SIPPING D. Petrie
Internet-Draft SIPez LLC.
Expires: April 26, 2007 S. Lawrence
Pingtel Corp.
M. Dolly
AT&T Labs
V.H. Hilt
Bell Labs/Lucent Technologies
October 23, 2006
A Schema and Guidelines for Defining Session Initiation Protocol User
Agent Profile Datasets
draft-petrie-sipping-profile-datasets-04.txt
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Abstract
This document defines the requirements and a format for SIP user
agent profile data. An overall schema is specified for the
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definition of profile datasets. The schema also provides for
expressing constraints for how multiple sources of profile data are
to be combined. This document provides a guide to considerations,
policies and syntax for defining datasets to be included in profile
data. It also explores some specific datasets to test the
requirements, assumptions and syntax.
Table of Contents
1. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1. Requirements Terminology . . . . . . . . . . . . . . . . . 4
2.2. Profile Data Terminology . . . . . . . . . . . . . . . . . 5
2.3. Overview . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Design Considerations . . . . . . . . . . . . . . . . . . . . 6
3.1. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . 6
3.1.1. Outbound Proxy Setting . . . . . . . . . . . . . . . . 7
3.1.2. Codec Settings . . . . . . . . . . . . . . . . . . . . 7
3.1.3. Transport Protocol Setting . . . . . . . . . . . . . . 11
3.2. Requirement Descriptions . . . . . . . . . . . . . . . . . 13
3.2.1. Implementer Extensibility . . . . . . . . . . . . . . 13
3.2.2. Flexible Capabilities . . . . . . . . . . . . . . . . 13
3.2.3. XML . . . . . . . . . . . . . . . . . . . . . . . . . 14
3.2.4. Access Control . . . . . . . . . . . . . . . . . . . . 14
3.2.5. Data Constraints and Range Definition . . . . . . . . 14
3.2.6. Support of User, Application, Device, Local
Network Sources . . . . . . . . . . . . . . . . . . . 15
3.2.7. The Ability to Specify Policy . . . . . . . . . . . . 16
4. Overall Dataset Schema . . . . . . . . . . . . . . . . . . . . 16
4.1. Data Primitives . . . . . . . . . . . . . . . . . . . . . 17
4.2. Use of Namespaces . . . . . . . . . . . . . . . . . . . . 17
4.3. The 'propertySet' Element . . . . . . . . . . . . . . . . 18
4.4. The Abstract 'setting_container' Element . . . . . . . . . 18
4.5. The Abstract 'setting' Element . . . . . . . . . . . . . . 18
4.5.1. The 'visibility' Attribute . . . . . . . . . . . . . . 18
4.5.2. The 'policy' Attributes . . . . . . . . . . . . . . . 19
4.5.3. The 'excludedPolicy' Attributes . . . . . . . . . . . 19
4.5.4. The 'direction' Attribute . . . . . . . . . . . . . . 20
4.5.5. The 'q' Attribute . . . . . . . . . . . . . . . . . . 20
4.6. The 'profileUri' Element . . . . . . . . . . . . . . . . . 20
4.7. The 'profileCredential' Element . . . . . . . . . . . . . 21
4.7.1. realm Element . . . . . . . . . . . . . . . . . . . . 21
4.7.2. authUser Element . . . . . . . . . . . . . . . . . . . 21
4.7.3. a1Digest Element . . . . . . . . . . . . . . . . . . . 21
4.7.4. password Element . . . . . . . . . . . . . . . . . . . 22
4.8. The 'profileContactUri' Element . . . . . . . . . . . . . 22
4.9. The 'profileInfo' Element . . . . . . . . . . . . . . . . 22
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4.10. Example Profile Dataset . . . . . . . . . . . . . . . . . 23
4.11. Merging Property Sets . . . . . . . . . . . . . . . . . . 24
4.11.1. Single Numeric Value Merging Algorithm . . . . . . . . 25
4.11.2. Multiple Enumerated Value Merging Algorithm . . . . . 25
4.11.3. Closest Value First Merging Algorithm . . . . . . . . 26
4.12. Common Types . . . . . . . . . . . . . . . . . . . . . . . 27
5. Defining Data Sets . . . . . . . . . . . . . . . . . . . . . . 27
5.1. Namespace . . . . . . . . . . . . . . . . . . . . . . . . 27
5.2. Property Definitions . . . . . . . . . . . . . . . . . . . 27
5.3. Merging Data Sets . . . . . . . . . . . . . . . . . . . . 28
6. Candidate Data Sets . . . . . . . . . . . . . . . . . . . . . 28
7. Security Considerations . . . . . . . . . . . . . . . . . . . 29
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 29
8.1. Content-type registration for
'application/uaprofile+xml' . . . . . . . . . . . . . . . 29
9. Change History . . . . . . . . . . . . . . . . . . . . . . . . 30
9.1. Changes from draft-petrie-sipping-profile-datasets-03 . . 30
9.2. Changes from draft-petrie-sipping-profile-datasets-02 . . 31
9.3. Changes from draft-petrie-sipping-profile-datasets-01 . . 31
9.4. Changes from draft-petrie-sipping-profile-datasets-00 . . 31
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 32
10.1. Normative References . . . . . . . . . . . . . . . . . . . 32
10.2. Informative References . . . . . . . . . . . . . . . . . . 33
Appendix A. Relax NG SIP UA Profile Schema . . . . . . . . . . . 33
Appendix B. Acknowledgments . . . . . . . . . . . . . . . . . . . 38
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 39
Intellectual Property and Copyright Statements . . . . . . . . . . 40
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1. Motivation
Today all SIP user agent implementers use proprietary means of
expressing and delivering user, device, and local network profile
information to the user agent. The SIP User Agent Profile Delivery
Framework [I-D.ietf-sipping-config-framework] and the Framework for
Session SIP Session Policies [I-D.hilt-sipping-session-policy-
framework] specify how SIP user agents locate and retrieve profile
data specific to the user, the device, and the local network. It is
important for SIP User Agents to be able to obtain and use these
multiple sources of profile data in order to support a wide range of
applications without undue complexity.
While these frameworks define the mechanisms for transmitting profile
data, they do not define a format for the actual profile data. This
document defines the requirements, the default/manditory to support
content type for [I-D.ietf-sipping-config-framework], a high level
schema for, and guide to how these datasets can be defined. The goal
is to enable any SIP user agent to obtain profile data and be
functional in a new environment independent of the implementation or
model of user agent. The nature of having profile data from four
potential sources requires the definition of policies on how to apply
the data in an interoperable way across implementations which may
have widely varying capabilities.
The ultimate objective of the framework described in the SIP User
Agent Profile Delivery Framework and this document is to provide a
start up experience similar to that of users of an analog telephone.
From the point of view of a user, you just plug in an analog
telephone and it works (assuming that you have made the right
arrangements with your local phone company). There is no end user
setup required to make an 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. All user agents do not provide telephone
capabilities, but the user set up experience goal is applicable to
most of the range of user agent capabilities.
2. Introduction
2.1. Requirements Terminology
Keywords "MUST", "MUST NOT", "REQUIRED", "SHOULD", "SHOULD NOT" and
"MAY" that appear in this document are to be interpreted as described
in RFC 2119[RFC2119].
