SIPPING D. Petrie
Internet-Draft SIPez LLC.
Expires: April 6, 2007 October 3, 2006
A Framework for Session Initiation Protocol User Agent Profile Delivery
draft-ietf-sipping-config-framework-09.txt
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Copyright Notice
Copyright (C) The Internet Society (2006).
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 that 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
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of SIP user agents. The contents and format of the profile data to
be defined is outside the scope of this document.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Requirements Terminology . . . . . . . . . . . . . . . . . . . 4
3. Profile Delivery Framework Terminology . . . . . . . . . . . . 5
4. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
5. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . . 7
5.1. Service Provider Use Case Scenario Bootstrapping with
Digest Authentication . . . . . . . . . . . . . . . . . . 7
5.2. Service Provider Use Case Scenario Bootstrapping with
Device Certificate . . . . . . . . . . . . . . . . . . . 9
6. Data Model . . . . . . . . . . . . . . . . . . . . . . . . . . 10
7. Profile Change Event Notification Package . . . . . . . . . . 11
7.1. Event Package Name . . . . . . . . . . . . . . . . . . . 12
7.2. Event Package Parameters . . . . . . . . . . . . . . . . 12
7.3. SUBSCRIBE Bodies . . . . . . . . . . . . . . . . . . . . 16
7.4. Subscription Duration . . . . . . . . . . . . . . . . . . 16
7.5. NOTIFY Bodies . . . . . . . . . . . . . . . . . . . . . . 16
7.6. Notifier processing of SUBSCRIBE requests . . . . . . . . 17
7.7. Notifier generation of NOTIFY requests . . . . . . . . . 19
7.8. Subscriber processing of NOTIFY requests . . . . . . . . 19
7.9. Handling of forked requests . . . . . . . . . . . . . . . 20
7.10. Rate of notifications . . . . . . . . . . . . . . . . . . 20
7.11. State Agents . . . . . . . . . . . . . . . . . . . . . . 20
7.12. Examples . . . . . . . . . . . . . . . . . . . . . . . . 20
7.13. Use of URIs to Retrieve State . . . . . . . . . . . . . . 21
7.13.1. Device URIs . . . . . . . . . . . . . . . . . . . . . 22
7.13.2. User URIs . . . . . . . . . . . . . . . . . . . . . . 24
7.13.3. Local Network URIs . . . . . . . . . . . . . . . . . 24
8. Profile Delivery Framework Details . . . . . . . . . . . . . . 25
8.1. Discovery of Subscription URI . . . . . . . . . . . . . . 25
8.1.1. Discovery of Local Network URI . . . . . . . . . . . 25
8.1.2. Discovery of Device URI . . . . . . . . . . . . . . . 26
8.1.3. Discovery of User URI . . . . . . . . . . . . . . . . 29
8.2. Enrollment with Profile Server . . . . . . . . . . . . . 29
8.3. Notification of Profile Changes . . . . . . . . . . . . . 29
8.4. Retrieval of Profile Data . . . . . . . . . . . . . . . . 30
8.5. Upload of Profile Changes . . . . . . . . . . . . . . . . 30
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 30
9.1. SIP Event Package . . . . . . . . . . . . . . . . . . . . 30
9.2. New HTTP Event Header . . . . . . . . . . . . . . . . . . 31
10. Security Considerations . . . . . . . . . . . . . . . . . . . 31
10.1. Confidential Profile Content in NOTIFY Request . . . . . 32
10.2. Confidential Profile Content via Content Indirection . . 33
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10.3. Integrity protection for non-confidential profiles . . . 34
10.4. Initial Enrollment Using a Manufacturer's Certificate . . 34
11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 36
12. Change History . . . . . . . . . . . . . . . . . . . . . . . . 36
12.1. Changes from
draft-ietf-sipping-config-framework-08.txt . . . . . . . 36
12.2. Changes from
draft-ietf-sipping-config-framework-07.txt . . . . . . . 36
12.3. Changes from
draft-ietf-sipping-config-framework-06.txt . . . . . . . 37
12.4. Changes from
draft-ietf-sipping-config-framework-05.txt . . . . . . . 37
12.5. Changes from
draft-ietf-sipping-config-framework-04.txt . . . . . . . 38
12.6. Changes from
draft-ietf-sipping-config-framework-03.txt . . . . . . . 38
12.7. Changes from
draft-ietf-sipping-config-framework-02.txt . . . . . . . 38
12.8. Changes from
draft-ietf-sipping-config-framework-01.txt . . . . . . . 39
12.9. Changes from
draft-ietf-sipping-config-framework-00.txt . . . . . . . 39
12.10. Changes from
draft-petrie-sipping-config-framework-00.txt . . . . . . 39
12.11. Changes from draft-petrie-sip-config-framework-01.txt . . 40
12.12. Changes from draft-petrie-sip-config-framework-00.txt . . 40
13. References . . . . . . . . . . . . . . . . . . . . . . . . . . 40
13.1. Normative References . . . . . . . . . . . . . . . . . . 40
13.2. Informative References . . . . . . . . . . . . . . . . . 41
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 44
Intellectual Property and Copyright Statements . . . . . . . . . . 45
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1. Introduction
Today all SIP (Session Initiation Protocol) [RFC3261] user agent
implementers use proprietary means of delivering user, device and
local network policy 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 (User Agent) implementers
will be able to use this framework as a means of delivering their
existing proprietary 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 namespaces [W3C.REC-xml-names11-20040204] 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 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. Requirements Terminology
Keywords "MUST", "MUST NOT", "REQUIRED", "SHOULD", "SHOULD NOT" and
"MAY" that appear in this document are to be interpreted as described
in [RFC2119].
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3. Profile Delivery Framework Terminology
profile - data set specific to a user, device, or the local network.
device - software or hardware appliance containing one or more SIP
user agents.
profile content server - The server that provides the content of the
profiles using the protocol specified by the URI scheme.
notifier - As defined in [RFC3265] the SIP user agent server which
processes SUBSCRIBE requests for events and sends NOTIFY requests
with profile data or URIs (Uniform Resource Identifiers) that
point to the data.
profile delivery server - The logical collection of the notifier and
the server which provides the contents of the notification either
directly in the NOTIFY requests or indirectly via profile URI(s).
hotelling- when a user moves to a new user agent (i.e. that is not
already provisioned to know the user's identity, credentials or
profile data) and gives the user agent sufficient information to
retrieve the user's profile(s). The user agent either permanently
or temporarily makes the user's profiles effective on that user
agent.
nomadic- when the user agent moves to a different local network
instance id- text identifier globally unique across all user agent
(soft and hard devices)
4. 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. The
means of discovery is described in Section 8.1.
Enrollment is the process by which a UA makes itself known to the
profile delivery server. In enrolling, the UA provides identity
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information, 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. A profile type
may represent one or more data sets. Enrollment which is performed
by the device by constructing and sending a SUBSCRIBE request to
profile delivery server for the event package described in Section 7.
Profile Retrieval is the process of retrieving the content for each
of the profiles requested by the UA. The profiles are retrieved
either directly or indirectly from the NOTIFY request body as
described in Section 7.5 and Section 8.4.
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 MAY retrieve the profile from the specified URI upon receipt of
the change notification. Profile change notification is provided by
the NOTIFY request for the event package as described in Section 7.8
and Section 8.3.
Profile Change Upload is the process by which a UA or other entity
(e.g. corporate directory or configuration management server) pushes
a change to the profile data back up to the profile delivery server.
This process is described in Section 8.5.
This framework defines a new SIP event package [RFC3265] to solve
enrollment and profile change notification steps. The event package
in Section 7 defines everything but the mandatory content type. This
makes this event package abstract until the content type is bound.
The profile content type definition is outside of scope for this
document. It is the author's belief that it would be a huge
accomplishment if all SIP user agents used this framework for
delivering their existing proprietary profiles. Even though this
does not accomplish interoperability of profiles, it is a big first
step in easing the administration of SIP user agents. The definition
of standard profiles and data sets (see [I-D.petrie-sipping-profile-
datasets] ) will enable interoperability as a subsequent step.
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
(see Section 8.1). SIP is only needed for the enrollment (see
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Section 8.2) and change notification functionality (see Section 8.3)
of the profile delivery framework. In many SIP environments (e.g.
carrier/subscriber and multi-site enterprise) firewall, NAT (Network
Address Translation) 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. The local network profile (see Section 6, Section 7.13.3
and Section 8.1.1) provides the means to get firewall and NAT
traversal mechanism information to the device. 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 should be noted that this document is scoped
to providing profiles for devices which contain one or more SIP user
agents. This framework may be applied to non-SIP devices, however
more general requirements for non-SIP devices are beyond the scope of
this document.
