SIMPLE WG M. Lonnfors
Internet-Draft Nokia Research Center
Expires: August 7, 2004 K. Kiss
Nokia
February 7, 2004
User agent capability presence status extension
draft-ietf-simple-prescaps-ext-00
Status of this Memo
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all provisions of Section 10 of RFC2026.
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This Internet-Draft will expire on August 7, 2004.
Copyright Notice
Copyright (C) The Internet Society (2004). All Rights Reserved.
Abstract
Interoperation of Instant Messaging and Presence systems has been
defined in IMPP working group. IMPP WG has come up with baseline
interoperable operations and formats for presence and instant
messaging systems. However, these base formats might need
standardized extensions in order to enable building rational
applications using presence and instant messaging. This memo proposes
an extension to PIDF presence document format to represent
"Indicating User Agent Capabilities in the Session Initiation
Protocol (SIP)" capabilities to be used in SIMPLE based presence
systems but may also be applied to other protocols as well.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . 4
1.1 Motivation . . . . . . . . . . . . . . . . . . . . . . . . 4
1.2 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2. Conventions . . . . . . . . . . . . . . . . . . . . . . . 5
3. Extension for "Indicating User Agent Capabilities in
the Session Initiation Protocol (SIP)" in PIDF documents . 5
3.1 Extension overview . . . . . . . . . . . . . . . . . . . . 5
3.2 <prescaps> element . . . . . . . . . . . . . . . . . . . . 6
3.3 <audio> element . . . . . . . . . . . . . . . . . . . . . 6
3.4 <application> element . . . . . . . . . . . . . . . . . . 6
3.5 <data> element . . . . . . . . . . . . . . . . . . . . . . 7
3.6 <control> element . . . . . . . . . . . . . . . . . . . . 7
3.7 <video> element . . . . . . . . . . . . . . . . . . . . . 7
3.8 <text> element . . . . . . . . . . . . . . . . . . . . . . 8
3.9 <type> element . . . . . . . . . . . . . . . . . . . . . . 8
3.10 <automata> element . . . . . . . . . . . . . . . . . . . . 9
3.11 <class> element . . . . . . . . . . . . . . . . . . . . . 9
3.12 <duplex> element . . . . . . . . . . . . . . . . . . . . . 9
3.13 <mobility> element . . . . . . . . . . . . . . . . . . . . 9
3.14 <description> element . . . . . . . . . . . . . . . . . . 9
3.15 <event-packages> element . . . . . . . . . . . . . . . . . 10
3.15.1 <event-package> . . . . . . . . . . . . . . . . . . . . . 10
3.16 <priority> element . . . . . . . . . . . . . . . . . . . . 10
3.17 <methods> element . . . . . . . . . . . . . . . . . . . . 10
3.17.1 <method> . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.18 <extensions> element . . . . . . . . . . . . . . . . . . . 11
3.18.1 <extension> . . . . . . . . . . . . . . . . . . . . . . . 11
3.19 <schemes> element . . . . . . . . . . . . . . . . . . . . 11
3.19.1 <scheme> . . . . . . . . . . . . . . . . . . . . . . . . . 11
3.20 <actor> element . . . . . . . . . . . . . . . . . . . . . 11
3.21 <is-focus> element . . . . . . . . . . . . . . . . . . . . 12
3.22 <languages> element . . . . . . . . . . . . . . . . . . . 12
3.22.1 <language> . . . . . . . . . . . . . . . . . . . . . . . . 12
3.23 Extension elements . . . . . . . . . . . . . . . . . . . . 13
3.23.1 <string> element . . . . . . . . . . . . . . . . . . . . . 13
3.23.2 <token> element . . . . . . . . . . . . . . . . . . . . . 13
3.23.3 <boolean> element . . . . . . . . . . . . . . . . . . . . 13
3.23.4 <numeric> element . . . . . . . . . . . . . . . . . . . . 13
4. Publishing and using 'prescaps' elements . . . . . . . . . 14
5. Generating SIP request based on 'prescaps' extension . . . 14
6. Using extension with PIDF document format . . . . . . . . 14
6.1 Contact URI . . . . . . . . . . . . . . . . . . . . . . . 15
7. Examples . . . . . . . . . . . . . . . . . . . . . . . . . 15
7.1 Example . . . . . . . . . . . . . . . . . . . . . . . . . 16
8. XML schema definitions . . . . . . . . . . . . . . . . . . 16
9. IANA Considerations . . . . . . . . . . . . . . . . . . . 22
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9.1 URN sub-namespace registration for
'urn:ietf:params:xml:ns:simple-prescaps-ext' . . . . . . . 23
10. Security Considerations . . . . . . . . . . . . . . . . . 23
11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . 24
Normative references . . . . . . . . . . . . . . . . . . . 24
Informative references . . . . . . . . . . . . . . . . . . 24
Authors' Addresses . . . . . . . . . . . . . . . . . . . . 25
Intellectual Property and Copyright Statements . . . . . . 27
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1. Introduction
Interoperation of instant messaging and presence systems has been
defined in IMPP working group. Working group has defined "A model for
Presence and Instant Messaging" [2] and also requirements for
protocols implementing such a system [3]. Common presence and instant
messaging (CPP/CPIM) defines common operations and formats which all
Presence and Instant Messaging services must agree upon so that basic
interoperability would be possible [5], [10]. The actual base format
for presence is being defined in PIDF [4]. The PIDF document format
has been designed to reduce the need for gatewaying and to allow
end-to-end security of presence data. It has taken very minimalistic
approach to support such operations. In order to make the PIDF format
usable by different presence applications, these applications usually
must extend the basic PIDF format by standard XML mechanism as
defined in [4].
