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+Network Working Group                                        M. Lonnfors
+Request for Comments: 5196                                       K. Kiss
+Category: Standards Track                                          Nokia
+                                                          September 2008
+
+
+  Session Initiation Protocol (SIP) User Agent Capability Extension to
+                Presence Information Data Format (PIDF)
+
+Status of This Memo
+
+   This document specifies an Internet standards track protocol for the
+   Internet community, and requests discussion and suggestions for
+   improvements.  Please refer to the current edition of the "Internet
+   Official Protocol Standards" (STD 1) for the standardization state
+   and status of this protocol.  Distribution of this memo is unlimited.
+
+Abstract
+
+   Presence Information Data Format (PIDF) defines a common presence
+   data format for Common Profile for Presence (CPP) compliant presence
+   protocols.  This memo defines a PIDF extension to represent SIP User
+   Agent capabilities.
+
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+Lonnfors & Kiss             Standards Track                     [Page 1]
+
+RFC 5196         User Agent Capability Presence Status    September 2008
+
+
+Table of Contents
+
+   1. Introduction ....................................................3
+      1.1. Motivation .................................................3
+      1.2. Scope ......................................................4
+   2. Conventions .....................................................4
+   3. Extension for "Indicating User Agent Capabilities in the
+      Session Initiation Protocol (SIP)" in PIDF Documents ............4
+      3.1. Overview of Operation ......................................4
+      3.2. Service capabilities .......................................5
+           3.2.1. <servcaps> Element ..................................5
+           3.2.2. <audio> Element .....................................5
+           3.2.3. <application> Element ...............................5
+           3.2.4. <data> Element ......................................6
+           3.2.5. <control> Element ...................................6
+           3.2.6. <video> Element .....................................6
+           3.2.7. <text> Element ......................................6
+           3.2.8. <message> Element ...................................7
+           3.2.9. <type> Element ......................................7
+           3.2.10. <automata> Element .................................7
+           3.2.11. <class> Element ....................................7
+           3.2.12. <duplex> Element ...................................8
+           3.2.13. <description> Element ..............................8
+           3.2.14. <event-packages> Element ...........................9
+           3.2.15. <priority> Element .................................9
+           3.2.16. <methods> Element .................................10
+           3.2.17. <extensions> Element ..............................11
+           3.2.18. <schemes> Element .................................11
+           3.2.19. <actor> Element ...................................12
+           3.2.20. <isfocus> Element .................................12
+           3.2.21. <languages> Element ...............................13
+      3.3. Device Capabilities .......................................13
+           3.3.1. <devcaps> Element ..................................13
+           3.3.2. <mobility> Element .................................14
+           3.3.3. <description> Element ..............................14
+   4. Usage Guidelines ...............................................15
+      4.1. Use of <supported> and <notsupported> Elements ............15
+   5. Examples .......................................................16
+   6. XML Schema Definitions .........................................17
+   7. IANA Considerations ............................................26
+      7.1. URN Sub-Namespace Registration for ........................26
+      7.2. Schema Registration for Schema ............................27
+   8. Security Considerations ........................................27
+   9. Acknowledgments ................................................27
+   10. References ....................................................27
+      10.1. Normative References .....................................27
+      10.2. Informative References ...................................28
+
+
+
+
+Lonnfors & Kiss             Standards Track                     [Page 2]
+
+RFC 5196         User Agent Capability Presence Status    September 2008
+
+
+1.  Introduction
+
+   Common Profile for Presence (CPP) [RFC3859] and Common Profile for
+   Instant Messaging (CPIM) [RFC3860] define common operations and
+   formats that all presence and instant messaging services must agree
+   upon so that basic interoperability is possible.  The actual base
+   format for the presence is defined in the Presence Information
+   Document Format (PIDF) [RFC3863].  The PIDF has been designed to
+   reduce the need for gatewaying and to allow end-to-end security of
+   presence information.  It has taken a very minimalistic approach to
+   support such operations.  In order to make the PIDF usable by
+   different presence applications, these applications usually must
+   extend the basic PIDF by standard XML mechanisms as defined in PIDF
+   [RFC3863].
+
+   The aim of this memo is to introduce a SIP-specific extension
+   mechanism to the PIDF that conveys the same SIP media feature tags as
+   described in [RFC3840].  With this extension, presence applications
+   based on SIP can have richer and more usable presence information
+   compared to the baseline PIDF.
+
+1.1.  Motivation
+
+   The PIDF [RFC3863] defines a <contact> element that may appear once
+   inside every <tuple> element.  The content of the <contact> element
+   encodes the CONTACT ADDRESS and CONTACT MEANS as defined in
+   [RFC2778].  The <contact> element is defined to be a URI of any
+   scheme.  In some implementations, the URI scheme can uniquely
+   identify the service the tuple intends to describe (e.g., im: URI
+   scheme usually represents Instant Messaging service).  However, this
+   may not be the case in all implementations.  For example in SIP, a
+   SIP URI scheme can represent different kinds of services.  A SIP URI
+   scheme can be used to contact voice services, video services, or
+   messaging services.  If it is not known by other means, it might be
+   hard for applications processing the presence information containing
+   only a SIP URI contact addresses to know what particular service the
+   tuple intends to describe.  Also, watchers receiving presence
+   information would probably benefit from getting more descriptive
+   information about what particular communication means or services are
+   supported by the presentity.
+
+   The User Agent Capabilities extension [RFC3840] defines a set of
+   extensions that allow user agents to express preferences about
+   request handling in SIP servers.  The same information can provide
+   value to watchers as well so that they can make more rational
+   decisions on how a presentity should be contacted if a presence
+   document contained this information.
+
+
+
+
+Lonnfors & Kiss             Standards Track                     [Page 3]
+
+RFC 5196         User Agent Capability Presence Status    September 2008
+
+
+1.2.  Scope
+
+   This document defines a PIDF extension, which enables SIP presence
+   implementations to represent User Agent Capabilities [RFC3840] within
+   presence information.
+
+   This extension does not replace media negotiation mechanisms defined
+   for SIP (e.g., SDP [RFC4566]).  The purpose of this extension is for
+   a presentity to give watchers hints about the presentity's
+   preferences, willingness, and capabilities to communicate before
+   watchers initiate communication with the presentity.
+
+2.  Conventions
+
+   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
+   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
+   document are to be interpreted as described in [RFC2119].
+
+   This memo makes use of the vocabulary defined in [RFC2778] and
+   [RFC3863].
+
+3.  Extension for "Indicating User Agent Capabilities in the Session
+    Initiation Protocol (SIP)" in PIDF Documents
+
+   This section presents the extension elements, attributes, their
+   values, and semantics.  This section also describes how this
+   extension can be further extended.
+
+   This extension is intended to be used within the PIDF [RFC3863] and
+   that particular usage is described here.  This extension may also be
+   used with other XML documents if appropriate.
+
+3.1.  Overview of Operation
+
+   This document defines how the features presented in [RFC3840] can be
+   provided as part of presence information.  Additionally, this memo
+   includes the "type" feature tag [RFC2913], "message" media type
+   feature tag [RFC4569], and the "language" feature tag [RFC4646]
+   definitions.  Adding these features to the PIDF means mapping them to
+   an XML formatted structure.