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2.2. Profile Data Terminology
property - a named configurable characteristic of a user agent. A
given property has a well-defined range of possible values. A
given property may be defined to have a range of values, allow for
simultaneous use of many values (as in a list of allowed
possibilities), or a set of related values that collectively form
a single profile information item.
setting - the binding of a specific value or set of values to a given
property.
profile - a collection of settings to be applied for a specific user,
device, or local network.
device - SIP user agent, either software or hardware appliance. This
is a logical concept, as there may be no physical dedicated device
or it may be part of an assembly of devices. In this document,
the terms "user agent" and "device" are interchangeable.
user profile - the profile that applies to a specific user. This is
best illustrated by the "hotelling" use case - a user has an
association for some period of time with a particular device. The
user profile is that set of profile data the user wants to
associate with that device (e.g. ringtones used when someone calls
them, the user's shortcuts).
device profile - data profile that applies to a specific device. In
the "hotelling" use case, this is the data that is bound to the
device itself independent of the user. It relates to specific
capabilities of the device and/or preferences of the owner of the
device.
local network profile - data that applies to the user agent in the
context of the local network. This is best illustrated by roaming
applications; a new device appears in the local network (or a
device appears in a new network, depending on the point of view).
The local network profile includes settings and perhaps policies
that allow the user agent to function in the local network (e.g.
how to traverse NAT or firewall, bandwidth constraints).
dataset - a collection of properties.
working profile - the set of property values actually set in a SIP
User Agent as a result of merging the profiles from all sources;
the actual effective profile for the user agent .
merging - the operation of resolving overlapping settings from
multiple profiles. Overlap occurs when the same property occurs
in multiple profiles (e.g. device, user, application, local
network).
2.3. Overview
In this document requirements are specified for containing and
expressing profile data for use on SIP user agents. Though much of
this can be considered independent of SIP there is one primary
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requirement that is not well satisfied through more generic profile
data mechanisms. SIP User Agent set up requires the agent to merge
settings, which may overlap, from potentially four different sources
(see [I-D.ietf-sipping-config-framework]); each source must not only
be able to provide profile information, but also express policies
regarding how the profile settings may be combined with that from
other sources.
A schema and syntax is defined in this document to specify properties
that may be aggregated to construct profiles. The general design
philosophy is that many small datasets provide flexibility to the
implementer to support the aggregated set that best matches the
capability of the user agent. The actual properties are not defined
in this document (see [I-D.ietf-sipping-media-policy-dataset] and
[reference: Core SIP Dataset]). However, some examples are explored
here to illustrate the proposed mechanisms and to validate the
requirements.
This document defines a set of considerations, syntax and policies
that must be specified when defining datasets. These are to help
authors of dataset specifications to define datasets that will work
in the overall schema defined in this document. The actual
specification of these datasets is outside the scope of this
document.
3. Design Considerations
The following section defines some of the design considerations that
were taken into account when defining the schema, syntax and policies
for generating and applying profile data. Section 3.2.6 describes
need for merging of the four dataset sources provided in [I-D.ietf-
sipping-config-framework].
3.1. Use Cases
In the following use case scenarios the device profile is provided by
the device owner/manager. The owner/manager may be a service
provider, an enterprise or a user administering the device setup.
The user is assumed to be the end user operating the user agent to
perform SIP functions such as telephony, IM etc. In the scenarios
that the user profile is provided, the user profile contains user
specific properties that the end user has set directly or indirectly
through an administration process. The local network profiles
represent the suggested policy behavior that the local network
operator would like user agents to adhere to [I-D.hilt-sipping-
session-policy-framework]. From a security perspective, the local
network operator cannot trust the user agent to follow the local
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network profile policy. The local network operator must use a means
external to the user agent to enforce these policies. The local
network profile is intended to express to the user agent, the
policies that the user agent should follow if the user agent wants to
function properly in the local network.
3.1.1. Outbound Proxy Setting
First consider the use cases for a simple user agent property: the
outbound proxy. It is not likely that the user would want to
influence the outbound proxy for SIP signaling. Conceptually an
application might wish to use a specific outbound proxy for signaling
related to that application. For this use case, assume that the only
the device owner/manager or the local network operator are likely to
want to set the outbound proxy property. The device profile defines
an outbound proxy perhaps so that the device owner/manager can
monitor all signaling. The local network operator also defines an
outbound proxy because the proxy allows the SIP signaling to get
through a NAT or firewall.
It seems there are few possible solutions to this conflict resolution
problem:
o The simple solution is to define a policy where the local network
profile overrides the device profile. In this approach the local
network profile wins.
o A comprehensive solution is to allow the aggregation of the
outbound proxies. In this scenario SIP messages would be sent
with a pre-populated route set that had two hops. First the
outbound proxy set in the local network profile, then the outbound
proxy set in the device profile.
The aggregation approach is closest to solving the requirements to
the use case above. By aggregating the two outbound proxies, the
local network provided outbound proxy allows the signaling to get out
of the local network and the device profile provided outbound proxy
is able to monitor all SIP signaling from the user agent.
3.1.2. Codec Settings
Use cases for the codec properties are illustrated here as they are
likely one of the more complicated sets of properties with respect to
merging and constraining across more than one profile. There are
reasonable scenarios where requirements can be rationalized that the
device, user and local network profiles may each wish to express
preferences and constrains of the codec properties. Without getting
into details or syntax of the codec properties, it is assumed that
codec properties will need to express a codec definition and a
preference order. This is the order that these codecs will be put in
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SDP for codec negotiation purposes.
The following scenarios illustrate some possible combinations of
sources of codec properties from the device, user and local network
profiles. The scenarios identify rationale for providing codec
properties in each of the profiles.
3.1.2.1. Codec Setting Not Set
In the scenario where a device has no profiles or the profiles
contain no codec properties, the device will enable a default set and
preference order of codecs. The default set and preference order of
codecs is a implementer specific choice. In some implementations it
is s subset of the codecs supported by the device.
3.1.2.2. Codec Set in Device Profile
Let us assume a scenario where user agents providing telephony
capabilities are deployed. The deployment has very simple
requirements such that the user agents have fixed locations and are
always associated with the same user. This scenario does not need
the separation between the user, device and local network profiles.
A single profile would suffice. Another scenario having similar
requirements is one where the user and local network profiles do not
provide any codec related properties. This might be because the user
does not care what codecs are used and the local network does not
wish to impose any constraints on the codes used in the network. In
the following use case, the device profile is the only source of
codec properties.
The codecs in the device profile may differ from the set of codecs
supported by the device, due to the administrator of the device
profile wanting:
o To have a uniform set of codecs used across all device types
o To exclude the use of a specific codec due to performance issues/
concerns
The resulting device profile data further will constrain the list of
codecs that get applied. In addition, the administrator may want to
list the order of which the codecs are to be applied. In this
scenario the device profile data will dictate the ordered list of
codecs to be applied. The use agent will ignore codec types included
in the profile that the user agent does not support.
3.1.2.3. Set in Device and User Profiles
In the following scenario users are allowed to express a preference
over codecs. Users are probably not likely to express specific codes
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in the form of G.7XX, etc. They are likely to want to express a
preference in the form of wideband, normal and low bandwidth. In the
following use case, device and user profiles contain codec
properties.
The user may prefer a higher quality codec to be used, if available.
Thereby the user profile data may provide an ordered list of codecs
to be applied. The device profile also specifies a list of codecs
and a default preference order.
The merging of the data sources is as follows:
o The ordering of the codecs will be determined from the user
profile data, which overrides the codec preference ordering from
the device profile data.
o The set of codecs that may be applied, are the codecs listed in
the user data constrained by the list of codecs from the device
profile data.
The case in which none of the codecs in the resulting merged profile
datasets are supported by the device, the profile data constitutes a
misconfiguration between device and user profiles. It may not be
possible to successfully establish a session in this case. It is
suggested that the user agent provide feedback to the user indicating
the misconfiguration. The user agent may also attempt to function in
the network by ignoring one or more of the profile constraints.