The aim of this memo is to introduce SIP/SIMPLE specific extension
mechanism for the PIDF document. With this extension SIMPLE based
applications can have richer and more usable formats compared to the
baseline PIDF data format. Aim of this document is to introduce
extension for "Indicating User Agent Capabilities in the Session
Initiation Protocol (SIP)" [6].
1.1 Motivation
The PIDF document format [4] defines a <contact> element which may
appear once inside every <tuple> element. The content of the
<contact> element encodes the CONTACT ADDRESS and CONTACT MEANS as
defined in [2]. The <contact> element is defined to be an URI. This
URI can be of any URI type. In some implementations this URI can
uniquely identify the application the tuple intends to describe (e.g.
im: URIs). However, this may not be the case in all implementations.
For example in SIP, a SIP URI can represent different kinds of
applications. A SIP URI can be used to contact voice applications,
video applications, or messaging applications. If it is not known by
other means, it might be hard for applications processing the
presence document containing only SIP URI contact addresses to know
what particular application the tuple intends to describe. Also
watchers receiving presence information would probably benefit for
getting more descriptive information about what particular
communication means or applications are supported by the presentity.
"Indicating User Agent Capabilities in the Session Initiation
Protocol (SIP)" document [6] defines a set of extensions which allow
callees to express preferences about request handling in SIP servers.
The same information could provide value also to presence watchers so
that they could make more rational decisions on how presentity should
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be contacted if presence document would contain similar information
as defined in "Indicating User Agent Capabilities in the Session
Initiation Protocol (SIP)" extension.
1.2 Scope
This document defines extension to the PIDF document format which
enables presence implementations based on SIP protocol to utilize
similar capabilities in presence document as what "Indicating User
Agent Capabilities in the Session Initiation Protocol (SIP)" document
[6] defines.
This extension does not replace media negotiation mechanisms defined
for SIP (e.g. SDP [14]), therefore media negotiation (e.g. choose of
voice and video codecs) MUST be performed according to [11]. This
extension is only aimed to give the watchers hints about the
presentity's preferences, willingness and capabilities to communicate
before watchers would initiate SIP based communication with the
presentity.
2. Conventions
In this document, the key words "MUST", "MUST NOT", "REQUIRED",
"SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY",
and "OPTIONAL" are to be interpreted as described in RFC 2119 [1] and
indicate requirement levels for compliant implementations.
This memo makes use of the vocabulary defined in RFC2778 [2], and in
PIDF [4].
3. Extension for "Indicating User Agent Capabilities in the Session
Initiation Protocol (SIP)" in PIDF documents
This section presents "Indicating User Agent Capabilities in the
Session Initiation Protocol (SIP)" extension namespace, its elements,
their values, and semantics. This section also describes how this
extension can be further extended. Extension is intended to be used
with "urn:ietf:params:xml:ns:pidf" namespace and that particular
usage is described here. This extension may also be used with other
namespaces if appropriate.
3.1 Extension overview
This extension adds features presented in "Indicating User Agent
Capabilities in the Session Initiation Protocol (SIP)" document [6]
into PIDF presence document format. Extension also includes type
feature tag [7] and language feature tag [8]. Features presented in
[6], [7], and [8] are added here without any change in their
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semantics. Bringing these features to PIDF presence document format
basically means mapping them to XML structure. Namespace identifier
for this extension is:
urn:ietf:params:xml:ns:simple-prescaps-ext
When this extension namespace is congregated with base PIDF document,
combined document must follow the same general formatting rules as
specified in [4] in chapter 4.1.
3.2 <prescaps> element
Root element of this extension namespace is <prescaps>. The root
element MUST be always present. This element MAY contain one or more
elements as specified later in this document.
<prescaps> element does not have any attributes and it MAY contain
other namespace declarations for the extensions used in the presence
XML document.
3.3 <audio> element
The <audio> element indicates that the device supports audio as a
streaming media type as defined in [6].