+
+   The presence data model [RFC4479] defines presence information
+   consisting of three types of data elements: person, service, and
+   device.  This memo follows this model so that one XML extension is
+   defined to describe device capabilities and another one to describe
+   service capabilities.
+
+
+
+
+
+Lonnfors & Kiss             Standards Track                     [Page 4]
+
+RFC 5196         User Agent Capability Presence Status    September 2008
+
+
+   The namespace URIs for elements defined by this document are URNs
+   using the namespace identifier 'ietf' defined by [RFC2648] and
+   extended by [RFC3688].
+
+   When these extension namespaces are congregated with the PIDF
+   document, the combined document MUST follow the same general
+   formatting rules as specified in Section 4.1 of [RFC3863].
+
+3.2.  Service capabilities
+
+   Elements belonging to service capabilities are used to describe
+   dynamic characteristics of a service.  These capabilities are
+   enclosed within the <servcaps> element which SHOULD be located in the
+   PIDF document as a child element of urn:ietf:params:xml:ns:pidf
+   namespace <tuple> [RFC3863] element.
+
+   The namespace identifier for these elements is:
+
+   urn:ietf:params:xml:ns:pidf:caps
+
+3.2.1.  <servcaps> Element
+
+   The root element of service capabilities is <servcaps>.  The root
+   element always has to be present.  This element can contain the
+   following child elements: <audio>, <application>, <data>, <control>,
+   <video>, <text>, <message>, <type>, <automata>, <class>, <duplex>,
+   <description>, <event-packages>, <priority>, <methods>, <extensions>,
+   <schemes>, <actor>, <isfocus>, and <languages> followed by any number
+   of optional extension elements from other namespaces.
+
+   A <servcaps> element can contain any number of optional extension
+   attributes from other namespaces.
+
+3.2.2.  <audio> Element
+
+   The <audio> element indicates that the service supports audio as a
+   streaming media type as defined in [RFC3840].
+
+   The <audio> element is a boolean type and does not have any
+   attributes.  The value 'true' indicates that service supports audio
+   media type, and the value 'false' indicates that service does not
+   support audio media type.
+
+3.2.3.  <application> Element
+
+   The <application> element indicates that the service supports
+   application as a streaming media type as defined in [RFC3840].
+
+
+
+
+Lonnfors & Kiss             Standards Track                     [Page 5]
+
+RFC 5196         User Agent Capability Presence Status    September 2008
+
+
+   The <application> element is a boolean type and does not have any
+   attributes.  The value 'true' indicates that service supports
+   application media type, and the value 'false' indicates that service
+   does not support application media type.
+
+3.2.4.  <data> Element
+
+   The <data> element indicates that the service supports data as a
+   streaming media type as defined in [RFC3840].
+
+   The <data> element is a boolean type and does not have any
+   attributes.  The value 'true' indicates that service supports data
+   media type, and the value 'false' indicates that service does not
+   support data media type.
+
+3.2.5.  <control> Element
+
+   The <control> element indicates that the service supports control as
+   a streaming media type as defined in [RFC3840].
+
+   The <control> element is a boolean type and does not have any
+   attributes.  The value 'true' indicates that service supports control
+   media type, and the value 'false' indicates that service does not
+   support control media type.
+
+3.2.6.  <video> Element
+
+   The <video> element indicates that the service supports video as a
+   streaming media type as defined in [RFC3840].
+
+   The <video> element is a boolean type and does not have any
+   attributes.  The value 'true' indicates that service supports video
+   media type, and the value 'false' indicates that service does not
+   support video media type.
+
+3.2.7.  <text> Element
+
+   The <text> element indicates that the service supports text as a
+   streaming media type as defined in [RFC3840].
+
+   The <text> element is a boolean type and does not have any
+   attributes.  The value 'true' indicates that service supports text
+   media type, and the value 'false' indicates that service does not
+   support text media type.
+
+
+
+
+
+
+
+Lonnfors & Kiss             Standards Track                     [Page 6]
+
+RFC 5196         User Agent Capability Presence Status    September 2008
+
+
+3.2.8.  <message> Element
+
+   The <message> element indicates that the service supports messaging
+   as a streaming media type as defined in [RFC4569].
+
+   The <message> element is a boolean type and does not have any
+   attributes.  The value 'true' indicates that service supports message
+   media type, and the value 'false' indicates that service does not
+   support message media type.
+
+3.2.9.  <type> Element
+
+   The <type> element indicates a MIME media content type (i.e., that
+   appears in a 'Content-type:' header of the corresponding MIME-
+   formatted data) as defined in [RFC2913].
+
+   The <type> element is a 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 [RFC2045].  Only
+   lowercase letters SHOULD be used.
+
+3.2.10.  <automata> Element
+
+   The <automata> element indicates whether the service represents an
+   automaton (such as a voicemail server, conference server, or
+   recording device) or a human as defined in [RFC3840].
+
+   The <automata> element is a boolean type and does not have any
+   attributes.  The value 'true' indicates that the service represents
+   an automaton, and the value 'false' indicates that it represents a
+   human.
+
+3.2.11.  <class> Element
+
+   The <class> element indicates the setting, business or personal, in
+   which a communications service is used as defined in [RFC3840].
+
+   The <class> element can contain two elements: <supported> and
+   <notsupported>.  Classes that are supported by the service can be
+   listed under the <supported> element, and classes that are not
+   supported by the service can be listed under the <notsupported>
+   element.
+
+   <supported> and <notsupported> elements can contain <business> and
+   <personal> elements followed by any number of optional extension
+   elements from other namespaces.  The semantics of business and
+   personal are defined in [RFC3840] as:
+
+
+
+
+Lonnfors & Kiss             Standards Track                     [Page 7]
+
+RFC 5196         User Agent Capability Presence Status    September 2008
+
+
+   o  <business>: The service is used for business communications.
+
+   o  <personal>: The service is used for personal communications.
+
+   Any value that is registered with IANA for the SIP media feature tag
+   registration tree as a sip.class media feature tag can be used as a
+   value of an extension element.  If the appropriate value is not
+   registered, it SHOULD be registered as defined in [RFC3840].
+
+3.2.12.  <duplex> Element
+
+   The <duplex> element lists whether a communications service can
+   simultaneously send and receive media ("full"), alternate between
+   sending and receiving ("half"), only receive ("receive-only"), or
+   only send ("send-only") as defined in [RFC3840].
+
+   The <duplex> element can contain two elements: <supported> and
+   <notsupported>.  Duplex modes that are supported by the service can
+   be listed under the <supported> element, and duplex modes that are
+   not supported by the service can be listed under the <notsupported>
+   element.
+
+   <supported> and <notsupported> elements can contain <full>, <half>,
+   <receive-only>, and <send-only> elements followed by any number of
+   optional extension elements from other namespaces.  The semantics of
+   these elements are defined in [RFC3840] as:
+
+   o  <full>: The service can simultaneously send and receive media.
+
+   o  <half>: The service can alternate between sending and receiving
+      media.
+
+   o  <receive-only>: The service can only receive media.
+
+   o  <send-only>: The service can only send media.
