP/2.0 MCI WorldCom [Page 21]
Internet Draft Service Examples October 1999 Via: SIP/2.0/UDP there.com:5060 Route: <sip:UserA@here.com> From: TheLittleGuy <sip:UserB@there.com>;tag=314159 To: TheBigGuy <sip:UserA@here.com> Call-Id: 12345600@here.com CSeq: 1 INVITE Contact: TheLittleGuy <sip:UserB@there.com> Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844527 2890844527 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@here.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP there.com:5060 From: TheLittleGuy <sip:UserB@there.com>;tag=314159 To: TheBigGuy <sip:UserA@here.com> Call-Id: 12345600@here.com CSeq: 1 INVITE Contact: TheLittleGuy <sip:UserB@there.com> Content-Type: application/sdp Content-Length: ... v=0 o=UserB 2890844527 2890844527 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 Via: SIP/2.0/UDP there.com:5060 From: TheLittleGuy <sip:UserB@there.com>;tag=314159 MCI WorldCom [Page 22]
Internet Draft Service Examples October 1999 To: TheBigGuy <sip:UserA@here.com>;tag=1234567 Call-Id: 12345600@here.com CSeq: 1 INVITE Contact: TheBigGuy <sip:UserA@there.com> Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 0.0.0.0 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 From: TheLittleGuy <sip:UserB@there.com>;tag=314159 To: TheBigGuy <sip:UserA@here.com>;tag=1234567 Call-Id: 12345600@here.com CSeq: 1 INVITE Contact: TheBigGuy <sip:UserA@there.com> Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP c=IN IP4 0.0.0.0 t=3034423619 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F14 ACK B-> Proxy 1 ACK sip:UserA@ss1.wcom.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 Route: <sip:UserA@here.com> From: TheLittleGuy <sip:UserB@there.com>;tag=314159 To: TheBigGuy <sip:UserA@here.com>;tag=1234567 Call-Id: 12345600@here.com CSeq: 1 ACK Content-Length: 0 MCI WorldCom [Page 23]
Internet Draft Service Examples October 1999 F15 ACK Proxy 1 -> A ACK sip: UserA@here.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP there.com:5060 From: TheLittleGuy <sip:UserB@there.com>;tag=314159 To: TheBigGuy <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@ss1.wcom.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 From: TheLittleGuy <sip:UserB@there.com> To: TheOtherGuy <sip:UserC@anywhere.com> Call-Id: 9876543210@there.com CSeq: 1 INVITE Contact: TheLittleGuy <sip:UserB@there.com> 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@anywhere.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP there.com:5060 Record-Route: <sip:ss1.wcom.com> From: TheLittleGuy <sip:UserB@there.com> To: TheOtherGuy <sip:UserC@anywhere.com> Call-Id: 9876543210@there.com CSeq: 1 INVITE MCI WorldCom [Page 24]
Internet Draft Service Examples October 1999 Contact: TheLittleGuy <sip:UserB@there.com> 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: TheLittleGuy <sip:UserB@there.com> To: TheOtherGuy <sip:UserC@anywhere.com> Call-Id: 9876543210@there.com CSeq: 1 INVITE Content-Length: 0 F19 180 Ringing C->Proxy 1 SIP/2.0 180 Ringing Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP there.com:5060 From: TheLittleGuy <sip:UserB@there.com> To: TheOtherGuy <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: TheLittleGuy <sip:UserB@there.com> To: TheOtherGuy <sip:UserC@anywhere.com>;tag=456654 Call-Id: 9876543210@there.com CSeq: 1 INVITE Content Length: 0 MCI WorldCom [Page 25]
Internet Draft Service Examples October 1999 F21 200 OK C->Proxy 1 SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP there.com:5060 Record-Route: <sip:ss1.wcom.com> From: TheLittleGuy <sip:UserB@there.com> To: TheOtherGuy <sip:UserC@anywhere.com>;tag=456654 Call-Id: 9876543210@there.com CSeq: 1 INVITE Contact: TheLittleGuy <sip:UserC@anywhere.com> 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:ss1.wcom.com> From: TheLittleGuy <sip:UserB@there.com> To: TheOtherGuy <sip:UserC@anywhere.com>;tag=456654 Call-Id: 9876543210@there.com CSeq: 1 INVITE Contact: TheOtherGuy <sip:UserC@anywhere.com> 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 MCI WorldCom [Page 26]
Internet Draft Service Examples October 1999 F23 ACK B->Proxy 1 ACK sip:UserC@ss1.wcom.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 Route: <sip:UserC@anywhere.com> From: TheLittleGuy <sip:UserB@there.com> To: TheOtherGuy <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@anywhere.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP there.com:5060 From: TheLittleGuy <sip:UserB@there.com> To: TheOtherGuy <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@ss1.wcom.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 Route: <sip:userC@anywhere.com> From: TheLittleGuy <sip:UserB@there.com> To: TheOtherGuy <sip:UserC@anywhere.com>;tag=456654 Call-Id: 9876543210@there.com CSeq: 2 BYE Content-Length: 0 F26 BYE Proxy 1 -> C BYE sip: UserC@anywhere.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP there.com:5060 From: TheLittleGuy <sip:UserB@there.com> To: TheOtherGuy <sip:UserC@anywhere.com>;tag=456654 MCI WorldCom [Page 27]
Internet Draft Service Examples October 1999 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 Via: SIP/2.0/UDP there.com:5060 From: TheLittleGuy <sip:UserB@there.com> To: TheOtherGuy <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: TheLittleGuy <sip:UserB@there.com> To: TheOtherGuy <sip:UserC@anywhere.com>;tag=456654 Call-Id: 9876543210@there.com CSeq: 2 BYE Content-Length: 0 F29 /* User B takes the call off hold */ INVITE B -> Proxy 1 INVITE sip:UserA@ss1.wcom.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 Route: <sip:UserA@here.com> From: TheLittleGuy <sip:UserB@there.com>;tag=314159 To: TheBigGuy <sip:UserA@here.com>;tag=1234567 Call-Id: 12345600@here.com CSeq: 2 INVITE Contact: TheLittleGuy <sip:UserB@there.com> 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 MCI WorldCom [Page 28]
Internet Draft Service Examples October 1999 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F30 INVITE Proxy 1 -> A INVITE sip:UserA@here.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP there.com:5060 From: TheLittleGuy <sip:UserB@there.com>;tag=314159 To: TheBigGuy <sip:UserA@here.com>;tag=1234567 Call-Id: 12345600@here.com CSeq: 2 INVITE Contact: TheLittleGuy <sip:UserB@there.com> 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 F31 200 OK A -> Proxy 1 SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP there.com:5060 From: TheLittleGuy <sip:UserB@there.com>;tag=314159 To: TheBigGuy <sip:UserA@here.com>;tag=1234567 Call-Id: 12345600@here.com CSeq: 2 INVITE Contact: TheBigGuy <sip:UserA@there.com> 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 MCI WorldCom [Page 29]
