3 Definitions, symbols and abbreviations

22.1413GPPPresence serviceStage 1TS

3.1 Definitions

Access rules: constraints on how the presence service makes presence information available to watchers. For each presentity’s presence information, the applicable access rules are managed by the principal that controls the presentity.

availability: a property of a presentity denoting its ability and willingness to communicate based on factors such as the identity or properties of the watcher and the preferences and/or policies that are associated with the presentity

fetcher: a form of watcher that has asked the presence service for the presence information of one or more presentities, but is not requesting a notification from the presence service of (future) changes in a presentity’s presence information.

identifier: a means of indicating a point of contact, intended for public use such as on a business card. Telephone numbers, email addresses, and typical home page URLs are all examples of identifier in other systems.

poller: a fetcher that requests presence information on a regular basis.

presence information: is a set of attributes characterising current properties of presentities such as status, an optional communication address and other optional attributes etc

presence service: the capability to support management of presence information between watchers and presentities, in order to enable applications and services to make use of presence information

presentity (presence entity): any uniquely identifiable entity that is capable of providing presence information to presence service. Examples of presentities are devices, services etc. Any presentity shall have one, and only one, principal associated with it.

principal: human, organisation, program, or collection of humans, organisations and/or programs that chooses to appear to the presence services as a single actor, distinct from all other principals. A principal is associated with one or more presentities and/or watchers. A principal is said to "own" a certain presentity or watcher if such an association exists. Within the context of this specification a subscriber may be a principal to one or more presentities and/or watchers. Examples: A subscriber may be a principal to the terminals (the presentities) he owns. A program, providing a stock exchange information service to customers, may be the principal to the market quotations (the presentities) it monitors.

Note: The case where a presentity is not a subscriber requires to be further considered

subscribed-watcher: a subscribed-watcher is a type of watcher, which requests notification from the presence service of changes in a presentity’s presence information, resulting in a watcher-subscription, as they occur in the future.

watcher-subscription: the information kept by the presence service about a subscribed-watcher’s request to be notified of changes in the presence information of one or more presentities

Note: This definition represents an entity’s request to obtain presence information, and is not related to the term "subscription" in [1]. Within this specification the term watcher-subscription (and its derivatives) purely refers to this relationship.

watcher: any uniquely identifiable entity that requests presence information about a presentity, or watcher information about a watcher, from the presence service. Special types of watcher are fetcher, poller, and subscribed-watcher. Any watcher shall have one, and only one, principal associated with it.

watcher information: information about watchers that have received or may receive presence information about a particular presentity within a particular recent span of time.

3.2 Abbreviations

For the purposes of this document the following abbreviations apply:

IETF Internet Engineering Task Force

LAN Local Area Network

VHE Virtual Home Environment