SIPPING D. Petrie
Internet-Draft SIPez LLC.
Expires: April 26, 2007 M. Dolly
AT&T Labs
V. Hilt
Bell Labs/Lucent Technologies
October 23, 2006
The Core Session Initiation Protocol User Agent Protocol Data Set
draft-petrie-sipping-sip-dataset-02.txt
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Copyright (C) The Internet Society (2006).
Abstract
This document defines the properties and format for the core SIP user
agent protocol dataset. The properties defined in this document are
expected to be common to most SIP user agents regardless of whether
the user agent support audio, video, text or any combination of
media. These core SIP properties are considered to be a dataset.
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Several datasets may be combined into documents or profiles that are
provided to SIP user agents so that they can operate with the desired
behavior.
Table of Contents
1. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. Requirements Terminology . . . . . . . . . . . . . . . . . 3
2.2. Profile Data Terminology . . . . . . . . . . . . . . . . . 3
2.3. Overview . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Core SIP Data Set . . . . . . . . . . . . . . . . . . . . . . 7
3.1. Transport Protocol Data Set . . . . . . . . . . . . . . . 7
3.1.1. transportProtocols Data Set Properties Definitions . . 7
3.1.2. transportProtocols Element Definition . . . . . . . . 7
3.1.3. Merging Different Sources of a transportProtocol
Data Set . . . . . . . . . . . . . . . . . . . . . . . 7
3.2. outboundProxy . . . . . . . . . . . . . . . . . . . . . . 8
3.2.1. outboundProxy Data Set Properties Definitions . . . . 8
3.2.2. outboundProxies Element Definition . . . . . . . . . . 8
3.2.3. outboundProxies Merging Different Sources of a
Data Set . . . . . . . . . . . . . . . . . . . . . . . 9
3.3. sipMethods . . . . . . . . . . . . . . . . . . . . . . . . 9
3.3.1. sipMethods Dataset Properties Definitions . . . . . . 9
3.3.2. sipMethod Element Definition . . . . . . . . . . . . . 9
3.3.3. sipMethods Merging Different Sources of a Data Set . . 9
3.4. sipOptionTags . . . . . . . . . . . . . . . . . . . . . . 10
3.4.1. sipOptionTags Data Set Properties Definitions . . . . 10
3.4.2. sipOptionTags Element Definition . . . . . . . . . . . 10
3.4.3. sipOptionTags Merging Different Sources of a Data
Set . . . . . . . . . . . . . . . . . . . . . . . . . 10
4. Example Profiles and Use . . . . . . . . . . . . . . . . . . . 10
4.1. Merge Two Data Sets . . . . . . . . . . . . . . . . . . . 10
4.2. Policy Filtering . . . . . . . . . . . . . . . . . . . . . 12
4.3. Override . . . . . . . . . . . . . . . . . . . . . . . . . 12
5. Security Considerations . . . . . . . . . . . . . . . . . . . 12
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13
6.1. Content-type registration for 'application/uapsip+xml' . . 13
7. Change History . . . . . . . . . . . . . . . . . . . . . . . . 13
7.1. Changes from draft-petrie-sipping-sip-dataset-01 . . . . . 14
7.2. Changes from draft-petrie-sipping-sip-dataset-00 . . . . . 14
7.3. Changes from draft-petrie-sipping-profile-datasets-01 . . 14
8. Normative References . . . . . . . . . . . . . . . . . . . . . 14
Appendix A. SIP Protocol Dataset Schema . . . . . . . . . . . . . 15
Appendix B. Acknowledgments . . . . . . . . . . . . . . . . . . . 19
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 20
Intellectual Property and Copyright Statements . . . . . . . . . . 21
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1. Motivation
The SIP Profile Data Sets defined in this document support the
principle to enable SIP User Agents to obtain and use profile data
sets from multiple sources in order to support a wide range of
applications without undue complexity.
The SIP Protocol Data Set is intended the be the lowest common
denominator among all user agent types regardless of capability.
