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Versions: (draft-petrie-sipping-config-framework) 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 RFC 6080

SIPPING                                                        D. Petrie
Internet-Draft                                             Pingtel Corp.
Expires: November 15, 2004                                  May 17, 2004


     A Framework for Session Initiation Protocol User Agent Profile
                                Delivery
               draft-ietf-sipping-config-framework-03.txt

Status of this Memo

   This document is an Internet-Draft and is in full conformance with
   all provisions of Section 10 of RFC2026.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
   other groups may also distribute working documents as
   Internet-Drafts.

   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."

   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/ietf/1id-abstracts.txt.

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html.

   This Internet-Draft will expire on November 15, 2004.

Copyright Notice

   Copyright (C) The Internet Society (2004).  All Rights Reserved.

Abstract

   This document defines the application of a set of protocols for
   providing profile data to SIP user agents.  The objective is to
   define a means for automatically providing profile data a user agent
   needs to be functional without user or administrative intervention.
   The framework for discovery, delivery, notification and updates of
   user agent profile data is defined here.  As part of this framework a
   new SIP event package is defined here for the notification of profile
   changes.  This framework is also intended to ease ongoing
   administration and upgrading of large scale deployments of SIP user
   agents.  The contents and format of the profile data to be defined is
   outside the scope of this document.



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Table of Contents

   1.   Motivation . . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.   Introduction . . . . . . . . . . . . . . . . . . . . . . . .   3
     2.1  Requirements Terminology . . . . . . . . . . . . . . . . .   3
     2.2  Profile Delivery Framework Terminology . . . . . . . . . .   4
     2.3  Overview . . . . . . . . . . . . . . . . . . . . . . . . .   4
   3.   Profile Change Event Notification Package  . . . . . . . . .   6
     3.1  Event Package Name . . . . . . . . . . . . . . . . . . . .   6
     3.2  Event Package Parameters . . . . . . . . . . . . . . . . .   6
     3.3  SUBSCRIBE Bodies . . . . . . . . . . . . . . . . . . . . .   9
     3.4  Subscription Duration  . . . . . . . . . . . . . . . . . .   9
     3.5  NOTIFY Bodies  . . . . . . . . . . . . . . . . . . . . . .   9
     3.6  Notifier processing of SUBSCRIBE requests  . . . . . . . .  10
     3.7  Notifier generation of NOTIFY requests . . . . . . . . . .  10
     3.8  Subscriber processing of NOTIFY requests . . . . . . . . .  11
     3.9  Handling of forked requests  . . . . . . . . . . . . . . .  11
     3.10   Rate of notifications  . . . . . . . . . . . . . . . . .  11
     3.11   State Agents . . . . . . . . . . . . . . . . . . . . . .  12
     3.12   Examples . . . . . . . . . . . . . . . . . . . . . . . .  12
     3.13   Use of URIs to Retrieve State  . . . . . . . . . . . . .  13
   4.   Profile Delivery Framework Details . . . . . . . . . . . . .  13
     4.1  Discovery of Subscription URI  . . . . . . . . . . . . . .  13
     4.2  Enrollment with Profile Server . . . . . . . . . . . . . .  15
     4.3  Notification of Profile Changes  . . . . . . . . . . . . .  15
     4.4  Retrieval of Profile Data  . . . . . . . . . . . . . . . .  15
     4.5  Upload of Profile Changes  . . . . . . . . . . . . . . . .  16
   5.   IANA Considerations  . . . . . . . . . . . . . . . . . . . .  16
     5.1  SIP Event Package  . . . . . . . . . . . . . . . . . . . .  16
   6.   Security Considerations  . . . . . . . . . . . . . . . . . .  16
     6.1  Symmetric Encryption of Profile Data . . . . . . . . . . .  16
   7.   Differences from Simple XCAP Package . . . . . . . . . . . .  17
   8.   Open Issues  . . . . . . . . . . . . . . . . . . . . . . . .  17
   9.   Change History . . . . . . . . . . . . . . . . . . . . . . .  17
     9.1  Changes from draft-ietf-sipping-config-framework-02.txt  .  18
     9.2  Changes from draft-ietf-sipping-config-framework-01.txt  .  18
     9.3  Changes from draft-ietf-sipping-config-framework-00.txt  .  18
     9.4  Changes from
          draft-petrie-sipping-config-framework-00.txt . . . . . . .  18
     9.5  Changes from draft-petrie-sip-config-framework-01.txt  . .  19
     9.6  Changes from draft-petrie-sip-config-framework-00.txt  . .  19
   10.  References . . . . . . . . . . . . . . . . . . . . . . . . .  19
        Author's Address . . . . . . . . . . . . . . . . . . . . . .  21
   A.   Acknowledgments  . . . . . . . . . . . . . . . . . . . . . .  21
        Intellectual Property and Copyright Statements . . . . . . .  22






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1.  Motivation

   Today all SIP user agent implementers use proprietary means of
   delivering user or device profiles to the user agent.  The profile
   delivery framework defined in this document is intended to enable a
   first phase migration to a standard means of providing profiles to
   SIP user agents.  It is expected that UA implementers will be able to
   use this framework as a means of delivering their existing
   proprietary user and device data profiles (i.e.  using their existing
   proprietary binary or text formats).  This in itself is a tremendous
   advantage in that a SIP environment can use a single profile delivery
   server for profile data to user agents from multiple implementers.
   Follow-on standardization activities can:
   1.  define a standard profile content format framework (e.g.  XML
       with name spaces [??] or name-value pairs [RFC0822]).
   2.  specify the content (i.e.  name the profile data parameters, xml
       schema, name spaces) of the data profiles.

