SIMPLE WG M. Lonnfors Internet-Draft K. Kiss Intended status: Standards Track Nokia Expires: November 15, 2008 May 14, 2008 Session Initiation Protocol (SIP) User Agent Capability Extension to Presence Information Data Format (PIDF) draft-ietf-simple-prescaps-ext-10 Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on November 15, 2008. Abstract Presence Information Data Format (PIDF) defines a common presence data format for Common Profile for Presence (CPP) compliant Presence protocols. This memo defines an extension to represent SIP User Agent capabilities in the Presence Information Document Format (PIDF) compliant presence documents. Lonnfors & Kiss Expires November 15, 2008 [Page 1]
Internet-Draft User Agent Capability Presence Status May 2008 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. Overview of operation . . . . . . . . . . . . . . . . . . 5 3.2. Service capabilities . . . . . . . . . . . . . . . . . . . 6 3.2.1. <servcaps> element . . . . . . . . . . . . . . . . . . 6 3.2.2. <audio> element . . . . . . . . . . . . . . . . . . . 6 3.2.3. <application> element . . . . . . . . . . . . . . . . 6 3.2.4. <data> element . . . . . . . . . . . . . . . . . . . . 7 3.2.5. <control> element . . . . . . . . . . . . . . . . . . 7 3.2.6. <video> element . . . . . . . . . . . . . . . . . . . 7 3.2.7. <text> element . . . . . . . . . . . . . . . . . . . . 7 3.2.8. <message> element . . . . . . . . . . . . . . . . . . 8 3.2.9. <type> element . . . . . . . . . . . . . . . . . . . . 8 3.2.10. <automata> element . . . . . . . . . . . . . . . . . . 8 3.2.11. <class> element . . . . . . . . . . . . . . . . . . . 8 3.2.12. <duplex> element . . . . . . . . . . . . . . . . . . . 9 3.2.13. <description> element . . . . . . . . . . . . . . . . 9 3.2.14. <event-packages> element . . . . . . . . . . . . . . . 10 3.2.15. <priority> element . . . . . . . . . . . . . . . . . . 10 3.2.16. <methods> element . . . . . . . . . . . . . . . . . . 11 3.2.17. <extensions> element . . . . . . . . . . . . . . . . . 11 3.2.18. <schemes> element . . . . . . . . . . . . . . . . . . 12 3.2.19. <actor> element . . . . . . . . . . . . . . . . . . . 12 3.2.20. <isfocus> element . . . . . . . . . . . . . . . . . . 13 3.2.21. <languages> element . . . . . . . . . . . . . . . . . 13 3.3. Device capabilities . . . . . . . . . . . . . . . . . . . 14 3.3.1. <devcaps> element . . . . . . . . . . . . . . . . . . 14 3.3.2. <mobility> element . . . . . . . . . . . . . . . . . . 14 3.3.3. <description> element . . . . . . . . . . . . . . . . 15 4. Usage guidelines . . . . . . . . . . . . . . . . . . . . . . . 15 4.1. Use of <supported> and <notsupported> elements . . . . . . 16 5. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 6. XML schema definitions . . . . . . . . . . . . . . . . . . . . 18 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 26 7.1. URN sub-namespace registration for 'urn:ietf:params:xml:ns:pidf:caps' . . . . . . . . . . . . 26 8. Security Considerations . . . . . . . . . . . . . . . . . . . 27 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 27 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 28 10.1. Normative references . . . . . . . . . . . . . . . . . . . 28 10.2. Informative references . . . . . . . . . . . . . . . . . . 28 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 29 Lonnfors & Kiss Expires November 15, 2008 [Page 2]
Internet-Draft User Agent Capability Presence Status May 2008 Intellectual Property and Copyright Statements . . . . . . . . . . 30 Lonnfors & Kiss Expires November 15, 2008 [Page 3]
Internet-Draft User Agent Capability Presence Status May 2008 1. Introduction Common Profile for Presence (CPP) [RFC3859] and Common Profile for Instant Messaging (CPIM) [RFC3860] define common operations and formats which all presence and instant messaging services must agree upon so that basic interoperability would be 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 data. 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 data compared to the baseline PIDF. 1.1. Motivation The PIDF [RFC3863] 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 [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 document 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 for 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 which allow user agents to express preferences about request handling in SIP servers. The same information can provide value also to presence watchers so that they can make more rational decisions on how a presentity should be contacted if a presence document contained similar information. Lonnfors & Kiss Expires November 15, 2008 [Page 4]
Internet-Draft User Agent Capability Presence Status May 2008 1.2. Scope This document defines PIDF extensions which enable SIP presence implementations to utilize User Agent Capabilities [RFC3840] within presence documents. This extension does not replace media negotiation mechanisms defined for SIP (e.g. SDP [RFC4566]). This extension is only aimed for presentities to give watchers hints about the presentity's preferences, willingness and capabilities to communicate before watchers initiate a 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 in [RFC3863]. 3. Extension for "Indicating User Agent Capabilities in the Session Initiation Protocol (SIP)" in PIDF documents This section presents all extension documents, their elements, their values, and semantics. This section also describes how this extension can be further extended. This extension is intended to be used within a 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 a part of presence data. Additionally, this memo includes the "type" feature tag [RFC2913], "message" media type feature tag [RFC4569] and the "language" feature tag [RFC4646] definitions. Bringing these features in the PIDF means mapping them to an XML formatted structure. The presence data model [RFC4479] defines presence data consisting of three types of data elements: person, service, and device. This memo follows this model so that one XML document is defined to describe device capabilities and another one to describe service capabilities. Lonnfors & Kiss Expires November 15, 2008 [Page 5]