+
+   Any value that is registered with IANA for the SIP media feature tag
+   registration tree as a sip.duplex media feature tag can be used as a
+   value of an extension element.  If the appropriate value is not
+   registered, it SHOULD be registered as defined in [RFC3840].
+
+3.2.13.  <description> Element
+
+   The <description> element provides a textual description of the
+   service as defined in [RFC3840].
+
+   The <description> element is of string type and does not have any
+   attributes.
+
+
+
+Lonnfors & Kiss             Standards Track                     [Page 8]
+
+RFC 5196         User Agent Capability Presence Status    September 2008
+
+
+   The <description> element SHOULD be labeled with the 'xml:lang'
+   attribute to indicate its language and script.  The specification
+   allows multiple occurrences of this elements so that the presentity
+   can convey <description> elements in multiple scripts and languages.
+   If no 'xml:lang' attribute is provided, the default value is
+   "i-default" as defined in [RFC2277].
+
+3.2.14.  <event-packages> Element
+
+   The <event-packages> element lists the event packages supported by a
+   service.
+
+   The <event-packages> element can contain two elements: <supported>
+   and <notsupported>.  Event packages that are supported by the service
+   can be listed under the <supported> element, and event packages that
+   are not supported by the service can be listed under the
+   <notsupported> element.
+
+   The <supported> and <notsupported> elements can contain any values
+   from the IANA SIP event types namespace registry followed by any
+   number of optional extension elements from other namespaces.  As of
+   this writing, the IANA SIP event types namespace registry includes
+   the following packages: <conference>, <dialog>, <kpml>,
+   <message-summary>, <poc-settings>, <presence>, <reg>, <refer>,
+   <Siemens-RTP-Stats>, <spirits-INDPs>, <spirits-user-prof>, and
+   <winfo>.
+
+3.2.15.  <priority> Element
+
+   The <priority> element indicates the call priorities the service is
+   willing to handle as defined in [RFC3840].
+
+   The <priority> element can contain two elements: <supported> and
+   <notsupported>.  Priority values that are supported by the service
+   can be listed under the <supported> element, and priority values that
+   are not supported by the service can be listed under the
+   <notsupported> element.
+
+   The <supported> and <notsupported> elements can contain any number of
+   <lowerthan>, <higherthan>, <equals>, and <range> elements followed by
+   any number of optional extension elements from other namespaces.
+
+3.2.15.1.  <lowerthan> Element
+
+   The <lowerthan> element has a single attribute called "maxvalue".
+   The "maxvalue" attribute is used to give the highest priority value
+   that the service is willing to support.  All values equal and below
+   that value are supported.
+
+
+
+Lonnfors & Kiss             Standards Track                     [Page 9]
+
+RFC 5196         User Agent Capability Presence Status    September 2008
+
+
+3.2.15.2.  <higherthan> Element
+
+   The <higherthan> element has a single attribute called "minvalue".
+   The "minvalue" attribute is used to give the lowest priority value
+   that the service is willing to support.  All values equal and above
+   that value are supported.
+
+3.2.15.3.  <equals> Element
+
+   The <equals> element is used to indicate the exact priority value
+   that the service is willing to handle.  The <equals> element has a
+   single attribute called "value".  The "value" attribute is used to
+   indicate the exact supported priority value.
+
+3.2.15.4.  <range> Element
+
+   The <range> element is used to indicate the priority range that the
+   service is willing to handle.  The <range> element has two attributes
+   called "minvalue" and "maxvalue".  The value of the "minvalue"
+   attribute indicates the lowest priority value supported by the
+   service, and the value of the "maxvalue" attribute indicates the
+   highest priority value supported by the service.
+
+3.2.16.  <methods> Element
+
+   The <methods> element indicates the SIP methods supported by a
+   service.  In this case, "supported" means that the service can
+   receive requests with this method.  In that sense, it has the same
+   connotation as the Allow header field as defined in [RFC3840].
+
+   The <methods> element can contain two elements: <supported> and
+   <notsupported>.  Methods that are supported by the service can be
+   listed under the <supported> element, and methods that are not
+   supported by the service can be listed under the <notsupported>
+   element.
+
+   The <supported> and <notsupported> elements can contain any values
+   from the methods table of the IANA SIP parameters registry table
+   followed by any number of optional extension elements from other
+   namespaces.  As of this writing, the IANA SIP parameters registry
+   includes the following methods:<ACK>, <BYE>, <CANCEL>, <INFO>,
+   <INVITE>, <MESSAGE>, <NOTIFY>, <OPTIONS>, <PRACK>, <PUBLISH>,
+   <REFER>, <REGISTER>, <SUBSCRIBE>, and <UPDATE>.
+
+
+
+
+
+
+
+
+Lonnfors & Kiss             Standards Track                    [Page 10]
+
+RFC 5196         User Agent Capability Presence Status    September 2008
+
+
+3.2.17.  <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 service.  Understood, in this context, means that the option
+   tag would be included in a Supported header field in a request as
+   defined in [RFC3840].
+
+   The <extensions> element can contain two elements: <supported> and
+   <notsupported>.  Extensions that are supported by the service can be
+   listed under the <supported> element, and extensions that are not
+   supported by the service can be listed under the <notsupported>
+   element.
+
+   The <supported> and <notsupported> elements can contain any values
+   from the option tags table of the IANA SIP parameters registry table
+   followed by any number of optional extension elements from other
+   namespaces.  As of this writing, the IANA SIP parameters registry
+   includes the following option tags: <rel100>, <early-session>,
+   <eventlist>, <from-change>, <gruu>, <histinfo>, <join>, <norefersub>,
+   <path>, <precondition>, <pref>, <privacy>, <recipient-list-invite>,
+   <recipient-list-subscribe>, <replaces>, <resource-priority>, <sdp-
+   anat>, <sec-agree>, <tdialog>, and <timer>.
+
+3.2.18.  <schemes> Element
+
+   The <schemes> element provides the set of URI schemes that are
+   supported by a service.  "Supported" implies, for example, that the
+   service would know how to handle a URI of that scheme in the Contact
+   header field of a redirect response as defined in [RFC3840].
+
+   The <schemes> element can contain two elements: <supported> and
+   <notsupported>.  Schemes that are supported by the service can be
+   listed under the <supported> element, and schemes that are not
+   supported by the service can be listed under the <notsupported>
+   element.
+
+   <supported> and <notsupported> elements can contain any number of <s>
+   elements, which can be used to describe individual schemes supported
+   by the service.
+
+3.2.18.1.  <s> Element
+
+   The <s> element is of string type and is used to describe an
+   individual scheme supported by the service.  Values that can be used
+   here are scheme names that are registered to the IANA URI scheme
+   registry.
+
+
+
+
+Lonnfors & Kiss             Standards Track                    [Page 11]
+
+RFC 5196         User Agent Capability Presence Status    September 2008
+
+
+3.2.19.  <actor> Element
+
+   The <actor> element indicates the type of entity that is available at
+   this URI as defined in [RFC3840].
+
+   The <actor> element can contain two elements: <supported> and
+   <notsupported>.  Actor types that are supported by the service can be
+   listed under the <supported> element, and actor types that are not
+   supported by the service can be listed under the <notsupported>
+   element.