The content delivery server may be either in the public network or
accessible through a private network. 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 (e.g. an HTTP client on the
UA can typically pull content from a server outside the NAT/
firewall.).
5. Use Cases
The following use cases are intended to help give an understanding of
how the profile delivery framework can be used. These use cases are
not intended to be exhaustive in demonstrating all of the
capabilities or ways the framework can be applied.
5.1. Service Provider Use Case Scenario Bootstrapping with Digest
Authentication
The following describes a use case scenario for bootstrapping a new
user agent, which has had no prior provisioned information, to the
point of being functional with a SIP Service Provider's system. In
this example scenario, the user has purchased a new SIP user agent.
The user signs up for the service to obtain three pieces of
information: a hostname, a user ID and a password. These three
pieces of information may be one-time use, that become invalid after
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the one use. This scenario assumes that no association or mapping
between the device and the user's account is created before the
following steps:
|Service Provider |
|Profile Delivery Server|
| ___ _____ |
| |SIP| |HTTPS| |
|_|___|_________|_____|_|
A A
| |
\___ |-5A) HTTP GET of device profile
\ |-6) HTTPS response w/device profile
\ | ______________
\ | | Residential |
4) NOTIFY on-\ \ | Router ____ |
existing TLS \ \ | |DHCP| |
connetion \ \ |_______|____|_|
\ \ A A
\ \ 1B) SUBSCRIBE-| |
\ \ local network| |
\ \ profile| |
\ \ | |
\ \ | |-1A) DHCP
\ \ | |request
\ \ | |
\ \ C=======D
3) SIP/TLS SUBSCRIBE to device profile-\ \ /^\
7) reSUBSCRIBE to device profile as-\ / \
configured in device profile / Device \
-----------
2) User enters service provider hostname
5B) User enters HTTP profile userID and password
1. The user plugs the device in to provide power and network
connectivity the first time (or installs the software in the case
of a software user agent). The device subscribes to the local
network to get the local network profile. However as the device
is plugged into a residential LAN or router, there is no profile
delivery server for the local network profile (see Section 8.1.1
and Section 7.13.3).
2. The device prompts the user for the hostname to subscribe to for
the device profile. The hostname was provided by the service
provider and is used as the host part of the SUBSCRIBE profile
URI described in Section 7.13.1. Note: in a scenario where the
system operator (e.g. enterprise) has control of the network, the
hostname for the SUBSCRIBE can be discovered (see Section 8.1.2)
to avoid the need for the user to enter the hostname.
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3. The device creates a TLS [RFC2246] connection for the SIP
SUBSCRIBE request to the provided hostname. The device verifies
the server's certificate. If the SubjectAltName does not match
the hostname or the certificate is not valid (as described in
Section 23 of [RFC3261]), the device warns the user and prompts
whether to continue.
4. The profile delivery server receives the SUBSCRIBE request for
the device profile and sends a NOTIFY with content indirection
containing the HTTPS URI for the device profile (see
Section 7.5).
5. The device receives the NOTIFY request with the device profile
URI. The device prompts the user for the user ID and password
provided by the service provider. The device does an HTTPS GET
to retrieve the device profile (see Section 8.4 and Section 7.8).
The profile delivery server challenges for Digest authentication.
The device re-sends the HTTPS GET with Digest credentials using
the user ID and password entered by the user.
6. The profile delivery server receives the HTTP GET request for the
device profile along with the user ID and password for the
specific user. At this point, the profile delivery server has
authenticated the user and can create an association between a
specific device identified in the HTTPS URI and the user or user
account (see Section 10.2). The profile delivery server provides
the device profile which may contain the on-going SUBSCRIBE
request URIs for the device, user and other profiles along with
credentials for retrieving the profiles.
7. The device receives the device profile from the HTTPS response,
re-SUBSCRIBEs using the device profile URI provided in the
profile. The device profile also may contain URIs for the
default user's user and other profile SUBSCRIBE request URIs for
the SIP event package defined in Section 7. The device uses
these URIs to retrieve user and other profiles in a similar way
to the device profile. After retrieving these profiles the
device is fully functional in the service provider's SIP service.
5.2. Service Provider Use Case Scenario Bootstrapping with Device
Certificate
The following describes another use case scenario where the device
implementor provides a certificate for the device which authenticates
the device ID. In this scenario, the user signs up for the SIP
service with the service provider and provides the device ID (see
Section 7.13.1 for more information on device ID) to the service
provider prior to the following steps, so that the service provider
has an association or mapping between the device ID and the user
account ahead of time. The service provider gives the user a
hostname to be entered on the device.
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1. Steps 1-3 occur the same as in the prior use case described in
Section 5.1.
2. The device receives the NOTIFY request with the device profile
URI. The device does an HTTPS GET to retrieve the device profile
(see Section 8.4 and Section 7.8).
3. The profile delivery server requests the device certificate in
the TLS connection used for the HTTPS GET. The device has a
certificate that contains the MAC address used in the device ID.
The device certificate is signed and provided by the implementor
for the purpose of authenticating the device ID in the initial
bootstrapping process only. The profile delivery server
validates the device ID and returns the device profile using
HTTPS.
4. The device receives the device profile in the HTTPS response.
The process continues in a similar way to step 7 in the above use
case. The device profile contains a more permanent device
certificate and private key or Digest authentication credentials
which are used for on-going device ID authentication.
6. Data Model
A conscious separation of device, user and local network profiles is
made in this document. This is useful to provide features such as
hotelling (described above) as well as securing or restricting user
agent functionality. For example, by maintaining this separation,
Alice may walk up to Bob's user agent and direct Bob's user agent to
get the Alice's profile data. In doing so the user agent can replace
the previous user's profile data while still keeping the device's and
the local network's profile data which 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 nomadic capabilities
(described above) as well as local policy data that may constrain the
user or device behavior relative to the local network. For example,
media types and codecs may be constrained to reflect the network's
capabilities.
The separation of these profiles also enables the separation of the
management of the profiles. The user profile may be managed by a
profile delivery server operated by the user's ISP. The device
profile may be delivered from a profile delivery server operated by
the user's employer. Other profile(s) may be delivered from the
user's ASP (Application Service Provider). The local network profile
may delivered by a WLAN (Wireless LAN) hotspot service provider.
Some interesting services and mobility applications are enabled with
this separation of profiles.
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A very high level data model is implied here with the separation of
these three profile types. Each profile type instance requires a
separate subscription to retrieve the profile. A loose hierarchy
exists mostly for the purpose of bootstrapping and discovery or
formation of the profile URIs. No other meaning is implied by this
hierarchy. However, the profile format and data sets to be defined
outside this document may define additional meaning to this
hierarchy. In the bootstrapping scenario, a device straight out of
the box (software or hardware) does not know anything about its user
or local network. The one thing that it does know is its instance
id. So the hierarchy of the profiles exists as follows.
The local network profile is subscribed to and retrieved based upon a
URI formed from the local network domain. The local network profile
is subscribed to first as it may contain information on how to
communicate to the Internet or primary network from the local network
(e.g. HTTP proxy, SIP firewall or NAT traversal information). The
device instance id is used to form the user id part of the URI for
subscribing to the device and local network profiles. The device
profile may contain a default user AOR (Address of Record) for that
device. The default user AOR may then be used to retrieve the user
profile. Applications to be used on the device may be defined in the
device and user profiles.
7. 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 presence of
the MIME type for content indirection [I-D.ietf-sip-content-indirect-
mech] in the Accept header indicates that the user agent supports
content indirection and that the profile delivery server SHOULD use
content indirection. Similarly the content type for the differential
notification of profile changes [I-D.ietf-simple-xcap-diff] may be
used in the Accept header to express support for receiving profile
change deltas.
The MIME types or formats of profiles to be delivered via this
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framework are to be defined in the documents that define the profile
contents. These profile MIME types specified in the Accept header
along with the profile types specified in the Event header parameter
"profile-type" SHOULD be used to specify which profiles get delivered
either directly or indirectly in the NOTIFY requests. As this event
package does not specify the mandatory content type, this package is
abstract. The profile definition documents will specify the
mandatory content type to make a concrete event package.
7.1. Event Package Name
The name of this package is "ua-profile". This value appears in the
Event header field present in SUBSCRIBE and NOTIFY requests for this
package as defined in [RFC3265].
