Patent Publication Number: US-6658095-B1

Title: Customized presence information delivery

Description:
FIELD OF THE INVENTION 
     The present invention relates to providing presence information, and in particular to customizing presence information delivery to provide multiple views of presence. 
     BACKGROUND OF THE INVENTION 
     Presence detection is a technology used to convey information about the availability of individuals. Individuals are often interested in the availability of others and, because they are often not co-located, they require mechanisms for conveying availability or status information. The devices that people interact with know bits and pieces about how available they are for communications or other forms of interaction with others at any instant. People who are on the phone are less available to most others for the duration of the call, but may want to be interrupted by selected callers. 
     The location of a person on a mobile phone is information that may be relevant for determining whether that person is available for a certain type of event. For example, someone traveling far away from home may not be available for physical interaction with their neighbors, but may be available to take a call. Similarly, someone near a particular restaurant at lunchtime is a potential consumer. 
     Presence related information is routinely generated in many devices connected to various networks. For example, a person using a Personal Computer (PC) attached to a network may generate various presence state information. An “On-line” state indicates a user has logged onto a network, such as the Internet or a corporate intranet, while an “Off-line” state indicates no connection is currently active between the user and the presence engine. “Idle” status implies the user&#39;s system, although logged on, has not been active recently. Similarly, a person who acknowledges a calendar event in a PC or personal digital assistant (PDA) essentially signals their limited availability to most others for some duration while at the same time indicates that the person is active on that device. This level of presence indication is useful, but it is sufficiently coarse to limit its utility. 
     Most presence systems rely on users to select presence indications through a menu on a PC or PDA or a button on a specific device. Keeping any presence indicator accurate to the actual availability status of the user potentially requires very frequent interaction by the user to supply status information. Such tedious human interaction potentially negates the effectiveness of presence-based communications systems. Some systems sense user interaction with a single device like a PC, which lessens the direct human input while decreasing overall accuracy, since using a mouse or keyboard certainly indicates the presence of the user at the device. However, it simultaneously indicates they are engaged in an activity with the device, the importance of which is unknown. The result is a convoluted view of availability. The user is certainly present to some degree, but may be busy and may not want to be disturbed. In these kinds of systems, the user still has to provide manual input to prevent being inappropriately represented and interrupted. 
     The reliability and usefulness of presence information depends on the type of information provided and the device from which the information is gathered. A person actively interacting with a computer indicates to some degree that she is available, but probably only to those on the same network. A PC or other network device inside a corporate network will have visibility, independently or through a corporate presence server, to many presence inputs related to many PCs or other devices on that network. Typically, however, a device inside a corporate firewall will be isolated from having access to presence data related to devices like mobile phones, that by their very nature interconnect through commercial service provider networks. 
     Even when reliable and useful presence information for a user is available, the basic concept of availability for communications is inherently dependent on who is wanting to communicate with the user. Likewise, the specifics of activities that the user is engaged in at any instant bear on the desirability to be contacted by various individuals. For example, when the user is on a conference call at work they may wish to be unavailable to their coworkers but available to their family members for urgent communications. Further, the user may wish to be accessible by select clients regardless of time, day, and location, wherein accessibility for other clients may be limited to normal working hours when the user is in the office. 
     Accordingly, there is a need for improving both the number and quality of inputs into a presence management system in order to more efficiently and effectively deliver presence information to users of the information. Further, there is a need for a presence management system capable of providing different views of availability for different audiences at any given time. 
     SUMMARY OF THE INVENTION 
     The present invention provides a presence system capable of monitoring state information derived from a plurality of sources over any number of disparate networks. The state information bears on the presence or availability of the user and may take many forms. Based on a profile provided by the user, the presence system evaluates the state information from one or more sources to create presence information to deliver to subscribers. The profile can define different categories of subscribers for which different presence information is provided. Based on available state information, the presence system can provide different views of presence for different subscribers to allow the user to control delivery and use of presence information. Accordingly, different subscribers may receive different presence information based on the same state information. Preferably, the presence information bears on the availability of the user and how to communicate with the user based on her availability. 
     Those skilled in the art will appreciate the scope of the present invention and realize additional aspects thereof after reading the following detailed description of the preferred embodiments in association with the accompanying drawing figures. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING FIGURES 
     The accompanying drawing figures incorporated in and forming a part of this specification illustrate several aspects of the invention, and together with the description serve to explain the principles of the invention. 