3.1.2.4. Set in Device and Local Profiles
In another scenario the user is not allowed or does not care to
express codec preferences. The owner/manager of the device defines
the set of codecs which may be used on the device along with a
preference ordering of codecs. There is no user profile or the user
profile contains no codec properties. The local network wishes to
define a policy over codec usage in the network. It is not clear
there is a requirement that the local network be able to express a
preference order. However the network operator is very likely to
want to express a set of codecs that can or should not be used. The
constraints that the local network operator wishes suggest may relate
to the goal of controlling bandwidth or conveying what will work over
the available WAN connection. In the following use case, device and
local network profiles provide codec properties. The local network
may limit the type of codecs that can be applied due to resources
available.
The merging of the data sources is as follows:
o The set of codecs that may be used is the ordered list of codecs
from the device profile data, further constrained by the local
network profile data.
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The case in which none of the codecs in the resulting merged profile
datasets are supported by the device, the profile data constitutes a
misconfiguration between local network and device. It may not be
possible to successfully establish a session in this case. It is
suggested that the user agent provide feedback to the user indicating
the misconfiguration. The user agent may also attempt to function in
the network by ignoring one or more of the profile constraints.
3.1.2.5. Set in Device, User and Local Profiles
In this scenario everyone has an opinion on the codecs to be used.
The device owner/manager wishes to define a set of codes based upon
best interoperability of known end points in the environment. The
user wishes to express preferences in the codecs (e.g. prefers
wideband audio). The local network wishes to constrain the codecs
based upon bandwidth (e.g. a wireless network with limited local
network bandwidth, a SOHO network with dialup connectivity, a small
office with shared 256kbps WAN connectivity). In the following
scenario, device, user and local network profiles provide codec
properties.
The merging of the data sources is as follows:
o The ordering of the codecs will be determined from the user
profile data, which overrides the ordering from the device profile
data.
o The set of codecs that may be used are the codecs listed in the
device profile data, constrained by the list of codecs from the
user profile data and further constrained by the list of codecs
from the local network profile data.
The case in which none of the codecs in the resulting merged profile
datasets are supported by the device, the profile data constitutes a
misconfiguration between device, user and local network profiles. It
may not be possible to successfully establish a session in this case.
It is suggested that the user agent provide feedback to the user
indicating the misconfiguration. The user agent may also attempt to
function in the network by ignoring one or more of the profile
constraints.
3.1.2.6. Derived Requirements
1. A device will have a set of codecs supported, that may be
offered. The list of codecs supported by a device may differ
from the list of codecs in the device profile data. The list of
codecs in the device profile data that get applied is the subset
of the codecs supported by the device. Codecs listed in profiles
that are not supported by the device are ignored.
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2. The device profile data will have a default ordered list of
codecs, which implies a preference order that may be offered.
3. The user profile data may provide an ordered list of user
preferred codecs. The ordering of the codecs in the user profile
data will override the ordering of the codecs in the device
profile data. The user list of codecs may further constrain the
list of codecs to be used.
4. The local network profile data may provide a list of codecs
supported. This list will further constrain the list of codecs
that may be offered.
5. The application profile data containing codec data will be
ignored.
6. The profiles need the ability to express codecs that may be used
and codecs that should not be used.
3.1.3. Transport Protocol Setting
This section describes use cases related to the use of the SIP
transport protocol settings for a user agent. It is assumed that
user agents are configurable to define what transport protocols (e.g.
UDP, TCP, TLS) are to be used for the SIP signaling as well as the
default order in which to attempt each of the protocol.
3.1.3.1. Setting Not Set
When none of the profiles are available or the profiles do not
specify the SIP transport protocol setting, the device's default
signaling transport(s) will be used.
3.1.3.2. Set in Device Profile
In the following scenario, the device profile is the only source of
profile data. The signaling transports contained in the device
profile may differ from the set of signaling transports supported by
the device. This may be due to the administrator of the device
profile wanting:
o To have a uniform use of signaling transports used across all
device types.
o To mandate TLS for security reasons.
o To exclude the use of a specific signaling transport due to
performance issues/concerns.
o To indicate the preferred, default order in which to attempt using
each of the transport protocols.
This will result in the device profile data further constraining the
list of signaling transports that could be used. The highest
preference ordered signaling transport from the device profile
dataset will be used first.
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3.1.3.3. Set in Device and User Profiles
The following scenario extends the prior case described above. SIP
transport protocol properties are provided in both the device and
user profiles. Consider that SIP user agents, like email agents, may
want to provide the user with options to:
o Mandate that secure transport must be used. If secure transport
is not possible the user does not want to use the user agent.
o Prefer secure transport. Attempt to use secure transport. If
secure transport will not work, use which ever transport protocol
will make communication work.
When the user mandates the use of secure signaling transports only,
the user wishes to constrain the available signaling transports to
TLS. When indicating a preference to secure transport, the use is
specifying a preference order for the use of transport protocols
where TLS is the highest priority.
Now consider the merging strategy required to accomplish the goals of
this use case scenario where the device and user profiles both
contain SIP transport protocol properties. The merging of the data
sources is as follows:
o The set of signaling transports that are allowed to be used is
constrained by the device profile data. This is further
constrained by the user profile data.
o The signaling transports attempted will be those from the merged,
constrained list in order of highest to lowest priority.
3.1.3.4. Set in Device and Local Profiles
In the following scenario, device and local network profile data is
available. The local network may have a limited set of signaling
transports that it supports due to NAT or firewall constraints.
The merging of the data sources is as follows:
o The set of signaling transports that may be used is the ordered
list of signaling transports from the device profile data, further
constrained by the local network profile data.
The case in which none of the local network data signaling transports
are supported by the device profile data constitutes a
misconfiguration between local network and device. The device might
not be able to successfully establish a session in this case.
3.1.3.5. Derived Requirements
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1. A device will have a set of signaling transports that it supports
(note: one can be a set), with a default signaling transport.
2. The set of signaling transports supported by a device may differ
from the set of signaling transports in the device profile data.
The set of signaling transports in the device profile data is an
ordered list, that is a subset of the set of signaling transports
supported by the device. This may be due to performance issues
associated with one of the signaling transport(s).
3. The user profile data may provide a list of preferred signaling
transports to be used (e.g., TLS for securing the signaling).
4. The local network profile data provides a list of signaling
transports supported, and will constrain the set of signaling
transports that could be used.
3.2. Requirement Descriptions
3.2.1. Implementer Extensibility
Implementers must be able to differentiate each implementation. In
addition, it does not serve user agent owners and administrators well
to require an orchestrated upgrade for all user agent implementations
and profile delivery servers before a new capability or feature can
be supported with the required profile data. Hence one of the most
important requirements is to support the ability of implementers to
extend specified standard datasets to include additional related
features and flexibility. It MUST be possible to extend a dataset
without breaking user agents that support that dataset. This may
require that user agents ignore parts of a dataset that it does not
implement or extensions that it does support.
3.2.2. Flexible Capabilities
User agents vary quite widely in their capabilities. Some user
agents function like traditional telephones. Some user agents
support only text messaging. Some user agents support many media
types such as video. Some user agents that function like a telephone
have a single line, some have large numbers of lines. There is no
such thing as one size fits all. It MUST be possible for an
implementer to choose which datasets to support based upon the
capabilities that are supported by the user agent. The schema for
containing the profile data MUST support a profile that contains only
the data sets that a user agent supports. This allows the profile
delivery server to create small profiles for specific devices.
However a user agent SHOULD ignore properties for capabilities that
it does not support. This allows the profile delivery server to be
ignorant of the capabilities of the device. The degree to which the
profile delivery server has intelligence of the user agent
capabilities is an implementation choice.