7.2. Event Package Parameters
This package defines the following new parameters for the event
header: "profile-type", "vendor", "model", "version", "effective-by",
and "network-user". The "effective-by" parameter is for use in
NOTIFY requests only. The "effective-by" parameter is ignored if it
appears in a SUBSCRIBE request. The other parameters are for use in
the SUBSCRIBE request and are ignored if they appear in NOTIFY
requests.
The "profile-type" parameter is used to indicate the token name of
the profile type the user agent wishes to obtain data or URIs for and
to be notified of subsequent changes. Using a token in this
parameter allows the URI semantics for retrieving the profiles to be
opaque to the subscribing user agent. All it needs to know is the
token value for this parameter. This document defines three logical
types 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 defined here are "device", "user" and
"local-network". Specifying "device" type profile(s) indicates the
desire for the profile data (URI when content indirection is used)
and change notification of the contents of the profile that is
specific to the device or user agent. Specifying "user" type profile
indicates the desire for the profile data (URI when content
indirection is used) and change notification of the profile content
for the user. Specifying "local-network" type profile indicates the
desire for profile data (URI when content indirection is used)
specific to the local network. The device, user or local network is
identified in the URI of the SUBSCRIBE request. A separate SUBSCRIBE
dialog is used for each profile type. The profile type associated
with the dialog can then be used to infer which profile type changed
and is contained in the NOTIFY or content indirection URI. The
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Accept header of the SUBSCRIBE request MUST include the MIME types
for all profile content types for which the subscribing user agent
wishes to retrieve profiles or receive change notifications. In the
following ABNF, EQUAL and token are defined in [RFC3261]. Additional
profile types may be defined in subsequent documents.
Profile-type = "profile-type" EQUAL profile-value
profile-value = profile-types / token
profile-types = "device" / "user" / "local-network"
The "device", "user" or "local-network" token in the profile-type
parameter may represent a class or set of profile properties. 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-type parameter. Also additional
content types may be defined along with the profile formats that
can be used in the Accept header of the SUBSCRIBE to filter or
indicate what data sets of the profile are desired.
The rationale for the separation of user, device and local network
type profiles is provided in Section 4. It should be noted that any
of the types may result in zero or more profiles or URIs being
provided in the NOTIFY request. As discussed, a default user may be
assigned to a device. The default user's AOR, if defined in the
device profile, may in turn be used as the URI to SUBSCRIBE to the
"user" profile type.
The data provided in the three types of profiles may overlap. As an
example, the codecs that a user prefers to use, the codecs that the
device supports (and the enterprise or device owner wishes to use),
the codecs that the local network can support (and the network
operator wishes to allow) all may overlap in how they are specified
in the three corresponding profiles. This policy for merging the
constraints across the multiple profile types can only unambiguously
be defined in the context of the profile syntax and semantics. This
is out of scope for this document and will be defined in a subsequent
document(s) that define the data profile format.
The "vendor", "model" and "version" parameter values are tokens
specified by the implementer of the user agent. These parameters
MUST be provided in the SUBSCRIBE request for all profile types. The
implementer SHOULD use their DNS domain name (e.g. example.com) as
the value of the "vendor" parameter so that it is known to be unique.
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
property X in a profile may work differently on two versions of the
same user agent. This gives the profile delivery server the ability
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to compensate for or take advantage of the differences. In the
following ABNF, EQUAL and quoted-string are defined in [RFC3261].
Vendor = "vendor" EQUAL quoted-string
Model = "model" EQUAL quoted-string
Version = "version" EQUAL quoted-string
The "network-user" parameter MUST be set when subscribing for device
profiles if the user's AOR is known. The "network-user" parameter
MUST be set when subscribing for "local-network" profiles if it is
known, unless the device is provisioned to preserve privacy within
the local network.
When the profile-type is "device", the SUBSCRIBE URI addresses the
device which must contain the device identity (see Section 7.13).
When the profile-type is "local-network", the SUBSCRIBE URI
addresses the local network profile resource id which must contain
the localdomain with no user part (see Section 7.13). The URIs
will not contain the user profile identifier. For this reason the
"network-user" parameter is needed to indicate the user profile
resource identifier associated with the "device" or URI.
The SUBSCRIBE server SHOULD authenticate the subscriber to verify the
resource identifier in the "network-user" parameter if the profile
provided is specific to the user (e.g. granting policies or
privileges beyond those of a default user). If the value of the
"profile-type" parameter is not "device" or "local-network", the
"network-user" parameter has no defined meaning and is ignored. If
the "network-user" parameter is provided in the SUBSCRIBE request, it
MUST be present in the NOTIFY request as well. In the following
ABNF, EQUAL, LDQUOT, RDQUOT and addr-spec are defined in [RFC3261].
Network-User = "network-user" EQUAL LDQUOT addr-spec RDQUOT
The entity that is subscribing and getting the "device" and
"local-network" profiles is the device. For this reason the From
field should indicate the device's identity. These profiles types
contain device specific information and it is the device's
identity that gets authenticated for the "device" profile.
Depending upon the local administration policy and segmentation of
services, the device identity and user profile identity
association may not be known to the configuration delivery server
ahead of time. Since the From field and SUBSCRIBE request URI
indicate the "device" profile resource identifier, the "network-
user" parameter is needed to indicate the additional resource
identifier for the user associated with this device.
When the profile-type is "device", the user agent SHOULD set the
"network-user" parameter to the "user" profile resource identifier if
it is known. This is an indication to the profile delivery server to
set or change the association of the default user with the device
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indicated in the SUBSCRIBE URI. If the profile delivery server
implements and allows this policy of setting the default user with a
device, the user agent can utilize this mechanism to allow a user to
login and make the user agent and user association permanent.
If the profile-type is "local-network" and users's AOR is known, the
user agent SHOULD assign the "network-user" parameter to be the
user's AOR. If the user has special privileges beyond that of a
default user in the local network, the "network-user" parameter
identifies the user to the local network.
The "effective-by" parameter in the Event header of the NOTIFY
request specifies the maximum number of seconds before the user agent
must attempt to make the new profile effective. The "effective-by"
parameter MAY be provided in the NOTIFY request for any of the
profile types. A value of 0 (zero) indicates that the subscribing
user agent must attempt to 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. The "effective-by" parameter is ignored in
all messages other than the NOTIFY request. In the following ABNF,
EQUAL and DIGIT are defined in [RFC3261].
Effective-By = "effective-by" EQUAL 1*DIGIT
The following are example Event headers which may occur in
SUBSCRIBE requests. These examples are not intended to be
complete SUBSCRIBE requests.
Event: ua-profile;profile-type=device;
vendor="vendor.example.com";model="Z100";version="1.2.3"
Event: ua-profile;profile-type="user";
vendor="premier.example.com";model="trs8000";version="5.5"
The following are example Event headers which may occur in
NOTIFY requests. These example headers are not intended to
be complete SUBSCRIBE requests.
Event: ua-profile;effective-by=0
Event: ua-profile;effective-by=3600
The following table shows the use of Event header parameters in
SUBSCRIBE requests for the three profile types:
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profile-type || device | user | local-network
=============================================
vendor || m | m | m
model || m | m | m
version || m | m | m
network-user || s | | s
effective-by || | |
m - mandatory
s - SHOULD be provided
o - optional
Non-specified means that the parameter has no meaning and
should be ignored.
The following table shows the use of Event header parameters in
NOTIFY requests for the three profile types:
profile-type || device | user | local-network
=============================================
vendor || | |
model || | |
version || | |
network-user || s | | s
effective-by || o | o | o
7.3. SUBSCRIBE Bodies
This package defines no use of the SUBSCRIBE request body. A body
contained in a SUBSCRIBE request for this event package is ignored.
Future documents may specify a filter-like mechanism using etags to
minimize the delivery or notification of profiles where the user
agent already has a current version.
7.4. Subscription Duration
As the presence (or lack of) a device or user agent is not very time
critical to the functionality of the profile delivery server, it is
recommended that the default subscription duration be 86400 seconds
(one day). A one-time fetch of a profile can be accomplished by
setting the Expires parameter to 0 as defined in [RFC3265] resulting
in a single NOTIFY with no change notification.
7.5. NOTIFY Bodies
The size of profile content is likely to be hundreds to several
thousands of bytes in size. For this reason, if the Accept header of
the SUBSCRIBE included the MIME type message/external-body,
indicating support for content indirection, the profile delivery
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server SHOULD use content indirection [I-D.ietf-sip-content-indirect-
mech] in the NOTIFY body for providing the profiles.
