Internet Engineering Task Force Internet Draft H. Schulzrinne (ed.) Columbia U. draft-ietf-simple-rpids-01.txt June 29, 2003 Expires: December 2003 RPIDS -- Rich Presence Information Data Format for Presence Based on the Session Initiation Protocol (SIP) STATUS OF THIS MEMO This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. 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 To view the list Internet-Draft Shadow Directories, see http://www.ietf.org/shadow.html. Abstract The Rich Presence Information Data Format for the Session Initiation Protocol (SIP) (RPIDS) adds elements to the Presence Information Data Format (PIDF) that provide additional information about the presentity and its contacts. This information can be translated into call routing behavior or be delivered to watchers. The information is designed so that much of it can be derived automatically, e.g., from calendar files or user activity. H. Schulzrinne (ed.) [Page 1] Internet Draft RPIDS June 29, 2003 1 Introduction The PIDF definition [1] describes a basic presence information data format for exchanging presence information in CPIM-compliant systems. It consists of a root element, zero or more elements carrying presence information, zero or more elements and zero or more extension elements from other name spaces. Each tuple defines a basic status of either "open" or "closed". This document provides additional status information for presentities and defines a Rich Presence Information Data Format for Presence Based on the Session Initiation Protocol (SIP) (RPIDS) to convey this information. This extension has three main goals: 1. Provide rich presence indication that is at least as powerful as common commercial presence systems. Such feature-parity simplifies transition to CPIM-compliant systems, both in terms of user acceptance and protocol conversion. 2. Maintain backwards-compatibility with PIDF, so that PIDF- only watchers and gateways can continue to function properly, naturally without access to the functionality described here. We make no assumptions how the information in the RPIDS is generated. Experience has shown that users are not always diligent about updating their presence status. Thus, we want to make it as easy as possible to derive RPIDS information from other information sources, such as calendars, the status of communication devices such as telephones, typing activity and physical presence detectors as commonly found in energy-management systems. The information in a presence document can be generated by a single entity or can be composed from information published by multiple entities. Many of the elements correspond to data commonly found in personal calendars. Thus, we attempted to align some of the extensions with the usage found in calendar formats such as iCal [12] and xCal [13], as noted below. Note that PIDF documents and this extension can be used in two different contexts, namely by the presentity to publish its presence status and by the presence server to notify some set of watchers. The presence server MAY compose, translate or filter the published H. Schulzrinne (ed.) [Page 2] Internet Draft RPIDS June 29, 2003 presence state before delivering customized presence information to the watcher. For example, it may merge presence information from multiple PUAs, remove whole elements, translate values in elements or remove information from elements. Mechanisms that filter calls and other communications to the presentity can subscribe to this presence information just like a regular watcher and in turn generate automated rules, such as scripts [14], that govern the actual communications behavior of the presentity. The flow diagram below illustrates this process. presentity | --> publish | --> PA (filter) --> notification 1 to A, B, C --> notification 2 to D, E --> notification 3 to F --> notification 4 to script gen. 2 RPIDS Features Below, we summarize and motivate the major additional features that RPIDS adds to PIDF. The PIDF definition does not clearly describe what a represents. We add an attribute (Section 6.4) that allows a presentity to label tuples in ways that make sense to the presentity, e.g., to group similar tuples by name. While the PIDF definition describes which means of communications are available for a presentity, it does not describe the activity that the presentity is currently engaged in. The (Section 6.2) element adds this information. The (Section 6.7) element indicates when the device was last used or simply whether it has been idle. To help the watcher gauge the appropriateness of different types of communications, we indicate the type of place the user is currently in, via the element (Section 6.9) and hint at the privacy available via . PIDF defines a element indicating the date and time of H. Schulzrinne (ed.) [Page 3] Internet Draft RPIDS June 29, 2003 the status change of a tuple. RPIDS adds a validity period for status values, and , as a hint how long the current status is likely to be valid (Section 6.5 and Section 6.13). Information about a tuple can be conveyed using the , and elements. An important sub-case is that a presentity is interruptible only under unusual circumstances, after mediation by some, typically human, authority such as a secretary or supervisor. We allow the presentity to convey that certain contact addresses actually belong to a different person, presumably one that can either interrupt the presentity or otherwise assist. The (Section 6.11) element allows to indicate that a particular tuple refers to a different principal or presentity. The PIDF document format [1] defines a element which may appear once inside every element. The content of the element encodes the CONTACT ADDRESS and CONTACT MEANS as defined in [3]. The element is defined to be an URI. This URI can be of any URI scheme. Some URI schemes uniquely identify the application the tuple intends to describe (e.g., "im" URIs). However, this is not be the case for all schemes. For example, a SIP URI can represent different kinds of applications, including voice, video, or messaging. If it is not known by other means, it can be hard for applications processing the presence document containing only SIP URI contact addresses to know what particular application the tuple intends to describe. Also, watchers receiving presence information would benefit for getting more descriptive information about what particular communication means or applications are supported by the presentity. We generally assume that the presence element describes a single human being or a group of humans. However, this is not required. A presentity can also be a "bot" or "avatar", for example. Note that this document does not defined a new content type. Rather, it inherits the content type from [1], namely application/cpim- pidf+xml 3 Scope This extension does not replace media negotiation mechanisms defined for SIP (e.g. SDP [4]), therefore media negotiation (e.g., choice of voice and video codecs) MUST be performed according to [5]. This extension is only aimed to give the watchers hints about the presentity's preferences, willingness and capabilities to communicate before watchers initiate SIP-based communication with the presentity. H. Schulzrinne (ed.) [Page 4] Internet Draft RPIDS June 29, 2003 4 Terminology and Conventions This memo makes use of the vocabulary defined in the IMPP Model document [3]. Terms such as CLOSED, INSTANT MESSAGE, OPEN, PRESENCE SERVICE, PRESENTITY, WATCHER, and WATCHER USER AGENT in the memo are used in the same meaning as defined therein. The key words MUST, MUSTNOT, REQUIRED, SHOULD, SHOULDNOT, RECOMMENDED, MAY, and OPTIONAL in this document are to be interpreted as described in BCP XX, RFC 2119 [6]. 5 The Meaning of "open" and "closed" PIDF describes the basic status values of "open" or "closed" only as "have meanings of general availability for other communications means". We define "closed" in our context as meaning that communication to the contact address will in all likelihood not succeed, is undesired or will not reach the intended party. (For example, a presentity may include a hotel phone number as a contact. After check-out, the phone number will still ring, but reach the chambermaid or the next guest. Thus, it would be declared "closed".) For "pres" contacts, "closed" means that no presence status information is available. The interpretation of "closed" was chosen since there is no other status value to indicate that a communications address is not reachable. Omitting the element does not work since it would confuse watchers that have not previously seen an "open" status for the same contact address. 6 RPIDS Elements 6.1 Introduction Below, we describe the RPIDS elements in detail. , , , ,