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3.2.3. XML
XML is perhaps not really a requirement, but a solution base upon
requirements. However it is hard to ignore the desire to utilize
readily available tools to manage and manipulate profile data such as
XSLT, XPATH and XCAP. The requirement that should be considered when
defining the schema and syntax is that many user agents have limited
resources for supporting advanced XML operation. The simplest XML
construct possible should be used, that support the required
functionality. It is not a requirement that user agents validate the
profile XML document. This relieves the requirement that the Relax
NG schema defined in this and other datasets documents be enforced on
the user agent. The Relax NG schema should not be used to strictly
validate profile XML documents. Unknown elements and attributes
should be ignored to allow extensions to be supported. Strict
enforcement of the Relax NG schema would make it very difficult to
deploy new user agents without lock step upgrades of the profile
delivery server. Guidelines for the Use of Extensible Markup
Language (XML) within IETF Protocols [RFC3470] provides useful
information in this regard.
3.2.4. Access Control
Many user agents (e.g. appliances and softphones running on PCs)
provide user interfaces that permit the user to edit properties that
are logically part of user, application, device or local network
profiles. Operators and administrators would like to be able to
specify what an end user can change in those profiles and what an end
user is not allowed to change. There may also be sensitive data the
user agent requires to function, but that the operator of the system
does not want the end user to see. For some properties the system
operator may allow the user a fixed set of choices among the
supported set of possible values. It MUST be possible to express
whether an end user may change a dataset property. It MUST be
possible to express that a property should not be made visible to the
end user. It MUST be possible to express allowable values or ranges
that the end user may change a property to. The access control
information SHOULD be optional to the dataset. It might be useful if
it was possible to express the access control independent of the
properties themselves. The access control specification by itself
might be useful to express a general policy that the device owner or
local network operator wish to impose.
3.2.5. Data Constraints and Range Definition
There is a need for property value types such as free form text,
token/enumerations, integers, real numbers, etc. Many of these
properties will have constrained values as opposed to the range of
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all possible values. These constrains may be due to protocol
definitions, implementation limitations, and/or the desire (e.g. by
the user, device owner, local network operator) to impose policy on
the user agent. The ability to express the property constraints is
useful from the perspective of access control as described in the
above section. It is also useful to parameterize a user interface
(e.g. on the user agent itself or on the profile delivery server)
which provides a facility to modify profile data. It MUST be
possible for the schema to specify property constraints as ranges or
discrete sets of possible values. These constrains SHOULD be
optional to the dataset. It might be useful if it was possible to
express the constraints independent of the properties themselves.
The constraints without the property values might be used to specify
the capabilities of a particular user agent implementation.
3.2.6. Support of User, Application, Device, Local Network Sources
[I-D.ietf-sipping-config-framework] specifies a mechanism where the
user agent retrieves profile data from as many as four different
sources. The separation of the user profile facilitates a hotelling
capability and the ability to easily re-assign a user to a different
device. The separation of the local network profile facilitates
properties specific to operating in the local network in a roaming
scenario (e.g. outbound proxy or NAT traversal properties). The
local network profile may also impose policy as describe in the next
section. The device profile facilitates device capability based
properties as well as a means for the device owner or manager (e.g.
enterprise or service provider) to impose policy.
The multiple potential sources of profile data add some complexity to
the user agent that must consolidate these separate profiles into a
single working profile. It would be simpler if we could define each
property as only allowed in one of the profiles. However it overly
constrains the profiles and takes away desired functionality such as
hotelling, roaming and shared profile management. It would also be
simpler if we could define one rule for all profile datasets and
properties by which we merge the profile (e.g. local network profile
overwrites user profile which overwrites device profile for all
data). However this too is overly restrictive and eliminates some
very useful functionality.
The rules to merge profile datasets needs to be defined for each
dataset. In some cases an entire dataset must be considered atomic
when merging one profile source with another. In other cases it
makes sense to merge profile datasets, aggregating properties from
the dataset provided in each of the profiles. It may also be
desirable to have the effect of filtering of dataset properties. The
desired effect might be for the owner of the device or the local
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network operator to constrain what values are allowed for properties
in the profiles. This may also be the mechanism to facilitate
imposing of policy as described in the next section. The operation
of resolving overlapping datasets from multiple profiles, regardless
of the means or net result, will be referred to as "merging" in this
document.
A profile must have the means to constrain the merging algorithm.
Due to the differences in the desired outcome for each data setting,
the merging algorithm is specific to the setting. When defining a
property setting, the merging algorithm must also be defined. A few
of the more commonly used merging algorithms are defined in this
document. Most settings are likely to use the common set defined in
this document. However authors of profile datasets may define new
algorithms for merging dataset properties (see Section 4.11 and
Section 5.3).
3.2.7. The Ability to Specify Policy
Local network operators would like to impose policy on users and
devices operating in their network. There is a need to constrain the
operation and require specific behavior in the network. This might
be as simple as to get access to the Internet, user agents must use a
specified outbound proxy and NAT traversal mechanism. The network
might have limited bandwidth such that the operator would like to
constrain codecs or media streams to keep the network functional.
The local network may provide emergency service behavior or
functionality properties that are more specific than those provided
by the device or user profile. The examples here focus on
constraints to impose policy from the local network. However the
facility to impose policy may be equally useful to the user and
device profiles.
It MUST be possible to impose policy in any of the profile sources
that constrains, overwrites or modifies properties provided in
datasets from other sources.
4. Overall Dataset Schema
Notifiers and Subscribers of the event package defined in [I-D.ietf-
sipping-config-framework] SHOULD support the content-type:
application/uaprofile+xml. The Notifier SHOULD indicate all of the
dataset schemas that is supports by listing all of the MIME types for
the supported datasets in the SUBSCRIBE request header: Accept. This
document defines an Relax NG Schema for that content-type with the
namespace: urn:ietf:params:xml:ns:uaprof, for SIP Profile Datasets
that provides:
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o a base element type "setting" from which all settings in other
schema definitions inherit (this allows other definitions to
specify the content models for ways of combining settings; it is
analogous to a C++ virtual base class).
o Attributes to the "setting" element that define constraints and
other properties used to impose policy that apply to the element
value. These attributes are inherited by elements that are
derived from the abstract settings element.
o A root element for all property sets (the outermost container).
The full text of the schema is in Appendix A; the following describes
the usage of the schema in defining properties and combining them to
construct the working profile of a User Agent.
4.1. Data Primitives
Each property in a profile data set is defined using XML Schema
Datatypes [W3C.REC-xmlschema-2] and Relax NG Schema. A property is
modeled by an XML element derived from the "setting" element in the
SIP Profile Data Set Schema. The element content is the setting
value.
Properties consisting of one single value can be expressed using a
single XML element. Properties that may consist of multiple values
require the use of container elements. A container element is
defined for such a property. This container can contain multiple XML
elements, which each defines a possible value for that property (see
examples in Section 4.5.2).
When constructing a property set, the creator of a profile may not be
able to know all of the capabilities of the User Agent that will
receive that property set. The creator of profile constraints or
policies should be aware that a user agent may ignore properties that
are unsupported or do not apply to its capabilities.
4.2. Use of Namespaces
XML namespaces [W3C.REC-xml-names-19990114] provide a means to
uniquely identify the elements and datatypes defined in a data set.
It is therefore RECOMMENDED that each data set specifies its own
namespace. The namespace URIs SHOULD be URNs [RFC2141], using the
namespace identifier 'ietf' defined by [RFC2648] and extended by
[I-D.mealling-iana-xmlns-registry]. The core schema defined in this
document defines the namespace: "urn:ietf:params:xml:ns:uaprof".
Profile datasets that extend this schema SHOULD define a new
namespace by appending a ":" and a unique name to the
"urn:ietf:params:xml:ns:uaprof" namespace. These namespaces MUST be
registered with IANA.
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4.3. The 'propertySet' Element
The root element of a property set is "propertySet"; it is the
container that is provided to the user agent. The elements contained
within a propertySet contain the specific properties which are to be
applied to the user agent. The properties may be simple types with a
single value, complex types or container elements with a list of
properties.