   One of the objectives of the framework described in this document is
   to provide a start up experience similar to that of users of an
   analog telephone.  When you plug in an analog telephone it just works
   (assuming the line is live and the switch has been provisioned).
   There is no end user configuration required to make analog phone
   work, at least in a basic sense.  So the objective here is to be able
   to take a new SIP user agent out of the box, plug it in or install
   the software and have it get its profiles without human intervention
   other than security measures.  This is necessary for cost effective
   deployment of large numbers of user agents.

   Another objective is to provide a scalable means for ongoing
   administration of profiles.  Administrators and users are likely to
   want to make changes to user and device profiles.

   Additional requirements for the framework defined in this document
   are described in: [I-D.ietf-sipping-ua-prof-framewk-reqs],
   [I-D.sinnreich-sipdev-req]

2.  Introduction


2.1  Requirements Terminology

   Keywords "MUST", "MUST NOT", "REQUIRED", "SHOULD", "SHOULD NOT" and
   "MAY" that appear in this document are to be interpreted as described
   in RFC 2119[RFC2119].






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2.2  Profile Delivery Framework Terminology

   profile - data set specific to a user or device.
   device - SIP user agent, either software or hardware appliance.
   profile content server - The server that provides the content of the
      profiles using the protocol specified by the URL scheme.
   notifier - The SIP user agent server which processes SUBSCRIBE
      requests for events and sends NOTIFY requests with profile data or
      URI(s) point to the data.
   profile delivery server - The logical collection of the SIP notifier
      and the server which provides the contents of the profile URI(s).

2.3  Overview

   The profile life cycle can be described by five functional steps.
   These steps are not necessarily discrete.  However it is useful to
   describe these steps as logically distinct.  These steps are named as
   follows:

   Discovery -  discover a profile delivery server
   Enrollment - enroll with the profile delivery server
   Profile Retrieval - retrieve profile data
   Profile Change Notification - receive notification of profile changes
   Profile Change Upload - upload profile data changes back to the
      profile delivery server

   Discovery is the process by which a UA finds the address and port at
   which it enrolls with the profile delivery server.  As there is no
   single discovery mechanism which will work in all network
   environments, a number of discovery mechanisms are defined with a
   prescribed order in which the UA tries them until one succeeds.

   Enrollment is the process by which a UA makes itself known to the
   profile delivery server.  In enrolling the UA provides identity
   information, name requested profile type(s) and supported protocols
   for profile retrieval.  It also subscribes to a mechanism for
   notification of profile changes.  As a result of enrollment, the UA
   receives the data or the URI for each of the profiles that the
   profile delivery server is able to provide.  Each profile type (set)
   requires a separate enrollment or SUBSCRIBE session.

   Profile Retrieval is the process of retrieving the content for each
   of the profiles the UA requested.

   Profile Change Notification is the process by which the profile
   delivery server notifies the UA that the content of one or more of
   the profiles has changed.  If the content is provided indirectly the
   UA SHOULD retrieve the profile from the specified URI upon receipt of



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   the change notification.

   Profile Upload is the process by which a UA or other entity (e.g.
   OSS, corporate directory or configuration management server) pushes a
   change to the profile data back up to the profile delivery server.

   This framework defines a new SIP event package [RFC3265] to solve
   enrollment and profile change notification steps.

   The question arises as to why SIP should be used for the profile
   delivery framework.  In this document SIP is used for only a small
   portion of the framework.  Other existing protocols are more
   appropriate for transport of the profile contents (to and from the
   user agent) and are suggested in this document.  The discovery step
   is simply a specified order and application of existing protocols.
   SIP is only needed for the enrollment and change notification
   functionality of the profile delivery framework.  In many SIP
   environments (e.g.  carrier/subscriber and multi-site enterprise)
   firewall, NAT and IP addressing issues make it difficult to get
   messages between the profile delivery server and the user agent
   requiring the profiles.

   With SIP the users and devices already are assigned globally routable
   addresses.  In addition the firewall and NAT problems are already
   presumably solved in the environments in which SIP user agents are to
   be used.  Therefore SIP is the best solution for allowing the user
   agent to enroll with the profile delivery server which may require
   traversal of multiple firewalls and NATs.  For the same reason the
   notification of profile changes is best solved by SIP.

   It is assumed that the content delivery server will be either in the
   public network or accessible through a DMZ.  The user agents
   requiring profiles may be behind firewalls and NATs and many
   protocols, such as HTTP, may be used for profile content retrieval
   without special consideration in the firewalls and NATs.

   A conscious separation of user, device and local network profiles is
   made in this document.  This is useful to provide features such as
   hoteling as well as securing or restricting user agent functionality.
   By maintaining this separation, a user may walk up to someone else's
   user agent and direct that user agent to get their profile data.  In
   doing so the user agent can replace the previous user's profile data
   while still keeping the devices profile data that may be necessary
   for core functionality and communication described in this document.
   The local network profiles are relevant to a visiting device which
   gets plugged in to a foreign network.  The concept of the local
   network providing profile data is useful to provide hoteling
   (described above) as well as local policy data that may constrain the



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   user or device behavior relative to the local network.  For example
   media types and codecs may be constrained to reflect the networks
   capabilities.