Internet Draft Service Examples October 1999 F32 200 OK Proxy 1 -> B SIP/2.0 200 OK Via: SIP/2.0/UDP there.com:5060 From: TheLittleGuy <sip:UserB@there.com>;tag=314159 To: TheBigGuy <sip:UserA@here.com>;tag=1234567 Call-Id: 12345600@here.com CSeq: 2 INVITE Contact: TheBigGuy <sip:UserA@there.com> 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 -> Proxy1 ACK sip:UserA@ss1.wcom.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 From: TheLittleGuy <sip:UserB@there.com>;tag=314159 To: TheBigGuy <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@here.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP there.com:5060 From: TheLittleGuy <sip:UserB@there.com>;tag=314159 To: TheBigGuy <sip:UserA@here.com>;tag=1234567 Call-Id: 12345600@here.com CSeq: 2 ACK Content-Length: 0 MCI WorldCom [Page 30]
Internet Draft Service Examples October 1999 F35 BYE A -> Proxy 1 BYE sip: UserB@ss1.wcom.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 Route: <sip:userB@there.com> From: TheBigGuy <sip:UserA@here.com>;tag=1234567 To: TheLittleGuy <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@there.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com>;tag=1234567 To: TheLittleGuy <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 Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com>;tag=1234567 To: TheLittleGuy <sip:UserB@there.com>;tag=314159 Call-Id: 12345600@here.com CSeq: 2 BYE Content-Length: 0 MCI WorldCom [Page 31]
Internet Draft Service Examples October 1999 F38 200 OK Proxy 1 -> A SIP/2.0 200 OK Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com>;tag=1234567 To: TheLittleGuy <sip:UserB@there.com>;tag=314159 Call-Id: 12345600@here.com CSeq: 2 BYE Content-Length: 0 2.3 Unattended Transfer User A call user B. User A then transfers User B to user C. User C then transfers User B to User D. User B hangs up the call. User A Proxy User B User C User D | | | | | | 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 | | | |<-m-m-m-m-m-m-m-m-m-m-m-m-m-m->| | | | | | | | | BYE (Also C) F10 | | | |--------------->| BYE (Also C) F11 | | | |------------->| | | | | | | | | | 200 OK F12 | | | | 200 OK F13 |<-------------| | | |<---------------| | | | MCI WorldCom [Page 32]
Internet Draft Service Examples October 1999 | | INVITE (ReqBy A) F14 | | | |<-------------| | | | | | | | | | INVITE (ReqBy A) F15 | | | |------------------------>| | | | | | | | |(100 Trying) F16 | | | |------------->| | | | | | | | | | 180 Ringing F17 | | | |<------------------------| | | | | | | | | 180 Ringing F18 | | | |------------->| | | | | | | | | | 200 OK F19| | | |<------------------------| | | | | | | | | 200 OK F20 | | | | |------------->| | | | | | | | | | ACK F21 | | | | |<-------------| | | | | | ACK F22 | | | |------------------------>| | | | | | | | | Both way RTP Established | | | |<-m-m-m-m>| | | | | | | | | BYE (Also D) F23| | | |<------------------------| | | | | | | | | BYE (Also D) F24 | | | |------------->| | | | | | | | | | 200 OK F25 | | | | |<-------------| | | | | |200 OK F26| | | |------------------------>| | | | | | | | | INVITE (ReqBy C) F27 | | | |<-------------| | | | | INVITE (ReqBy C) F28 | | |----------------------------------->| | | | | | | |(100 Trying) F29 | | | |------------->| | | | | | 180 Ringing F30 | | |<-----------------------------------| MCI WorldCom [Page 33]
Internet Draft Service Examples October 1999 | | | | | | | 180 Ringing F31 | | | |------------->| | | | | | | | | | | |200 OK F32| | |<-----------------------------------| | | | | | | | 200 OK F33 | | | | |------------->| | | | | | | | | | ACK F34 | | | | |<-------------| | | | | | | | | | | | ACK F35 | | |----------------------------------->| | | | | | | | Both way RTP Established | | | |<-m-m-m-m-m-m-m-m-m->| | | BYE F36 | | | | |<-------------| | BYE F37 | | |----------------------------------->| | | | | | | | | |200 OK F38| | |<-----------------------------------| | | | | | | | 200 OK F39 | | | | |------------->| | | | | | | | | | | | | F1 Invite A -> Proxy 1 INVITE sip:UserB@ss1.wcom.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com> Call-Id: 12345600@here.com CSeq: 1 INVITE Contact: TheBigGuy <sip:UserA@here.com> Proxy-Authorization: DIGEST username="UserA", realm="MCI WorldCom SIP", nonce="ea9c8e88df84f1cec4341ae6cbe5a359", opaque="", uri="sip:ss1.wcom.com", response="dfe56131d1958046689cd83306477ecc" Content-Type: application/sdp Content-Length: ... MCI WorldCom [Page 34]
Internet Draft Service Examples October 1999 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 /* Proxy 1 accepts the credentials and forwards the INVITE User B. Client for A prepares to receive data on port 49170 from the network. */ Invite Proxy 1 -> B INVITE sip:UserB@there.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP here.com:5060 Record-Route: <sip:ss1.wcom.com> From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com> Call-Id: 12345600@here.com CSeq: 1 INVITE Contact: TheBigGuy <sip:UserA@here.com> 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: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com> Call-Id: 12345600@here.com CSeq: 1 INVITE Content-Length: 0 F4 180 Ringing B->Proxy 1 MCI WorldCom [Page 35]
Internet Draft Service Examples October 1999 SIP/2.0 180 Ringing Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=314159 Call-Id: 12345600@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: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <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 Via: SIP/2.0/UDP here.com:5060 Record-Route: <sip:ss1.wcom.com> From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=314159 Call-Id: 12345600@here.com CSeq: 1 INVITE Contact: TheLittleGuy <sip:UserB@there.com> 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 MCI WorldCom [Page 36]
Internet Draft Service Examples October 1999 SIP/2.0 200 OK Via: SIP/2.0/UDP here.com:5060 Record-Route: <sip:ss1.wcom.com> From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=314159 Call-Id: 12345600@here.com CSeq: 1 INVITE Contact: TheLittleGuy <sip:UserB@there.com> 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@ss1.wcom.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 Route: <sip:UserB@there.com> From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <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@there.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=314159 Call-Id: 12345600@here.com CSeq: 1 ACK Content-Length:0 F10 /* User A transfers User B to User C */ BYE A -> Proxy 1 MCI WorldCom [Page 37]