The <audio> element can contain 'negated' attribute. This attribute
is of boolean type. Value 'true' indicates that device supports audio
media type and value 'false' indicates that device does not support
audio media type as defined in [6]. Default value for 'negated'
attribute is 'false'.
<audio> element can contain any number of <type> elements which can
be used to describe audio media types supported by the device. If
'negated' attribute has value 'true' it is NOT RECOMMENTED to include
<type> elements. Media types included in <type> elements MUST start
with 'audio/'.
3.4 <application> element
The <application> element indicates that the device supports
application as a streaming media type as defined in [6].
The <application> element can contain 'negated' attribute. This
attribute is of boolean type. Value 'true' indicates that device
supports application media type and value 'false' indicates that
device does not support application media type as defined in [6].
Default value for 'negated' attribute is 'false'.
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<application> element can contain any number of <type> elements which
can be used to describe application media types supported by the
device. If 'negated' attribute has value 'true' it is NOT RECOMMENTED
to include <type> elements. Media types included in <type> elements
MUST start with 'application/'.
3.5 <data> element
The <data> element indicates that the device supports data as a
streaming media type as defined in [6].
The <data> element can contain 'negated' attribute. This attribute is
of boolean type. Value 'true' indicates that device supports data
media type and value 'false' indicates that device does not support
data media type as defined in [6]. Default value for 'negated'
attribute is 'false'.
<data> element can contain any number of <type> elements which can be
used to describe data media types supported by the device. If
'negated' attribute has value 'true' it is NOT RECOMMENTED to include
<type> elements. Media types included in <type> elements MUST start
with 'data/'.
3.6 <control> element
The <control> element indicates that the device supports control as a
streaming media type as defined in [6].
The <control> element can contain 'negated' attribute. This attribute
is of boolean type. Value 'true' indicates that device supports
control media type and value 'false' indicates that device does not
support control media type as defined in [6]. Default value for
'negated' attribute is 'false'.
<control> element can contain any number of <type> elements which can
be used to describe control media types supported by the device. If
'negated' attribute has value 'true' it is NOT RECOMMENTED to include
<type> elements. Media types included in <type> elements MUST start
with 'control/'.
3.7 <video> element
The <video> element indicates that the device supports video as a
streaming media type as defined in [6].
The <video> element can contain 'negated' attribute. This attribute
is of boolean type. Value 'true' indicates that device supports video
media type and value 'false' indicates that device does not support
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video media type as defined in [6]. Default value for 'negated'
attribute is 'false'.
<video> element can contain any number of <type> elements which can
be used to describe video media types supported by the device. If
'negated' attribute has value 'true' it is NOT RECOMMENTED to include
<type> elements. Media types included in <type> elements MUST start
with 'video/'.
3.8 <text> element
The <text> element indicates that the device supports text as a
streaming media type as defined in [6].
The <text> element can contain 'negated' attribute. This attribute is
of boolean type. Value 'true' indicates that device supports text
media type and value 'false' indicates that device does not support
text media type as defined in [6]. Default value for 'negated'
attribute is 'false'.
<text> element can contain any number of <type> elements which can be
used to describe text media types supported by the device. If
'negated' attribute has value 'true' it is NOT RECOMMENTED to include
<type> elements. Media types included in <type> elements MUST start
with 'text/'.
3.9 <type> element
The <type> element indicates indicates a MIME media content type
(i.e. that appears in a 'Content-type:' header of the corresponding
MIME-formatted data) as defined in [7].
The <type> element is of string type and does not have any
attributes. It must be a string of the form "type/subtype", where
'type' and 'subtype' are defined by the MIME specification [17]. Only
lower-case letters should be used.
This element can be used inside <audio>, <video>, <text>, <data>,
<application>, and <control> elements.
Open issue: Do we need to also allow separate <type> elements outside
media tags? This would allow representation of other media type
which are not included into this document (like multipart or
message).
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3.10 <automata> element
The <automata> element indicates whether the UA represents an
automata (such as a voicemail server, conference server, IVR, or
recording device) or a human as defined in [6].
The <automata> element is of boolean type and does not have any
attributes. Value 'true' indicates that the UA represents an automata
and value 'false' indicates that it represents a human.
3.11 <class> element
The <class> element indicates the setting, business or personal, in
which a communications device is used as defined in [6].
The <class> element is of string type and does not have any
attributes. Possible values include: "business" and "personal".
3.12 <duplex> element
The <duplex> element lists whether a communications device can
simultaneously send and receive media ("full"), alternate between
sending and receiving ("half"), can only receive ("receive-only") or
only send ("send-only") defined in [6].
The <duplex> element is of string type and does not have any
attributes. possible values include: "full", "half", "receive-only",
and "send-only".
3.13 <mobility> element
The <mobility> element indicates whether the device is fixed (meaning
that it is associated with a fixed point of contact with the
network), or mobile (meaning that it is not associated with a fixed
point or contact). Note that cordless phones are fixed, not mobile,
based on this definition.as defined in [6].