4.4. The Abstract 'setting_container' Element
The "setting_container" element is the abstract element in which a
list of properties which allow mutliple values may be contained.
Elements derived from the "setting_container" element may contain
zero or more elements derived from the "setting" element. The
"setting_container" element has an "excludedPolicy" attribute.
4.5. The Abstract 'setting' Element
The setting element is the abstract element from which all profile
properties or settings shall inherit.
The setting element has a number of attributes that provide
functionalities, which are generally useful for many properties.
These attributes are inherited by properties that are derived from
the settings element. This enables the re-use of common
functionalities and ensures a common syntax for these elements across
different data sets. The following functionalities are provided by
attributes of the settings element:
o Property Access Control: 'visibility' attribute
o Policies: 'policy' attribute
Additional attributes are defined in the schema that may used in
elements derived from "setting". By default these attributes cannot
be set. These attribute must be explicitly added to elements derived
from the "setting" element:
o Unidirectional Properties: 'direction' attribute
o Preferences: 'q' attribute
4.5.1. The 'visibility' Attribute
The attribute "visibility" is defined on the "setting" element to
specify whether or not the user agent is permitted to display the
property value to the user. This is used to hide setting values that
the profile administrator may not want the user to see or know. The
"visibility" attribute has two possible values:
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o visible: specifies that display of the property value is not
restricted. This is the default value of the attribute if it is
not specified.
o hidden: Specifies that the user agent SHOULD NOT display the
property value. Display of the property value may be allowed
using special administrative interfaces, but is not appropriate to
the ordinary user.
4.5.2. The 'policy' Attributes
The setting element has an optional 'policy' attribute. The policy
attribute is used to define the constraining properties of an
element. It defines how the element value is used by an endpoint
(e.g. whether it can or can not be used in a session). The following
values are defined for the 'policy' attribute:
o allow: the value contained in the element is allowed and SHOULD be
used in sessions. This is the default value that is used if the
'policy' attribute is omitted.
o disallow: the value contained in the element is forbidden and
SHOULD NOT be used in sessions.
The policy attribute can be omitted if the default policy 'allow'
applies.
OPEN ISSUE: The policy attribute may not be needed for elements
outside of a settings_container. Further clarification is needed
on this. Using the policy attribute only inside containers would
further simplify the specification of profile data.
4.5.3. The 'excludedPolicy' Attributes
The "setting_container" element has an optional 'excludedPolicy'
attribute. This attribute specifies the default policy for all
values that are not in the container. Elements that are present in
the container have their own 'policy' attribute, which defines the
policy for that element. The following values are defined for the
'excludedPolicy' attribute:
o allow: values not listed in the container are allowed and MAY be
used in sessions. This is the default value that is used if the
'excludedPolicy' attribute is omitted.
o disallow: values not listed in the container are forbidden and
MUST NOT be used in sessions.
The excludedPolicy attribute can be omitted if the default policy
'allow' applies. The following example shows a policy that allows
the media type audio and disallows all other media types in sessions
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(effectively, this construct requires the use of audio):
<media-types excludedPolicy="disallow">
<media-type policy="allow">audio</media-type>
</media-types>
4.5.4. The 'direction' Attribute
Some properties are unidirectional and only apply to messages or data
streams transmitted into one direction. For example, a property for
media streams can be restricted to outgoing media streams only.
Unidirectional properties can be expressed by adding a 'direction'
attribute to the respective element.
The 'direction' attribute can have the following values:
o recvonly: the property only applies to incoming messages/streams.
o sendonly: the property only applies to outgoing messages/streams.
o sendrecv: the property applies to messages/streams in both
directions. This is the default value that is used if the
'direction' attribute is omitted.
4.5.5. The 'q' Attribute
It should be possible to express a preference for a certain value, if
multiple values are allowed within a property. For example, it
should be possible to express that the codecs G.711 and G.729 are
allowed, but G.711 is preferred. Preferences can be expressed by
adding a 'q' attribute to a property element. Elements derived from
the "setting" element for which multiple occurrences and values are
allowed SHOULD have a "q" attribute if the order is significant.
Typically these elements are contained in an element derived from the
"setting_container" element. The 'q' attribute is only meaningful if
the 'policy' attribute set to 'allowed'. It must be ignored in all
other cases.
An element with a higher 'q' value is preferred over one with a lower
'q' value. 'q' attribute values range from 0 to 1. The default value
is 0.5.
4.6. The 'profileUri' Element
The <profileUri> element contains the URI of this profile on the
profile server. The value contained in the profileUri element may be
different than the URI subscribe to when retrieving this profile.
When the user agent retrieves a profile where the profileUri is
different than the subscribe to URI, the user agent SHOULD
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unsubscribe to the current URI and then subscribe to the new URI.
The <profileUri> element is optional and MAY occur only once inside a
<propertySet> element. The profileUri element is specific to the
local-network, device, user or application profile in which it
occurs. It has no meaning outside of the profile in which it occurs
and SHOULD NOT be merged.
4.7. The 'profileCredential' Element
The <profileCredential> element contains the digest authentication
information that SHOULD be used for authentication for the profile
subscription via SIP or profile retrieval via HTTP, HTTPS, etc. The
profileCredential element is optional and MAY occur only once inside
a propertySet element. The profileCredential element is specific to
the local-network, device, user or application profile in which it
occurs. It has no meaning outside of the profile in which it occurs
and SHOULD NOT be merged. The profileCredential element MUST contain
exactly one of each of the elements: realm, authUser and one of
either a1Digest or password.
4.7.1. realm Element
The realm element contains the string that defines the realm to which
this credential pertains. The value of the realm element is the same
as the realm parameter in the [RFC2617] headers: WWW-Authenticate,
Authorization and the SIP [RFC3261] headers: Proxy-Authenticate and
Proxy-Authorization. If a match of the realm value is found, the
user agent uses the values in the authUser and a1Digest elements
contained in the profileCredential element. Exactly one realm
element MUST be contained in a profileCredential element. A wildcard
of "*" MAY be used as the realm value in which case the user agent
MUST calculate the A1 DIGEST for the realm given in the
authentication challenge. If the wildcard is given for the realm,
the clear text form of the password contained in the password element
MUST also be used.
4.7.2. authUser Element
The authUser element contains the string value of the "username"
parameter which SHOULD be used in Authorization and Proxy-
Authorization request headers when retrying a request that was
challenged for authentication. Exactly one authUser element SHOULD
be contained in a profileCredential element.
4.7.3. a1Digest Element
The a1Digest element contains a string with the value of the A1
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digest of the username, realm and password as defined in [RFC2617].
At most one a1Digest element MUST be contained in a profileCredential
element. The a1Digest element MUST NOT exist in a profileCredential
element containing a password element. The username and realm used
to construct the value of the a1Digest element MUST match the values
of the realm and authUser elements contained in the profileCredential
element with the a1Digest element.
4.7.4. password Element
The password element contains the clear text password for use with
DIGEST Authentication [RFC2617]. At most one password MUST be
contained in a profileCredential element. The password element MUST
NOT exist in a profileCredential element containing a a1Digest
element. The user agent uses this password along with the realm and
authUser elements to calculate the A1 digest used for DIGEST
Authentication.
4.8. The 'profileContactUri' Element
The <profileContactUri> element contains a contact URI (e.g. a SIP,
HTTP URI or email address) under which the issuer of this profile can
be reached. The contact element may, for example, contain the
address of a support hotline.
The <profileContactUri> element is optional and MAY occur multiple
times inside a <propertySet> element. Multiple instances of the
profileContactUri element allow multiple URI schemes to be provided
for contact information. The user agent MAY use the URI contained
profile-contact-info element which has a URI scheme that the user
agent supports and can make work to provide support help for the
profile. The user agent MAY provide the URIs to the user to contact
the creator of the profile through other communication channels. The
profileContactUri element is specific to the local-network, device,
user or application profile in which it occurs. It has no meaning
outside of the profile in which it occurs and SHOULD NOT be merged.