     FIG. 1 is a block representation of a communication environment constructed according to one embodiment of the present invention. 
     FIG. 2 is a logical representation of a presence system according to one embodiment of the present invention. 
     FIG. 3 is a flow diagram outlining a provisioning process according to one embodiment of the present invention. 
     FIG. 4 is a flow diagram outlining overall operation of a presence system according to one embodiment of the present invention. 
     FIG. 5 is a flow diagram outlining the processing of state information according to one embodiment of the present invention. 
     FIG. 6 is a communication flow outlining an exemplary process for automatically providing state information from a telephony system. 
     FIG. 7 is a block representation of a telephony switch constructed according to one embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The embodiments set forth below represent the necessary information to enable those skilled in the art to practice the invention and illustrate the best mode of practicing the invention. Upon reading the following description in light of the accompanying drawing figures, those skilled in the art will understand the concepts of the invention and will recognize applications of these concepts not particularly addressed herein. It should be understood that these concepts and applications fall within the scope of the disclosure and the accompanying claims. 
     The present invention provides a presence system capable of gathering state information provided by a user and derived from a plurality of sources associated with the user over any number of disparate networks. The sources of state information are devices used by a user throughout a normal day and configured to provide state information to the presence system. The sources may be able to monitor normal user interactions and automatically provide corresponding state information to the presence system without requiring the user to enter or otherwise provide information bearing on their status or availability. Additionally, the user may provide state information to the presence system directly or indirectly via an associated device. The presence system will evaluate the state information to create presence information to deliver to subscribers. The state information bears on the presence or availability of the user and may take many forms. The presence information may range from a complex analysis of state information from the user and associated devices to simply the states of selected devices or status provided by the user. 
     Based on a profile provided by the user, the presence system evaluates the state information to create the presence information to deliver to subscribers. The profile can define different categories of subscribers for which different presence information is provided. Based on available state information, the presence system can provide different views of presence for different subscribers to allow the user to control delivery and use of presence information. Accordingly, different subscribers may receive different presence information based on the same state information. Preferably, the presence information bears on the availability of the user and how to communicate with the user based on the user&#39;s availability. The following outlines numerous sources of state information along with the provisioning and operation of a presence system. 
     With reference to FIG. 1, a communication environment that is capable of automatically generating presence information based on state information provided by the user and/or derived from a plurality of sources is illustrated. The communication environment may include a circuit-switched network  10 , such as the public switched telephone network (PSTN) or a cellular communication network, and a packet-switched network  12 , such as the Internet, which supports packet-switched communications. The circuit-switched network  10  may include various types of switches  14  to facilitate circuit-switched communications for landline or wireless communications. The circuit-switched network  10  supports communications with various types of telephony devices  16 , such as a traditional landline telephone  16 A or a mobile telephone  16 B. In a wireless communication embodiment, the switches  14  cooperate with base stations (not shown), which facilitate wireless communications with mobile terminals, such as the mobile telephone  16 B. Those skilled in the art will recognize the functionality of the switches  14  and other components in the circuit-switched network  10  to facilitate circuit-switched communications with the landline and wireless telephony devices  16 . 
     The switch  14  is defined as being either an integrated device or multi-component system facilitating circuit-switched communication and including call server or call control functionality, which is traditionally provided in intelligent networks (IN), such as those implementing SS7 and the like. Typically, the switches  14  cooperate with a provisioning database  18 , which provides information allowing a switch  14  to properly identify, locate, and provision the various telephony devices  16  in the circuit-switched network  10 . 
     A presence system  20  capable of gathering state information provided by a user or derived from a plurality of sources, which are directly or indirectly associated with the user over any number of disparate networks, is located on the packet-switched network  12 . An exemplary source for indirectly providing state information is the switch  14 , which may be configured to provide the state of the user&#39;s telephony device  16 , its location, or a combination thereof, directly or indirectly to the presence system  20 . 