The <mobility> element is of string type and does not have any
attributes. Possible values include: "fixed" and "mobile"
3.14 <description> element
The <description> element provides a textual description of the
device as defined in [6].
The <description> element is of string type and does not have any
attributes.
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3.15 <event-packages> element
The <event-packages> element lists the event packages [12] supported
by a device.
<event-packages> element can contain any number of <event-package>
elements which can be used to describe individual event packages
supported by the device.
3.15.1 <event-package>
The <event-package> is string type element and it is used to describe
individual event package supported by the device. The <event-package>
element can contain 'negated' attribute. This attribute is of boolean
type. Value 'true' indicates that device supports particular event
package and value 'false' indicates that device does not support
particular event package as defined in [6]. Default value for
'negated' attribute is 'false'.
The values for this tag equal the event package names that are
registered by each event package as defined in [6].
3.16 <priority> element
The <priority> element indicates the call priorities the device is
willing to handle. A value of X means that the device is willing to
take requests with priority X and higher as defined in [6].
The <priority> element is of integer type does not have any
attributes.
3.17 <methods> element
The <methods> element indicates the SIP methods supported by this UA.
In this case, "supported" means that the UA can receive requests with
this method. In that sense, it has the same connotation as the Allow
header field as defined in [6].
<methods> element can contain any number of <method> elements which
can be used to describe individual methods supported by the device.
3.17.1 <method>
The <method> is string type element and it is used to describe
individual method supported by the device. The <method> element can
contain 'negated' attribute. This attribute is of boolean type. Value
'true' indicates that device supports particular method and value
'false' indicates that device does not support particular method as
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defined in [6]. Default value for 'negated' attribute is 'false'.
3.18 <extensions> element
The <extensions> element is a list of SIP extensions (each of which
is defined by an option-tag registered with IANA) that are understood
by the UA. Understood, in this context, means that the option tag
would be included in a Supported header field in a request as defined
in [6].
<extensions> element can contain any number of <extension> elements
which can be used to describe individual extensions supported by the
device.
3.18.1 <extension>
The <extension> is string type element and it is used to describe
individual extension supported by the device. The <extension> element
can contain 'negated' attribute. This attribute is of boolean type.
Value 'true' indicates that device supports particular extension and
value 'false' indicates that device does not support particular
extension as defined in [6]. Default value for 'negated' attribute is
'false'.
3.19 <schemes> element
The <schemes> element provides the set of URI schemes that are
supported by a UA. Supported implies, for example, that the UA would
know how to handle a URI of that scheme in the Contact header field
of a redirect response as defined in [6].
<schemes> element can contain any number of <scheme> elements which
can be used to describe individual schemes supported by the device.
3.19.1 <scheme>
The <scheme> is string type element and it is used to describe
individual scheme supported by the device. The <scheme> element can
contain 'negated' attribute. This attribute is of boolean type. Value
'true' indicates that device supports particular scheme and value
'false' indicates that device does not support particular scheme as
defined in [6]. Default value for 'negated' attribute is 'false'.
3.20 <actor> element
The <actor> element indicates the type of entity that is available at
this URI as defined in [6].
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The <actor> element is of string type and does not have any
attributes. Possible values include:
o principal: The device provides communication with the principal
that is associated with the device. Often this will be a specific
human being, but it can be an automata (for example, when calling
a voice portal).
o attendant: The device provides communication with an automaton or
person that will act as an intermediary in contacting the
principal associated with the device, or a substitute.
o msg-taker: The device provides communication with an automaton or
person that will take messages and deliver them to the principal.
o information: The device provides communication with an automaton
or person that will provide information about the principal.
3.21 <is-focus> element
The <is-focus> element indicates that the UA is a conference server,
also known as a focus, and will mix together the media for all calls
to the same URI as defined in [6].
The <is-focus> element is of boolean type and does not have any
attributes.
3.22 <languages> element
The <languages> element indicates Ability to display particular human
languages as as defined in [8].
<languages> element can contain any number of <language> elements
which can be used to describe individual languages supported by the
device.
3.22.1 <language>
The <language> is string type element and it is used to describe
individual language supported by the device. The <language> element
can contain 'negated' attribute. This attribute is of boolean type.
Value 'true' indicates that device supports particular language and
value 'false' indicates that device does not support particular
language as defined in [6]. Default value for 'negated' attribute is
'false'.
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3.23 Extension elements
This section defines how extension features present in "Indicating
User Agent Capabilities in the Session Initiation Protocol (SIP)"
[6] can be used in this extension.
3.23.1 <string> element
<string> element can be used to represent string type feature tags.
This element MUST NOT be used to represent standard tags discussed in
this document, for example to represent <language> tags. <string>
element has one mandatory attribute called 'name'. This attribute is
string type and it MUST contain the name of the feature tag. <string>
has optional attribute 'negated' which is boolean type attribute.