+
+   The <supported> and <notsupported> elements can contain <principal>,
+   <attendant>, <msg-taker>, and <information> elements followed by any
+   number of optional extension elements from other namespaces.
+
+   The semantics of these elements are defined in [RFC3840] as:
+
+   o  <principal>: The service provides communication with the principal
+      that is associated with the service.  Often this will be a
+      specific human being, but it can be an automaton (for example,
+      when calling a voice portal).
+
+   o  <attendant>: The service provides communication with an automaton
+      or a person that will act as an intermediary in contacting the
+      principal associated with the service, or a substitute.
+
+   o  <msg-taker>: The service provides communication with an automaton
+      or a person that will take messages and deliver them to the
+      principal.
+
+   o  <information>: The service provides communication with an
+      automaton or a person that will provide information about the
+      principal.
+
+   Any value that is registered with IANA for the SIP media feature tag
+   registration tree as a sip.actor media feature tag can be used as a
+   value of an extension element.  If the appropriate value is not
+   registered, it SHOULD be registered as defined in [RFC3840].
+
+3.2.20.  <isfocus> Element
+
+   The <isfocus> element indicates that the service is a conference
+   server, also known as a focus as defined in [RFC3840].
+
+   The <isfocus> element is of boolean type and does not have any
+   attributes.  The value 'true' indicates that service is a conference
+   server and the value 'false' indicates that service does not support
+   conferencing.
+
+
+
+Lonnfors & Kiss             Standards Track                    [Page 12]
+
+RFC 5196         User Agent Capability Presence Status    September 2008
+
+
+3.2.21.  <languages> Element
+
+   The <languages> element indicates the ability to display particular
+   human languages as defined in [RFC4646].
+
+   The <languages> element can contain two elements: <supported> and
+   <notsupported>.  Languages that are supported by the service can be
+   listed under the <supported> element, and languages that are not
+   supported by the service can be listed under the <notsupported>
+   element.
+
+   <supported> and <notsupported> elements can contain any number of <l>
+   elements which can be used to describe individual languages supported
+   by the service.
+
+3.2.21.1.  <l> Element
+
+   The <l> element is of string type and is used to describe an
+   individual language supported by the service.  Values that can be
+   used here are language subtags that are registered to the IANA
+   language subtag registry as per [RFC4646].
+
+3.3.  Device Capabilities
+
+   Elements belonging to device capabilities are used to describe
+   dynamic characteristics of a device.  These capabilities are enclosed
+   within the <devcaps> element, which SHOULD be located in the PIDF
+   document as a child element of the
+   urn:ietf:params:xml:ns:pidf:data-model namespace <device> element
+   [RFC4479].
+
+   The namespace identifier for these elements is urn:
+
+   ietf:params:xml:ns:pidf:caps
+
+3.3.1.  <devcaps> Element
+
+   The root element of device capabilities is <devcaps>.  The root
+   element always has to be present.  This element can contain the
+   following child elements: <mobility> and <description> followed by
+   any number of optional extension elements from other namespaces.
+
+   A <devcaps> element can contain any number of optional extension
+   attributes from other namespaces.
+
+
+
+
+
+
+
+Lonnfors & Kiss             Standards Track                    [Page 13]
+
+RFC 5196         User Agent Capability Presence Status    September 2008
+
+
+3.3.2.  <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 of
+   contact).  Note that cordless phones are fixed, not mobile, based on
+   this definition as defined in [RFC3840].
+
+   The <mobility> element can contain two elements: <supported> and
+   <notsupported>.  Mobility modes that are supported by the device can
+   be listed under the <supported> element and mobility modes that are
+   not supported by the device can be listed under the <notsupported>
+   element.
+
+   The <supported> and <notsupported> elements can contain <fixed> and
+   <mobile> elements followed by any number of optional extension
+   elements from other namespaces.
+
+   The semantics of these elements are defined in [RFC3840] as:
+
+   o  <fixed>: The device is stationary.
+
+   o  <mobile>: The device can move around with the user.
+
+   Any value that is registered with IANA to the SIP media feature tag
+   registration tree as sip.mobility media feature tag can be used as a
+   value of an extension element.  If the appropriate value is not
+   registered, it SHOULD be registered as defined in [RFC3840].
+
+3.3.3.  <description> Element
+
+   The <description> element provides a textual description of the
+   device as defined in [RFC3840].
+
+   The <description> element is of string type and does not have any
+   attributes.
+
+   The <description> element SHOULD be labeled with the 'xml:lang'
+   attribute to indicate its language and script.  The specification
+   allows multiple occurrences of this element so that the presentity
+   can convey <description> elements in multiple scripts and languages.
+   If no 'xml:lang' attribute is provided, the default value is
+   "i-default" as defined in [RFC2277].
+
+
+
+
+
+
+
+
+Lonnfors & Kiss             Standards Track                    [Page 14]
+
+RFC 5196         User Agent Capability Presence Status    September 2008
+
+
+4.  Usage Guidelines
+
+   The User Agent Capabilities extension [RFC3840] recommends that a UA
+   provides complete information in its contact predicate.  However, it
+   may be that the presentity is not willing to publish presence
+   information that would be consistent with actual device or service
+   capabilities (e.g., presentity may not want to indicate that he/she
+   supports voice when the service actually is able to support it).
+   Authorization rules or policies in the presence server may limit or
+   modify the presence information published by the presentity.  Also,
+   combining presence information from multiple sources may result in
+   loss or mismatch of information.
+
+   It is RECOMMENDED that Presence User Agents (PUAs) using this
+   extension provide as complete presence information as they can.  If
+   the PUA is publishing sensitive information using this extension, it
+   SHOULD obtain permission from the presentity.  PUAs can indicate the
+   explicitly supported capabilities using the <supported> element, and
+   the capabilities that are explicitly not supported using the
+   <notsupported> element.
+
+   It is not mandated that presence information be consistent with
+   actual service or device capabilities.  However, it is in the
+   presentity's best interest to avoid publishing false presence
+   information and provide accurate information to help minimize
+   unsuccessful communication invitations.  Otherwise, watchers may
+   conclude that communication cannot be established with the
+   presentity, but in reality it would be possible; or watchers may
+   conclude that certain communication capabilities are available, but
+   in reality a communication establishment attempt would fail using
+   those capabilities.  In any case, watchers should not expect the
+   presence information represented by this extension to be fully
+   aligned with the actual presentity's service or device capabilities.
+   As explained in Section 1.2, presence of this extension does not
+   replace the use of SIP signaling for capability negotiation.
+
+4.1.  Use of <supported> and <notsupported> Elements
+
+   PUAs should add information under <supported> and <notsupported>
+   elements only when they believe it may affect the decision making in
+   the watcher's end, i.e., information should be relevant and valuable
+   for the watcher.  Listing all possible information under <supported>
+   and <notsupported> is rarely needed.
+
+   For example, if the PUA wants to advertise a message service that
+   supports the MESSAGE method, it should add it under the <supported>
+   element in the <methods> element.  Even if the service does not
+
+
+
+
+Lonnfors & Kiss             Standards Track                    [Page 15]
+
+RFC 5196         User Agent Capability Presence Status    September 2008
+
+
+   support other methods, it is unlikely that listing all the methods
+   not supported under the <notsupported> element would provide any
+   value to the watcher.