This data set contains properties that all user agents require. That
does not mean that all of these properties are mandatory.
[I-D.ietf-sipping-config-framework] defines a configuration framework
for finding, retrieving and change notification of profile data for
SIP [RFC3261] user agents. It is intended that the SIP dataset
defined in this document may be contained in the user, device and
local-network profiles described in the configuration framework.
[I-D.petrie-sipping-profile-datasets] defines a general XML schema to
contain user agent profile data. This document defines core SIP
specific data by extending the profile data sets schema. The MIME
type defined for this schema may be used by the user agent to
indicate the support for this schema and content in the profile.
2. Introduction
This document defines the properties and format for the core SIP user
agent profile data set. The following properties are defined in this
document:
transportProtocols
outboundProxies
sipMethods
sipOptionTags
and, are expected to be common to most SIP user agents regardless of
whether the user agent support audio, video, text or any combination
of media. These core SIP properties are considered to to be a data
set.
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].
2.2. Profile Data Terminology
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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 range of values, allow for
simultaneous use of many values (as in a list of allowed
possibilities), or be 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).
data set - 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. user, device, local network).
2.3. Overview
This document defines a new MIME type: application/uapsip+xml which
SHOULD be used by user agents to indicate support for this schema.
The XML namespace: urn:ietf:params:xml:ns:uaprof:sip is used for the
extensions to the SIP UA Profile Dataset [I-D.petrie-sipping-profile-
datasets] schema defined here.
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The Core SIP UA Protocol dataset is defined in Section 3 and complies
with the guidelines provided in Section 5 of [I-D.petrie-sipping-
profile-datasets]. The Relax NG Schema defined in this document
extends the profile datasets schema to define the core SIP settings
which are likely to be common to all types of SIP user agents. The
SIP transport protocol(s) and ports, outbound proxy(s), SIP methods
and option tags to be enabled on the user agent may be configured
with this dataset.
Section 4 provides illustrative example profiles and use cases for
merging. Security considerations are addresed in Section 5.
The following is an example instance of the SIP protocol data set.
Note the use of the policy attribute.
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sip:a1b2c3d4e5f6@example.com
example.com
fred
b6b577fd12aa7e1df8d60735ef56fc2e
tel:+16175551212
sip:411@example.com
http:example.com/sipProfile.html
This is an example profile from example.com
UDP
5092
TCP
5092
TLS
5092
sip:example.com
sip:dmz.example.com
sip:local.example.com
REFER
METHOD
session
join
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3. Core SIP Data Set
The XML schema defined in this document extends the root element
"propertySet" schema defined in I-D.petrie-sipping-profile-datasets.
3.1. Transport Protocol Data Set
3.1.1. transportProtocols Data Set Properties Definitions
transportProtocols - This property contains properties related to SIP
transport protocols, and is an XML element that extends on the XML
"setting_container" element contained in the root "propertySet"
element. It serves as a container for a list of SIP transport
protcols to allow or disallow. There may be zero or one elements.
3.1.2. transportProtocols Element Definition
transportProtocol - The "transportProtocol" is an XML element that
extends the "setting" element contained in the
"transportProtocols" element. The "transportProtocol" element
contains properties related to a SIP transport protocol. It names
the transport protocol, defines whether the protocol is enabled or
not and defines the port to which that protocol is bound. If the
protocol is named it defaults to enabled if not explicitly set.
If the port property is not set, it defaults to the default
specified by the specification which binds the protocol to SIP.
The user agent should enable all the set transport protocols that
are supported by the user agent. The user agent ignores protocol
bindings that it does not support. The user agent may default
transport protocols that it supports to enabled, if a protocol
property for that transport protocol is not present in the data
set. The order of the list of transportProtocol setting values
indicated by the "q" attribute indicates the order of preference.
There may be zero or more "transportProtocol" elements in the
"transportProtocols" element.
name - This XML element identifies the specific transport protocol,
and extends the "setting" element contained in transportProtocols.