3.  Profile Change Event Notification Package

   This section defines a new SIP event package [RFC3265].  The purpose
   of this event package is to send to subscribers notification of
   content changes to the profile(s) of interest and to provide the
   location of the profile(s) via content indirection
   [I-D.ietf-sip-content-indirect-mech] or directly in the body of the
   NOTIFY.  Frequently the profiles delivered to the user agent are much
   larger (e.g.  several KB or even several MB) than the MTU of the
   network.  These larger profiles will cause larger than normal SIP
   messages and consequently higher impact on the SIP servers and
   infrastructure.  To avoid the higher impact and load on the SIP
   infrastructure, content indirection SHOULD be used if the profile is
   large enough to cause packet fragmentation over the transport
   protocol.  The user agent SHOULD specify the profile delivery means
   and format via the MIME type in the Accepts header.

   The MIME types or formats of profile to be delivered via this
   framework are to be defined in other documents.  These profile MIME
   types specified in the Accepts header along with the profile types
   specified in the Event header parameter "profile-name" MAY be used to
   specify which profiles get delivered either directly or indirectly in
   the NOTIFY requests.  When content indirection is not used, it is
   more important to specify the minimum set of profiles, as the entire
   content for all of the profiles is included in the NOTIFY request.

3.1  Event Package Name

   The name of this package is "sip-profile".  This value appears in the
   Event header field present in SUBSCRIBE and NOTIFY requests for this
   package as defined in [RFC3265].

3.2  Event Package Parameters

   This package defines the following new parameters for the event
   header: profile-name, vendor, model, version, effective-by.  The
   effective-by parameter is for use in NOTIFY requests only.  The
   others are for use in the SUBSCRIBE request, but may be used in
   NOTIFY requests as well.

   The profile-name parameter is used to indicate the token name of the
   profile type the user agent wishes to obtain URIs for or to
   explicitly specify the URI to which it is to be notified of change.
   Using a token in this parameter allows the URL semantics for



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   retrieving the profiles to be opaque to the subscribing user agent.
   All it needs to know is the token value for this parameter.  However
   in some cases the user agent may know the URI of the profile and only
   wishes to know about changes to the profile.  The user agent MAY
   supply the URI for the profile as the value of the profile-name
   parameter.  This document defines three type categories of profiles
   and their token names.  The contents or format of the profiles is
   outside the scope of this document.  The three types of profiles
   define here are "user", "device" and "local".  Specifying device type
   profile(s) indicates the desire for the profile(s) (URIs when content
   indirection is used) and change notification of all profiles that are
   specific to the device or user agent.  Specifying user type
   profile(s) indicates the desire for the profiles(s) or URI(s) and
   change notification of all profile(s) that are specific to the user.
   Specifying local type profiles indicates the desire for profile(s) or
   URI(s) specific to the local network.  The user, device or local
   network is identified in the URI of the SUBSCRIBE request.  The
   Accept header of the SUBSCRIBE request MUST include the MIME types
   for all profile content types that the subscribing user agent wishes
   to retrieve profiles or receive change notifications.

      The user, device or local token in the profile-name parameter may
      represent a class or set of profiles as opposed to a single
      profile.  As standards are defined for specific profile contents
      related to the user device or local network, it may be desirable
      to define additional tokens for the profile-name header.  This is
      to allow a user agent to subscribe to that specific profile as
      opposed to the entire class or set of user or device profiles.

   The rational for the separation of user, device and local network
   type profiles is provided in Section 2.3.  It should be noted that
   any of the types may indicate that zero or more profiles or URIs are
   provided in the NOTIFY request.  As discussed, a default user may be
   assigned to a device.  In this scenario the profile delivery server
   may provide the URI(s) in the NOTIFY request for the default user
   when subscribing to the device profile type.  Effectively the device
   profile type becomes a superset of the user profile type
   subscription.  That is the list of profile URIs (or MIME parts if
   multiple profiles are provided directly in the NOTIFY) provided when
   requesting profile type "device" includes the profiles provided when
   subscribing for profile type "user" for the default user of that
   device.  The user type is still useful in this scenario to allow the
   user agent to obtain profile data or URIs for a user other than the
   default user.  This provides the ability to support a hoteling
   function where a user may "login" to any user agent and have it use a
   user's profile(s).

   The data provided in the three types of profiles may overlap.  As an



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   example the codecs that a user prefers to use, the codecs that the
   device supports (and the enterprise wishes to use), the codecs that
   the local network can support (and the management wishes to allow)
   all may overlap in how they are specified in the three corresponding
   profiles.  Typically these should be applied in the order of the
   least to most constraint (i.e.  user, device then local network).
   However this policy of merging the constraints across the multiple
   profile types can only unambiguously be defined along with the
   profile format and syntax.  This is out of scope for this document.

   The "vendor", "model" and "version" parameter values are tokens
   specified by the vendor of the user agent.  These parameters are
   useful to the profile delivery server to affect the profiles
   provided.  In some scenarios it is desirable to provide different
   profiles based upon these parameters.  For example feature parameter
   X in a profile may work differently on two versions of user agent.
   This gives the profile deliver server the ability to compensate for
   or take advantage of the differences.