+
+   In case of conflicting information, i.e., the same child element
+   appears under the <supported> and <notsupported> elements with the
+   same value, the watcher can safely assume that the listed capability
+   is supported regardless of the inclusion of the capability under the
+   <notsupported> element.
+
+5.  Examples
+
+   <?xml version="1.0" encoding="UTF-8"?>
+   <presence xmlns="urn:ietf:params:xml:ns:pidf"
+         xmlns:caps="urn:ietf:params:xml:ns:pidf:caps"
+         xmlns:mod="urn:ietf:params:xml:ns:pidf:data-model"
+         entity="pres:someone@example.com">
+
+     <tuple id="joi9877866786ua9">
+       <status>
+         <basic>open</basic>
+       </status>
+       <caps:servcaps>
+         <caps:audio>true</caps:audio>
+         <caps:description xml:lang="en">
+            Example service
+         </caps:description>
+         <caps:description xml:lang="hu">
+            Pe'lda szolga'ltata's
+         </caps:description>
+         <caps:duplex>
+           <caps:supported>
+             <caps:full/>
+           </caps:supported>
+         </caps:duplex>
+         <caps:message>true</caps:message>
+         <caps:methods>
+           <caps:supported>
+             <caps:ACK/>
+             <caps:BYE/>
+             <caps:INVITE/>
+             <caps:MESSAGE/>
+           </caps:supported>
+         </caps:methods>
+         <caps:priority>
+           <caps:supported>
+             <caps:lowerthan maxvalue="10"/>
+           </caps:supported>
+
+
+
+Lonnfors & Kiss             Standards Track                    [Page 16]
+
+RFC 5196         User Agent Capability Presence Status    September 2008
+
+
+         </caps:priority>
+         <caps:schemes>
+           <caps:supported>
+             <caps:s>sip</caps:s>
+           </caps:supported>
+         </caps:schemes>
+         <caps:video>false</caps:video>
+       </caps:servcaps>
+       <contact>sip:someone@example.com</contact>
+     </tuple>
+     <mod:device id="hgt67">
+       <caps:devcaps>
+         <caps:mobility>
+           <caps:supported>
+             <caps:mobile/>
+           </caps:supported>
+         </caps:mobility>
+       </caps:devcaps>
+       <mod:deviceID
+        >urn:uuid:d27459b7-8213-4395-aa77-ed859a3e5b3a</mod:deviceID>
+     </mod:device>
+   </presence>
+
+6.  XML Schema Definitions
+
+   This section gives the XML schema definitions for the extensions
+   defined in this document.  The namespace identifier for this schema
+   is urn:ietf:params:xml:ns:pidf:caps.
+
+<?xml version="1.0" encoding="UTF-8"?>
+<xs:schema xmlns:tns="urn:ietf:params:xml:ns:pidf:caps"
+  xmlns:xs="http://www.w3.org/2001/XMLSchema"
+  targetNamespace="urn:ietf:params:xml:ns:pidf:caps"
+  elementFormDefault="qualified"
+  attributeFormDefault="unqualified">
+
+<!-- This import brings in the XML language
+     attribute xml:lang-->
+
+ <xs:import namespace="http://www.w3.org/XML/1998/namespace"
+  schemaLocation="http://www.w3.org/2001/xml.xsd"/>
+
+<!-- ROOT -->
+ <xs:element name="servcaps" type="tns:servcapstype"/>
+ <xs:complexType name="servcapstype">
+  <xs:sequence>
+   <xs:element name="actor" type="tns:actortype"
+    minOccurs="0"/>
+
+
+
+Lonnfors & Kiss             Standards Track                    [Page 17]
+
+RFC 5196         User Agent Capability Presence Status    September 2008
+
+
+   <xs:element name="application" type="tns:applicationtype"
+    minOccurs="0"/>
+   <xs:element name="audio" type="tns:audiotype" minOccurs="0"/>
+   <xs:element name="automata" type="tns:automatatype"
+    minOccurs="0"/>
+   <xs:element name="class" type="tns:classtype"
+    minOccurs="0"/>
+   <xs:element name="control" type="tns:controltype"
+    minOccurs="0"/>
+   <xs:element name="data" type="tns:datatype"
+    minOccurs="0"/>
+   <xs:element name="description" type="tns:descriptiontype"
+    minOccurs="0" maxOccurs="unbounded"/>
+   <xs:element name="duplex" type="tns:duplextype"
+    minOccurs="0"/>
+   <xs:element name="event-packages" type="tns:event-packagestype"
+    minOccurs="0"/>
+   <xs:element name="extensions" type="tns:extensionstype"
+    minOccurs="0"/>
+   <xs:element name="isfocus" type="tns:isfocustype"
+    minOccurs="0"/>
+   <xs:element name="message" type="tns:messagetype"
+    minOccurs="0"/>
+   <xs:element name="methods" type="tns:methodstype"
+    minOccurs="0"/>
+   <xs:element name="languages" type="tns:languagestype"
+    minOccurs="0"/>
+   <xs:element name="priority" type="tns:prioritytype"
+    minOccurs="0"/>
+   <xs:element name="schemes" type="tns:schemestype"
+    minOccurs="0"/>
+   <xs:element name="text" type="tns:texttype"
+    minOccurs="0"/>
+   <xs:element name="type" type="tns:typetype"
+    minOccurs="0" maxOccurs="unbounded"/>
+   <xs:element name="video" type="tns:videotype"
+    minOccurs="0"/>
+   <xs:any namespace="##other" processContents="lax"
+    minOccurs="0" maxOccurs="unbounded"/>
+  </xs:sequence>
+ <xs:anyAttribute namespace="##any" processContents="lax"/>
+ </xs:complexType>
+
+ <xs:element name="devcaps" type="tns:devcaps"/>
+ <xs:complexType name="devcaps">
+  <xs:sequence>
+   <xs:element name="description" type="tns:descriptiontype"
+    minOccurs="0" maxOccurs="unbounded"/>
+
+
+
+Lonnfors & Kiss             Standards Track                    [Page 18]
+
+RFC 5196         User Agent Capability Presence Status    September 2008
+
+
+   <xs:element name="mobility" type="tns:mobilitytype"
+    minOccurs="0"/>
+   <xs:any namespace="##other" processContents="lax"
+    minOccurs="0" maxOccurs="unbounded"/>
+  </xs:sequence>
+ <xs:anyAttribute namespace="##any" processContents="lax"/>
+ </xs:complexType>
+
+ <!-- AUDIO -->
+ <xs:simpleType name="audiotype">
+  <xs:restriction base="xs:boolean"/>
+ </xs:simpleType>
+
+ <!-- APPLICATION -->
+ <xs:simpleType name="applicationtype">
+  <xs:restriction base="xs:boolean"/>
+ </xs:simpleType>
+
+ <!-- DATA -->
+ <xs:simpleType name="datatype">
+  <xs:restriction base="xs:boolean"/>
+ </xs:simpleType>