Internet Draft Service Examples October 1999 BYE sip: UserB@ss1.wcom.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 Route: <sip:userB@there.com> From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=314159 Call-Id: 12345600@here.com CSeq: 2 BYE Also: TheOtherGuy <sip:UserC@anywhere.com> Content-Length: 0 F11 BYE Proxy 1 -> B BYE sip: UserB@there.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=314159 Call-Id: 12345600@here.com CSeq: 2 BYE Also: TheOtherGuy <sip:UserC@anywhere.com> Content-Length: 0 F12 200 OK B -> Proxy 1 SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <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: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=314159 Call-Id: 12345600@here.com CSeq: 2 BYE Content-Length: 0 MCI WorldCom [Page 38]
Internet Draft Service Examples October 1999 F14 Invite B -> Proxy 1 INVITE sip:UserC@ss1.wcom.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 From: TheLittleGuy <sip:UserB@there.com> To: TheOtherGuy <sip:UserC@anywhere.com> Call-Id: 9876543210@there.com CSeq: 1 INVITE Contact: TheLittleGuy <sip:UserB@there.com> Content-Type: application/sdp Requested-By: TheBigGuy <sip:UserA@here.com> 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 F15 Invite Proxy 1 -> C INVITE sip:UserC@anywhere.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP there.com:5060 Record-Route: <sip:ss1.wcom.com> From: TheLittleGuy <sip:UserB@there.com> To: TheOtherGuy <sip:UserC@anywhere.com> Call-Id: 9876543210@there.com CSeq: 1 INVITE Contact: TheLittleGuy <sip:UserB@there.com> Content-Type: application/sdp Requested-By: TheBigGuy<sip:UserA@here.com> 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 MCI WorldCom [Page 39]
Internet Draft Service Examples October 1999 F16 (100 Trying) Proxy 1-> B SIP/2.0 100 Trying Via: SIP/2.0/UDP there.com:5060 From: TheLittleGuy <sip:UserB@there.com> To: TheOtherGuy <sip:UserC@anywhere.com> Call-Id: 9876543210@there.com CSeq: 1 INVITE Content-Length: 0 F17 180 Ringing C->Proxy 1 SIP/2.0 180 Ringing Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP there.com:5060 From: TheLittleGuy <sip:UserB@there.com> To: TheOtherGuy <sip:UserC@anywhere.com>;tag=456654 Call-Id: 9876543210@here.com CSeq: 1 INVITE Content Length:0 F18 180 Ringing Proxy 1->B SIP/2.0 180 Ringing Via: SIP/2.0/UDP there.com:5060 From: TheLittleGuy <sip:UserB@there.com> To: TheOtherGuy <sip:UserC@anywhere.com>;tag=456654 Call-Id: 9876543210@there.com CSeq: 1 INVITE Content Length: 0 F19 200 OK C->Proxy 1 SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP there.com:5060 Record-Route: <sip:ss1.wcom.com> From: TheLittleGuy <sip:UserB@there.com> To: TheOtherGuy <sip:UserC@anywhere.com>;tag=456654 Call-Id: 9876543210@there.com CSeq: 1 INVITE MCI WorldCom [Page 40]
Internet Draft Service Examples October 1999 Contact: TheLittleGuy <sip:UserC@anywhere.com> 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 F20 200 OK Proxy 1-> B SIP/2.0 200 OK Via: SIP/2.0/UDP there.com:5060 Record-Route: <sip:ss1.wcom.com> From: TheLittleGuy <sip:UserB@there.com> To: TheOtherGuy <sip:UserC@anywhere.com>;tag=456654 Call-Id: 9876543210@there.com CSeq: 1 INVITE Contact: TheOtherGuy <sip:UserC@anywhere.com> 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 F21 ACK B->Proxy 1 ACK sip:UserC@ss1.wcom.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 Route: <sip:UserC@anywhere.com> From: TheLittleGuy <sip:UserB@there.com> To: TheOtherGuy <sip:UserC@anywhere.com>;tag=456654 Call-Id: 9876543210@there.com CSeq: 1 ACK Content-Length:0 MCI WorldCom [Page 41]
Internet Draft Service Examples October 1999 F22 ACK Proxy 1->C ACK sip: UserC@anywhere.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP there.com:5060 From: TheLittleGuy <sip:UserB@there.com> To: TheOtherGuy <sip:UserC@anywhere.com>;tag=456654 Call-Id: 9876543210@there.com CSeq: 1 ACK Content-Length:0 F23 BYE B -> Proxy 1 BYE sip: UserB@ss1.wcom.com SIP/2.0 Via: SIP/2.0/UDP anywhere.com:5060 Route: <sip:userB@there.com> From: TheOtherGuy <sip:UserC@anywhere.com>;tag=456654 To: TheLittleGuy <sip:UserB@there.com> Also: TheNewGuy<sip:UserD@nowhere.com> Call-Id: 9876543210@there.com CSeq: 200 BYE Content-Length: 0 F24 BYE Proxy 1 -> C BYE sip: UserB@there.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP anywhere.com:5060 From: TheOtherGuy <sip:UserC@anywhere.com>;tag=456654 To: TheLittleGuy <sip:UserB@there.com>;tag=1234567 Also: TheNewGuy<sip:UserD@nowhere.com> Call-Id: 9876543210@there.com CSeq: 200 BYE Content-Length: 0 F25 200 OK C -> Proxy 1 SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP anywhere.com:5060 From: TheOtherGuy <sip:UserC@anywhere.com>;tag=456654 MCI WorldCom [Page 42]
Internet Draft Service Examples October 1999 To: TheLittleGuy <sip:UserB@there.com>;tag=1234567 Call-Id: 9876543210@there.com CSeq: 200 BYE Content-Length: 0 F26 200 OK Proxy 1 -> B SIP/2.0 200 OK Via: SIP/2.0/UDP anywhere.com:5060 From: TheOtherGuy <sip:UserC@anywhere.com>;tag=456654 To: TheLittleGuy <sip:UserB@there.com>;tag=1234567 Call-Id: 9876543210@there.com CSeq: 200 BYE Content-Length: 0 F27 Invite B -> Proxy 1 INVITE sip:UserD@ss1.wcom.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 From: TheLittleGuy <sip:UserB@there.com> To: TheNewGuy <sip:UserD@nowhere.com> Call-Id: 123123123@there.com CSeq: 1 INVITE Contact: TheLittleGuy <sip:UserB@there.com> Content-Type: application/sdp Requested-By: TheOtherGuy <sip:UserC@here.com> 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 F28 /* Proxy 1 accepts the credentials and forwards the INVITE to User D. Client for B prepares to receive data on port 49170 from the network. */ Invite Proxy 1 -> D INVITE sip:UserD@nowhere.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP there.com:5060 MCI WorldCom [Page 43]
Internet Draft Service Examples October 1999 Record-Route: <sip:ss1.wcom.com> From: TheLittleGuy <sip:UserB@there.com> To: TheNewGuy <sip:UserD@nowhere.com> Call-Id: 123123123@there.com CSeq: 1 INVITE Contact: TheLittleGuy <sip:UserB@there.com> Content-Type: application/sdp Requested-By: TheOtherGuy<sip:UserC@here.com> 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 F29 (100 Trying) Proxy 1-> B SIP/2.0 100 Trying Via: SIP/2.0/UDP there.com:5060 From: TheLittleGuy <sip:UserB@there.com> To: TheNewGuy <sip:UserD@nowhere.com> Call-Id: 123123123@there.com CSeq: 1 INVITE Content-Length: 0 F30 180 Ringing D->Proxy 1 SIP/2.0 180 Ringing Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP there.com:5060 From: TheLittleGuy <sip:UserB@there.com> To: TheNewGuy <sip:UserD@nowhere.com>;tag=789789 Call-Id: 123123123@there.com CSeq: 1 INVITE Content Length:0 F31 180 Ringing Proxy 1->B SIP/2.0 180 Ringing Via: SIP/2.0/UDP there.com:5060 MCI WorldCom [Page 44]
