Completion of Calls for the Session Initiation Protocol (SIP)
RFC 6910
Internet Engineering Task Force (IETF) D. Worley
Request for Comments: 6910 Ariadne Internet Services, Inc.
Category: Standards Track M. Huelsemann
ISSN: 2070-1721 R. Jesske
Deutsche Telekom
D. Alexeitsev
TeleFLASH
April 2013
Completion of Calls for the Session Initiation Protocol (SIP)
Abstract
The "completion of calls" feature defined in this specification
allows the caller of a failed call to be notified when the callee
becomes available to receive a call.
For the realization of a basic solution without queuing, this
document references the usage of the dialog event package (RFC 4235)
that is described as 'Automatic Redial' in "Session Initiation
Protocol Service Examples" (RFC 5359).
For the realization of a more comprehensive solution with queuing,
this document introduces an architecture for implementing these
features in the Session Initiation Protocol where "completion of
calls" implementations associated with the caller's and callee's
endpoints cooperate to place the caller's request for completion of
calls into a queue at the callee's endpoint; when a caller's request
is ready to be serviced, re-attempt of the original, failed call is
then made.
The architecture is designed to interoperate well with existing
completion of calls solutions in other networks.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc6910.
Worley, et al. Standards Track [Page 1]
RFC 6910 Completion of Calls April 2013
Copyright Notice
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Table of Contents
1. Introduction ....................................................3
2. Requirements Terminology ........................................4
3. Terminology .....................................................4
4. Solution ........................................................6
4.1. CC Architecture ............................................6
4.2. CC Procedures ..............................................8
4.3. Automatic Redial as a Fallback ............................11
4.4. Differences from SS7 ......................................11
5. CC Queue Model .................................................12
6. Caller's Agent Behavior ........................................13
6.1. Receiving the CC Possible Indication ......................13
6.2. Subscribing to CC .........................................13
6.3. Receiving a CC Recall Notification ........................14
6.4. Initiating a CC Call ......................................15
6.5. Suspending CC .............................................15
6.6. Resuming CC ...............................................15
7. Callee's Monitor Behavior ......................................16
7.1. Sending the CC Possible Indication ........................16
7.2. Receiving a CC Subscription ...............................17
7.3. Sending a CC Notification .................................18
7.4. Receiving a CC Call .......................................19
7.5. Receiving a CC Suspension .................................19
7.6. Receiving a CC Resumption .................................20
8. Examples .......................................................20
9. 'call-completion' Event Package ................................24
9.1. Event Package Name ........................................24
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