Value 'false' indicates that feature tag is supported and value
'true' indicates that feature tag is not supported. Default value is
'false'.
3.23.2 <token> element
<token> element can be used to represent token type feature tags.
This element MUST NOT be used to represent standard tags discussed in
this document, for example to represent <language> tags. <token>
element has one mandatory attribute called 'name'. This attribute is
string type and it MUST contain the name of the feature tag. <string>
has optional attribute 'negated' which is boolean type attribute.
Value 'false' indicates that feature tag is supported and value
'true' indicates that feature tag is not supported. Default value is
'false'.
3.23.3 <boolean> element
<boolean> element can be used to represent boolean type feature tags.
This element MUST NOT be used to represent standard tags discussed in
this document, for example to represent <is-focus> tag. <boolean>
element has one mandatory attribute called 'name'. This attribute is
string type and it MUST contain the name of the feature tag.
<boolean> can have two values: value 'true' indicates that feature
tag is supported and value 'false' indicates that feature tag is not
supported.
3.23.4 <numeric> element
<numeric> element can be used to represent numeric type feature tags.
This element MUST NOT be used to represent standard tags discussed in
this document, for example to represent <priority> tag. <numeric>
element has one mandatory attribute called 'name'. This attribute is
string type and it MUST contain the name of the feature tag.
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<numeric> has optional attribute 'negated' which is boolean type
attribute. Value 'false' indicates that feature tag is supported and
value 'true' indicates that feature tag is not supported. Default
value is 'false'.
4. Publishing and using 'prescaps' elements
In [6] it is recommended that a UA provide complete information in
its contact predicate. However, it may be that presentity is not
willing to publish such presence information which would be
consistent with actual device capabilities (e.g. presentity may not
want to indicate that he/she supports voice when the device actually
is able to support it). Also authorization rules or policies in
presence server may limit or modify published presence information in
a way that all published presence information may not end up to all
possible watchers.
It is RECOMMENTED that Presence User Agent (PUA) using this extension
provider as complete presence information as it can. However, it is
not mandated that this presence information should be consistent with
actual device capabilities. Also, watchers SHOULD NOT expect that
presence information represented by this extension fully represents
actual presentity's device capabilities.
5. Generating SIP request based on 'prescaps' extension
UA receiving PIDF documents with 'prescaps' extension may wish to
generate SIP request which would route to UA having capabilities
described by 'prescaps' extension. UA MAY add Accept-Contact: header
based on 'prescaps' extension elements. However, as discussed in
Section 4 device capabilities described by this extension may not be
consistent what UA has indicated in its registration. Due to this
request may not route to correct UA.
6. Using extension with PIDF document format
This section presents guidelines how extension can be used with PIDF
document format.
PIDF format allows use of extension XML namespaces inside <presence>,
<tuple>, and <status> elements. <presence> element is intended to
describe presentity as a whole. 'Prescaps' extension is related to
contact address defined by PIDF to which this extension is applied
to. These contact addresses can only appear inside <tuple> elements.
The use of this extension in <presence> element level is NOT
RECOMMENDED for this purpose.
'Prescaps' extension elements SHOULD be placed inside <status>
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element. Root element <prescaps> MUST NOT appear more than once
inside a single <tuple> element but can appear multiple times in
PIDF document format inside different <tuple> elements.
6.1 Contact URI
"Indicating User Agent Capabilities in the Session Initiation
Protocol (SIP)" [6] has restrictions what kind of URIs can be used
with callee capabilities. As Address of Record of the presentity
represents the union of all presentity's device capabilities it is
RECOMMENTED that contact URI in <contact> element used with this
specifications SHOULD be Address of Record of the presentity.
7. Examples
This section presents examples how this extension can be used with
base PIDF document format.
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7.1 Example
<?xml version="1.0" encoding="UTF-8"?>
<presence xmlns="urn:ietf:params:xml:ns:pidf"
xmlns:ext="urn:ietf:params:xml:ns:simple-prescaps-ext
entity="pres:someone@example.com">
<tuple id="joi9877866786ua9">
<status>
<basic>open</basic>
<ext:prescaps>
<ext:video negated="false"/>
<ext:audio negated="false">
<ext:type>audio/gsm</ext:type>
<ext:type>audio/amr-wb</ext:type>
</ext:audio>
<ext:text negated="true"/>
<ext:mobile>true</ext:mobile>
<ext:methods>
<ext:method>INVITE</ext:method>
<ext:method>MESSAGE</ext:method>
<ext:method>ACK</ext:method>
<ext:method>BYE</ext:method>
<ext:method>CANCEL</ext:method>
<ext:method negated="true">REFER</ext:method>
</ext:methods>
<ext:string name="myString" negated="false">myvalue
</ext:string>
</ext:prescaps>
</status>
<contact>sip:someone@example.com</contact>
</tuple>
</presence>
8. XML schema definitions
This section gives the XML Schema Definition for the extension
defined in this document which can be used in the context of
"application/cpim-pidf+xml" content type.