+
+ <!-- CONTROL -->
+ <xs:simpleType name="controltype">
+  <xs:restriction base="xs:boolean"/>
+ </xs:simpleType>
+
+ <!-- VIDEO -->
+ <xs:simpleType name="videotype">
+  <xs:restriction base="xs:boolean"/>
+ </xs:simpleType>
+
+ <!-- TEXT -->
+ <xs:simpleType name="texttype">
+  <xs:restriction base="xs:boolean"/>
+ </xs:simpleType>
+
+ <!-- MESSAGE -->
+ <xs:simpleType name="messagetype">
+  <xs:restriction base="xs:boolean"/>
+ </xs:simpleType>
+
+ <!-- TYPE -->
+ <xs:simpleType name="typetype">
+  <xs:restriction base="xs:string"/>
+ </xs:simpleType>
+
+
+
+
+Lonnfors & Kiss             Standards Track                    [Page 19]
+
+RFC 5196         User Agent Capability Presence Status    September 2008
+
+
+ <!-- AUTOMATA -->
+ <xs:simpleType name="automatatype">
+  <xs:restriction base="xs:boolean"/>
+ </xs:simpleType>
+
+ <!-- CLASS -->
+ <xs:complexType name="classtype">
+  <xs:sequence>
+   <xs:element name="supported" type="tns:classtypes"
+    minOccurs="0"/>
+   <xs:element name="notsupported" type="tns:classtypes"
+    minOccurs="0"/>
+  </xs:sequence>
+ </xs:complexType>
+ <xs:complexType name="classtypes">
+  <xs:sequence>
+   <xs:element name="business" type="xs:string"
+    minOccurs="0"/>
+   <xs:element name="personal" type="xs:string"
+    minOccurs="0"/>
+   <xs:any namespace="##other" processContents="lax"
+    minOccurs="0"
+    maxOccurs="unbounded"/>
+  </xs:sequence>
+ </xs:complexType>
+
+ <!-- DUPLEX -->
+ <xs:complexType name="duplextype">
+  <xs:sequence>
+   <xs:element name="supported" type="tns:duplextypes"
+    minOccurs="0"/>
+   <xs:element name="notsupported" type="tns:duplextypes"
+    minOccurs="0"/>
+  </xs:sequence>
+ </xs:complexType>
+ <xs:complexType name="duplextypes">
+  <xs:sequence>
+   <xs:element name="full" type="xs:string"
+    minOccurs="0"/>
+   <xs:element name="half" type="xs:string"
+    minOccurs="0"/>
+   <xs:element name="receive-only" type="xs:string"
+    minOccurs="0"/>
+   <xs:element name="send-only" type="xs:string"
+    minOccurs="0"/>
+   <xs:any namespace="##other" processContents="lax"
+    minOccurs="0" maxOccurs="unbounded"/>
+  </xs:sequence>
+
+
+
+Lonnfors & Kiss             Standards Track                    [Page 20]
+
+RFC 5196         User Agent Capability Presence Status    September 2008
+
+
+ </xs:complexType>
+
+ <!-- DESCRIPTION -->
+ <xs:complexType name="descriptiontype">
+  <xs:simpleContent>
+   <xs:extension base="xs:string">
+    <xs:attribute ref="xml:lang"/>
+   </xs:extension>
+  </xs:simpleContent>
+ </xs:complexType>
+
+ <!-- EVENT-PACKAGES -->
+ <xs:complexType name="event-packagestype">
+  <xs:sequence>
+   <xs:element name="supported" type="tns:eventtypes"
+    minOccurs="0"/>
+   <xs:element name="notsupported" type="tns:eventtypes"
+    minOccurs="0"/>
+  </xs:sequence>
+ </xs:complexType>
+ <xs:complexType name="eventtypes">
+  <xs:sequence>
+   <xs:element name="conference" type="xs:string"
+    minOccurs="0"/>
+   <xs:element name="dialog" type="xs:string"
+    minOccurs="0"/>
+   <xs:element name="kpml" type="xs:string"
+    minOccurs="0"/>
+   <xs:element name="message-summary" type="xs:string"
+    minOccurs="0"/>
+   <xs:element name="poc-settings" type="xs:string"
+    minOccurs="0"/>
+   <xs:element name="presence" type="xs:string"
+    minOccurs="0"/>
+   <xs:element name="reg" type="xs:string"
+    minOccurs="0"/>
+   <xs:element name="refer" type="xs:string"
+    minOccurs="0"/>
+   <xs:element name="Siemens-RTP-Stats"
+    type="xs:string" minOccurs="0"/>
+   <xs:element name="spirits-INDPs"
+    type="xs:string" minOccurs="0"/>
+   <xs:element name="spirits-user-prof"
+    type="xs:string" minOccurs="0"/>
+   <xs:element name="winfo" type="xs:string"
+    minOccurs="0"/>
+   <xs:any namespace="##other" processContents="lax"
+    minOccurs="0" maxOccurs="unbounded"/>
+
+
+
+Lonnfors & Kiss             Standards Track                    [Page 21]
+
+RFC 5196         User Agent Capability Presence Status    September 2008
+
+
+  </xs:sequence>
+ </xs:complexType>
+
+ <!-- PRIORITY -->
+ <xs:complexType name="prioritytype">
+  <xs:sequence>
+   <xs:element name="supported" type="tns:prioritytypes"
+    minOccurs="0"/>
+   <xs:element name="notsupported" type="tns:prioritytypes"
+    minOccurs="0"/>
+  </xs:sequence>
+ </xs:complexType>
+ <xs:complexType name="prioritytypes">
+  <xs:sequence>
+   <xs:element name="equals" type="tns:equalstype"
+    minOccurs="0" maxOccurs="unbounded"/>
+   <xs:element name="higherhan" type="tns:higherthantype"
+    minOccurs="0" maxOccurs="unbounded"/>
+   <xs:element name="lowerthan" type="tns:lowerthantype"
+    minOccurs="0" maxOccurs="unbounded"/>
+   <xs:element name="range" type="tns:rangetype"
+    minOccurs="0" maxOccurs="unbounded"/>
+   <xs:any namespace="##other" processContents="lax"
+    minOccurs="0" maxOccurs="unbounded"/>
+  </xs:sequence>
+ </xs:complexType>
+ <xs:complexType name="lowerthantype">
+  <xs:attribute name="maxvalue" type="xs:integer"
+   use="required"/>
+ </xs:complexType>
+ <xs:complexType name="higherthantype">
+  <xs:attribute name="minvalue" type="xs:integer"
+   use="required"/>
+ </xs:complexType>
+ <xs:complexType name="equalstype">
+  <xs:attribute name="value" type="xs:integer"
+   use="required"/>
+ </xs:complexType>
+ <xs:complexType name="rangetype">
+  <xs:attribute name="minvalue" type="xs:integer"
+   use="required"/>
+  <xs:attribute name="maxvalue" type="xs:integer"
+   use="required"/>
+ </xs:complexType>
+
+ <!-- METHODS -->
+ <xs:complexType name="methodstype">
+  <xs:sequence>
+
+
+
+Lonnfors & Kiss             Standards Track                    [Page 22]
+
+RFC 5196         User Agent Capability Presence Status    September 2008
+
+
+   <xs:element name="supported" type="tns:methodtypes"
+    minOccurs="0"/>
+   <xs:element name="notsupported" type="tns:methodtypes"
+    minOccurs="0"/>
+  </xs:sequence>
+ </xs:complexType>
+ <xs:complexType name="methodtypes">
+  <xs:sequence>