4.9. The 'profileInfo' Element
The <profileInfo> element provides a short textual description of the
property that should be intelligible to the human user. This element
may, for example, contain information about the nature of this
profile, such as "Access Network Profile". The text in the
<profileInfo> element is in particular be helpful when a user needs
to decide whether or not to use a newly downloaded profile or when
problems with a profile (e.g. a policy conflict) occur. A user agent
MAY display this information in these cases.
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The <profileInfo> element is optional and MAY occur only once inside
a <propertySet> element. The profileInfo element is specific to the
local-network, device, user or application profile in which it
occurs. It has not meaning outside of the profile in which it occurs
and SHOULD NOT be merged.
4.10. Example Profile Dataset
The following XML example shows a SIP Profile Dataset with example
extension setting elements: ddd, foo, bar, boo, containerElement and
setting container elements: myContainer, myContainer1, myContainer2
and container3.
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<?xml version="1.0" encoding="UTF-8"?>
<propertySet xmlns="urn:ietf:params:xml:ns:uaprof">
<profileUri>sip:a1b2c3d4e5f6@example.com</profileUri>
<profileCredential>
<realm>example.com</realm>
<authUser>fred</authUser>
<a1Digest>b6b577fd12aa7e1df8d60735ef56fc2e</a1Digest>
<!-- <password>123</password> -->
</profileCredential>
<profileContactUri>tel:+16175551212</profileContactUri>
<profileContactUri>sip:411@example.com</profileContactUri>
<profileContactUri>
http:example.com/sipProfile.html
</profileContactUri>
<profileInfo>
This is an example profile from example.com
</profileInfo>
<ddd xmlns="blatz" policy="allow">fff</ddd>
<foo xmlns="blatz" visibility="visible" policy="allow"
direction="sendrecv" q="0">
</foo>
<bar xmlns="blatz" visibility="hidden" policy=""
direction="sendonly" q="0.1000">
</bar>
<myContainer xmlns="blatz" excludedPolicy="disallow">
<containerElement q="0.1">aaa</containerElement>
<containerElement>bbb</containerElement>
<containerElement q="0.8">ccc</containerElement>
</myContainer>
<boo xmlns="newns" q="1">ggg</boo>
<myContainer1 xmlns="blatz" excludedPolicy="allow">
<myContainer2 xmlns="newns" excludedPolicy="allow">
</myContainer2>
</myContainer1>
<container3 xmlns="ns3">
<containerElement q="0.1">111</containerElement>
<containerElement>222</containerElement>
<containerElement q="0.8">333</containerElement>
</container3>
</propertySet>
4.11. Merging Property Sets
A UA may receive property sets from multiple sources, which need to
be merged into a single combined document the UA can work with.
Properties that have a single value (e.g. the maximum bandwidth
allowed) require that a common value is determined for this property
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during the merging process. The merging rules for determining this
value need to be defined individually for each element in the schema
definition. Properties that allow multiple values (i.e. property
containers) need to be merged by combining the values from the
different data sets. The following sections describe common merging
algorithms. A data set definition may refer to these algorithms.
4.11.1. Single Numeric Value Merging Algorithm
A general merging rule for elements with numeric values is to select
the largest or the smallest value. For example, a merging rule for a
<max-bandwidth> element would be to select the smallest value from
the values that are in the competing data sets.
4.11.2. Multiple Enumerated Value Merging Algorithm
Multiple values in property containers are merged by combining the
values from each of the competing data sets. This is accomplished by
copying the elements from each property container into the merged
container. Elements with identical values are only copied once. The
'policy' attribute of two elements with the same value is adjusted
during the merging process according to Table 1. If an element
exists only in one property container, then the default policy of the
other container (i.e. the excludedPolicy) is used when accessing
Table 1. For example, if an element is disallowed in one data set
and the element is not contained in the other data set but the
default policy is allowed for that data set, then the values
disallowed and allowed are used to access Table 1. Consequently, the
element will be disallowed in the merged data set. Finally, the
excludedPolicy attributes of the containers are also merged using
Table 1. In addition to these merging rules, each schema may define
specific merging rules for each property container.
set 1 \ set 2 | allow | disallow
--------------+----------+----------
allow | allow | disallow
disallow | disallow | disallow
Table 1: merging policies.
The following example illustrates the merging process for two data
sets. All elements are merged into one container and the policy
attributes are adjusted according to Table 1. The merged container
has the default policy disallow, which is determined using Table 1.
The entry for PCMA in the merged data set is redundant since it has
the default policy.
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Data set 1:
<codecs excludedPolicy='allow'>
<codec policy='disallow'>PCMA</codec>
</codecs>
Data set 2:
<codecs excludedPolicy='disallow'>
<codec policy='allow'>PCMA</codec>
<codec policy='allow'>G729</codec>
</codecs>
Merged data set:
<codecs excludedPolicy='disallow'>
<codec policy='disallow'>PCMA</codec>
<codec policy='allow'>G729</codec>
</codecs>
Some constellations of policy attributes result in an illegal merged
data set. They constitute a conflict that can not be resolved
automatically. For example, two data sets may define two non-
overlapping sets of allowed audio codecs and both disallow all other
codes. The resulting merged set of codecs would be empty, which is
illegal according to the schema definition of the codecs element. If
the use of these properties is enforced by both networks, the UA may
experience difficulties or may not be able to set up a session at
all.
The combined property set MUST again be valid and well-formed
according to the schema definitions. A conflict occurs if the
combined property set is not a well-formed document after the merging
process is completed.
4.11.3. Closest Value First Merging Algorithm
Some properties require that the values from different data sets are
ordered based on the origin of the data set during the merging
process. Property values that come from a domain close to the user
agent take precedence over values that were in a data set delivered
by a remote domain. This order can be used, for example, to select
the property value from the closest domain. In many cases, this is
the local domain of the user agent. For example, the URI of an
outbound proxy could be merged this way. This order can also be used
to generate an ordered list of property values during the merging
process. For example, multiple values for media intermediaries can
be ordered so that the closest media intermediary is traversed before
the second closest intermediary and so on.
This merging algorithm requires that the source of a data set is
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considered.
If property sets are delivered through the configuration framework
[I-D.ietf-sipping-config-framework], the value received through a
subscription using the "local-network" profile-type takes precedence
over values received through other profile-type subscriptions.
OPEN ISSUE: Can we define an order for 'device', 'user', and
'application' profiles?
The session-specific policy mechanism [I-D.hilt-sipping-session-
policy-framework] provides an order among policy servers. This order
is based on the order, in which a SIP message traverses the network,
starting with the closest domain. This order can directly be used to
order property values as described above.
4.12. Common Types
The schema also defines a set of common types that are used in
defining data sets (e.g. DataIpPort). [Need to document common
types.]
5. Defining Data Sets
This section covers several issues that should be take into
consideration when specifying new data set schemas. This is intended
to be a guide to authors writing specifications defining a new data
set schema or extensions to existing ones.
5.1. Namespace
It is RECOMMENDED that a data set defines a new XML namespace
[W3C.REC-xml-names-19990114] to scope all of the properties that are
defined in the name space.
5.2. Property Definitions
The properties defined in a data set schema may be simple (i.e.
having a single value) or they may be complex (i.e. a container with
multiple values). Each property in the data set SHOULD inherit from
the "setting" element. Complex properties and all of their child
elements each should inherit from "setting" as well.
A data set specification should contain a section which defines the
meaning of all of the properties contained in the data set. The
objective is to define the property such that implementers have a
clear definition and semantics to interpret properties in a
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consistent way. User agents not only need to use the same profile
content, they need to apply the properties in a consistent way to
achieve true interoperability.