   The "network-user" parameter is used when subscribing for local
   network profiles.  If the value of the profile-name parameter is not
   "local", the "network-user" parameter has no defined meaning.  If the
   user has special privileges beyond that of an anonymous user in the
   local network, the "network-user" parameter identifies the user to
   the local network.  The value of this parameter is the user's address
   of record.  The SUBSCRIBE server may authenticate the subscriber to
   verify this AOR.

   The "effective-by" parameter in the Event header of the NOTIFY
   specifies the maximum number of seconds before the user agent MUST
   make the new profile effective.  A value of 0 (zero) indicates that
   the user agent MUST make the profiles effective immediately (despite
   possible service interruptions).  This gives the profile delivery
   server the power to control when the profile is effective.  This may
   be important to resolve an emergency problem or disable a user agent
   immediately.

   SUBSCRIBE request example:
   Event: sip-profile;profile-name=device;
               vendor=acme;model=Z100;version=1.2.3

   Event: sip-profile;profile-name=
      "http://example.com/services/user-profiles/users/freds.xml";
               vendor=premier;model=trs8000;version=5.5

   NOTIFY request examples:
   Event:sip-profile;effective-by=0




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   Event:sip-profile;effective-by=3600



3.3  SUBSCRIBE Bodies

   This package defines no new use of the SUBSCRIBE request body.

3.4  Subscription Duration

   As the presence (or lack of) a device or user agent it not very time
   critical to the functionality of the profile delivery server, it is
   recommended that default subscription duration be 86400 seconds (one
   day).

3.5  NOTIFY Bodies

   The size of profile content is likely to be hundreds to several
   thousand bytes in size.  Frequently even with very modest sized SDP
   bodies, SIP messages get fragmented causing problems for many user
   agents.  For this reason the profile delivery server MUST use content
   indirection [I-D.ietf-sip-content-indirect-mech] in the NOTIFY body
   for providing the profiles if the Accept header of the SUBSCRIBE
   included the MIME type: message/external-body indicating support for
   content indirection.

   When delivering profiles via content indirection the profile delivery
   server MUST include the Content-ID defined in
   [I-D.ietf-sip-content-indirect-mech] for each profile URL.  This is
   to avoid unnecessary download of the profiles.  Some user agents are
   not able to make a profile effective without rebooting or restarting.
   Rebooting is probably something to be avoided on a user agent
   performing services such as telephony.  In this way the Content-ID
   allows the user agent to avoid unnecessary interruption of service as
   well.  The Content-Type MUST be specified for each URI.

      Initially it is expected that most user agent implementers will
      use a proprietary content type for the profiles retrieved from the
      URIs(s).  It is hoped that over time a standard content type will
      be specified that will be adopted by implementers of user agents.
      One direction that appears to be promising for this content is to
      use XML with name spaces [??] to segment the data into sets that
      the user agent implementer may choose to support based upon
      desired feature set.  The specification of the content is out of
      the scope of this document.

   Likewise the URL scheme used in the content indirection is outside
   the scope of this document.  This document is agnostic to the URL



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   schemes as the profile content may dictate what is required.  It is
   expected that TFTP [RFC3617], FTP [??], HTTP [RFC2616], HTTPS
   [RFC2818], LDAP [RFC3377], XCAP [I-D.rosenberg-simple-xcap] and other
   URL schemes are supported by this package and framework.

3.6  Notifier processing of SUBSCRIBE requests

   The general rules for processing SUBSCRIBE requests [RFC3265] apply
   to this package.  If content indirection is used for delivering the
   profiles, the notifier does not need to authenticate the subscription
   as the profile content is not transported in the SUBSCRIBE or NOTIFY
   transaction messages.  With content indirection only URLs are
   transported in the NOTIFY request which may be secured using the
   techniques in Section 6.  If content indirection is not used, SIPS
   and SIP authentication SHOULD be used.

   The behavior of the profile delivery server is left to the
   implementer.  The profile delivery server may be as simple as a SIP
   SUBSCRIBE UAS and NOTIFY UAC front end to a simple HTTP server
   delivering static files that are hand edited.  At the other extreme
   the profile delivery server can be part of a configuration management
   system that integrates with a corporate directory and IT system or
   carrier OSS, where the profiles are automatically generated.  The
   design of this framework intentionally provides the flexibility of
   implementation from simple/cheap to complex/expensive.

   If the user or device is not known to the profile delivery server,
   the implementer MAY accept the subscription or reject it.  It is
   recommended that the implementer accept the subscription.  It is
   useful for the profile delivery server to maintain the subscription
   as an administrator may add the user or device to the system,
   defining the profile contents.  This allows the profile delivery
   server to immediately send a NOTIFY request with the profile URIs.
   If the profile delivery server does not accept the subscription from
   an unknown user or device, the administer or user must manually
   provoke the user agent to reSUBSCRIBE.  This may be difficult if the
   user agent and administrator are at different sites.

3.7  Notifier generation of NOTIFY requests

   As in [RFC3265], the profile delivery server MUST always send a
   NOTIFY request upon accepting a subscription.  If the device or user
   is unknown to the profile delivery server and it chooses to accept
   the subscription, the implementer has two choices.  A NOTIFY MAY be
   sent with no body or content indirection containing the profile
   URI(s).  Alternatively a NOTIFY MAY be sent with URI(s) pointing to a
   default data set.  Typically this data set allows for only limited
   functionality of the user agent (e.g.  a phone user agent with data



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   to call help desk and emergency services.).  This is an
   implementation and business policy decision.

