Session Initiation Protocol (SIP) Session Timer Glare Handling
draft-ietf-sipcore-sessiontimer-race-01

• Status
• IESG evaluation record
• IESG writeups
• Email expansions
• History

• Versions
• 00
• 01

SIPCORE Working Group                                        C. Holmberg
Internet-Draft                                                  Ericsson
Updates: 4028 (if approved)                                March 5, 2018
Intended status: Standards Track
Expires: September 6, 2018

     Session Initiation Protocol (SIP) Session Timer Glare Handling
                draft-ietf-sipcore-sessiontimer-race-01

Abstract

   This document updates RFC 4028, by clarifying the procedures for
   negotiating usage of the Session Initiation Protocol (SIP) session
   timer mechansim, in order to avoid a race condition where both
   endpoints trigger simultaneous negotiations.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   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."

   This Internet-Draft will expire on September 6, 2018.

Copyright Notice

   Copyright (c) 2018 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Holmberg                Expires September 6, 2018               [Page 1]
Internet-Draft             Session timer glare                March 2018

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Problem Statement . . . . . . . . . . . . . . . . . . . .   2
     1.2.  Solution  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Conventions . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Update to RFC 4028  . . . . . . . . . . . . . . . . . . . . .   3
     3.1.  Update to Section 7.2 . . . . . . . . . . . . . . . . . .   3
     3.2.  Update to Section 7.4 . . . . . . . . . . . . . . . . . .   4
     3.3.  Update to Section 8.1 . . . . . . . . . . . . . . . . . .   5
     3.4.  Update to Section 9 . . . . . . . . . . . . . . . . . . .   6
   4.  Security considerations . . . . . . . . . . . . . . . . . . .   7
   5.  IANA considerations . . . . . . . . . . . . . . . . . . . . .   7
   6.  Normative references  . . . . . . . . . . . . . . . . . . . .   7
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   7

1.  Introduction

   [RFC4028] defines a mechanism, where periodic SIP requests are sent
   in order to allow SIP user agents and proxies to determine whether a
   SIP session is still active.

   The usage of the mechanism is negotiated using two new SIP header
   fields (Session-Expires and Min-SE), a new option tag ('timer') and a
   new SIP response code (422).

1.1.  Problem Statement

   1.  Section 7.4 of [RFC4028] says that, in a session refresh request
   sent within a dialog with an active session timer, the Session-
   Expires header field should be included in the request.  However, the
   text is unclear regarding including the Session-Expires header field
   in a session refresh request when a negotiation of session timer
   usage is still ongoing, e.g., if one user agent is sending a request
   that contains a Session-Expires header field and, before it receives
   the associated 2xx response, receives a request from the peer user
   agent that also contains a Session-Expires header field.  Such
   scenario might cause a glare situation, with conflicting negotiation
   parameters.

   2.  The absence of the Session-Expires header field in a 2xx response
   to an (re-)INVITE request [RFC3261] or UPDATE request [RFC3311] means
   that the mechanism isn't used.  This can be used to reject the usage
   of the mechanism when sending a response.  However, the text is
   unclear that this only applies to cases where the associated SIP
   request contained a Session-Expires header field.

Holmberg                Expires September 6, 2018               [Page 2]
Internet-Draft             Session timer glare                March 2018

1.2.  Solution

   This document updates [RFC4028], by clarifying the procedures for
   negotiating usage of the Session Initiation Protocol (SIP) [RFC3261]