When delivering profiles via content indirection, the profile
delivery server MUST include the Content-ID MIME header described in
[I-D.ietf-sip-content-indirect-mech] for each profile URI. 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 something to be avoided on a user agent performing
services such as telephony. By examining the Content-ID, the user
agent can recognize if it already has the indirected content, thus
avoiding unnecessary interruption of service. The Content-Type MUST
be specified for each URI. For minimal interoperability, the profile
delivery server MUST support the "http:" and "https:" URI schemes for
content indirection. Other URI schemes MAY also be provided in the
content indirection. However the security considerations are define
for content indirection using HTTP and HTTPS. Other protocols MAY be
supported for content indirection, but are out of scope of this
document.
Initially user agent implementers may use a proprietary content
type for the profiles retrieved from the URI(s). This is a good
first step towards easing the management of user agents. Standard
profile contents, content type and formats will need to be defined
for true interoperability of profile delivery. The specification
of the content is out of the scope of this document.
The URI scheme [RFC2396] used in content indirection may be dictated
by the profile content that is required. It is expected that FTP
[RFC0959], HTTP [RFC2616], HTTPS [RFC2818], LDAP [RFC3377], XCAP
[I-D.ietf-simple-xcap] and other URI schemes could be used by this
package and framework if the subscribing user agent and profile
delivery server both support the same scheme. The negotiation of the
URI scheme is described in the following sections.
7.6. 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 URIs are
transported in the NOTIFY request which may be secured using the
techniques in Section 10. If content indirection is not used, the
subscribe server SHOULD reject SUBSCRIBE requests from connections
that are not over TLS and SHOULD challenge the SUBSCRIBE request with
SIP Digest authentication. The subscriber MUST support the "http:"
or "https:" URI scheme for content indirection. If the subscriber
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wishes to use a URI scheme other than "http:", the subscriber must
use the "schemes" Contact header field parameter to indicate the URI
scheme as defined in [I-D.ietf-sip-content-indirect-mech]. For
example the subscriber may request that content indirection use the
"ldaps:" URI scheme by including "ldaps" in the "scheme" Contact
header parameter of the SUBSCRIBE request. If the subscriber does
not specify the URI scheme, the notifier may use either "http:" or
"https:".
The profile generation 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 operations support systems,
where the profiles are automatically generated. The design of
this framework intentionally provides the flexibility of
implementation from simple/cheap to complex/expensive.
The "profile-type" parameter can be thought of as a filter to
indicate which profile(s) are to be provided. If the profile type
indicated in the "profile-type" Event header parameter is not
provisioned or provided to any users in the domain, the profile
delivery server the Notifier SHOULD return a 404 responce to the
SUBSCRIBE request.
If the specific user or device is not known to the profile delivery
server, the implementer MAY accept the subscription or reject it. It
is a policy decision whether to maintain the subscription dialog for
an unprovisioned user or device. It is recommended that the
implementer accept the subscription. It is useful for the profile
delivery server to maintain the subscription for unprovisioned users
or devices as an administrator may add the user or device to the
system after the initial subscription, 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 re-
subscribe. This may be difficult if the user agent and administrator
are at different locations.
A user agent can provide hotelling by collecting a user's AOR and the
credentials needed to SUBSCRIBE and retrieve the user's profiles.
Hotelling functionality is achieved by subscribing to the user's AOR
and specifying the "user" profile type. This same mechanism can also
be used to secure a user agent, requiring a non-mobile user to login
to enable functionality beyond the default user's restricted
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functionality.
When the Event header "profile-type" is "device" and the user agent
has provided the user's AOR in the "network-user" parameter, the
profile delivery server MAY set or change the default user associated
with the device indicated in the SUBSCRIBE URI. This is an
implementation or policy decision. The profile delivery server
SHOULD authenticate the user for the SUBSCRIBE request before
changing the default user associated with the device.
7.7. 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 a body or content
indirection containing URI(s) pointing to a default data set. The
data sets provided may allow for only limited functionality of the
user agent (e.g. a telephony user agent that only permits calls to
the help desk and emergency services). This is an implementation and
business policy decision for the profile delivery server.
If the URI in the SUBSCRIBE request is a known identity and is
provisioned with the requested profile type (i.e. as specified in the
profile-type parameter of the Event header), the profile delivery
server SHOULD send a NOTIFY with profile data or content indirection
(if the content indirection mime type was included in the Accept
header) containing the URI for the profile. To protect the integrity
of the profile data or indirect content profile data URIs, the
notifier SHOULD send the NOTIFY request on the same TLS connection as
the SUBSCRIBE request came in on if TLS was used.
The profile delivery server may specify when the new profiles must be
made effective by the user agent. The profile delivery server MAY
specify a maximum time in seconds (zero or more) in the
"effective-by" event header parameter. The user agent uses the
"effective-by" parameter to determine when to make the new profiles
effective for all dialogs.
7.8. 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 attempt to make the profiles effective within the time in
seconds given in the "effective-by" Event header parameter if present
in the NOTIFY request (see Section 7.7). By default, the user agent
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makes the profiles effective as soon as it thinks that it is non-
obtrusive to do so. For example, when there are no active calls.
Profile changes SHOULD affect behavior on all new dialogs which are
created after the notification, but may not be able to affect
existing dialogs. The user agent SHOULD use one of the techniques
specified in Section 10 to securely retrieve the profiles. If the
subscriber included the MIME type message/external-body for content
indirection in the SUBSCRIBE request Accept header, the subscriber
MUST support the http: or https: URI schemes for content indirection.
If the subscriber indicated alternative URI schemes for content
indirection it MUST also indicate support for http: or https:. The
subscriber should still be prepared to use http: or https: as the
profile delivery server may not support the alternative URI schemes.
The subscriber MUST be prepared to receive a NOTIFY request with no
body. The subscriber MUST NOT reject the NOTIFY request with no
body. The subscription dialog MUST NOT be termnated by the NOTIFY
with no body.
The subscriber should maintain the dialog as it was the profile
delivery server's policy decision to create the dialog. Most
likely the NOTIFY body is empty because the user or device is not
provisioned in the profile delivery server. The notifier decided
to maintain the dialog so that it can NOTIFY the subscribe of the
availablity of the profile immediately after the user or device
gets provisioned. If the subscriber ended the dialog after
receiving the NOTIFY with no body, the subscriber would need to be
manually provoked to resubscribe.
7.9. 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].
7.10. 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.
7.11. State Agents
State agents are not applicable to this event package.
7.12. Examples
Example SUBSCRIBE and NOTIFY request using content indirection: Note:
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The Event and Via header fields are continued on a second line due to
format constraints of this document.
SUBSCRIBE sip:MAC%3aFF00000036C5@acme.example.com SIP/2.0
Event: ua-profile;profile-type=device;vendor="vendor.example.com";
model="Z100";version="1.2.3";network-user="sip:betty@example.com"
From: sip:MAC%3aFF00000036C5@acme.example.com;tag=1234
To: sip:MAC%3aFF00000036C5@acme.example.com
Call-ID: 3573853342923422@10.1.1.44
CSeq: 2131 SUBSCRIBE
Contact: sip:MAC%3aFF00000036C5@10.1.1.44
Via: SIP/2.0/TCP 10.1.1.41;
branch=z9hG4bK6d6d35b6e2a203104d97211a3d18f57a
Accept: message/external-body, application/x-z100-device-profile
Content-Length: 0
NOTIFY sip:MAC%3aFF00000036C5@10.1.1.44 SIP/2.0
Event: ua-profile;effective-by=3600;
network-user="sip:betty@example.com"
From: sip:MAC%3aFF00000036C5@acme.example.com;tag=abcd
To: sip:MAC%3aFF00000036C5@acme.example.com;tag=1234
Call-ID: 3573853342923422@10.1.1.44
CSeq: 321 NOTIFY
Via: SIP/2.0/UDP 192.168.0.3;
branch=z9hG4bK1e3effada91dc37fd5a0c95cbf6767d1
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/ff00000036c5";
size=1234
Content-Type: application/x-z100-device-profile
Content-ID: <39EHF78SA@example.com>
--boundary42--
7.13. Use of URIs to Retrieve State
The URI for the SUBSCRIBE request is formed differently depending
upon which profile type the subscription is for. This allows the
different profile types to be potentially managed by different
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profile delivery servers (perhaps even operated by different
entities). The To and From field will typically contain the same URI
as is used in the original SUBSCRIBE request URI.
7.13.1. Device URIs
The URI for the "device" type profile (device URI) is based upon the
identity of the device. The device URI MUST be unique across all
devices and implementations. If an instance id is used as the user
part of the device URI, it SHOULD remain the same for the lifetime of
the user agent. The device URI is used to identify which profile is
associated with a specific instance of a user agent.