The following information should be defined for each property in a
data set:
o description: describe the meaning and application of the property.
o cardinality: define how many instances of this property element
may occur in a data set (e.g. zero, one or many) as well as its
relationship to any other properties in this or other data sets.
o default value: define the default value of this property if it is
not set. Describe if the default is different if the property is
present and not set vs. completely absent from the data set.
Define if the default varies in relation to another property.
5.3. Merging Data Sets
User agents may receive data sets from multiple sources. They need
to merge these data sets in order to create an overall data set they
can work with. Collisions on data sets may occur if multiple sources
provide different values for the same properties. These collisions
need to be resolved during the merging process.
A data set schema MUST define rules for merging data sets from
different sources for each property that is defined. Considerations
for merging data sets are discussed in Section 4.11. A data set
schema must define if and how these consideration apply and MAY
define alternative merging rules for specific settings. A data set
schema must also identify combinations of properties that constitute
a conflict that can't resolved. It may provide additional guidelines
for the behavior of a user agent in these cases.
6. Candidate Data Sets
The following sections name some of the candidate data sets that are
or may be defined. These data sets can be aggregated to form
profiles appropriate to the capabilities of a user agent
implementation.
o SIP Protocol Data Set: the lowest common denominator set of
properties common to all SIP user agents of any capability. A
schema covering the elements of this data set can be found in
[I-D.petrie-sipping-sip-dataset].
o Media Data Set: this data set contains media related policies. A
schema covering the elements of this data set can be found in
[I-D.ietf-sipping-media-policy-dataset].
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o Identity Data Set: AORs and lines (see [I-D.petrie-sipping-
identity-dataset])
o HTTP Protocol Data Set: server settings. Proxy for clients.
o NAT Traversal Data Set: settings for STUN, TURN etc.
o SIP Digit Maps Data Set: [I-D.petrie-sipping-voip-features-
dataset]
o VoIP Features: [I-D.petrie-sipping-voip-features-dataset]
o Address Book:
o Buddy List:
7. Security Considerations
Security is mostly a delivery problem. The delivery framework SHOULD
provide a secure means of delivering the profile data as it may
contain sensitive data that would be undesirable if it were stolen or
sniffed. Storage of the profile on the profile delivery server and
user agent is an implementation problem. The profile delivery server
and the user agent SHOULD provide protection that prevents
unauthorized access of the profile data. The profile delivery server
and the user agent SHOULD enforce the access control policies defined
in the profile data sets if present.
[The point of the access control construct on the data set is to
provide some security policy on the visibility and ability to
change sensitive properties. Does the access control mechanism
also create a security problem where the local network can set or
hide properties from the user?]
Some transport mechanisms for delivery of the profile data do not
provide a secure means of delivery. In addition some user agents may
not have the resources to support the secure mechanism used for
delivery (e.g. TLS).
8. IANA Considerations
XML name space registration: urn:ietf:params:xml:ns:uaprof
8.1. Content-type registration for 'application/uaprofile+xml'
To: ietf-types@iana.org
Subject: Registration of MIME media type application/uaprofile+xml
MIME media type name: application
MIME subtype name: uaprofile+xml
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Required parameters: (none)
Optional parameters: charset Indicates the character encoding of
enclosed XML. Default is UTF-8.
Encoding considerations: Uses XML, which can employ 8-bit characters,
depending on the character encoding used. See RFC 3023 [RFC
3023], section 3.2.
Security considerations: This content type is designed to carry SIP
user agent profile data, which may be considered private
information. Appropriate precautions should be adopted to limit
disclosure of this information.
Interoperability considerations: This content type provides a common
format for exchange of SIP user agent profile information.
Published specification: RFC XXXX (Note to RFC Editor: Please fill in
XXXX with the RFC number of this specification)
Applications which use this media type: SIP user agents and profile
delivery servers.
Additional information: Magic number(s): File extension(s): Macintosh
File Type Code(s):
Person & email address to contact for further information: Daniel
Petrie EMail: dan.ietf AT sipez DOT com
Intended usage: LIMITED USE
Author/Change controller: This specification is a proposed work item
of the IETF SIPPING working group, with mailing list address:
sipping@ietf.edu.
Other information: This media type is a specialization of
application/xml [RFC 3023], and many of the considerations
described there also apply to application/uaprof+xml.
9. Change History
[[RFC Editor: Please remove this entire section upon publication as
an RFC.]]
9.1. Changes from draft-petrie-sipping-profile-datasets-03
Converted the XML schema to use Relax NG and created a valid schema.
Defined XML name space for schema: "urn:ietf:params:xml:ns:uaprof"
Defined mime type: application/uaprofile+xml to be used as default
content type for the configuration framework.
Changed names of elements, attributes and other data types which
contained "-" or "_" to use camel case.
Added password element so that credential can contain either A1
digest or clear text password as the clear text password is required
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by the user agent in some cases (e.g. http GET) or to wildcard the
realm.
9.2. Changes from draft-petrie-sipping-profile-datasets-02
Removed "mandatory" policy attribute value to simplify use and
profile merging issues.
Session Independent Policy draft was split into separate media
dataset draft and policy drafts. Fixed references and information in
this draft to reflect the two drafts.
Added concrete properties contained in elements: profileUri,
profileCredential, profileContactUri and profileInfo. Prior to this
draft, there were only abstract elements defined in this draft.
These elements have been added to contain information that is
specific to the profile and are independent of the specific profile
datasets contained in the profile.
Split references into normative and informative sections.
Numerous editorial changes
9.3. Changes from draft-petrie-sipping-profile-datasets-01
Split out the core SIP Protocol dataset into a separate draft.
Schema changes: created setting_container, added q and direction
attributes along with other tweaks to the schema.
Better integration and coordination with [I-D.ietf-sipping-media-
policy-dataset]. The media/codec dataset is now completely contained
in the policy draft.
9.4. Changes from draft-petrie-sipping-profile-datasets-00
Added use case scenarios for codecs, SIP transport protocol and
outbound proxy to better illustrate requirements. Some of the
derived requirements are listed with the use cases.
Added settings element attributes "policy" and "visibility" to
provide merging constraints and access control capability. Removed
the element based merging constraints using the: forbid, set_any,
set_all and set_one elements. This greatly simplifies the degree of
XML operations required to perform the request merging.
Defined default merging policy and profile source precedence along
with the option for different policies to be describe in specific
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settings definition documents.
Added example merging with XML profiles from device and user for the
SIP transport protocol.
10. References
10.1. Normative References
[I-D.hilt-sipping-session-policy-framework]
Hilt, V., "A Framework for Session Initiation Protocol
(SIP) Session Policies",
draft-hilt-sipping-session-policy-framework-01 (work in
progress), March 2006.
[I-D.ietf-sipping-config-framework]
Petrie, D., "A Framework for Session Initiation Protocol
User Agent Profile Delivery",
draft-ietf-sipping-config-framework-09 (work in progress),
October 2006.
[I-D.mealling-iana-xmlns-registry]
Mealling, M., "The IETF XML Registry",
draft-mealling-iana-xmlns-registry-05 (work in progress),
June 2003.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[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.
[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.
[W3C.REC-xml-names-19990114]
Hollander, D., Bray, T., and A. Layman, "Namespaces in
XML", W3C REC REC-xml-names-19990114, January 1999.
[W3C.REC-xmlschema-1]
Thompson, H., Beech, D., Maloney, M., and N. Mendelsohn,
"XML Schema Part 1: Structures", W3C REC-xmlschema-1,
May 2001, <http://www.w3.org/TR/xmlschema-1/>.