Internet Draft Service Examples October 1999 From: TheLittleGuy <sip:UserB@there.com> To: TheNewGuy <sip:UserD@nowhere.com>;tag=789789 Call-Id: 123123123@there.com CSeq: 1 INVITE Content Length: 0 F32 200 OK D->Proxy 1 SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP there.com:5060 Record-Route: <sip:ss1.wcom.com> From: TheLittleGuy <sip:UserB@there.com> To: TheNewGuy <sip:UserD@nowhere.com>;tag=789789 Call-Id: 123123123@there.com CSeq: 1 INVITE Contact: TheNewGuy <sip:UserD@nowhere.com> Content-Type: application/sdp Content-Length: ... v=0 o=UserD 2890844527 2890844527 IN IP4 client.nowhere.com s=Session SDP c=IN IP4 150.151.152.153 t=3094598698 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F33 200 OK Proxy 1-> B SIP/2.0 200 OK Via: SIP/2.0/UDP there.com:5060 Record-Route: <sip:ss1.wcom.com> From: TheLittleGuy <sip:UserB@there.com> To: TheNewGuy <sip:UserD@nowhere.com>;tag=789789 Call-Id: 123123123@there.com CSeq: 1 INVITE Contact: TheNewGuy <sip:UserD@nowhere.com> Content-Type: application/sdp Content-Length: ... v=0 o=UserD 2890844527 2890844527 IN IP4 client.nowhere.com s=Session SDP c=IN IP4 150.151.152.153 MCI WorldCom [Page 45]
Internet Draft Service Examples October 1999 t=3094598698 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F34 ACK B->Proxy 1 ACK sip:UserD@ss1.wcom.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 Route: <sip:UserD@nowhere.com> From: TheLittleGuy <sip:UserB@there.com> To: TheNewGuy <sip:UserD@nowhere.com>;tag=789789 Call-Id: 123123123@there.com CSeq: 1 ACK Content-Length:0 F35 ACK Proxy 1->D ACK sip: UserD@nowhere.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP there.com:5060 From: TheLittleGuy <sip:UserB@there.com> To: TheNewGuy <sip:UserD@nowhere.com>;tag=789789 Call-Id: 123123123@there.com CSeq: 1 ACK Content-Length:0 F36 BYE B -> Proxy 1 BYE sip: UserD@ss1.wcom.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 Route: <sip:userD@nowhere.com> From: TheLittleGuy <sip:UserB@there.com> To: TheNewGuy <sip:UserD@nowhere.com>;tag=789789 Call-Id: 123123123@there.com CSeq: 2 BYE Content-Length: 0 F37 BYE Proxy 1 -> D BYE sip: UserD@nowhere.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060 MCI WorldCom [Page 46]
Internet Draft Service Examples October 1999 Via: SIP/2.0/UDP there.com:5060 From: TheLittleGuy <sip:UserB@there.com> To: TheNewGuy <sip:UserD@nowhere.com>;tag=789789 Call-Id: 123123123@there.com CSeq: 2 BYE Content-Length: 0 F38 200 OK D -> Proxy 1 SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP there.com:5060 From: TheLittleGuy <sip:UserB@there.com> To: TheNewGuy <sip:UserD@nowhere.com>;tag=789789 Call-Id: 123123123@there.com CSeq: 2 BYE Content-Length: 0 F39 200 OK Proxy 1 -> B SIP/2.0 200 OK Via: SIP/2.0/UDP there.com:5060 From: TheLittleGuy <sip:UserB@there.com> To: TheNewGuy <sip:UserD@nowhere.com>;tag=789789 Call-Id: 123123123@there.com CSeq: 2 BYE Content-Length: 0 MCI WorldCom [Page 47]
Internet Draft Service Examples October 1999 2.4 Attended Transfer User A calls user B. User A puts User B on hold, and Calls user C to announce transfer. User A terminates call with User C. User A transfers User B to User C. The call flow for this session would be a combination of Consultation Hold and Unattended Transfer. 2.5 Call Forwarding Unconditional User B wants all calls forwarded to a Private Dialing Plan number 777-3660. (This information is known by the proxy). User A calls User B. The Proxy server rewrites the request URI, and forwards the INVITE to a gateway. 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 | |<-m-m-m-m-m-m-m-m-m-m-m-m-m-m->| | | | | BYE F10 | | |--------------->| BYE F11 | | |------------->| | | | | | 200 OK F12 | | 200 OK F13 |<-------------| |<---------------| | | | | MCI WorldCom [Page 48]
Internet Draft Service Examples October 1999 F1 INVITE A->Proxy INVITE sip:UserB@ss1.wcom.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com> Call-Id: 12345600@here.com CSeq: 1 INVITE Contact: TheBigGuy <sip:UserA@here.com> Proxy-Authorization: DIGEST username="UserA", realm="MCI WorldCom SIP", nonce="ea9c8e88df84f1cec4341ae6cbe5a359", opaque="", uri="sip:ss1.wcom.com", response="dfe56131d1958046689cd83306477ecc" 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 /* Proxy 1 accepts the credentials and forwards the INVITE the gateway for the extension that User B wants his calls forwarded to. Client for A prepares to receive data on port 49170 from the network. */ INVITE Proxy->B2 INVITE sip:7773660,phone- context=p1234@gw1.wcom.com;user=phone SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP here.com:5060 Record-Route: <sip:ss1.wcom.com> From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com> Call-Id: 12345600@here.com CSeq: 1 INVITE Contact: TheBigGuy <sip:UserA@here.com> Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com c=IN IP4 100.101.102.103 MCI WorldCom [Page 49]
Internet Draft Service Examples October 1999 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 s=Session SDP t=3034423619 0 F3 (100 Trying) Proxy->A SIP/2.0 100 Trying Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com> Call-Id: 12345600@here.com CSeq: 1 INVITE Content-Length: 0 F4 180 Ringing B2->Proxy SIP/2.0 180 Ringing Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=314159 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: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=314159 Call-Id: 12345600@here.com CSeq: 1 INVITE Content Length: 0 F6 200 OK B2->Proxy SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP here.com:5060 MCI WorldCom [Page 50]
Internet Draft Service Examples October 1999 Record-Route: <sip:ss1.wcom.com> From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=314159 Call-Id: 12345600@here.com CSeq: 1 INVITE Contact: <sip:7773660,phone- context=p1234@gw1.wcom.com;user=phone > Content-Type: application/sdp Content-Length: ... v=0 o=GATEWAY1 2890844527 2890844527 IN IP4 gatewayone.wcom.com t=0 0 c=IN IP4 gatewayone.wcom.com 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:ss1.wcom.com> From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=314159 Call-Id: 12345600@here.com CSeq: 1 INVITE Contact: TheLittleGuy <sip:7773660,phone- context=p1234@gw1.wcom.com;user=phone > Content-Type: application/sdp Content-Length: ... v=0 o=GATEWAY1 2890844527 2890844527 IN IP4 gatewayone.wcom.com t=0 0 c=IN IP4 gatewayone.wcom.com m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000 F8 ACK A->Proxy ACK sip:7773660,phone-context=p1234@gw1.wcom.com;user=phone SIP/2.0 Via: SIP/2.0/UDP here.com:5060 Route: < sip:7773660,phone- context=p1234@gw1.wcom.com;user=phone > MCI WorldCom [Page 51]