If the user agent changed its device URI, the profile delivery
server would not know the association between the profile and the
device. This would also make it difficult for the profile
delivery server to track user agents under profile management.
The profile delivery server may decide to provide the same device
profile to all devices of the same vendor, model and version.
However this is a implementation choice of the profile delivery
server. The subscribing device has no way of knowing whether the
profiles for each device are different. For this reason the
device must always use a unique id in the device SUBSCRIBE request
URI. As an example the device profile for similar devices may
differ with properties such as the default user. This is how the
bootstrapping mechanism works as described in Section 8.1.3.
The URI for the device type profile MUST use a unique identifier as
the user portion of the URI. The host and port portion of the URI is
set to that of the domain or address of the profile delivery server
which manages that user agent. A means of discovering the host and
port portion is discussed in Section 8.1. There is an administration
aspect of the unique identifier, that makes it desirable for the id
to be obtainable or predictable prior to installation of the device
(hard or soft). Also from a human factors perspective, ids that are
easily distinguished and communicated will make the administrators
job a little easier. The MAC address or a UUID [RFC4122] SHOULD be
used for constructing a unique identifier to be used in the user
portion of the device URI.
If the identifier is a MAC address, it MUST be formatted as the
characters "MAC:" followed by a 12 digit hexadecimal representation
of the MAC address. The address can not include ":", whitespace, or
other formatting.
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The MAC address of the device may be used if there will always be
no more than one user agent using that MAC address over time (e.g.
a dedicated telephone appliance). The MAC address may not be used
if more than one user agent instance exists using the same MAC
address (e.g. multiple instances of a softphone may run on a
general purpose computing device). The advantage of the MAC
address is that many vendors put bar codes on the device with the
actual MAC address on it. A bar code scanner is a convenient
means of collecting the instance id for input and provisioning on
the profile delivery server. If the MAC address is used, it is
recommended that the MAC address is rendered in all upper case
with no punctuation for consistency across implementations. A
prefix of "MAC:" should be added to the MAC address to form a
proper URN [RFC2141]. For example a device managed by
sipuaconfig.example.com using its MAC address to form the device
URI might look like:
sip:MAC%3a00DF1E004CD0@sipuaconfig.example.com.
UHEX = DIGIT / %x41-46 ;uppercase A-F
MAC = %x4d.41.43 ; MAC in caps
mac-ident = MAC ":" 12UHEX
When the MAC address is not used in the device URI, a UUID [RFC4122]
for the device SHOULD be used.
For devices where there is no MAC address or the MAC address is
not unique to an instance of a user agent (e.g. multiple
softphones on a computer or a gateway with multiple logical user
agents) it is RECOMMENDED that a UUID [RFC4122] is used as the
user portion of the device URI. The same approach to defining a
user agent instance ID as [I-D.ietf-sip-outbound] should be used.
When constructing the instance id, the implementer should also
consider that a human may need to manually enter the instance id
to provision the device in the profile delivery server (e.g.
longer strings are more error prone in data entry). When the URN
is used as the user part of the URI, it MUST be URL escaped. The
":" is not a legal character (without being escaped) in the user
part of a addr-spec [RFC4122]. For example the instance ID:
urn:uuid:f81d4fae-7ced-11d0-a765-00a0c91e6bf6 would be escaped to
look as follows in a URI:
sip:urn%3auuid%3af81d4fae-7ced-11d0-a765-00a0c91e6bf6@example.com.
Soft user agents are likely to need to use this approach due to
the multi-user nature of general purpose computers. The software
installer program might generate the uuid as part of the install
process so that it remains persistent for the installation. It
may also be desirable that any upgrades of the software maintain
the unique id. However these are all implementation choices.
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7.13.2. User URIs
The URI for the "user" type profile is based upon the identity of the
user. It is an administration policy on how user profile identities
are assigned. Typically the user's address of record (AOR) is used
as the URI in the SUBSCRIBE request. A new user agent or device may
not know the user's AOR. The user's AOR may be obtained as part of a
default user property in the device profile. Alternatively the user
agent may prompt the user for an AOR and credentials to be used to
authenticate the request. This can provide a login and/or hotelling
feature on the user agent. The user agent may be pre-provisioned
with the user's AOR or provided as information on a SIM or flash key.
These are only examples and not an exhaustive list of sources for the
user AOR.
7.13.3. Local Network URIs
The URI for the "local-network" type profile is based upon the
identity of the local network. When subscribing to the local network
profile, the user part of the SUBSCRIBE request URI SHOULD NOT be
provided. The From field user part of the SUBSCRIBE request SHOULD
be the same device ID used as the user part of the device profile
SUBSCRIBE request URI defined in Section 7.13.1. The host and port
part of the request URI and From field is the local network name/
domain. The discovery of the local network name or domain is
discussed in Section 8.1. The user agent may provide the user's AOR
as the value to the "network-user" event header parameter. This is
useful if the user has privileges in the local network beyond those
of the default user. When "network-user" is provided the profile
delivery server SHOULD authenticate the user before providing the
profile if additional privileges are granted. Example URI: sip:
example.com
The local network profile SUBSCRIBE request URI does not have a
user part so that the URI is distinct between the "local" and
"device" URIs when the domain is the same for the two. This
provides a means of routing to the appropriate profile delivery
server in domains where they are distinct servers. The From field
uses the device ID in the user part of the local network request
URI so that every device in the network has a unique and constant
From field. Even though every device may get the same or similar
local network profiles, the uniqueness of the From field provides
an important capability. Having unique From fields allows the
management of the local network to track user agents present in
the network and consequently also manage resources such as
bandwidth and port allocation.
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8. 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.
8.1. Discovery of Subscription URI
The discovery approach varies depending upon which profile type URI
is to be discovered. The order of discovery is important in the
bootstrapping situation as the user agent may not have any
information provisioned. The local network profile should be
discovered first as it may contain key information such as how to
traverse a NAT/firewall to get to outside services (e.g. the user's
profile delivery server). The device profile URI should be
discovered next. The device profile may contain the default user's
AOR or firmware/software information that should be updated first
before proceeding with the discovery process. The user profile
subscription URI should be discovered last. The URIs are formed
differently for each of the profile types. This is to support the
delegation of the profile management to potentially three different
entities. However all three profile types may be provided by the
same entity. As the user agent has no way of knowing whether the
profiles are provide by one or more different profile delivery
servers ahead of time, it must subscribe to all three profile types
in separate SUBSCRIBE requests to get the profiles.
8.1.1. Discovery of Local Network URI
The "discovered" host for the "local-network" profile subscription
URI is the local IP network domain for the user agent, either
provisioned as part of the device's static network configuration or
discovered via DHCP [RFC2131](option 15 [RFC2132]). The local
network profile subscription URI SHOULD not be remembered if the user
agent moves from one local network to another other. The user agent
should perform the local network discovery to construct the network
profile subscription request URI every time it starts up or network
connectivity is regained.
For example: The user agent requested and received the local
domain name via DHCP: airport.example.net. If the device ID is:
MAC:00DF1E004CD0, the local network profile SUBSCRIBE request URI
would look like: sip:MAC%3a00DF1E004CD0@airport.example.net. The
user agent should send this request using the normal SIP locating
mechanisms defined in [RFC3263]. The Event header would look like
the following if the user agent decided to provide
sip:alice@example.com as the user's AOR. (Alice may have a prior
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arrangement with the local network operator giving her special
privileges.):
Event: ua-profile;profile-type=local-network;
network-user="sip:alice@example.com"
8.1.2. Discovery of Device URI
The discovery function is needed to bootstrap user agents to the
point of knowing where to enroll with the profile delivery server.
Section 7.13.1 describes how to form the user part of the device
profile SUBSCRIBE request URI used 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 device URI. Due to the wide
variation of environments in which the enrolling user agent may
reside (e.g. behind residential router, enterprise LAN, WLAN hotspot,
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. The user agent may be pre-provisioned with the host and
port (e.g. service providers may pre-provision a device before
sending it to a subscriber, provide a SIM or flash key, etc.) in
which case this discovery mechanism is not needed. Before performing
the discovery steps, the user agent should provide a means to skip
the discovery stage and manually enter the device URI host and port.
In addition, the user agent should allow the user to accept or reject
the discovered host and port in case an alternative to the discovered
host and port is desired.