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[W3C.REC-xmlschema-2]
Biron, P. and A. Malhotra, "XML Schema Part 2: Datatypes",
W3C REC-xmlschema-2, May 2001,
<http://www.w3.org/TR/xmlschema-2/>.
10.2. Informative References
[I-D.ietf-sipping-media-policy-dataset]
Hilt, V., "A User Agent Profile Data Set for Media
Policy", draft-ietf-sipping-media-policy-dataset-01 (work
in progress), April 2006.
[I-D.petrie-sipping-identity-dataset]
Petrie, D., "The Session Initiation Protocol User Agent
Identity Profile Data Set",
draft-petrie-sipping-identity-dataset-00 (work in
progress), October 2005.
[I-D.petrie-sipping-sip-dataset]
Petrie, D., "The Core Session Initiation Protocol User
Agent Profile Data Set",
draft-petrie-sipping-sip-dataset-01 (work in progress),
October 2005.
[I-D.petrie-sipping-voip-features-dataset]
Petrie, D., "The Session Initiation Protocol User Agent
VoIP Features Data Set",
draft-petrie-sipping-voip-features-dataset-00 (work in
progress), October 2005.
[RFC2141] Moats, R., "URN Syntax", RFC 2141, May 1997.
[RFC2648] Moats, R., "A URN Namespace for IETF Documents", RFC 2648,
August 1999.
[RFC3470] Hollenbeck, S., Rose, M., and L. Masinter, "Guidelines for
the Use of Extensible Markup Language (XML) within IETF
Protocols", BCP 70, RFC 3470, January 2003.
Appendix A. Relax NG SIP UA Profile Schema
<?xml version="1.0"?>
<grammar xmlns="http://relaxng.org/ns/structure/1.0"
ns="urn:ietf:params:xml:ns:uaprof"
datatypeLibrary="http://www.w3.org/2001/XMLSchema-datatypes">
<start>
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<element name="propertySet">
<optional>
<ref name="ElementProfileUri"/>
</optional>
<optional>
<ref name="ElementProfileCredential"/>
</optional>
<zeroOrMore>
<element name="profileContactUri">
<!-- who to contact for help with this profile -->
<data type="anyURI"/>
</element>
</zeroOrMore>
<optional>
<element name="profileInfo">
<text/>
</element>
</optional>
<zeroOrMore>
<choice>
<ref name="PropertySetExtension"/>
<ref name="ElementGenericSetting"/>
<ref name="ElementGenericSettingContainer"/>
</choice>
</zeroOrMore>
</element>
</start>
<!-- example setting with all setting attributes -->
<!-- <define name="ElementFoo">
<element name="foo">
<ref name="SettingAttributes"/>
<text/>
</element>
</define>
-->
<define name="ElementProfileUri">
<!-- URI to subscribe to for this profile -->
<element name="profileUri">
<ref name="DataSipUri"/>
</element>
</define>
<define name="ElementProfileCredential">
<!-- credentials for subscribing or getting profile -->
<element name="profileCredential">
<ref name="DataCredential"/>
</element>
</define>
<define name="PropertySetExtension">
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<!-- place to add new settings in other namespaces -->
<empty/>
</define>
<define name="ElementGenericSettingContainer">
<element>
<anyName>
<except>
<nsName ns="urn:ietf:params:xml:ns:uaprof"/>
<nsName ns=""/>
</except>
</anyName>
<ref name="SettingContainerAttributes"/>
<zeroOrMore>
<ref name="AttributeGeneric"/>
</zeroOrMore>
<!-- container can have containers or settings not both -->
<choice>
<zeroOrMore>
<ref name="ElementGenericSetting"/>
</zeroOrMore>
<zeroOrMore>
<ref name="ElementGenericSettingContainer"/>
</zeroOrMore>
</choice>
</element>
</define>
<define name="ElementGenericSetting">
<element>
<anyName>
<except>
<nsName ns="urn:ietf:params:xml:ns:uaprof"/>
<nsName ns=""/>
</except>
</anyName>
<ref name="SettingAttributes"/>
<zeroOrMore>
<ref name="AttributeGeneric"/>
</zeroOrMore>
<zeroOrMore>
<choice>
<text/>
<ref name="ElementGenericSetting"/>
</choice>
</zeroOrMore>
</element>
</define>
<define name="AttributeGeneric">
<attribute>
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<anyName>
<except>
<nsName ns="urn:ietf:params:xml:ns:uaprof"/>
<nsName ns=""/>
</except>
</anyName>
</attribute>
</define>
<define name="DataCredential">
<element name="realm">
<text/>
</element>
<element name="authUser">
<text/>
</element>
<choice>
<element name="a1Digest">
<data type="string">
<param name="pattern">[0-9,a-f]{32,32}</param>
</data>
</element>
<element name="password">
<text/>
</element>
</choice>
</define>
<define name="DataSipUri">
<choice>
<data type="anyURI">
<param name="pattern">sip:.*</param>
</data>
<data type="anyURI">
<param name="pattern">sips:.*</param>
</data>
</choice>
</define>
<define name="DataSipNameAddr">
<choice>
<data type="anyURI"><!-- need to tighten this up -->
<param name="pattern">"?.*"?<?sip:.*</param>
</data>
<data type="anyURI">
<param name="pattern">"?.*"?<?sips:.*</param>
</data>
</choice>
</define>
<define name="SettingContainerAttributes">
<optional>
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<attribute name="excludedPolicy">
<ref name="DataPolicies"/>
</attribute>
</optional>
</define>
<define name="SettingAttributes">
<interleave>
<optional>
<ref name="AttributePolicy"/>
</optional>
<optional>
<ref name="AttributeVisibility"/>
</optional>
<optional>
<ref name="AttributeDirection"/>
</optional>
<optional>
<ref name="AttributeQ"/>
</optional>
</interleave>
</define>
<define name="AttributePolicy">
<attribute name="policy">
<ref name="DataPolicies"/>
</attribute>
</define>
<define name="DataPolicies">
<choice>
<value></value><!-- default of allow -->
<value>allow</value>
<value>disallow</value>
</choice>
</define>
<define name="AttributeVisibility">
<attribute name="visibility">
<choice>
<value></value><!-- default of visible -->
<value>visible</value>
<value>hidden</value>
</choice>
</attribute>
</define>
<define name="AttributeDirection">
<attribute name="direction">
<choice>
<value></value><!-- default of sendrecv -->
<value>sendrecv</value>
<value>sendonly</value>
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<value>recvonly</value>
</choice>
</attribute>
</define>
<define name="AttributeQ">
<attribute name="q">
<data type="float">
<!-- default of 0.5 -->
<param name="minInclusive">0</param>
<param name="maxInclusive">1</param>
</data>
</attribute>
</define>
<define name="DataIpPort">
<data type="integer">
<param name="minInclusive">1</param>
<param name="maxInclusive">65535</param>
</data>
</define>
<define name="DataIpTransport">
<choice>
<value></value><!-- default of UDP -->
<value>UDP</value>
<value>TCP</value>
<value>TLS</value>
<value>DTLS</value>
<value>SCTP</value>
</choice>
</define>
</grammar>
Appendix B. Acknowledgments
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Authors' Addresses
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/
Scott Lawrence
Pingtel Corp.
400 W. Cummings Park
Suite 2200
Woburn, MA 01801
US
Phone: "Scott Lawrence (+1 781 938 5306)" <sip:slawrence@pingtel.com>
Email: slawrence AT pingtel DOT com
URI: http://skrb.org/scott/
Martin Dolly
AT&T Labs
200 Laurel Avenue
Middletowm, NJ 07748
US
Phone:
Email: mdolly AT att DOT com
URI:
Volker Hilt
Bell Labs/Lucent Technologies
101 Crawfords Corner Rd
Holmdel, NJ 07733
USA
Email: volkerh@bell-labs.com
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