   A user or device known and fully provisioned on the profile delivery
   server SHOULD send a NOTIFY with profile data or content indirection
   containing URIs for all of the profiles associated with the user or
   device (i.e.  whichever specified in the profile-name parameter).
   The device may be associated with a default user.  The URI(s) for
   this default user profiles MAY be included with the URI(s) of the
   device if the profile type specified is device.

   A user agent can provide Hoteling by collecting a user’s AOR and
   credentials needed to SUBSCRIBE and retrieve the user profiles from
   the URI(s).  Hoteling functionality is achieved by subscribing to the
   AOR and specifying the "user" profile type.  This same mechanism can
   be used to secure a user agent, requiring a user to login to enable
   functionality beyond the default user’s restricted functionality.

   The profile delivery server MAY specify when the new profiles MUST be
   made effective by the user agent.  By default the user agent makes
   the profiles effective as soon as it thinks that it is non-obtrusive.
   Profile changes SHOULD effect behavior all new sessions which are
   created after the notification, but may not be able to effect
   existing sessions.  However the profile delivery server MAY specify a
   maximum time in seconds (zero or more), in the effective-by event
   header parameter, by which the user agent MUST make the new profiles
   effective for all sessions.

3.8  Subscriber processing of NOTIFY requests

   The user agent subscribing to this event package MUST adhere to the
   NOTIFY request processing behavior specified in [RFC3265].  The user
   agent MUST make the profiles effective as specified in the NOTIFY
   request (see Section 3.7).  The user agent SHOULD use one of the
   techniques specified in [RFC3265] to securely retrieve the profiles.

3.9  Handling of forked requests

   This event package allows the creation of only one dialog as a result
   of an initial SUBSCRIBE request.  The techniques to achieve this are
   described in section 4.4.9 of [RFC3265].

3.10  Rate of notifications

   It is anticipated that the rate of change for user and device
   profiles will be very infrequent (i.e.  days or weeks apart).  For
   this reason no throttling or minimum period between NOTIFY requests
   is specified for this package.



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3.11  State Agents

   State agents are not applicable to this event package.

3.12  Examples


   SUBSCRIBE sip:00df1e004cd0@example.com SIP/2.0
   Event: sip-profile;profile-name=device;vendor=acme;
                            model=Z100;version=1.2.3
   From: sip:00df1e004cd0@acme.com;tag=1234
   To: sip:00df1e004cd0@acme.com;tag=abcd
   Call-ID: 3573853342923422@10.1.1.44
   CSeq: 2131 SUBSCRIBE
   Contact: sip:00df1e004cd0@10.1.1.44
   Content-Length: 0



   NOTIFY sip:00df1e004cd0@10.1.1.44 SIP/2.0
   Event: sip-profile;effective-by=3600
   From: sip:00df1e004cd0@acme.com;tag=abcd
   To: sip:00df1e004cd0@acme.com;tag=1234
   Call-ID: 3573853342923422@10.1.1.44
   CSeq: 321 NOTIFY
   MIME-Version: 1.0
   Content-Type: multipart/mixed; boundary=boundary42
   Content-Length: ...

   --boundary42
   Content-Type: message/external-body;
       access-type="URL";
       expiration="Mon, 24 June 2002 09:00:00 GMT";
           URL="http://www.example.com/devices/fsmith";
           size=2222

   Content-Type: application/z100-user-profile
   Content-ID: <69ADF2E92@example.com>

   --boundary42
   Content-Type: message/external-body;
       access-type="URL";
       expiration="Mon, 24 June 2002 09:00:00 GMT";
           URL="http://www.example.com/devices/ff00000036c5";
           size=1234

   Content-Type: application/z100-device-profile
   Content-ID: <39EHF78SA@example.com>



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   --boundary42--


3.13  Use of URIs to Retrieve State

   The profile type specified determines what goes in the user part of
   the SUBSRIBE URI.  If the profile type requested is "device", the
   user part of the URI is an identity that MUST be unique across all
   user agents from all implementers.  This identity must be static over
   time so that the profile delivery server can keep a specific device
   and its identity associated with its profiles.  For Ethernet hardware
   type user agents supporting only a single user at a time this is most
   easily accomplished using its MAC address.  Software based user
   agents running on general purpose hardware may also be able to use
   the MAC address for identity.  However in situations where multiple
   instances of user agents are running on the same hardware it may be
   necessary to use another scheme, such as using a unique serial number
   for each software user agent instance.
      For example a device having a MAC address of 00df1e004cd0 might
      subscribe to the device profile URI:
      sip:00df1e004cd0@sipuaconfig.example.com.  When subscribing to a
      user profile for user Fred S.  the user agent would subscribe to
      the URI: sip:freds@sipuaconfig.example.com

   If the profile type requested is "user", the URI in the SUBSCRIBE
   request is the address of record for the user.  This allows the user
   to specify (e.g.  login) to the user agent by simply entering their
   known identity.

   If the profile type specified in the profile-name parameter is
   "local", the URI in the SUBSCRIBE request has the user ID: anonymous.
   The host part of the URI is the local network name.  This typically
   is discovered as part of the DHCP request/response or provisioned as
   part of the static IP configuration for the device.  When subscribing
   to the local network profile type the device should provide the
   user's address of record in the "network-user" parameter, if the AOR
   is known to the device.  Example URI: sip:ananymous@example.com

4.  Profile Delivery Framework Details

   The following describes how different functional steps of the profile
   delivery framework work.  Also described here is how the event
   package defined in this document provides the enrollment and
   notification functions within the framework.

