Session Initiation Protocol (SIP) Call Control - Transfer
RFC 5589
| Document | Type |
RFC - Best Current Practice
(June 2009; Errata)
Also known as BCP 149
|
|
|---|---|---|---|
| Last updated | 2015-10-14 | ||
| Stream | IETF | ||
| Formats | plain text pdf html bibtex | ||
| Stream | WG state | (None) | |
| Document shepherd | No shepherd assigned | ||
| IESG | IESG state | RFC 5589 (Best Current Practice) | |
| Consensus Boilerplate | Unknown | ||
| Telechat date | |||
| Responsible AD | Cullen Jennings | ||
| Send notices to | (None) | ||
Network Working Group R. Sparks
Request for Comments: 5589 Tekelec
BCP: 149 A. Johnston, Ed.
Category: Best Current Practice Avaya
D. Petrie
SIPez LLC
June 2009
Session Initiation Protocol (SIP) Call Control - Transfer
Status of This Memo
This document specifies an Internet Best Current Practices for the
Internet Community, and requests discussion and suggestions for
improvements. Distribution of this memo is unlimited.
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Abstract
This document describes providing Call Transfer capabilities in the
Session Initiation Protocol (SIP). SIP extensions such as REFER and
Replaces are used to provide a number of transfer services including
blind transfer, consultative transfer, and attended transfer. This
work is part of the SIP multiparty call control framework.
Sparks, et al. Best Current Practice [Page 1]
RFC 5589 SIP CC Transfer June 2009
Table of Contents
1. Overview ........................................................3
2. Actors and Roles ................................................3
3. Terminology .....................................................4
4. Requirements ....................................................4
5. Using REFER to Achieve Call Transfer ............................5
6. Basic Transfer ..................................................6
6.1. Successful Transfer ........................................8
6.2. Transfer with Dialog Reuse ................................11
6.3. Failed Transfer ...........................................15
6.3.1. Target Busy ........................................16
6.3.2. Transfer Target Does Not Answer ....................17
7. Transfer with Consultation Hold ................................18
7.1. Exposing Transfer Target ..................................18
7.2. Protecting Transfer Target ................................19
7.3. Attended Transfer .........................................24
7.4. Recovery When One Party Does Not Support REFER ............28
7.5. Attended Transfer When Contact URI Is Not Known to
Route to a User Agent .....................................29
7.6. Semi-Attended Transfer ....................................37
7.7. Attended Transfer Fallback to Basic Transfer ..............42
8. Transfer with Referred-By ......................................45
9. Transfer as an Ad Hoc Conference ...............................49
10. Transfer with Multiple Parties ................................52
11. Gateway Transfer Issues .......................................54
11.1. Coerce Gateway Hairpins to the Same Gateway ..............54
11.2. Consultative Turned Blind Gateway Glare ..................55
12. Security Considerations .......................................55
13. Acknowledgments ...............................................56
14. References ....................................................56
14.1. Normative References .....................................56
14.2. Informative References ...................................57
Sparks, et al. Best Current Practice [Page 2]
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