<?xml version="1.0" encoding="UTF-8"?>
<xs:schema
targetNamespace="urn:ietf:params:xml:ns:simple-prescaps-ext"
xmlns:tns="urn:ietf:params:xml:ns:simple-prescaps-ext"
xmlns:xs="http://www.w3.org/2001/XMLSchema"
elementFormDefault="qualified"
attributeFormDefault="unqualified">
<!-- This import brings in the XML language
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attribute xml:lang-->
<xs:import namespace="http://www.w3.org/XML/1998/namespace"
schemaLocation="http://www.w3.org/2001/xml.xsd"/>
<xs:element name="prescaps" type="tns:prescaps"/>
<xs:complexType name="prescaps">
<xs:sequence>
<xs:element name="audio" type="tns:audio" minOccurs="0"/>
<xs:element name="application" type="tns:application"
minOccurs="0"/>
<xs:element name="data" type="tns:data" minOccurs="0"/>
<xs:element name="control" type="tns:control"
minOccurs="0"/>
<xs:element name="video" type="tns:video" minOccurs="0"/>
<xs:element name="text" type="tns:text" minOccurs="0"/>
<xs:element name="automata" type="tns:automata"
minOccurs="0"/>
<xs:element name="class" type="tns:class" minOccurs="0"/>
<xs:element name="duplex" type="tns:duplex" minOccurs="0"/>
<xs:element name="mobility" type="tns:mobility"
minOccurs="0"/>
<xs:element name="description" type="tns:description"
minOccurs="0"/>
<xs:element name="event-packages" type="tns:event-packages"
minOccurs="0"/>
<xs:element name="priority" type="tns:priority"
minOccurs="0"/>
<xs:element name="methods" type="tns:methods"
minOccurs="0"/>
<xs:element name="extensions" type="tns:extensions"
minOccurs="0"/>
<xs:element name="schemes" type="tns:schemes"
minOccurs="0"/>
<xs:element name="actor" type="tns:actor" minOccurs="0"
maxOccurs="4"/>
<xs:element name="is-focus" type="tns:is-focus"
minOccurs="0"/>
<xs:element name="languages" type="tns:languages"
minOccurs="0"
maxOccurs="unbounded"/>
<xs:element name="string" type="tns:string" minOccurs="0"
maxOccurs="unbounded"/>
<xs:element name="token" type="tns:token" minOccurs="0"
maxOccurs="unbounded"/>
<xs:element name="boolean" type="tns:boolean" minOccurs="0"
maxOccurs="unbounded"/>
<xs:element name="numeric" type="tns:numeric" minOccurs="0"
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maxOccurs="unbounded"/>
<xs:any namespace="##other" processContents="lax"
minOccurs="0" maxOccurs="unbounded"/>
</xs:sequence>
</xs:complexType>
<xs:complexType name="audio">
<xs:sequence>
<xs:element name="type" type="tns:type" minOccurs="0"
maxOccurs="unbounded"/>
</xs:sequence>
<xs:attribute name="negated" type="xs:boolean"
default="false"/>
</xs:complexType>
<xs:complexType name="application">
<xs:sequence>
<xs:element name="type" type="tns:type" minOccurs="0"
maxOccurs="unbounded"/>
</xs:sequence>
<xs:attribute name="negated" type="xs:boolean"
default="false"/>
</xs:complexType>
<xs:complexType name="data">
<xs:sequence>
<xs:element name="type" type="tns:type" minOccurs="0"
maxOccurs="unbounded"/>
</xs:sequence>
<xs:attribute name="negated" type="xs:boolean"
default="false"/>
</xs:complexType>
<xs:complexType name="control">
<xs:sequence>
<xs:element name="type" type="tns:type" minOccurs="0"
maxOccurs="unbounded"/>
</xs:sequence>
<xs:attribute name="negated" type="xs:boolean"
default="false"/>
</xs:complexType>
<xs:complexType name="video">
<xs:sequence>
<xs:element name="type" type="tns:type" minOccurs="0"
maxOccurs="unbounded"/>
</xs:sequence>
<xs:attribute name="negated" type="xs:boolean"
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default="false"/>
</xs:complexType>
<xs:complexType name="text">
<xs:sequence>
<xs:element name="type" type="tns:type" minOccurs="0"
maxOccurs="unbounded"/>
</xs:sequence>
<xs:attribute name="negated" type="xs:boolean"
default="false"/>
</xs:complexType>
<xs:simpleType name="type">
<xs:restriction base="xs:string"/>
</xs:simpleType>
<xs:simpleType name="automata">
<xs:restriction base="xs:boolean"/>
</xs:simpleType>
<xs:simpleType name="class">
<xs:restriction base="xs:string">
<xs:enumeration value="personal"/>
<xs:enumeration value="business"/>
</xs:restriction>
</xs:simpleType>
<xs:simpleType name="duplex">
<xs:restriction base="xs:string">
<xs:enumeration value="full"/>
<xs:enumeration value="half"/>
<xs:enumeration value="receive-only"/>