Internet-Draft User Agent Capability Presence Status May 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 PIDF document as a child element of urn:ietf:params:xml:ns:pidf namespace <tuple> [RFC3863] element. 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 has to be always present. This element can contain following elements: <audio>, <application>, <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 Expires November 15, 2008 [Page 6]
Internet-Draft User Agent Capability Presence Status May 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 Expires November 15, 2008 [Page 7]
Internet-Draft User Agent Capability Presence Status May 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 lower-case 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 <supported> element and classes that are not supported by the service can be listed under <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 Expires November 15, 2008 [Page 8]
Internet-Draft User Agent Capability Presence Status May 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 <supported> element and duplex modes that are not supported by the service can be listed under <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.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]. 3.2.13. <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 Expires November 15, 2008 [Page 9]
Internet-Draft User Agent Capability Presence Status May 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 <supported> element and event packages that are not supported by the service can be listed under <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 today 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 <supported> element and priority values that are not supported by the service can be listed under <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 Expires November 15, 2008 [Page 10]
Internet-Draft User Agent Capability Presence Status May 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 "min" and "max". Value of the "min" attribute indicates lowest priority value supported by the service and the value of the "max" 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 <supported> element and methods that are not supported by the service can be listed under <notsupported> element. The <supported> and <notsupported> elements can contain <ACK>, <BYE>, <CANCEL>, <INFO>, <INVITE>, <MESSAGE>, <NOTIFY>, <OPTIONS>, <PRACK>, <PUBLISH>, <REFER>, <REGISTER>, <SUBSCRIBE>, and <UPDATE> elements followed by any number of optional extension elements from other namespaces. Any value that is registered with IANA for the SIP methods namespace registry can be used as a value of an extension element. 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 Lonnfors & Kiss Expires November 15, 2008 [Page 11]
Internet-Draft User Agent Capability Presence Status May 2008 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 <supported> element and extensions that are not supported by the service can be listed under <notsupported> element. The <supported> and <notsupported> elements can contain any values from the IANA SIP parameters registry option tags table followed by any number of optional extension elements from other namespaces. As of today the IANA SIP parameters registry includes the following option tags: <rel100>, <early-session>, <eventlist>, <from-change>, <gruu>, <histinfo>, <join>, <norefersub>, <path>, <precondition>, <pref>, <privacy>, <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 <supported> element and schemes that are not supported by the service can be listed under <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 it is used to describe individual scheme supported by the service. Values that can be used here are scheme names that are registered to IANA URI scheme registry. 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 Lonnfors & Kiss Expires November 15, 2008 [Page 12]
Internet-Draft User Agent Capability Presence Status May 2008 listed under <supported> element and actor types that are not supported by the service can be listed under <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 automata (for example, when calling a voice portal). o <attendant>: The service provides communication with an automata or 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 automata or person that will take messages and deliver them to the principal. o <information>: The service provides communication with an automata or 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.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]. 3.2.20. <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. 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 <supported> element and languages that are not supported Lonnfors & Kiss Expires November 15, 2008 [Page 13]
Internet-Draft User Agent Capability Presence Status May 2008 by the service can be listed under <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 it is used to describe individual language supported by the service. Values that can be used here are language names that are registered to IANA 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 urn:ietf:params:xml:ns:pidf:data-model namespace <device> element [RFC4479]. 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 has to be always present. This element can contain following 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. 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 <supported> element and all mobility modes that are not supported by the device can be listed under <notsupported> element. Lonnfors & Kiss Expires November 15, 2008 [Page 14]
Internet-Draft User Agent Capability Presence Status May 2008 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 register to IANA to 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 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]. 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 presentity is not willing to publish presence information which 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 presence server may limit or modify the published presence information in a way that all published presence information may not end up to all possible watchers. Also combining presence document from multiple sources may result in lose 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 Lonnfors & Kiss Expires November 15, 2008 [Page 15]