There must be exactly one "name" element in a "transportProtocol".
port - This element identifies the port for binding the transport
protocol, and extends the "setting" element contained in
transportProtocols. There must be exactly one "port" element in a
"transportProtocol".
3.1.3. Merging Different Sources of a transportProtocol Data Set
The "transportProtocol" property uses the "policy" attribute to
identify whether the transport protocol is allowed or disallowed.
The "q" attribute is used for ordering of the list. In addition, a
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visibility attribute may be present.
If there are matches on multiple "name" element values, the "policy"
attribute will determine which is allowed or not. As defined in
Merging Datasets [I-D.petrie-sipping-profile-datasets] properties
with conflicting "policy" attribute value of "allow" and "disallow"
are assumed to be "disallowed". If there are multiple
"transportProtocol" elements from different profiles with the same
"name" element value and "policy" attribute values of "allows", then
the resulting merged "transportProtocols" element will contain one
"transportProtocol" element having a "name" element of that value.
The "port" element value will be determined in the following order of
the source profile, when there are multiple "transportProtocol"
elements from different profiles with the same "name" element value
and "policy" attribute value of "allow":
Local
Device
User
Application
3.2. outboundProxy
3.2.1. outboundProxy Data Set Properties Definitions
outboundProxies - The "outboundProxies" property is an XML element
that extends on the XML "setting" element contained in the root
"propertySet" element. It serves as a container for a list of
outbound proxies. There may be zero or one element. The default
outbound proxy, through which all SIP requests, not explicitly
routed, should be sent. The format of this parameter is of name-
addr as specified in [RFC3261]. This property is optional. If
absent or not set, SIP requests are sent to directly to the URI of
the request. If set the effect of this property is to add a loose
route as defined in [RFC3261] for the next hop destination.
3.2.2. outboundProxies Element Definition
outboundProxies - The "outboundProxy" is an XML element that extends
the XML "setting" element contained in "outboundProxies". There
may be zero, one or many "outboundProxy" elements. It provides
default value for an outbound proxy, through which all SIP
requests, not explicitly routed, should be sent. The format of
this parameter is of name-addr as specified in [RFC3261]. This
property is optional. If absent or not set, SIP requests are sent
to directly to the URI of the request. If set the effect of this
property is to add a loose route as defined in [RFC3261] for the
next hop destination. Multiple "outboundProxy" elements may be
contained in the "outboundProxies" element to form a route set.
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The user agent MUST use this route set for all requests that are
outside of or initiate a dialog. The user agent MUST NOT use this
route set for requests within an established dialot. The user
agent should use the route set formed as described in [RFC3261]
for requests within an established dialog.
3.2.3. outboundProxies Merging Different Sources of a Data Set
The aggregation approach is used to resolve conflicts. By
aggregating the multiple outbound proxies, the local network profile
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. The order of the
resulting merged, route set is determined by the "q" attibute.
3.3. sipMethods
3.3.1. sipMethods Dataset Properties Definitions
sipMethods - This property contains properties related to SIP
Methods, and is an XML element that extends on the XML "setting"
element contained in the root "propertySet" element. It serves as
a container for a list of SIP request methods to allow or
disallow. Typically, only provide by the device dataset. The
"sipMethods" element is intended to provide a means of enabling or
diabling features in the SIP user agent based upon the SIP request
method.
3.3.2. sipMethod Element Definition
sipMethod - An element to specify a SIP method, and extends the
"setting" element contained in the "sipMethods" element. There
may be zero or more elements. For user agents that support the
method indicated, this element serves as a switch to enable or
disable the named SIP method as indicated by the "policy"
attribute. The direction attribute is used to indicate asymmetric
support of the method. The sendonly value in the direction
attribute means that the user agent MAY send requests of the give
method name but MUST reject all incoming requests for the method
type.
3.3.3. sipMethods Merging Different Sources of a Data Set
The "sipMethods" Data Set uses the aggregation merging policy defined
in [I-D.petrie-sipping-profile-datasets]. When multiple "sipMethod"
elements with the same value are provided, the "policy" attribute is
used to determine precidence.