<xs:enumeration value="send-only"/>
</xs:restriction>
</xs:simpleType>
<xs:simpleType name="mobility">
<xs:restriction base="xs:string">
<xs:enumeration value="fixed"/>
<xs:enumeration value="mobile"/>
</xs:restriction>
</xs:simpleType>
<xs:simpleType name="description">
<xs:restriction base="xs:string"/>
</xs:simpleType>
<xs:complexType name="event-packages">
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<xs:sequence>
<xs:element name="event-package" type="tns:event-package"
minOccurs="0" maxOccurs="unbounded"/>
</xs:sequence>
</xs:complexType>
<xs:complexType name="event-package">
<xs:simpleContent>
<xs:extension base="xs:string">
<xs:attribute name="negated" type="xs:boolean"/>
</xs:extension>
</xs:simpleContent>
</xs:complexType>
<xs:simpleType name="priority">
<xs:restriction base="xs:integer"/>
</xs:simpleType>
<xs:complexType name="methods">
<xs:sequence>
<xs:element name="method" type="tns:method"
minOccurs="0" maxOccurs="unbounded"/>
</xs:sequence>
</xs:complexType>
<xs:complexType name="method">
<xs:simpleContent>
<xs:extension base="xs:string">
<xs:attribute name="negated" type="xs:boolean"/>
</xs:extension>
</xs:simpleContent>
</xs:complexType>
<xs:complexType name="extensions">
<xs:sequence>
<xs:element name="extension" type="tns:extension"
minOccurs="0" maxOccurs="unbounded"/>
</xs:sequence>
</xs:complexType>
<xs:complexType name="extension">
<xs:simpleContent>
<xs:extension base="xs:string">
<xs:attribute name="negated" type="xs:boolean"/>
</xs:extension>
</xs:simpleContent>
</xs:complexType>
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<xs:complexType name="schemes">
<xs:sequence>
<xs:element name="scheme" type="tns:scheme"
minOccurs="0" maxOccurs="unbounded"/>
</xs:sequence>
</xs:complexType>
<xs:complexType name="scheme">
<xs:simpleContent>
<xs:extension base="xs:string">
<xs:attribute name="negated" type="xs:boolean"/>
</xs:extension>
</xs:simpleContent>
</xs:complexType>
<xs:simpleType name="actor">
<xs:restriction base="xs:string">
<xs:enumeration value="principal"/>
<xs:enumeration value="attendant"/>
<xs:enumeration value="msg-taker"/>
<xs:enumeration value="information"/>
</xs:restriction>
</xs:simpleType>
<xs:simpleType name="is-focus">
<xs:restriction base="xs:boolean"/>
</xs:simpleType>
<xs:complexType name="languages">
<xs:sequence>
<xs:element name="language" type="tns:language"
minOccurs="0" maxOccurs="unbounded"/>
</xs:sequence>
</xs:complexType>
<xs:complexType name="language">
<xs:simpleContent>
<xs:extension base="xs:string">
<xs:attribute name="negated" type="xs:boolean"/>
</xs:extension>
</xs:simpleContent>
</xs:complexType>
<!-- Extension tag definitions -->
<xs:complexType name="token">
<xs:simpleContent>
<xs:extension base="xs:string">
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<xs:attribute name="name" type="xs:string"
use="required"/>
<xs:attribute name="negated" type="xs:boolean"
default="false"/>
</xs:extension>
</xs:simpleContent>
</xs:complexType>
<xs:complexType name="string">
<xs:simpleContent>
<xs:extension base="xs:string">
<xs:attribute name="name" type="xs:string"
use="required"/>
<xs:attribute name="negated" type="xs:boolean"
default="false"/>
</xs:extension>
</xs:simpleContent>
</xs:complexType>
<xs:complexType name="boolean">
<xs:simpleContent>
<xs:extension base="xs:boolean">
<xs:attribute name="name" type="xs:string"
use="required"/>
</xs:extension>
</xs:simpleContent>
</xs:complexType>
<xs:complexType name="numeric">
<xs:simpleContent>
<xs:extension base="xs:integer">
<xs:attribute name="name" type="xs:string"
use="required"/>
<xs:attribute name="negated" type="xs:boolean"
default="false"/>
</xs:extension>
</xs:simpleContent>
</xs:complexType>
</xs:schema>
Figure 2
9. IANA Considerations
This memo calls for IANA to register a new XML namespace URN as
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defined in [15]
9.1 URN sub-namespace registration for
'urn:ietf:params:xml:ns:simple-prescaps-ext'
URI:
urn:ietf:params:xml:ns:simple-prescaps-ext
Description:
This is the XML namespace for XML elements defined by [[[RFCXXXX]]]
to describe communication means extension for CPIM-PIDF presence
document format in application/cpim-pidf+xml content type.