1. The first discovery mechanism for the device SUBSCRIBE request
URI Section 7.13.1 is to use the host and port of the outbound
proxy discovered by the SIP DHCP option 120 [RFC3361]. If the
SIP DHCP option is not provided in the DHCP response or if the
SUBSCRIBE request to the ua-profile event receives no response or
a failure response other than for authentication, the next
discovery mechanism should be tried.
For example: Consider a dedicated hardware device with a
single user agent having the MAC address: abc123efd456. The
user agent sends a DHCP request including the request for the
DHCP option for SIP: 120 (see [RFC3361]). If the DHCP
response includes an answer for option 120, then the DNS name
or IP address included is used in the host part of the device
URI. For this example let's assume: example.com. The device
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URI would look like: sip:MAC%3aABC123EFD456@example.com. The
user agent should send this request using the normal SIP
locating mechanisms defined in [RFC3263]. If the response
fails then, the next discovery mechanism is tried.
2. The local IP network domain for the user agent, either configured
or discovered via DHCP option 15, 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 ua-profile event, the next discovery mechanism
should be tried.
For example: The user agent requested and received the local
domain name (option 15 [RFC2132]) in the DHCP response:
boston.example.com. The device URI would look like:
sip:MAC%3aABC123EFD456@boston.example.com. The user agent
should send this request using the normal SIP locating
mechanisms defined in [RFC3263]. If the response fails then,
the next discovery mechanism is tried.
3. The fully qualified host name constructed by concatenating
"sipuaconfig" and the local IP network domain (as provided via
DHCP option 15 or provisioned) 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 ua-profile event, the next discovery mechanism
should be tried.
For example: The user agent requested and received the local
domain name via DHCP as in the above example:
boston.example.com. The device URI would look like:
sip:MAC%3aABC123EFD456@sipuaconfig.boston.example.com. The
user agent should send this request using the normal SIP
locating mechanisms defined in [RFC3263]. If the response
fails then, the next discovery mechanism is tried.
4. If all other discovery techniques fail, a manual means for the
user to enter the host and port used to construct the SUBSCRIBE
request URI MUST be provided by the user agent.
Two approaches to the manual discovery process are suggested. In the
first approach using SIP, the user agent provides a means for
entering the subscription host and port information for the request
URI along with the user id and password to be used for authentication
of the SUBSCRIBE request. With this approach the user agent begins
with the enrollment process followed by the change notification and
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profile retrieval steps.
An alternative to the manual discovery using SIP, is to start with
the retrieve process. The user agent provides a means of entering a
HTTPS URI along with the user id and password to be used for
authentication of the retrieval of the profile. The retrieved device
profile may contain the properties for the SUBSCRIBE request URI and
credentials to enroll and get change notification of profile changes.
This approach bootstraps the process in a different step in the
cycle, but uses the same profile framework. When the device starts
with retrieval of the profile via HTTPS (instead of a SIP SUBSCRIBE
to the event package), the device MUST provide the Event header in
the HTTPS request using the same format as described for the
SUBSCRIBE request (see Section 7.2) . The Event header is necessary
to determine which profile is requested as well as for providing
specific information about the device.
This document defines a new HTTP request header "Event". The syntax
of the HTTP Event header is the same as the SIP Event header defined
in this document. The purpose of the HTTP Event header, just like
the SIP Event header is to define the content of the state
information to be retrieved. In particular, the state information is
the device, user or local network profile for the device. The SIP
Event header parameters for this event package ("profile-type",
"vendor", "model", "version") are also manditory for the HTTP Event
header as they are used to provide information as to what profile
type is requested along with information about the device which may
impact the contents of the profile.
Once a user agent has been successfully discovered, enrolled and
received a NOTIFY response with profile data or URI(s), the user
agent should cache (i.e. store persistently) the device profile
SUBSCRIBE request URI (rather than reconstructing it as described in
the discovery process every time the device is restarted) to avoid
having to rediscover the profile delivery server again in the future.
Caching of the device URI is necessary when the user agent is likely
to move to different local network domains as the local network may
not be the provider for the device's profile. The user agent should
not cache the device 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 7.6) with no profile data or 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 device
profile SUBSCRIBE URI until profile data or 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. In this example, the user agent
cached the SUBSCRIBE URI from the visited LAN which did not
provide profiles. When the UA is 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.
8.1.3. Discovery of User URI
The user's AOR may be pre-provisioned or provided via SIM or flash
key, etc. The device profile may define a default user and AOR. If
provided in the device profile and a pre-provisioned user AOR is not
provided, the default user's AOR is used to subscribe to the "user"
profile. If not provided through the above two approaches, the AOR
to be used for the "user" subscription URI, is "discovered" manually
by prompting the user. The URI obtained in the discovery steps
described above for the "user" profile subscription is stored
persistently in the device until explicitly reset or updated by the
user or profile.
8.2. Enrollment with Profile Server
Enrollment is accomplished by subscribing to the event package
described in Section 7. The enrollment process is useful to the
profile delivery server as it makes the server aware of user agents
to which it may deliver profiles. These include user agents that the
profile delivery server is provisioned to provide profiles to, those
present to which the server may 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 explicitly provisioned to do so. However the profile delivery
server SHOULD accept (with 2xx response) SUBSCRIBE requests from any
user agent as explained in Section 7.5.
8.3. Notification of Profile Changes
The NOTIFY request in the ua-profile event package serves two
purposes. First it provides the user agent with a means to obtain
the profile data directly or via URI(s) for desired profiles without
requiring the end user to manually enter them. It also provides the
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means for the profile delivery server to notify the user agent that
the content of the profiles has changed and should be made effective.
Optionally the differential changes may be obtained by notification
by including the content-type: "application/xcap-diff+xml" defined in
[I-D.ietf-simple-xcap-diff] in the Accept header of the SUBSCRIBE
request.
8.4. Retrieval of Profile Data
The user agent retrieves its needed profile(s) directly or via the
URI(s) provided in the NOTIFY request as specified in Section 7.5.
The profile delivery server SHOULD secure the content of the profiles
using one of the techniques described in Section 10. The user agent
SHOULD make the new profiles effective in the timeframe described in
Section 7.2.
The contents of the profiles SHOULD be cached (i.e. stored
persistently) by the user agent. The cache should be used if the
user agent is unable to successfully SUBSCRIBE or receive the NOTIFY
providing the most recent profile. The cached profile should be
replaced each time a profile is received in a NOTIFY or retrieved via
content indirection. This it to avoid the situation where the
content delivery server being not available, leaves the user agent
non-functional. The user agent should verify that it has the latest
profile content using the "hash" parameter defined in [I-D.ietf-sip-
content-indirect-mech].
8.5. 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 URI
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. A means for pushing changes up into
the profile delivery server for XCAP is defined in [I-D.ietf-simple-
xcap].
9. IANA Considerations
There are several IANA considerations associated with this
specification.
9.1. SIP Event Package
This specification registers a new event package as defined in
[RFC3265]. The following information required for this registration:
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Package Name: ua-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 dan.ietf AT SIPez DOT com
New event header parameters: profile-type, vendor, model, version,
effective-by, network-user
The profile-type parameter has predefined values. The other new
event header parameters do not.
The following table illustrates the additions to the IANA SIP Header
Field Parameters and Parameter Values: (Note to RFC Editor: Please
fill in XXXX with the RFC number of this specification)
Predefined
Header Field Parameter Name Values Reference
---------------------------- --------------- --------- ---------
Event profile-type Yes [RFCXXXX]
Event vendor No [RFCXXXX]
Event model No [RFCXXXX]
Event version No [RFCXXXX]
Event effective-by No [RFCXXXX]
Event network-user No [RFCXXXX]
9.2. New HTTP Event Header
This document defines a new permanent HTTP request header field:
Event
Header field name: Event
Applicable protocol: http
Status: standard
Author/Change controller: IETF
Specification document(s): [RFCXXXX] (Note to RFC Editor: Please
fill in XXXX with the RFC number of this specification).
10. Security Considerations
Profiles may contain sensitive data such as user credentials and
personal information. The protection of this data depends upon how
the data is delivered. Some profiles may be safe to deliver without
the need to protect the content. For example in some environments
the local network profile may contain the list of codecs that are
acceptable for use in the network and information on NAT traversal
such as a STUN server to use. As the information in this example
local network profile does not contain passwords or sensitive
information it may be acceptable to provide it without authentication
or confidentiality (encryption). We refer to these as non-
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confidential profiles. Non-confidential profiles require message
integrity and profile server authentication, as described in
Section 10.3. However any profiles that contain personal
information, passwords or credentials (confidential profiles) require
mutual authentication, confidentiality, and message integrity, and
must follow the guidance provided in the next two subsections.
