Lemonade Notifications Architecture
RFC 5551

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Network Working Group                                    R. Gellens, Ed.
Request for Comments: 5551                                      Qualcomm
Category: Informational                                      August 2009

                  Lemonade Notifications Architecture

Abstract

   Notification and filtering mechanisms can make email more enjoyable
   on mobile and other constrained devices (such as those with limited
   screen sizes, memory, data transfer rates, etc.).  Notifications make
   the client aware of significant events (such as the arrival of new
   mail) so it can react (such as by fetching interesting mail
   immediately).  Filtering reduces the visible mail to a set of
   messages that meet some criteria for "interesting".  This
   functionality is included in the goals of the Lemonade (Enhancements
   to Internet email to Support Diverse Service Environments) Working
   Group.

   This document also discusses the use of server-to-server
   notifications, and how server to server notifications fit into an
   architecture that provides server to client notifications.

Status of This Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard of any kind.  Distribution of this
   memo is unlimited.

Copyright Notice

   Copyright (c) 2009 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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   modifications of such material outside the IETF Standards Process.
   Without obtaining an adequate license from the person(s) controlling
   the copyright in such materials, this document may not be modified

Gellens                      Informational                      [Page 1]
RFC 5551          Lemonade Notifications Architecture        August 2009

   outside the IETF Standards Process, and derivative works of it may
   not be created outside the IETF Standards Process, except to format
   it for publication as an RFC or to translate it into languages other
   than English.

Table of Contents

   1. Introduction ....................................................2
      1.1. Conventions Used in This Document ..........................2
   2. Notifications Logical Architecture and LEMONADE Profile .........2
   3. Event-Based Synchronization .....................................4
   4. Push Email ......................................................5
   5. Server-to-Server Notifications Rationale ........................5
      5.1. Notifications Discussion ...................................6
      5.2. Server to Server Notifications Scope .......................7
      5.3. Basic Operation ............................................8
      5.4. Event Order ...............................................10
      5.5. Reliability ...............................................10
   6. Security Considerations ........................................10
   7. References .....................................................11
      7.1. Normative References ......................................11
      7.2. Informative References ....................................11
   8. Contributors ...................................................12

1.  Introduction

   The Lemonade work [LEMONADE-PROFILE] identified a need to provide
   notification and filtering mechanisms for use with IMAP [IMAP].

   In addition, external groups that make use of IETF work also
   expressed such requirements (see, for example, [OMA-LEMONADE-ARCH];
   Open Mobile Alliance (OMA) requirements for within-IMAP ("inband")
   and out-of-IMAP ("outband") server to client notifications are listed
   in [OMA-ME-RD]).

1.1.  Conventions Used in This Document

   Within this document, the terms "Lemonade Profile" and "Lemonade"
   generally refer to the revised Lemonade Profile document, RFC 5550
   [LEMONADE-PROFILE].

2.  Notifications Logical Architecture and LEMONADE Profile

   The target logical architecture for the LEMONADE Profile is described
   in the revised Lemonade Profile document [LEMONADE-PROFILE].

   Figure 1 illustrates how notification and filtering fit in the
   context of Lemonade.

Gellens                      Informational                      [Page 2]
RFC 5551          Lemonade Notifications Architecture        August 2009

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