Internet Draft Service Examples October 1999 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=314159 Call-Id: 12345600@here.com CSeq: 1 ACK Content-Length:0 F9 ACK Proxy->B4 ACK sip:7773660,phone-context=p1234@gw1.wcom.com;user=phone SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=314159 Call-Id: 12345600@here.com CSeq: 1 ACK Content-Length:0 F10 BYE A -> Proxy 1 BYE sip:7773660,phone-context=p1234@gw1.wcom.com;user=phone SIP/2.0 Via: SIP/2.0/UDP here.com:5060 Route: < sip:7773660,phone- context=p1234@gw1.wcom.com;user=phone > From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=314159 Call-Id: 12345600@here.com CSeq: 2 BYE Content-Length: 0 F11 BYE Proxy 1 -> B2 BYE sip:7773660,phone-context=p1234@gw1.wcom.com;user=phone SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=314159 Call-Id: 12345600@here.com CSeq: 2 BYE Content-Length: 0 MCI WorldCom [Page 52]
Internet Draft Service Examples October 1999 F12 200 OK B2 -> Proxy 1 SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <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: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=314159 Call-Id: 12345600@here.com CSeq: 2 BYE Content-Length: 0 MCI WorldCom [Page 53]
Internet Draft Service Examples October 1999 2.6 Call Forwarding - Busy 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. User A Proxy User B1 User B2 | | | | | INVITE F1 | | | |--------------->| INVITE F2 | | | |------------->| | |(100 Trying) F3 | | | |<---------------|486 Busy Here 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 | |<-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m->| | | | | | BYE F13 | | | |--------------->| | BYE F14 | | |--------------------------------->| | | | 200 OK F15 | | 200 OK F16 |<---------------------------------| |<---------------| | | | | | | MCI WorldCom [Page 54]
Internet Draft Service Examples October 1999 F1 INVITE A->Proxy INVITE sip:UserB@ss1.wcom.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com> Call-Id: 12345600@here.com CSeq: 1 INVITE Contact: TheBigGuy <sip:UserA@here.com> Proxy-Authorization: DIGEST username="UserA", realm="MCI WorldCom SIP", nonce="ea9c8e88df84f1cec4341ae6cbe5a359", opaque="", uri="sip:ss1.wcom.com", response="dfe56131d1958046689cd83306477ecc" 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@ there.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060; branch=1 Via: SIP/2.0/UDP here.com:5060 Record-Route: <sip:SS2@ss1.wcom.com> From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com> Call-Id: 12345600@here.com CSeq: 1 INVITE Contact: TheBigGuy <sip:UserA@here.com> 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 MCI WorldCom [Page 55]
Internet Draft Service Examples October 1999 a=rtpmap:0 PCMU/8000 F3 (100 Trying) Proxy->A SIP/2.0 100 Trying Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <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=1 Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=123456 Call-Id: 12345600@here.com CSeq: 1 INVITE Content-Length: 0 F5 ACK Proxy->B1 ACK sip: UserB1@ss1.wcom.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060; branch=1 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=123456 Call-Id: 12345600@here.com CSeq: 1 ACK Content-Length: 0 F6 INVITE Proxy->B2 INVITE sip:UserB2@ there.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=2 Via: SIP/2.0/UDP here.com:5060 Record-Route: <sip:ss1.wcom.com> From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com> MCI WorldCom [Page 56]
Internet Draft Service Examples October 1999 Call-Id: 12345600@here.com CSeq: 1 INVITE Contact: TheBigGuy <sip:UserA@here.com> 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 B4->Proxy SIP/2.0 180 Ringing Via: SIP/2.0/UDP ss1.wcom.com:5060; branch=2 Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=7654321 Call-Id: 12345600@here.com 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: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <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=2 Via: SIP/2.0/UDP here.com:5060 Record-Route: <sip:ss1.wcom.com> From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=7654321 MCI WorldCom [Page 57]
Internet Draft Service Examples October 1999 Call-Id: 12345600@here.com CSeq: 1 INVITE Contact: TheLittleGuy <sip:UserB2@there.com> 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:ss1.wcom.com> From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=7654321 Call-Id: 12345600@here.com CSeq: 1 INVITE Contact: TheLittleGuy <sip:UserB2@there.com> 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 F11 ACK A->Proxy ACK sip:UserB2@there.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 Route: <sip:UserB2.there.com> From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=7654321 Call-Id: 12345600@here.com CSeq: 1 ACK Content-Length: 0 MCI WorldCom [Page 58]
Internet Draft Service Examples October 1999 F12 ACK Proxy->B2 ACK sip: UserB2@there.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=7654321 Call-Id: 12345600@here.com CSeq: 1 ACK Content-Length: 0 F13 /* RTP streams are established between A and B2 */ /* User A eventually hangs up with User B2. */ BYE A->Proxy BYE sip: UserB2@ss1.wcom.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 Route: <sip:userB2@there.com> From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=7654321 Call-Id: 12345600@here.com CSeq: 2 BYE Content-Length: 0 F14 BYE Proxy->B2 BYE sip: UserB2@there.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <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 Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> MCI WorldCom [Page 59]
Internet Draft Service Examples October 1999 To: TheLittleGuy <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: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=7654321 Call-Id: 12345600@here.com CSeq: 2 BYE Content-Length: 0 MCI WorldCom [Page 60]
Internet Draft Service Examples October 1999 2.7 Call Forwarding û No Answer 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. 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 | | | |<-------------| | | | | | | | | INVITE F8 | | |--------------------------------->| | | | 180 Ringing F9 | | |<---------------------------------| | | | 200 OK F10 | | |<---------------------------------| | 200 OK F11 | | | |<---------------| | | | ACK F12 | | | |--------------->| | ACK F13 | | |--------------------------------->| | | | | | Both way RTP Established | |<-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m->| | | | | | BYE F14 | | | |--------------->| | BYE F15 | | |--------------------------------->| | | | 200 OK F16 | | 200 OK F17 |<---------------------------------| |<---------------| | | | | | | MCI WorldCom [Page 61]