Registrant Contact:
IETF, SIMPLE working group, <simple@ietf.org>
Mikko Lonnfors, <mikko.lonnfors@nokia.com>
XML:
BEGIN
<?xml version="1.0"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML Basic 1.0//EN"
"http://www.w3.org/TR/xhtml-basic/xhtml-basic10.dtd">
<html xmlns="http://www.w3.org/1999/xhtml
<head>
<meta http-equiv="content-type"
content="text/html;charset=iso-8859-1"/>
<title>PIDF User Agent capability extension</title>
</head>
<body>
<h1>Namespace for PIDF User Agent capability extension</h1>
<h2>application/cpim-pidf+xml</h2>
<p>See <a href="[[[URL of published RFC]]]">RFCXXXX</a>.</p>
</body>
</html>
END
10. Security Considerations
All security considerations specified in CPIM [5] and in PIDF [4]
documents apply also to this document. For clarity some of the
security considerations are repeated here.
Because presence is very privacy-sensitive information, the transport
protocol for the presence information SHOULD have capabilities to
protect protocol messages from possible threats, such as
eavesdropping, corruption, tamper and replay attacks. The protocols
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SHOULD be able to use security mechanisms which are standardized or
being standardized in IETF. However, it depends on the actual
transport protocols which security mechanisms should be used, and it
is beyond the scope of this memo.
11. Acknowledgements
Authors of this document would like to thank following people for
their contributions and valuable comments: Paul Kyzivat, Jonathan
Rosenberg, Markus Isomaki, Eva Leppanen, and Hisham Khartabil.
Normative references
[1] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997.
[2] Day, M., Rosenberg, J. and H. Sugano, "A Model for Presence and
Instant Messaging", RFC 2778, February 2000.
[3] Day, M., Aggarwal, S., Mohr, G. and J. Vincent, "Instant
Messaging / Presence Protocol Requirements", RFC 2779, February
2000.
[4] Sugano, H., Fujimoto, S., Klyne, G., Bateman, A., Carr, W. and
J. Peterson, "Presence Information Data Format (PIDF)",
draft-ietf-impp-cpim-pidf-08 (work in progress), May 2003.
[5] Peterson, J., "Common Profile for Presence (CPP)",
draft-ietf-impp-pres-04 (work in progress), August 2003.
[6] Schulzrinne, H., Rosenberg, J. and P. Kyzivat, "Indicating User
Agent Capabilities in the Session Initiation Protocol (SIP)",
draft-ietf-sip-callee-caps-03 (work in progress), December 2003.
[7] Klyne, G., "MIME Content Types in Media Feature Expressions",
RFC 2913, September 2000.
[8] Hoffman, P., "Registration of Charset and Languages Media
Features Tags", RFC 2987, November 2000.
Informative references
[9] Schulzrinne, H., Rosenberg, J. and P. Kyzivat, "Caller
Preferences for the Session Initiation Protocol (SIP)",
draft-ietf-sip-callerprefs-10 (work in progress), October 2003.
[10] Peterson, J., "Common Profile for Instant Messaging (CPIM)",
draft-ietf-impp-im-04 (work in progress), August 2003.
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[11] 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.
[12] Roach, A., "Session Initiation Protocol (SIP)-Specific Event
Notification", RFC 3265, June 2002.
[13] Rosenberg, J., "Session Initiation Protocol (SIP) Extensions
for Presence", draft-ietf-simple-presence-10.txt (work in
progress), May 2002.
[14] Handley, M. and V. Jacobson, "SDP: Session Description
Protocol", RFC 2327, April 1998.
[15] Mealling, M., "The IETF XML Registry",
draft-mealling-iana-xmlns-registry-05 (work in progress), June
2002.
[16] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) part two: Media Types", RFC 2046, November
1996.
[17] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) part one:Format of Internet Message Bodies",
RFC 2045, November 1996.
[18] Alvestrand, H., "Tags for the Identification of Languages", RFC
1766, March 1995.
[19] Holtman, K., Mutz, A. and T. Hardie, "Media Feature Tag
Registration Procedure", RFC 2046, March 1999.
Authors' Addresses
Mikko Lonnfors
Nokia Research Center
Itamerenkatu 11-13 00180
Helsinki
Finland
Phone: +358 71 8008000
EMail: mikko.lonnfors@nokia.com
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Krisztian Kiss
Nokia
12278 Scripps Summit Drive
San Diego
US
Phone: +18582049141
EMail: krisztian.kiss@nokia.com
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HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
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