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3.4. sipOptionTags
3.4.1. sipOptionTags Data Set Properties Definitions
sipOptionTags - This property specifies a container for a list of SIP
option tags that are allowed or disallowed, and is an XML element
that extends on the XML "setting" element contained in the root
"propertySet" element. For user agents that suppport features
indicated by option tags, this element serves as a list of
features to turn on or off as indicated by the "policy" attribute
in the "sipOptionTag" element.
3.4.2. sipOptionTags Element Definition
sipOptionTag - An element to specify a SIP option tag, and extends
the "setting" element and is contained in "sipOptionTags" element.
There may be zero or more elements "sipOptionTag". For user
agents that suppport features indicated by option tags, this
element serves as a switch to enable or disable the named SIP
option as indicated by the policy attribute in the "sipOptionTag"
element.
3.4.3. sipOptionTags Merging Different Sources of a Data Set
The sipOptionTags Data Set uses the default aggregation merging
policy defined in [I-D.petrie-sipping-profile-datasets]. When
multiple "sipMethod" elements with the same value are provided, the
"policy" attribute is used to determine precidence.
4. Example Profiles and Use
4.1. Merge Two Data Sets
Consider the use case described in [I-D.petrie-sipping-profile-
datasets] where the user wishes to indicate that only secure SIP
transport should be used. The device profile may contain SIP
Protocol Data Set (see Section 3.1) settings that look like the
following:
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UDP
5060
TCP
5060
TLS
5061
sip:outproxy.example.com
INFO
join
The user profile which indicates that only TLS should be used would
look like (Note: this example also indicates that port 5061 should be
used. This may be more constrained than the user really wants.):
TLS
5061
UDP
TCP
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The merged result of the device and user profile would look like:
TLS
5061
UDP
TCP
sip:outproxy.example.com
INFO
join
4.2. Policy Filtering
(allowed and disallowed protocols)
4.3. Override
(device prefers default ports 5060, local net requires port 11000)
5. Security Considerations
Security is mostly a profile delivery problem. The delivery
framework MUST 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 MUST provide protection that
prevents unauthorized access of the profile data. The profile
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delivery server and the user agent MUST enforce the access control
policies defined in the profile data sets if present.
6. IANA Considerations
XML name space registration: urn:ietf:params:xml:ns:uaprof:sip
6.1. Content-type registration for 'application/uapsip+xml'
To: ietf-types@iana.org
Subject: Registration of MIME media type application/uapsip+xml
MIME media type name: application
MIME subtype name: uapsip+xml
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 SIP settings
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/uapsip+xml.
7. Change History
[[RFC Editor: Please remove this entire section upon publication as
an RFC.]]
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7.1. Changes from draft-petrie-sipping-sip-dataset-01
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:sip"
Changed names of elements, attributes and other data types which
contained "-" or "_" to use camel case.
Defined mime type: application/uapsip+xml to be used for indication
of support for this content type (e.g. with the config. framework).
7.2. Changes from draft-petrie-sipping-sip-dataset-00
Removed references to policy attribribute value: "mandatory".
A few minor edits to refresh the draft"
7.3. Changes from draft-petrie-sipping-profile-datasets-01
The core SIP profile data set was split out from the examples in
draft-petrie-sipping-profile-datasets-01 to create a stand alone data
set definition.
8. Normative References
[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.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.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[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.
[RFC3470] Hollenbeck, S., Rose, M., and L. Masinter, "Guidelines for
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the Use of Extensible Markup Language (XML) within IETF
Protocols", BCP 70, RFC 3470, January 2003.
[W3C.REC-xml-names]
Bray, T., Hollander, D., and A. Layman, "Namespaces in
XML", W3C REC-xml-names, 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, .
[W3C.REC-xmlschema-2]
Biron, P. and A. Malhotra, "XML Schema Part 2: Datatypes",
W3C REC-xmlschema-2, May 2001,
.
Appendix A. SIP Protocol Dataset Schema
The following is the schema for the SIP protocol data set.