+   <xs:element name="ACK" type="xs:string" minOccurs="0"/>
+   <xs:element name="BYE" type="xs:string" minOccurs="0"/>
+   <xs:element name="CANCEL" type="xs:string" minOccurs="0"/>
+   <xs:element name="INFO" type="xs:string" minOccurs="0"/>
+   <xs:element name="INVITE" type="xs:string" minOccurs="0"/>
+   <xs:element name="MESSAGE" type="xs:string" minOccurs="0"/>
+   <xs:element name="NOTIFY" type="xs:string" minOccurs="0"/>
+   <xs:element name="OPTIONS" type="xs:string" minOccurs="0"/>
+   <xs:element name="PRACK" type="xs:string" minOccurs="0"/>
+   <xs:element name="PUBLISH" type="xs:string" minOccurs="0"/>
+   <xs:element name="REFER" type="xs:string" minOccurs="0"/>
+   <xs:element name="REGISTER" type="xs:string" minOccurs="0"/>
+   <xs:element name="SUBSCRIBE" type="xs:string" minOccurs="0"/>
+   <xs:element name="UPDATE" type="xs:string" minOccurs="0"/>
+   <xs:any namespace="##other" processContents="lax" minOccurs="0"
+    maxOccurs="unbounded"/>
+  </xs:sequence>
+ </xs:complexType>
+
+ <!-- EXTENSIONS -->
+ <xs:complexType name="extensionstype">
+  <xs:sequence>
+   <xs:element name="supported" type="tns:extensiontypes"
+    minOccurs="0"/>
+   <xs:element name="notsupported" type="tns:extensiontypes"
+    minOccurs="0"/>
+  </xs:sequence>
+ </xs:complexType>
+ <xs:complexType name="extensiontypes">
+  <xs:sequence>
+   <xs:element name="rel100" type="xs:string" minOccurs="0"/>
+   <xs:element name="early-session" type="xs:string" minOccurs="0"/>
+   <xs:element name="eventlist" type="xs:string" minOccurs="0"/>
+   <xs:element name="from-change" type="xs:string" minOccurs="0"/>
+   <xs:element name="gruu" type="xs:string" minOccurs="0"/>
+   <xs:element name="hist-info" type="xs:string" minOccurs="0"/>
+   <xs:element name="join" type="xs:string" minOccurs="0"/>
+   <xs:element name="norefersub" type="xs:string" minOccurs="0"/>
+   <xs:element name="path" type="xs:string" minOccurs="0"/>
+   <xs:element name="precondition" type="xs:string" minOccurs="0"/>
+
+
+
+Lonnfors & Kiss             Standards Track                    [Page 23]
+
+RFC 5196         User Agent Capability Presence Status    September 2008
+
+
+   <xs:element name="pref" type="xs:string" minOccurs="0"/>
+   <xs:element name="privacy" type="xs:string" minOccurs="0"/>
+   <xs:element name="recipient-list-invite" type="xs:string"
+    minOccurs="0"/>
+   <xs:element name="recipient-list-subscribe" type="xs:string"
+    minOccurs="0"/>
+   <xs:element name="replaces" type="xs:string" minOccurs="0"/>
+   <xs:element name="resource-priority" type="xs:string" minOccurs="0"/>
+   <xs:element name="sdp-anat" type="xs:string" minOccurs="0"/>
+   <xs:element name="sec-agree" type="xs:string" minOccurs="0"/>
+   <xs:element name="tdialog" type="xs:string" minOccurs="0"/>
+   <xs:element name="timer" type="xs:string" minOccurs="0"/>
+   <xs:any namespace="##other" processContents="lax"
+    minOccurs="0" maxOccurs="unbounded"/>
+  </xs:sequence>
+ </xs:complexType>
+
+ <!-- SCHEMES -->
+ <xs:complexType name="schemestype">
+  <xs:sequence>
+   <xs:element name="supported" minOccurs="0">
+    <xs:complexType>
+     <xs:sequence>
+      <xs:element name="s" type="xs:string" maxOccurs="unbounded"/>
+     </xs:sequence>
+    </xs:complexType>
+   </xs:element>
+   <xs:element name="notsupported" minOccurs="0">
+    <xs:complexType>
+     <xs:sequence>
+      <xs:element name="s" type="xs:string" maxOccurs="unbounded"/>
+     </xs:sequence>
+    </xs:complexType>
+   </xs:element>
+  </xs:sequence>
+ </xs:complexType>
+
+ <!-- ACTOR -->
+ <xs:complexType name="actortype">
+  <xs:sequence>
+   <xs:element name="supported" type="tns:actortypes"
+    minOccurs="0"/>
+   <xs:element name="notsupported" type="tns:actortypes"
+    minOccurs="0"/>
+  </xs:sequence>
+ </xs:complexType>
+ <xs:complexType name="actortypes">
+  <xs:sequence>
+
+
+
+Lonnfors & Kiss             Standards Track                    [Page 24]
+
+RFC 5196         User Agent Capability Presence Status    September 2008
+
+
+   <xs:element name="attendant" type="xs:string" minOccurs="0"/>
+   <xs:element name="information" type="xs:string" minOccurs="0"/>
+   <xs:element name="msg-taker" type="xs:string" minOccurs="0"/>
+   <xs:element name="principal" type="xs:string" minOccurs="0"/>
+   <xs:any namespace="##other" processContents="lax" minOccurs="0"
+    maxOccurs="unbounded"/>
+  </xs:sequence>
+ </xs:complexType>
+
+ <!-- ISFOCUS -->
+ <xs:simpleType name="isfocustype">
+  <xs:restriction base="xs:boolean"/>
+ </xs:simpleType>
+
+ <!-- LANGUAGES -->
+ <xs:complexType name="languagestype">
+  <xs:sequence>
+   <xs:element name="supported" minOccurs="0">
+    <xs:complexType>
+     <xs:sequence>
+      <xs:element name="l" type="xs:string" maxOccurs="unbounded"/>
+     </xs:sequence>
+    </xs:complexType>
+   </xs:element>
+   <xs:element name="notsupported" minOccurs="0">
+    <xs:complexType>
+     <xs:sequence>
+      <xs:element name="l" type="xs:string" maxOccurs="unbounded"/>
+     </xs:sequence>
+    </xs:complexType>
+   </xs:element>
+  </xs:sequence>
+ </xs:complexType>
+
+ <!-- MOBILITY -->
+ <xs:complexType name="mobilitytype">
+  <xs:sequence>
+   <xs:element name="supported" type="tns:mobilitytypes"
+    minOccurs="0"/>
+   <xs:element name="notsupported" type="tns:mobilitytypes"
+    minOccurs="0"/>
+  </xs:sequence>
+ </xs:complexType>
+ <xs:complexType name="mobilitytypes">
+  <xs:sequence>
+   <xs:element name="fixed" type="xs:string"
+    minOccurs="0"/>
+   <xs:element name="mobile" type="xs:string"
+
+
+
+Lonnfors & Kiss             Standards Track                    [Page 25]
+
+RFC 5196         User Agent Capability Presence Status    September 2008
+
+
+    minOccurs="0"/>
+   <xs:any namespace="##other" processContents="lax" minOccurs="0"
+    maxOccurs="unbounded"/>
+  </xs:sequence>
+ </xs:complexType>
+</xs:schema>
+
+7.  IANA Considerations
+
+   IANA has registered one new XML namespace URN and one schema as
+   defined in [RFC3688].