4.1  Discovery of Subscription URI

   The discovery function is needed to bootstrap user agents to the



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   point of knowing where to enroll with the profile delivery server.
   Section 3.13 describes how to form the URI used to send the SUBSCRIBE
   request for enrollment.  However the bootstrapping problem for the
   user agent (out of the box) is what to use for the host and port in
   the URI.  Due to the wide variation of environments in which the
   enrolling user agent may reside (e.g.  behind residential router,
   enterprise LAN, ISP, dialup modem) and the limited control that the
   administrator of the profile delivery server (e.g.  enterprise,
   service provider) may have over that environment, no single discovery
   mechanism works everywhere.  Therefore a number of mechanisms SHOULD
   be tried in the specified order: SIP DHCP option [RFC3361], SIP DNS
   SRV [RFC3263], DNS A record and manual.

   1.  The first discovery mechanism that SHOULD be tried is to
       construct the SUBSCRIBE URI as described in Section 3.13 using
       the host and port of out bound proxy discovered by the SIP DHCP
       option as described in [RFC3361].  If the SIP DHCP option is not
       provided in the DHCP response, no SIP response or a SIP failure
       response other than for authorization is received for the
       SUBSCRIBE request to the sip-profile event, the next discovery
       mechanism SHOULD be tried.
   2.  The local IP network domain for the user agent, either configured
       or discovered via DHCP, should be used with the technique in
       [RFC3263] to obtain a host and port to use in the SUBSCRIBE URI.
       If no SIP response or a SIP failure response other than for
       authorization is received for the SUBSCRIBE request to the
       sip-profile event, the next discovery mechanism SHOULD be tried.
   3.  The fully qualified host name constructed using the host name
       "sipuaconfig" and concatenated with the local IP network domain
       should be tried next using the technique in [RFC3263] to obtain a
       host and port to use in the SUBSCRIBE URI.  If no SIP response or
       a SIP failure response other than for authorization is received
       for the SUBSCRIBE request to the sip-profile event, the next
       discovery mechanism SHOULD be tried.
   4.  If all other discovery techniques fail, the user agent MUST
       provide a manual means for the user to enter the host and port
       used to construct the SUBSCRIBE URI.

   Once a user agent has successfully discovered, enrolled, received a
   NOTIFY response with profile data or URI(s), the user agent SHOULD
   cache the SUBCRIBE URI to avoid having to rediscover the profile
   delivery server again in the future.  The user agent SHOULD NOT cache
   the SUBSCRIBE URI until it receives a NOTIFY with profile data or
   URI(s).  The reason for this is that a profile delivery server may
   send 202 responses to SUBSCRIBE requests and NOTIFY responses to
   unknown user agent (see Section 3.6) with no URIs.  Until the profile
   delivery server has sent a NOTIFY request with profile data or
   URI(s), it has not agreed to provide profiles.



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      To illustrate why the user agent should not cache the SUBSCRIBE
      URI until profile URI(s) are provided in the NOTIFY, consider the
      following example:  a user agent running on a laptop plugged into
      a visited LAN in which a foreign profile delivery server is
      discovered.  The profile delivery server never provides profile
      URIs in the NOTIFY request as it is not provisioned to accept the
      user agent.  The user then takes the laptop to their enterprise
      LAN.  If the user agent cached the SUBSCRIBE URI from the visited
      LAN (which did not provide profiles), when subsequently placed in
      the enterprise LAN which is provisioned to provide profiles to the
      user agent, the user agent would not attempt to discover the
      profile delivery server.

4.2  Enrollment with Profile Server

   Enrollment is accomplished by subscribing to the event package
   described in Section 3.  The enrollment process is useful to the
   profile delivery server as it makes the server aware of user agent to
   which it may delivery profiles (those user agents the profile
   delivery server is provisioned to provide profiles to; those present
   that the server may be provide profiles in the future; and those that
   the server can automatically provide default profiles).  It is an
   implementation choice and business policy as to whether the profile
   delivery server provides profiles to user agents that it is not
   provisioned to do so.  However the profile server SHOULD accept (with
   2xx response) SUBSCRIBE requests from any user agent.

4.3  Notification of Profile Changes

   The NOTIFY request in the sip-profile event package serves two
   purposes.  First it provides the user agent with a means to obtain
   the profile data or URI(s) for desired profiles without requiring the
   end user to manually enter them.  It also provides the means for the
   profile delivery server to notify the user agent that the content of
   the profiles have changed and should be made effective.

4.4  Retrieval of Profile Data

   The user agent retrieves its needed profile(s) via the URI(s)
   provided in the NOTIFY request as specified in Section 3.5.  The
   profile delivery server SHOULD secure the content of the profiles
   using one of the techniques described in Section 6.  The user agent
   SHOULD make the new profiles effective in the timeframe described in
   Section 3.2.

   The contents of the profiles SHOULD be cached by the user agent.
   This it to avoid the situation where the content delivery server is
   not available, leaving the user agent non-functional.



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4.5  Upload of Profile Changes

   The user agent or other service MAY push changes up to the profile
   delivery server using the technique appropriate to the profile's URL
   scheme (e.g.  HTTP PUT method, FTP put command).  The technique for
   pushing incremental or atomic changes MUST be described by the
   specific profile data framework.