Profile specifications that define schemas MUST identify if they
contain confidential data to indicate which of the security
approaches described here should be used.
The profile data is delivered in either the NOTIFY request or via the
URI scheme indicated in the content indirection in the NOTIFY
request. The security approach is different for these two delivery
mechanisms.
Subscribers implementing this specification MUST implement either
HTTP or HTTPS. Subscribers also MUST implement the hash verification
scheme described in SIP content indirection [I-D.ietf-sip-content-
indirect-mech]. SIP profile delivery servers MUST implement both
HTTP and HTTPS, and SHOULD implement a SIP Authentication Service as
described in the SIP Identity mechanism [I-D.ietf-sip-identity]. All
SIP entities are already required to implement SIP Digest
authentication [RFC3261].
10.1. Confidential Profile Content in NOTIFY Request
When the profile data is delivered directly in the NOTIFY request,
the SUBSCRIBE request MUST be authenticated using the SIP Digest
authentication mechanism. As the profile content is delivered in the
resulting NOTIFY request to the subscription, authenticating the
SUBSCRIBE is the only way to prevent unauthorized access to the
profile data. To provide message integrity and confidentiality over
the profile data, a direct TLS connection MUST be established for the
SUBSCRIBE request. The device SHOULD authenticate the server via the
TLS connection, which also provides a means of verifying (as
described in [RFC3261]) that a direct TLS connection was used (e.g.
The device may prompt the user to verify the SubjectAltName in the
server's certificate.). The server may challenge the device for its
certificate, when establishing the TLS connection, to obtain the
public key to use to S/MIME encode the NOTIFY request body containing
the profile data. Because the device verified that it has a direct
TLS connection by verifying the server's certificate and the server
verified the identity of the device using Digest Authentication, the
server can assume the certificate provided by the device is
authenticated. The use of S/MIME in the NOTIFY request does not
relieve the need to authenticate the SUBSCRIBE request using SIP
Digest authentication. In this scenario S/MIME only provides message
integrity and confidentiality of the content of the profile. If
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S/MIME is not used for the profile data in the NOTIFY request, the
notifier MUST use the same direct TLS connection established by the
device for the SUBSCRIBE request to send the notification. In this
scenario the use of a user-specific ID and secret for Digest
Authentication can be used to establish an association between the
user ID and the device ID provided in the device profile SUBSCRIBE
request.
10.2. Confidential Profile Content via Content Indirection
When the profile data is delivered via content indirection,
authentication, integrity, confidentiality are all provided in the
profile indirection retrieval scheme. When content indirection is
used, the SUBSCRIBE request does not need to be authenticated. There
is a TLS certificate approach and a Digest Authentication approach
which may be used to provide the required security. The profile
delivery server MUST support both of these methods. The device MUST
support the Digest Authentication method to provide minimal
interoperability.
For the TLS certificate approach, the device requests the profile
using HTTPS. To provide authentication, the server challenges the
device for its certificate. The server obtains the user part of the
SIP URI in the Subject Alternative Name field of the device's
certificate. The user part of the SIP URI in the device's
certificate is used as the device ID to authenticate if the device is
authorized to retrieve the specified profile. The device
certificates chain of authorities MUST also be verified. This
approach for providing security requires that the device ID and
associated user are provisioned for authentication as part of the
content indirection retrieval.
For the Digest Authentication approach, HTTPS SHOULD be used to
provide confidentiality of the profile data. HTTP Digest
Authentication [RFC2617] MUST be used to authenticate and authorize
the device to retrieve the profile. The shared secret used in the
Digest Authentication is provided through out of band means to the
device or user of the device. The same credentials used for SIP
Digest authentication (e.g. authentication of SIP SUBSCRIBE and
REGISTER requests) are used in the HTTPS request. Other URI schemes
may be used, but are not defined in this document. A non-replayable
authentication mechanism such as Digest authentication MUST be used
for the content indirection URI scheme which provides the profile
data (e.g. LDAP, HTTP and HTTPS all support Digest authentication).
URI schemes which provide no authentication or only clear-text
authentication SHOULD NOT be used for profile delivery as they are
vulnerable to replay attacks (e.g. TFTP does not provide
authentication).
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Without a suitable authentication mechanism, the content
indirection profile delivery URI scheme is susceptible to replay
attacks. Even if the profile is symmetrically encrypted, if it
can be retrieved through a replay attack, the encrypted profile
can be used for offline attacks to crack the encryption key.
The profile delivery scheme MUST use channel security such as TLS
(e.g. HTTPS) to protect the content from being snooped in transport
to the user agent. Mutual authentication using the client and server
certificates MAY be used to verify the authenticity of the user or
device identity and the profile delivery server identity. The user
agent SHOULD provide a mechanism for the user to approve the
SUBSCRIBE server identity or provision the acceptable server identity
through out of band means.
10.3. Integrity protection for non-confidential profiles
Even for non-confidential profiles, the subscriber MUST verify the
authenticity of the profile delivery server, and MUST verify that the
integrity of the profile data and content indirection URI, if one is
provided. To meet these requirements in the SIP messaging the NOTIFY
request MUST use a SIP Identity header [I-D.ietf-sip-identity], or
S/MIME. If content is provided via redirection, the content
indirection "hash" parameter MUST be included unless the profile data
is delivered via a protocol which natively provides authentication
and message integrity, such as HTTP or LDAP protected by TLS. The
content retrieved via the content indirection URI MUST be integrity
checked using the "hash" parameter.
For example, Alice subscribes to the local domain profile for
paris.example.com. She receives a NOTIFY request which uses content
indirection, including a "hash" parameter. Alice uses the Identity
header from the NOTIFY to verify that the request came from
paris.example.com and that the body was not modified. Then she
fetches the content at the provided URI and verifies that the hash
she calculates from the profile matches the hash provided in the SIP
signaling.
10.4. Initial Enrollment Using a Manufacturer's Certificate
A UA with a manufacturer certificate can use this certificate for
initial enrollment into the configuration framework. In order to
safely deploy this scenario, the profile delivery server MUST
maintain a list of enrolled devices and a separate list of devices
which it expects to enroll.
When the device sends a subscription request to the notifier, the
notifier extracts the device-id from the user part of the Request URI
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and checks if the device is expected to enroll. If the device is
expected, the notifier provides an https: URL to the subscriber and
uses the SIP Identity mechanism to protect the integrity of this URL.
This URL MUST contain enough information that the profile content
server can correlate a request to this URL with the device-id that
was in the subscription.
The subscriber then establishes a TLS connection to the profile
content server and performs ordinary authentication of the server
certificate. During the TLS handshake, the profile content server
requests the certificate of the subscriber. The subscriber provides
its device certificate. Typically this certificate is created by the
manufacturer of the device. If no client certificate is provided,
the profile content server SHOULD return a 403 Forbidden response.
Next the profile content server checks the client certificate
according to the following steps:
1. The client certificate MUST be valid, and MUST be rooted in a
certificate authority that the administrator of the profile
content server trusts to assert a valid "enrollment identity",
for example a MAC address, serial number, or device-id.
2. The profile content server MUST verify that the device-id
provided in the https: URL corresponds to the subject or
subjectAltName of the client certificate, in an implementation
specific way. For example, the profile content server could
extract the MAC address from the device-id and the certificate
and compare them. How device certificates are arranged is not
standardized at the time of this writing, and is outside the
scope of this document.
3. The profile content server SHOULD verify that the issuer of the
certificate is expected and authorized to assert an enrollment
identity for this type of device. In other words, the profile
content server should not allow acme.example to assert an
enrollment identity for a device manufactured by rival company
widgets.example.
4. The profile content server MUST verify that the device referred
to by the device-id is not already enrolled.
5. The profile content server MUST verify that the device referred
to by the device-id is expected to enroll at the current time.
Typically, an administrator would configure a time-window of
hours or days during which a new device can enroll.
If the profile content server successfully performs all these steps,
it provides an initial device profile to the subscriber in the body
of the HTTP response. This initial device profile MUST contain new
credentials (for example, credentials for Digest authentication) that
the subscriber can use for subsequent authentication. Integrity and
confidentiality of the new profile is provided since the response is
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sent over a TLS channel. If one of the verification steps above
fails, the profile content server sends a 403 Forbidden response.
Entities other than the profile content server do not accept
manufacturer device certificates to secure ordinary communications,
such as SIP TLS or SIP S/MIME.