+
+7.1.  URN Sub-Namespace Registration for
+      'urn:ietf:params:xml:ns:pidf:caps'
+
+   URI:
+   urn:ietf:params:xml:ns:pidf:caps
+
+   Description:
+   This is the XML namespace for XML elements defined by RFC 5196 to
+   describe service and device capabilities in application/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>Namespace for PIDF user agent capability
+               extension</title>
+   </head>
+   <body>
+       <h1>Namespace for PIDF service capability extension</h1>
+       <h2>urn:ietf:params:xml:ns:pidf:caps</h2>
+       <p>
+         See <a href="http://www.rfc-editor.org/rfc/rfc5196.txt">RFC
+         5196</a>.
+       </p>
+    </body>
+
+
+
+Lonnfors & Kiss             Standards Track                    [Page 26]
+
+RFC 5196         User Agent Capability Presence Status    September 2008
+
+
+    </html>
+   END
+
+7.2.  Schema Registration for Schema
+      'urn:ietf:params:xml:schema:pidf:caps'
+
+   URI:
+   urn:ietf:params:xml:schema:pidf:caps
+
+   Registrant Contact:
+   IESG
+
+   XML:
+   See Section 6
+
+8.  Security Considerations
+
+   All security considerations specified in [RFC3859] and [RFC3863]
+   apply to this document.  Compared to PIDF [RFC3863], this presence
+   document format may reveal additional information about user's
+   service and device capabilities.  Thus, the PUA SHOULD always obtain
+   permission from the presentity when publishing sensitive information
+   using this extension.
+
+9.  Acknowledgments
+
+   Authors of this document would like to thank the following people for
+   their contributions and valuable comments: Paul Kyzivat, Jonathan
+   Rosenberg, Markus Isomaki, Eva Leppanen, Miguel Garcia, Jari
+   Urpalainen, and Hisham Khartabil.
+
+10.  References
+
+10.1.  Normative References
+
+   [RFC2045]  Freed, N. and N. Borenstein, "Multipurpose Internet Mail
+              Extensions (MIME) part one: Format of Internet Message
+              Bodies", RFC 2045, November 1996.
+
+   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
+              Requirement Levels", BCP 14, RFC 2119, March 1997.
+
+   [RFC2277]  Alvestrand, H., "IETF Policy on Character Sets and
+              Languages", BCP 18, RFC 2277, January 1998.
+
+   [RFC2913]  Klyne, G., "MIME Content Types in Media Feature
+              Expressions", RFC 2913, September 2000.
+
+
+
+
+Lonnfors & Kiss             Standards Track                    [Page 27]
+
+RFC 5196         User Agent Capability Presence Status    September 2008
+
+
+   [RFC3688]  Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
+              January 2004.
+
+   [RFC3840]  Schulzrinne, H., Rosenberg, J., and P. Kyzivat,
+              "Indicating User Agent Capabilities in the Session
+              Initiation Protocol (SIP)", RFC 3840, August 2004.
+
+   [RFC3859]  Peterson, J., "Common Profile for Presence (CPP)",
+              RFC 3859, August 2004.
+
+   [RFC3863]  Sugano, H., Fujimoto, S., Klyne, G., Bateman, A., Carr,
+              W., and J. Peterson, "Presence Information Data Format
+              (PIDF)", RFC 3863, August 2004.
+
+   [RFC4479]  Rosenberg, J., "A Data Model for Presence", RFC 4479,
+              July 2006.
+
+   [RFC4646]  Phillips, A. and M. Davis, "Tags for Identifying
+              Languages", BCP 47, RFC 4646, September 2006.
+
+10.2.  Informative References
+
+   [RFC2648]  Moats, R., "A URN namespace for IETF documents", RFC 2648,
+              August 1999.
+
+   [RFC2778]  Day, M., Rosenberg, J., and H. Sugano, "A Model for
+              Presence and Instant Messaging", RFC 2778, February 2000.
+
+   [RFC3860]  Peterson, J., "Common Profile for Instant Messaging
+              (CPIM)", RFC 3860, August 2004.
+
+   [RFC4566]  Handley, M., Jacobson, V., and C. Perkins, "SDP: Session
+              Description Protocol", RFC 4566, July 2006.
+
+   [RFC4569]  Camarillo, G., "Internet Assigned Numbers Authority (IANA)
+              Registration of the Message Media Feature Tag", RFC 4569,
+              July 2006.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Lonnfors & Kiss             Standards Track                    [Page 28]
+
+RFC 5196         User Agent Capability Presence Status    September 2008
+
+
+Authors' Addresses
+
+   Mikko Lonnfors
+   Nokia
+   P.O. Box 321
+   Helsinki
+   Finland
+
+   Phone: +358 71 8008000
+   EMail: mikko.lonnfors@nokia.com
+
+
+   Krisztian Kiss
+   Nokia
+   313 Fairchild Dr
+   Mountain View, CA 94043
+   US
+
+   Phone: +1 650 391 5969
+   EMail: krisztian.kiss@nokia.com
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Lonnfors & Kiss             Standards Track                    [Page 29]
+
+RFC 5196         User Agent Capability Presence Status    September 2008
+
+
+Full Copyright Statement
+
+   Copyright (C) The IETF Trust (2008).
+
+   This document is subject to the rights, licenses and restrictions
+   contained in BCP 78, and except as set forth therein, the authors
+   retain all their rights.
+
+   This document and the information contained herein are provided on an
+   "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
+   OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND
+   THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS
+   OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF
+   THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
+   WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
+
+Intellectual Property
+
+   The IETF takes no position regarding the validity or scope of any
+   Intellectual Property Rights or other rights that might be claimed to
+   pertain to the implementation or use of the technology described in
+   this document or the extent to which any license under such rights
+   might or might not be available; nor does it represent that it has
+   made any independent effort to identify any such rights.  Information
+   on the procedures with respect to rights in RFC documents can be
+   found in BCP 78 and BCP 79.
+
+   Copies of IPR disclosures made to the IETF Secretariat and any
+   assurances of licenses to be made available, or the result of an
+   attempt made to obtain a general license or permission for the use of
+   such proprietary rights by implementers or users of this
+   specification can be obtained from the IETF on-line IPR repository at
+   http://www.ietf.org/ipr.
+
+   The IETF invites any interested party to bring to its attention any
+   copyrights, patents or patent applications, or other proprietary
+   rights that may cover technology that may be required to implement
+   this standard.  Please address the information to the IETF at
+   ietf-ipr@ietf.org.
+
+
+
+
+
+
+
+
+
+
+
+
+Lonnfors & Kiss             Standards Track                    [Page 30]
+