5.  IANA Considerations

   There are several IANA considerations associated with this
   specification.

5.1  SIP Event Package

   This specification registers a new event package as defined in
   [RFC3265].  The following information required for this registration:
      Package Name: sip-profile
      Package or Template-Package: This is a package
      Published Document: RFC XXXX (Note to RFC Editor: Please fill in
      XXXX with the RFC number of this specification).
      Person to Contact: Daniel Petrie dpetrie@pingtel.com
      New event header parameters: profile-name, vendor, model, version,
      effective-by

6.  Security Considerations

   Profiles may contain sensitive data such as user credentials.  The
   protection of this data depends upon how the data is delivered.  If
   the data is delivered in the NOTIFY body, SIP authentication MUST be
   used for SUBSCRIPTION and SIPS and/or S/MIME MAY be use to encrypt
   the data.  If the data is provided via content indirection, SIP
   authentication is not necessary for the SUBSCRIBE request.  With
   content indirection the data is protected via the authentication,
   authorization and encryption mechanisms provided by the profile URL
   scheme.  Use of the URL scheme security mechanisms via content
   indirection simplifies the security solution as the SIP event package
   does not need to authenticate, authorize or protect the contents of
   the SIP messages.  Effectively the profile delivery server will
   provide profile URI(s) to anyone.  The URLs themselves are protected
   via authentication, authorization and snooping (e.g.  via HTTPS).

6.1  Symmetric Encryption of Profile Data

   If the URL scheme used for content indirection does not provide
   authentication, authorization or encryption, a technique to provide
   this is to encrypt the profiles on the content delivery server using
   a symmetric encryption algorithm using a shared key.  The encrypted



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   profiles are delivered by the content delivery server via the URIs
   provided in the NOTIFY requests.  Using this technique the profile
   delivery server does not need to provide authentication or
   authorization for the retrieval as the profiles are obscured.  The
   user agent must obtain the username and password from the user or
   other out of band means to generate the key and decrypt the profiles.

7.  Differences from Simple XCAP Package

   The author of this document had an action item from the July 2003
   IETF SIPPING WG meeting to consider resolving the differences of the
   sip-profile and simple XCAP package [I-D.ietf-simple-xcap-package].
   It is the author's opinion that XCAP [I-D.rosenberg-simple-xcap] can
   be supported by the framework and event package defined in this
   document and that this package provides a superset of the
   functionality in the XCAP package.  The following lists the
   differences between the event packaged defined in this document vs.
   the one defined in [I-D.ietf-simple-xcap-package].

   The simple XCAP package requires that the relative path be known and
   specified by the user agent when subscribing for change notification.
   The event package in this document requires a token or complete URI
   be known and specified when subscribing.  The advantage of the token
   is that bootstrapping is easier and well defined.  It also leaves the
   freedom of specifying and changing the entire path of the profile URL
   up to the profile delivery server.

   The event package defined in this document allows multiple URIs to be
   provided in the NOTIFY request body as a result of a single token
   specified in the SUBSCRIBE event parameter: profile-name.  This
   allows the profile delivery server to provide sets of profiles that
   the user agent may not have enough information to specify in the
   SUBSCRIBE URI (e.g.  at boot strapping time the user agent may not
   know the user's identity, but the profile delivery server may know
   the default user for the device's identity) or the doc-component of
   the simple XCAP package.

   All other functional differences between
   draft-ietf-sipping-config-framework-00 and
   draft-ietf-simple-xcap-package-00 are believed to be resolved in this
   version of this document.

8.  Open Issues


9.  Change History

   Many thanks to those who contributed and commented on the many



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   iterations of this document.  Detailed input was provided by Jonathan
   Rosenberg from Dynamicsoft, Henning Schulzrinne from Columbia U.,
   Cullen Jennings from Cisco, Rohan Mahy from Cisco, Rich Schaaf from
   Pingtel, Volker Hilt from Bell Labs.

9.1  Changes from draft-ietf-sipping-config-framework-02.txt

   Added the concept of the local network as a source of profile data.
   There are now three separate logical sources for profile data: user,
   device and local network.  Each of these requires a separate
   subscription to obtain.

9.2  Changes from draft-ietf-sipping-config-framework-01.txt

   Changed the name of the profile-type event parameter to profile-name.
   Also allow the profile-name parameter to be either a token or an
   explicit URI.

   Allow content indirection to be optional.  Clarified the use of the
   Accept header to indicate how the profile is to be delivered.

   Added some content to the Iana section.

9.3  Changes from draft-ietf-sipping-config-framework-00.txt

   This version of the document was entirely restructured and re-written
   from the previous version as it had been micro edited too much.

   All of the aspects of defining the event package are now organized in
   one section and is believed to be complete and up to date with
   [RFC3265].

   The URI used to subscribe to the event package is now either the user
   or device address or record.

   The user agent information (vendor, model, MAC and serial number) are
   now provided as event header parameters.

   Added a mechanism to force profile changes to be make effective by
   the user agent in a specified maximum period of time.

   Changed the name of the event package from sip-config to sip-profile

   Three high level securityapproaches are now specified.