Internet-Draft User Agent Capability Presence Status May 2008 SHOULD obtain a permission from a user. PUAs can indicate all the explicitly supported capabilities using the <supported> element and all the explicitly not supported capabilities using the <notsupported> element, where appropriate. It is not mandated that presence information should be consistent with actual service or device capabilities. However, it is the presentity's best interest to avoid publishing false presence information and provide accurate information to help to minimize unsuccessful communication invitations. Otherwise, watchers may conclude that communication cannot be established with the presentity but in reality it would be possible, or 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 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 MESSAGE method it should add it under <supported> in <methods> element. Even if the service does not support other methods it is unlikely that listing all the not supported methods under <notsupported> would provide any value to the watcher. In case of conflicting information, i.e. same child element appears under <supported> and <notsupported> elements with 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"> Lonnfors & Kiss Expires November 15, 2008 [Page 16]
Internet-Draft User Agent Capability Presence Status May 2008 <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:supported> </caps:methods> <caps:priority> <caps:supported> <caps:lowerthan maxvalue="10"/> </caps:supported> </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 Lonnfors & Kiss Expires November 15, 2008 [Page 17]
Internet-Draft User Agent Capability Presence Status May 2008 >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. 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"/> <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" Lonnfors & Kiss Expires November 15, 2008 [Page 18]
Internet-Draft User Agent Capability Presence Status May 2008 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"/> <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> Lonnfors & Kiss Expires November 15, 2008 [Page 19]
Internet-Draft User Agent Capability Presence Status May 2008 <!-- 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> <!-- 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"/> Lonnfors & Kiss Expires November 15, 2008 [Page 20]
Internet-Draft User Agent Capability Presence Status May 2008 <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> </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"/> Lonnfors & Kiss Expires November 15, 2008 [Page 21]
Internet-Draft User Agent Capability Presence Status May 2008 </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"/> </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"/> Lonnfors & Kiss Expires November 15, 2008 [Page 22]
Internet-Draft User Agent Capability Presence Status May 2008 <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> <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"/> Lonnfors & Kiss Expires November 15, 2008 [Page 23]
Internet-Draft User Agent Capability Presence Status May 2008 <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"/> <xs:element name="pref" type="xs:string" minOccurs="0"/> <xs:element name="privacy" 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> Lonnfors & Kiss Expires November 15, 2008 [Page 24]
Internet-Draft User Agent Capability Presence Status May 2008 <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> <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> Lonnfors & Kiss Expires November 15, 2008 [Page 25]
Internet-Draft User Agent Capability Presence Status May 2008 </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" minOccurs="0"/> <xs:any namespace="##other" processContents="lax" minOccurs="0" maxOccurs="unbounded"/> </xs:sequence> </xs:complexType> </xs:schema> Figure 1 7. IANA Considerations This memo calls for IANA to register one new XML namespace URNs 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: Lonnfors & Kiss Expires November 15, 2008 [Page 26]
Internet-Draft User Agent Capability Presence Status May 2008 This is the XML namespace for XML elements defined by [[[RFCXXXX]]] 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="[[[URL of published RFC]]]">RFCXXXX</a>.</p> </body> </html> END 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 user when publishing sensitive information using this extension. 9. Acknowledgments Authors of this document would like to thank following people for their contributions and valuable comments: Paul Kyzivat, Jonathan Rosenberg, Markus Isomaki, Eva Leppanen, Miguel Garcia, Jari Urpalainen, and Hisham Khartabil. Lonnfors & Kiss Expires November 15, 2008 [Page 27]
Internet-Draft User Agent Capability Presence Status May 2008 10. References 10.1. Normative references [RFC3859] Peterson, J., "Common Profile for Presence (CPP)", RFC 3859, August 2004. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3863] Sugano, H., Fujimoto, S., Klyne, G., Bateman, A., Carr, W., and J. Peterson, "Presence Information Data Format (PIDF)", RFC 3863, August 2004. [RFC3840] Schulzrinne, H., Rosenberg, J., and P. Kyzivat, "Indicating User Agent Capabilities in the Session Initiation Protocol (SIP)", RFC 3840, August 2004. [RFC2913] Klyne, G., "MIME Content Types in Media Feature Expressions", RFC 2913, September 2000. [RFC4646] Phillips, A. and M. Davis, "Tags for Identifying Languages", RFC 4646, September 2006. [RFC3688] Mealling, M., "The IETF XML Registry", RFC 3688, BCP 81, January 2004. [RFC4479] Rosenberg, J., "A Data Model for Presence", RFC 4479, July 2006. [RFC2045] Freed, N. and N. Borenstein, "Multipurpose Internet Mail Extensions (MIME) part one: Format of Internet Message Bodies", RFC 2045, November 1996. [RFC2277] Alvestrand, H., "IETF Policy on Character Sets and Languages", RFC 2277, January 1998. 10.2. Informative references [RFC4569] Camarillo, G., "Internet Assigned Numbers Authority (IANA) Registration of the Message Media Feature Tag", RFC 4569, July 2006. [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. Lonnfors & Kiss Expires November 15, 2008 [Page 28]
Internet-Draft User Agent Capability Presence Status May 2008 [RFC2778] Day, M., Rosenberg, J., and H. Sugano, "A Model for Presence and Instant Messaging", RFC 2778, February 2000. [RFC2648] Moats, R., "A URN namespace for IETF documents", RFC 2648, Aug. 1999. 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 Expires November 15, 2008 [Page 29]
Internet-Draft User Agent Capability Presence Status May 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 Expires November 15, 2008 [Page 30]