Internet Draft Service Examples October 1999 F1 INVITE A->Proxy INVITE sip:UserB@ss1.wcom.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com> Call-Id: 12345600@here.com CSeq: 1 INVITE Contact: TheBigGuy <sip:UserA@here.com> Proxy-Authorization: DIGEST username="UserA", realm="MCI WorldCom SIP", nonce="ea9c8e88df84f1cec4341ae6cbe5a359", opaque="", uri="sip:ss1.wcom.com", response="dfe56131d1958046689cd83306477ecc" 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@ there.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060; branch=1 Via: SIP/2.0/UDP here.com:5060 Record-Route: <sip:ss1.wcom.com> From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com> Call-Id: 12345600@here.com CSeq: 1 INVITE Contact: TheBigGuy <sip:UserA@here.com> 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 MCI WorldCom [Page 62]
Internet Draft Service Examples October 1999 F3 (100 Trying) Proxy->A SIP/2.0 100 Trying Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <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=1 Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <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: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=3145678 Call-Id: 12345600@here.com CSeq: 1 INVITE Content-Length: 0 F6 /* B1 rings until a configurable timer expires in the Proxy. The Proxy sends Cancel and proceeds down the list of routes. */ CANCEL Proxy->B1 CANCEL sip:UserB1@ss1.wcom.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060; branch=1 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=3145678 Call-Id: 12345600@here.com CSeq: 1 CANCEL MCI WorldCom [Page 63]
Internet Draft Service Examples October 1999 Content-Length: 0 F7 200 OK B1->Proxy SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060; branch=1 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=3145678 Call-Id: 12345600@here.com CSeq: 1 CANCEL Content-Length: 0 F8 INVITE Proxy->B2 INVITE sip:UserB4@ there.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=2 Via: SIP/2.0/UDP here.com:5060 Record-Route: <sip:ss1.wcom.com> From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com> Call-Id: 12345600@here.com CSeq: 1 INVITE Contact: TheBigGuy <sip:UserA@here.com> 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=2 Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=123456 Call-Id: 12345600@here.com CSeq: 1 INVITE MCI WorldCom [Page 64]
Internet Draft Service Examples October 1999 Content-Length: 0 F10 200 OK B2->Proxy SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060; branch=2 Via: SIP/2.0/UDP here.com:5060 Record-Route: <sip:ss1.wcom.com> From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=123456 Call-Id: 12345600@here.com CSeq: 1 INVITE Contact: TheLittleGuy <sip:UserB2@there.com> 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 F11 200 OK Proxy->A SIP/2.0 200 OK Via: SIP/2.0/UDP here.com:5060 Record-Route: <sip:ss1.wcom.com> From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=123456 Call-Id: 12345600@here.com CSeq: 1 INVITE Contact: TheLittleGuy <sip:UserB2@there.com> 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 MCI WorldCom [Page 65]
Internet Draft Service Examples October 1999 F12 ACK A->Proxy ACK sip:UserB2@there.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 Route: <sip:UserB2@there.com> From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=123456 Call-Id: 12345600@here.com CSeq: 1 ACK Content-Length: 0 F13 ACK Proxy->B2 ACK sip: UserB2@there.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=123456 Call-Id: 12345600@here.com CSeq: 1 ACK Content-Length: 0 F14/* RTP streams are established between A and B2*/ /* User A Hangs Up with User B2. */ BYE A->Proxy BYE sip: UserB2@ss1.wcom.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 Route: <sip:userB2@there.com> From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=123456 Call-Id: 12345600@here.com CSeq: 2 BYE Content-Length: 0 F15 BYE Proxy->B2 BYE sip: UserB2@there.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=123456 MCI WorldCom [Page 66]
Internet Draft Service Examples October 1999 Call-Id: 12345600@here.com CSeq: 2 BYE Content-Length: 0 F16 200 OK B2->Proxy SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=123456 Call-Id: 12345600@here.com CSeq: 2 BYE Content-Length: 0 F17 200 OK Proxy->A SIP/2.0 200 OK Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=123456 Call-Id: 12345600@here.com CSeq: 2 BYE Content-Length: 0 2.8 3-way Call 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 signalling relationship between User A and User C. 2.9 Single Line Extension Single Line Extension (Sequential, First Wins implementation), a call will ring several extensions in sequence. The extension to MCI WorldCom [Page 67]
Internet Draft Service Examples October 1999 answer the call becomes the active set, no other sets may join the call. The signalling for this implementation of Single Line Extension and Find-Me is the same, the difference may be in the provisioning of the service. 2.10 Find-Me 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 signalling for the implementation of Single Line Extension and Find-Me is the same, the difference may be in the provisioning of the service. User A Proxy User User User User B1 B2 B3 B4 | | | | | | | INVITE F1 | | | | | |--------------->| INVITE F2 | | | | | |------------->| | | | |(100 Trying) F3 | | | | | |<---------------|180 Ringing F4| | | | | |<-------------| | | | | 180 Ringing F5 | | | | | |<---------------| | | | | | | Request Timeout | | | | | | | | | | | | | | | | | CANCEL F6 | | | | | |------------->| | | | | | 200 OK F7 | | | | | |<-------------| | | | | | INVITE F8| | | | |-------------------->| | | | | 480 Not Logged In F9| | | | |<--------------------| | | | | ACK F10| | | | |-------------------->| | | | | | | | | | | | INVITE F11| | | |--------------------------->| | | | 486 Busy Here F12| | | |<---------------------------| | MCI WorldCom [Page 68]
Internet Draft Service Examples October 1999 | | | ACK F13| | | |--------------------------->| | | | | | INVITE F14| | |---------------------------------->| | | | 180 Ringing F15| | |<----------------------------------| | | | | 200 OK F16| | 200 OK F17 |<----------------------------------| |<---------------| | | | | | ACK F18 | | | | | |--------------->| | | ACK F19| | |---------------------------------->| | | | | | | | Both way RTP Established | | |<-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m>| | | | | | | | | | | BYE F20| | BYE F21 |<----------------------------------| |<---------------| | | | | | 200 OK F22 | | | | | |--------------->| | | 200 OK F23| | |---------------------------------->| | | | | | | F1 INVITE A->Proxy INVITE sip:UserB@ss1.wcom.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com> Call-Id: 12345600@here.com CSeq: 1 INVITE Contact: TheBigGuy <sip:UserA@here.com> Proxy-Authorization: DIGEST username="UserA", realm="MCI WorldCom SIP", nonce="ea9c8e88df84f1cec4341ae6cbe5a359", opaque="", uri="sip:ss1.wcom.com", response="dfe56131d1958046689cd83306477ecc" Content-Type: application/sdp Content-Length: ... v=0 s= Session SDP o=UserA 2890844526 2890844526 IN IP4 client.here.com c=IN IP4 100.101.102.103 t=0 0 m=audio 49170 RTP/AVP 0 MCI WorldCom [Page 69]