9.4  Changes from draft-petrie-sipping-config-framework-00.txt

   Changed name to reflect SIPPING work group item



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   Synchronized with changes to SIP DHCP [RFC3361], SIP [RFC3261] and
   [RFC3263], SIP Events [RFC3265] and content indirection
   [I-D.ietf-sip-content-indirect-mech]

   Moved the device identity parameters from the From field parameters
   to User-Agent header parameters.

   Many thanks to Rich Schaaf of Pingtel, Cullen Jennings of Cisco and
   Adam Roach of Dyamicsoft for the great comments and input.

9.5  Changes from draft-petrie-sip-config-framework-01.txt

   Changed the name as this belongs in the SIPPING work group.

   Minor edits

9.6  Changes from draft-petrie-sip-config-framework-00.txt

   Split the enrollment into a single SUBSCRIBE dialog for each profile.
   The 00 draft sent a single SUBSCRIBE listing all of the desired.
   These have been split so that each enrollment can be routed
   differently.  As there is a concept of device specific and user
   specific profiles, these may also be managed on separate servers.
   For instance in a roaming situation the device might get its profile
   data from a local server which knows the LAN specific profile data.
   At the same time the user specific profiles might come from the
   user's home environment profile delivery server.

   Removed the Config-Expires header as it is largely superfluous with
   the SUBSCRIBE Expires header.

   Eliminated some of the complexity in the discovery mechanism.

   Suggest caching information discovered about a profile delivery
   server to avoid an avalanche problem when a whole building full of
   devices powers up.

   Added the User-Profile From header field parameter so that the device
   can request a user specific profile for a user that is different from
   the device's default user.

10  References

   [I-D.ietf-simple-xcap-package]
              Rosenberg, J., "A Session Initiation Protocol (SIP) Event
              Package for Modification Events  for the Extensible Markup
              Language (XML) Configuration Access Protocol (XCAP)
              Managed Documents", draft-ietf-simple-xcap-package-01



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              (work in progress), February 2004.

   [I-D.ietf-sip-content-indirect-mech]
              Olson, S., "A Mechanism for Content Indirection in Session
              Initiation Protocol (SIP)  Messages",
              draft-ietf-sip-content-indirect-mech-03 (work in
              progress), June 2003.

   [I-D.ietf-sipping-ua-prof-framewk-reqs]
              Petrie, D. and C. Jennings, "Requirements for SIP User
              Agent Profile Delivery Framework",
              draft-ietf-sipping-ua-prof-framewk-reqs-00 (work in
              progress), March 2003.

   [I-D.rosenberg-simple-xcap]
              Rosenberg, J., "The Extensible Markup Language (XML)
              Configuration Access Protocol (XCAP)",
              draft-rosenberg-simple-xcap-00 (work in progress), May
              2003.

   [I-D.sinnreich-sipdev-req]
              Butcher, I., Lass, S., Petrie, D., Sinnreich, H. and C.
              Stredicke, "SIP Telephony Device Requirements,
              Configuration and Data", draft-sinnreich-sipdev-req-03
              (work in progress), February 2004.

   [RFC0822]  Crocker, D., "Standard for the format of ARPA Internet
              text messages", STD 11, RFC 822, August 1982.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2131]  Droms, R., "Dynamic Host Configuration Protocol", RFC
              2131, March 1997.

   [RFC2132]  Alexander, S. and R. Droms, "DHCP Options and BOOTP Vendor
              Extensions", RFC 2132, March 1997.

   [RFC2246]  Dierks, T. and C. Allen, "The TLS Protocol Version 1.0",
              RFC 2246, January 1999.

   [RFC2616]  Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
              Masinter, L., Leach, P. and T. Berners-Lee, "Hypertext
              Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.

   [RFC2617]  Franks, J., Hallam-Baker, P., Hostetler, J., Lawrence, S.,
              Leach, P., Luotonen, A. and L. Stewart, "HTTP
              Authentication: Basic and Digest Access Authentication",



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              RFC 2617, June 1999.

   [RFC2818]  Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000.

   [RFC3261]  Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
              A., Peterson, J., Sparks, R., Handley, M. and E. Schooler,
              "SIP: Session Initiation Protocol", RFC 3261, June 2002.

   [RFC3263]  Rosenberg, J. and H. Schulzrinne, "Session Initiation
              Protocol (SIP): Locating SIP Servers", RFC 3263, June
              2002.

   [RFC3265]  Roach, A., "Session Initiation Protocol (SIP)-Specific
              Event Notification", RFC 3265, June 2002.

   [RFC3361]  Schulzrinne, H., "Dynamic Host Configuration Protocol
              (DHCP-for-IPv4) Option for Session Initiation Protocol
              (SIP) Servers", RFC 3361, August 2002.

   [RFC3377]  Hodges, J. and R. Morgan, "Lightweight Directory Access
              Protocol (v3): Technical Specification", RFC 3377,
              September 2002.

   [RFC3617]  Lear, E., "Uniform Resource Identifier (URI) Scheme and
              Applicability Statement for the Trivial File Transfer
              Protocol (TFTP)", RFC 3617, October 2003.


Author's Address

   Daniel Petrie
   Pingtel Corp.
   400 W. Cummings Park
   Suite 2200
   Woburn, MA  01801
   US

   Phone: "Dan Petrie (+1 781 938 5306)"<sip:dpetrie@pingtel.com>
   EMail: dpetrie@pingtel.com
   URI:   http://www.pingtel.com/

Appendix A.  Acknowledgments









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   This document and the information contained herein is provided on an
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