11. Acknowledgements
Many thanks to those who contributed and commented on the many
iterations of this document. Detailed input was provided by Jonathan
Rosenberg from Cisco, Henning Schulzrinne from Columbia University,
Cullen Jennings from Cisco, Rohan Mahy from Plantronics, Rich Schaaf
from Pingtel, Volker Hilt from Bell Labs, Adam Roach of Estacado
Systems, Hisham Khartabil from Telio, Henry Sinnreich from MCI,
Martin Dolly from AT&T Labs, John Elwell from Siemens, Elliot Eichen
and Robert Liao from Verizon, Dale Worley from Pingtel, Francois
Audet from Nortel, Roni Even from Polycom, Jason Fischl from
Counterpath.
12. Change History
[[RFC Editor: Please remove this entire section upon publication as
an RFC.]]
12.1. Changes from draft-ietf-sipping-config-framework-08.txt
The request URI for profile-type=localnet now SHOULD not have a
user part to make routing easier. The From field SHOULD now
contain the device id so that device tracking can still be done.
Described the concept of profile-type as a filter and added
normative text requiring 404 for profile types not provided.
Moved "application" profile type to
draft-ietf-sipping-xcap-config-01. The "application" value for
the profile-type parameter will also be used as a requirement that
XCAP be supported.
Fixed text on certificate validation.
Added new HTTP header: Event to IANA section and clean up the IANA
section.
Added diagram for service provider use case schenario.
Added clarification for HTTP Event header.
Added clarification of subscriber handling of NOTIFY with no body.
12.2. Changes from draft-ietf-sipping-config-framework-07.txt
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Made XCAP informative reference. Removed "document" and "auid"
event header parameters, and Usage of XCAP section to be put in
separate supplementary draft.
Fixed ABNF for network-user to be addr-spec only (not name-addr)
and to be quoted as well.
Synchronized with XCAP path terminology. Removed XCAP path
definition as it is already defined in XCAP.
User agent instance ID is now defined in output (not GRUU).
Clarified the rational for the network-user parameter.
Added text to suggest URIs for To and From fields.
Clarified use of network-user parameter.
Allow the use of the auid and document parameters per request by
the OMA.
12.3. Changes from draft-ietf-sipping-config-framework-06.txt
Restructured the introduction and overview section to be more
consistent with other Internet-Drafts.
Added additional clarification for the Digest Authentication and
Certificate based authentication cases in the security section.
Added two use case scenarios with cross referencing to better
illustrate how the framework works. Added better cross
referencing in the overview section to help readers find where
concepts and functionality is defined in the document.
Clarified the section on the use of XCAP. Changed the Event
parameter "App-Id" to "auid". Made "auid" mutually exclusive to
"document". "auid" is now only used with XCAP.
Local network subscription URI changed to <device-id>@
<local-network> (was anonymous@<local-network>). Having a
different request URI for each device allows the network
management to track user agents and potentially manage bandwidth,
port allocation, etc.
Changed event package name from sip-profile to ua-profile per
discussion on the list and last IETF meeting.
Changed "local" profile type token to "local-network" per
discussion on the list and last IETF meeting.
Simplified "Vendor", "Model", "Version" event header parameters to
allow only quoted string values (previously allowed token as
well).
Clarified use of the term cache.
Added references for ABNF constructs.
Numerous editorial changes. Thanks Dale!
12.4. Changes from draft-ietf-sipping-config-framework-05.txt
Made HTTP and HTTPS profile transport schemes mandatory in the
profile delivery server. The subscribing device must implement
HTTP or HTTPS as the profile transport scheme.
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Rewrote the security considerations section.
Divided references into Normative and Informative.
Minor edits throughout.
12.5. Changes from draft-ietf-sipping-config-framework-04.txt
Clarified usage of instance-id
Specify which event header parameters are mandatory or optional
and in which messages.
Included complete list of event header parameters in parameter
overview and IANA sections.
Removed TFTP reference as protocol for profile transport.
Added examples for discovery.
Added ABNF for all event header parameters.
Changed profile-name parameter back to profile-type. This was
changed to profile-name in 02 when the parameter could contain
either a token or a path. Now that the path is contained in the
separate parameter: "document", profile-type make more sense as
the parameter name.
Fixed some statements that should have and should not have been
normative.
Added the ability for the user agent to request that the default
user associated with the device be set/changed using the "network-
user" parameter.
A bunch of editorial nits and fixes.
12.6. Changes from draft-ietf-sipping-config-framework-03.txt
Incorporated changes to better support the requirements for the use
of this event package with XCAP and SIMPLE so that we can have one
package (i.e. simple-xcap-diff now defines a content type not a
package). Added an additional profile type: "application". Added
document and app-id Event header parameters in support of the
application profile. Define a loose high level data model or
relationship between the four profile types. Tried to edit and fix
the confusing and ambiguous sections related to URI formation and
discovery for the different profile types. Better describe the
importance of uniqueness for the instance id which is used in the
user part of the device URI.
12.7. 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.
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12.8. 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.
12.9. 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 ua-profile
Three high level security approaches are now specified.
12.10. Changes from draft-petrie-sipping-config-framework-00.txt
Changed name to reflect SIPPING work group item
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 Estacado Systems for the great comments and input.
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12.11. Changes from draft-petrie-sip-config-framework-01.txt
Changed the name as this belongs in the SIPPING work group.
Minor edits
12.12. 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 nomadic 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.
13. References
13.1. Normative References
[I-D.ietf-sip-content-indirect-mech]
Burger, E., "A Mechanism for Content Indirection in
Session Initiation Protocol (SIP) Messages",
draft-ietf-sip-content-indirect-mech-05 (work in
progress), October 2004.
[I-D.ietf-sip-identity]
Peterson, J. and C. Jennings, "Enhancements for
Authenticated Identity Management in the Session
Initiation Protocol (SIP)", draft-ietf-sip-identity-06
(work in progress), October 2005.
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[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, 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",
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.
[RFC4122] Leach, P., Mealling, M., and R. Salz, "A Universally
Unique IDentifier (UUID) URN Namespace", RFC 4122,
July 2005.
13.2. Informative References
[I-D.ietf-simple-xcap]
Rosenberg, J., "The Extensible Markup Language (XML)
Configuration Access Protocol (XCAP)",
draft-ietf-simple-xcap-11 (work in progress), May 2006.
[I-D.ietf-simple-xcap-diff]
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Rosenberg, J., "An Extensible Markup Language (XML)
Document Format for Indicating A Change in XML
Configuration Access Protocol (XCAP) Resources",
draft-ietf-simple-xcap-diff-03 (work in progress),
October 2006.
[I-D.ietf-sip-outbound]
Jennings, C. and R. Mahy, "Managing Client Initiated
Connections in the Session Initiation Protocol (SIP)",
draft-ietf-sip-outbound-04 (work in progress), June 2006.
[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.petrie-sipping-profile-datasets]
Petrie, D., "A Schema and Guidelines for Defining Session
Initiation Protocol User Agent Profile Data Sets",
draft-petrie-sipping-profile-datasets-03 (work in
progress), October 2005.
[I-D.sinnreich-sipdev-req]
Sinnreich, H., "SIP Telephony Device Requirements and
Configuration", draft-sinnreich-sipdev-req-08 (work in
progress), October 2005.
[RFC0822] Crocker, D., "Standard for the format of ARPA Internet
text messages", STD 11, RFC 822, August 1982.
[RFC0959] Postel, J. and J. Reynolds, "File Transfer Protocol",
STD 9, RFC 959, October 1985.
[RFC2131] Droms, R., "Dynamic Host Configuration Protocol",
RFC 2131, March 1997.
[RFC2141] Moats, R., "URN Syntax", RFC 2141, May 1997.
[RFC2396] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifiers (URI): Generic Syntax", RFC 2396,
August 1998.
[RFC3377] Hodges, J. and R. Morgan, "Lightweight Directory Access
Protocol (v3): Technical Specification", RFC 3377,
September 2002.
[W3C.REC-xml-names11-20040204]
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Hollander, D., Tobin, R., Bray, T., and A. Layman,
"Namespaces in XML 1.1", World Wide Web Consortium
FirstEdition REC-xml-names11-20040204, February 2004,
<http://www.w3.org/TR/2004/REC-xml-names11-20040204>.
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Author's Address
Daniel Petrie
SIPez LLC.
34 Robbins Rd
Arlington, MA 02476
US
Phone: "+1 617 273 4000
Email: dan.ietf AT SIPez DOT com
URI: http://www.SIPez.com/
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Petrie Expires April 6, 2007 [Page 45]