Internet Draft Service Examples October 1999 a=rtpmap:0 PCMU/8000 F2 INVITE Proxy->B1 INVITE sip:UserB1@ there.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060; branch=1 Via: SIP/2.0/UDP here.com:5060 Record-Route: <sip:ss1.wcom.com> From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com> Call-Id: 12345600@here.com CSeq: 1 INVITE Contact: TheBigGuy <sip:UserA@here.com> 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: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <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=1 Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=123456 Call-Id: 12345600@here.com CSeq: 1 INVITE MCI WorldCom [Page 70]
Internet Draft Service Examples October 1999 Content-Length: 0 F5 180 Ringing Proxy->A SIP/2.0 180 Ringing Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=123456 Call-Id: 12345600@here.com CSeq: 1 INVITE Content-Length: 0 F6 /* B1 rings for until a configurable timer in the Proxy expires. The Proxy then sends Cancel and proceeds down the list of routes. */ CANCEL Proxy->B1 CANCEL sip:UserB1@ss1.wcom.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060; branch=1 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <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=1 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com> Call-Id: 12345600@here.com CSeq: 1 CANCEL Content-Length: 0 F8 INVITE Proxy->B2 INVITE sip:UserB2@ there.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060; branch=2 Via: SIP/2.0/UDP here.com:5060 Record-Route: <sip:ss1.wcom.com> From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com> MCI WorldCom [Page 71]
Internet Draft Service Examples October 1999 Call-Id: 12345600@here.com CSeq: 1 INVITE Contact: TheBigGuy <sip:UserA@here.com> 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 480 Not Logged In B2->Proxy SIP/2.0 480 Not Logged In Via: SIP/2.0/UDP ss1.wcom.com:5060; branch=2 Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=314756 Call-Id: 12345600@here.com CSeq: 1 INVITE Content-Length: 0 F10 ACK Proxy->B2 ACK sip: UserB2@ss1.wcom.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060; branch=2 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=314756 Call-Id: 12345600@here.com CSeq: 1 ACK Content-Length: 0 F11 INVITE Proxy->B3 INVITE sip:UserB3@ there.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060; branch=3 Via: SIP/2.0/UDP here.com:5060 Record-Route: <sip:ss1.wcom.com> From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com> MCI WorldCom [Page 72]
Internet Draft Service Examples October 1999 Call-Id: 12345600@here.com CSeq: 1 INVITE Contact: TheBigGuy <sip:UserA@here.com> 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 F12 486 Busy Here B3->Proxy SIP/2.0 486 Busy Here Via: SIP/2.0/UDP ss1.wcom.com:5060; branch=3 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=7654321 Call-Id: 12345600@here.com CSeq: 1 INVITE Content-Length: 0 F13 ACK Proxy->B3 ACK sip: UserB3@ss1.wcom.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=7654321 Call-Id: 12345600@here.com CSeq: 1 ACK Content-Length: 0 F14 INVITE Proxy->B4 INVITE sip:UserB4@ there.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060;branch=4 Via: SIP/2.0/UDP here.com:5060 Record-Route: <sip:ss1.wcom.com> From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com> Call-Id: 12345600@here.com MCI WorldCom [Page 73]
Internet Draft Service Examples October 1999 CSeq: 1 INVITE Contact: TheBigGuy <sip:UserA@here.com> 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 F15 180 Ringing B4->Proxy SIP/2.0 180 Ringing Via: SIP/2.0/UDP ss1.wcom.com:5060; branch=4 Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=7137136 Call-Id: 12345600@here.com CSeq: 1 INVITE Content-Length: 0 F16 200 OK B4->Proxy SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060; branch=4 Via: SIP/2.0/UDP here.com:5060 Record-Route: <sip:ss1.wcom.com> From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=7137136 Call-Id: 12345600@here.com CSeq: 1 INVITE Contact: TheLittleGuy <sip:UserB4@there.com> 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 MCI WorldCom [Page 74]
Internet Draft Service Examples October 1999 F17 200 OK Proxy->A SIP/2.0 200 OK Via: SIP/2.0/UDP here.com:5060 Record-Route: <sip:ss1.wcom.com> From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=7137136 Call-Id: 12345600@here.com CSeq: 1 INVITE Contact: TheLittleGuy <sip:UserB4@there.com> 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 F18 ACK A->Proxy ACK sip:UserB4@there.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 Route: <UserB4@there.com> From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=7137136 Call-Id: 12345600@here.com CSeq: 1 ACK Content-Length: 0 F19 ACK Proxy->B4 ACK sip: UserB4@there.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com>;tag=7137136 Call-Id: 12345600@here.com CSeq: 1 ACK Content-Length: 0 MCI WorldCom [Page 75]
Internet Draft Service Examples October 1999 F20 /* RTP streams are established between A and B4*/ /* User B4 Hangs Up with User A. */ BYE B4->Proxy BYE sip: UserA@here.com SIP/2.0 Via: SIP/2.0/UDP there.com:5060 Route: <sip:UserA@here.com> From: TheLittleGuy <sip:UserB@there.com>;tag=7137136 To: TheBigGuy <sip:UserA@here.com> Call-Id: 12345600@here.com CSeq: 2 BYE Content-Length: 0 F21 BYE Proxy->A BYE sip: UserA@here.com SIP/2.0 Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP there.com:5060 From: TheLittleGuy <sip:UserB@there.com>;tag=7137136 To: TheBigGuy <sip:UserA@here.com>;tag=1234567 Call-Id: 12345600@here.com CSeq: 2 BYE Content-Length: 0 F22 200 OK A->Proxy SIP/2.0 200 OK Via: SIP/2.0/UDP ss1.wcom.com:5060 Via: SIP/2.0/UDP there.com:5060 From: TheLittleGuy <sip:UserB@there.com>;tag=7137136 To: TheBigGuy <sip:UserA@here.com>;tag=1234567 Call-Id: 12345600@here.com CSeq: 2 BYE Content-Length: 0 F23 200 OK Proxy->B4 SIP/2.0 200 OK Via: SIP/2.0/UDP there.com:5060 From: TheLittleGuy <sip:UserB@there.com>;tag=7137136 To: TheBigGuy <sip:UserA@here.com>;tag=1234567 MCI WorldCom [Page 76]
