Session Timers in the Session Initiation Protocol (SIP)
draft-holmberg-sipcore-rfc4028bis-00
SIPCORE Working Group C. Holmberg
Internet-Draft Ericsson
Obsoletes: 4028 (if approved) S. Donovan
Intended status: Standards Track J. Rosenberg
Expires: June 23, 2019 Cisco Systems
December 20, 2018
Session Timers in the Session Initiation Protocol (SIP)
draft-holmberg-sipcore-rfc4028bis-00.txt
Abstract
This document defines an extension to the Session Initiation Protocol
(SIP). This extension allows for a periodic refresh of SIP sessions
through a re-INVITE or UPDATE request. The refresh allows both user
agents and proxies to determine whether the SIP session is still
active. The extension defines two new header fields: Session-
Expires, which conveys the lifetime of the session, and Min-SE, which
conveys the minimum allowed value for the session timer.
Status of This Memo
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This Internet-Draft will expire on June 23, 2019.
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Holmberg, et al. Expires June 23, 2019 [Page 1]
Internet-Draft Session Timer December 2018
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Overview of Operation . . . . . . . . . . . . . . . . . . . . 4
5. Session-Expires Header Field Definition . . . . . . . . . . . 6
6. Min-SE Header Field Definition . . . . . . . . . . . . . . . 8
7. 422 Response Code Definition . . . . . . . . . . . . . . . . 8
8. UAC Behavior . . . . . . . . . . . . . . . . . . . . . . . . 9
9. Generating an Initial Session Refresh Request . . . . . . . . 9
10. Processing a 2xx Response . . . . . . . . . . . . . . . . . . 9
11. Processing a 422 Response . . . . . . . . . . . . . . . . . . 11
12. Generating Subsequent Session Refresh Requests . . . . . . . 11
13. Proxy Behavior . . . . . . . . . . . . . . . . . . . . . . . 12
14. Processing of Requests . . . . . . . . . . . . . . . . . . . 13
15. Processing of Responses . . . . . . . . . . . . . . . . . . . 14
16. Session Expiration . . . . . . . . . . . . . . . . . . . . . 15
17. UAS Behavior . . . . . . . . . . . . . . . . . . . . . . . . 15
18. Performing Refreshes . . . . . . . . . . . . . . . . . . . . 17
19. Security Considerations . . . . . . . . . . . . . . . . . . . 18
20. Inside Attacks . . . . . . . . . . . . . . . . . . . . . . . 18
21. Outside Attacks . . . . . . . . . . . . . . . . . . . . . . . 19
22. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19
23. IANA Registration of Min-SE and Session-Expires Header Fields 19
24. IANA Registration of the 422 (Session Interval Too Small)
Response Code . . . . . . . . . . . . . . . . . . . . . . . . 20
25. IANA Registration of the 'timer' Option Tag . . . . . . . . . 20
26. Example Call Flow . . . . . . . . . . . . . . . . . . . . . . 20
27. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 25
28. References . . . . . . . . . . . . . . . . . . . . . . . . . 25
28.1. Normative References . . . . . . . . . . . . . . . . . . 25
28.2. Informative References . . . . . . . . . . . . . . . . . 25
Appendix A. . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 26
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