Internet Draft Service Examples October 1999 Call-Id: 12345600@here.com CSeq: 2 BYE Content-Length: 0 2.11 Call Management (Incoming Call Screening) 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. User A Proxy User B | | | | INVITE F1 | | |--------------->| | | | | | 407 Proxy Authorization F2 | |<---------------| | | | | | ACK F3 | | |--------------->| | | | | | INVITE F4 | | |--------------->| | | | | | 403 Screening Failure (Terminating) F5 |<---------------| | | | | | ACK F3 | | |--------------->| | | | | F1 Invite A->Proxy1 INVITE sip:UserB@ss1.wcom.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com> Call-Id: 12345600@here.com CSeq: 1 INVITE Contact: TheBigGuy <sip:UserA@here.com> Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com MCI WorldCom [Page 77]
Internet Draft Service Examples October 1999 c=IN IP4 100.101.102.103 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 s=Session SDP t=3034423619 0 F2 /* Proxy 1 challenges User A for authentication */ 407 Proxy Authorization Required Proxy 1 -> A SIP/2.0 407 Proxy Authorization Required Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com> Call-Id: 12345600@here.com CSeq: 1 INVITE Proxy-Authenticate: Digest realm="MCI WorldCom SIP", domain="wcom.com", nonce="ea9c8e88df84f1cec4341ae6cbe5a359", opaque="", stale="FALSE", algorithm="MD5" Content-Length:0 F3 ACK A -> Proxy 1 ACK sip:UserB@ss1.wcom.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com> Call-Id: 12345600@here.com CSeq: 1 ACK Content-Length:0 F4 /* User A responds by sending an INVITE with authentication credentials in it. */ Invite A -> Proxy 1 INVITE sip:UserB@ss1.wcom.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com> Call-Id: 12345601@here.com CSeq: 1 INVITE Contact: TheBigGuy <sip:UserA@here.com> Proxy-Authorization: DIGEST username="UserA", realm="MCI WorldCom SIP", nonce="ea9c8e88df84f1cec4341ae6cbe5a359", opaque="", uri="sip:ss1.wcom.com", response="dfe56131d1958046689cd83306477ecc" MCI WorldCom [Page 78]
Internet Draft Service Examples October 1999 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 (Terminating) Proxy 1 -> A SIP/2.0 403 Screening Failure (Terminating) Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com> Call-Id: 12345601@here.com CSeq: 1 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: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com> Call-Id: 12345601@here.com CSeq: 1 ACK Content-Length:0 MCI WorldCom [Page 79]
Internet Draft Service Examples October 1999 2.12 Call Management (Outgoing Call Screening) 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. User A Proxy User B | | | | INVITE F1 | | |--------------->| | | | | | 407 Proxy Authorization F2 | |<---------------| | | | | | ACK F3 | | |--------------->| | | | | | INVITE F4 | | |--------------->| | | | | | 403 Screening Failure (Originating) F5 |<---------------| | | | | | ACK F3 | | |--------------->| | | | | F1 Invite A->Proxy1 INVITE sip:UserB@ss1.wcom.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com> Call-Id: 12345600@here.com CSeq: 1 INVITE Contact: TheBigGuy <sip:UserA@here.com> 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 MCI WorldCom [Page 80]
Internet Draft Service Examples October 1999 F2 /* Proxy 1 challenges User A for authentication */ 407 Proxy Authorization Required Proxy 1 -> A SIP/2.0 407 Proxy Authorization Required Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com> Call-Id: 12345600@here.com CSeq: 1 INVITE Proxy-Authenticate: Digest realm="MCI WorldCom SIP", domain="wcom.com", nonce="ea9c8e88df84f1cec4341ae6cbe5a359", opaque="", stale="FALSE", algorithm="MD5" Content-Length:0 F3 ACK A -> Proxy 1 ACK sip:UserB@ss1.wcom.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com> Call-Id: 12345600@here.com CSeq: 1 ACK Content-Length:0 F4 /* User A responds be sending an INVITE with authentication credentials in it. */ Invite A -> Proxy 1 INVITE sip:UserB@ss1.wcom.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com> Call-Id: 12345601@here.com CSeq: 1 INVITE Contact: TheBigGuy <sip:UserA@here.com> Proxy-Authorization: DIGEST username="UserA", realm="MCI WorldCom SIP", nonce="ea9c8e88df84f1cec4341ae6cbe5a359", opaque="", uri="sip:ss1.wcom.com", response="dfe56131d1958046689cd83306477ecc" Content-Type: application/sdp Content-Length: ... v=0 o=UserA 2890844526 2890844526 IN IP4 client.here.com s=Session SDP MCI WorldCom [Page 81]
Internet Draft Service Examples October 1999 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 SIP/2.0 403 Screening Failure (Originating) Via: SIP/2.0/UDP here.com:5060 From: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com> Call-Id: 12345601@here.com CSeq: 1 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: TheBigGuy <sip:UserA@here.com> To: TheLittleGuy <sip:UserB@there.com> Call-Id: 12345601@here.com CSeq: 1 ACK Content-Length:0 MCI WorldCom [Page 82]
Internet Draft Service Examples October 1999 3 Author's Addresses Robert Sparks MCI WorldCom 2400 N Glenville Drive Phone: +1-972-729-5241 Richardson, TX 75082 Email: Robert.Sparks@wcom.com Chris Cunningham MCI WorldCom 400 International Parkway Phone: +1-972-729-3110 Richardson, TX 75081 Email: Chris.Cunningham@wcom.com Alan Johnston MCI WorldCom 100 S 4th Street Phone: +1-314-342-7360 St. Louis, MO 63104 Email: alan.johnston@wcom.com Steve Donovan MCI WorldCom 901 International Parkway Phone: +1-972-729-1621 Richardson, TX 65081 Email: steven.r.donovan@wcom.com Kevin Summers MCI WorldCom 2400 N Glenville Drive Phone: +1-972-729-7976 Richardson, TX 75082 Email: Kevin.Summers@wcom.com 4 Acknowledgments The authors wish to thank the following for their assistance and review of this document: Denise Caballero, Matt Cannon, David Devanathan, John Hearty, Denise Ingram, Steve McKinnon, Danny Mistry, Bich Nguyen, Scott Orton, Greg Osterhout, Joe Pizzimenti, Tom Redman, Henry Sinnreich, Ilya Slain, Pat Sollee, John Truetken, Doug Weisenberg, Dean Willis and others from MCI WorldCom, 3Com, Cisco, Lucent and Nortel. MCI WorldCom [Page 83]
Internet Draft Service Examples October 1999 5 References [1] S. Bradner, "The Internet Standards Process -- Revision 3", BCP 9, RFC2026, October 1996. [2] A. Johnston, et. al., "SIP Telephony Call Flow Examples", Internet Draft, Internet Engineering Task Force, October 1999, Work in Progress. [2] H. Schulzrinne, J. Rosenberg, "SIP Call Control Services", Internet Draft, Internet Engineering Task Force, June 17, 1999, Work in Progress. [3] M. Handley, H. Schulzrinne, E. Schooler, and J. Rosenberg, "SIP: Session Initiation Protocol", RFC 2543, March 1999. MCI WorldCom [Page 84]