     The presence system  20  may be configured by a user device, such as a PC  22 , and operates to collect state information provided by users or various devices of the users, process the state information to derive presence information, and provide the presence information to presence applications  24 , automatically or in response to a request. Each presence application  24  is associated with a subscriber device (not shown), and provides alerts to the associated subscriber based on presence information associated with a user and derived from the presence system  20 . Preferably, the presence application  24  subscribes to the presence system  20  and identifies the users whose presence information is desired. The presence system  20  will accept these subscriptions as well as register participating users and their associated devices. The presence system  20  may also implement various presence delivery rules to allow users to control the dissemination of their presence information to subscribers. Notably, various profiles may be established to allow select groups of subscribers to obtain more presence information than other groups. In particular, the users may define multiple categories of subscribers, which will have different presence rules. The different presence rules are used by the presence system to provide different views of presence for a given user to the different subscribers, at any given time and based on given state information. One or more subscribers may be associated with a category. Accordingly, each registered user may implement filters or rules to control dissemination of their presence information based on the subscriber or group of subscribers. In the converse, subscribers receiving presence information of others may also establish profiles identifying the users whose presence information is desired and the types of presence information they wish to receive. 
     A registrar  26  may be provided on the packet-switched network  12  to maintain a relationship between the logical and the physical addresses of devices that directly or indirectly communicate with the presence system  20 . Such registration is typically required only when there is a change between the logical or user addresses and the physical addresses of a given device. 
     In one embodiment, the switch  14  is configured to provide state information corresponding to the status, mode, state, location, or a combination thereof associated with a telephony device  16  to the presence system  20 . In this embodiment, it is preferable to provide a proxy server  28  to act as a liaison between the switch  14  and the presence system  20 . As such, the switch  14  will provide presence information to the proxy server  28 , which will represent the switch  14  to the presence system  20  in traditional proxy fashion. Those skilled in the art will recognize that the proxy server  28  is optional and may prove beneficial with certain communication protocols. 
     The presence information provided to the presence system  20  from the switch  14  will depend on the application and the type of communication environment. For example, the traditional landline telephone  16 A will not change location, and will typically provide location information only as a part of registration, and dynamically provide a mechanism to determine state information relating to its operation. For example, the switch  14  that serves the telephone  16 A can determine whether the phone is on-hook or off-hook, and thus determine whether the user is engaged in a telephone call. More sophisticated systems may be able to determine whether the party is on a conference call, on hold, and whether any settings on the phone indicate that the user is in or out of the office. Accordingly, the state information gathered by the switch  14  in association with the operation of telephone  16 A is used to create presence information to send to the presence system  20  via the proxy server  28 . 
     For mobile terminals, such as the mobile telephone  16 B, the servicing mobility switching center (SMSC), which is represented by switch  14 , may gather all of the state information described above, as well as provide dynamic location information derived directly from the mobile terminal  16 B or from the circuit-switched network  10 . Accordingly, the state information for mobile devices may be supplemented with location information, which provides the presence system  20  the opportunity to distribute presence information to the various presence applications  24  based on dynamic location, if so desired. The location information may be provided by the mobile terminal  16 B, if equipped with location detection technology, such as that provided by the Global Positioning System (GPS), wherein the mobile terminal  16 B receives the GPS coordinates and may provide either the coordinates to the switch  14 , which will determine the mobile terminal&#39;s location, or may process the GPS information to determine a location, which is then sent to the switch  14 . Alternatively, triangulation techniques may be used to determine the mobile terminal&#39;s location, which may be stored in a location database  30  or like device. The location database  30  may be accessed via the switch  14  to obtain location information, or the location database  30  may be configured such that the presence system  20  or an associated device may directly access it via the packet-switched network  12 . 
     Packet-based telephony devices, such as the packet telephone system  32 , essentially emulate the operation of circuit-switched telephony devices  16  entirely over the packet-switched network  12 . Thus, state information associated with a fixed or mobile packet telephone system  32  may be configured to automatically provide state information, and perhaps location information, to the presence system  20  directly or indirectly via a proxy server  28 . The packet telephone system  32  will include a user interface  34  and a control system  36 . As those skilled in the art will recognize, the packet telephone system  32  may be integrated into a single device, or may be implemented in multiple devices in a client-server configuration. For the latter case, the proxy server  28  may be further configured to support various operational features of the packet telephone system  32 . 
     The user interface  34  may include a microphone and speaker to facilitate voice communications, as well as various keypads and displays to allow user interaction in traditional fashion. The control system  36  will operate to support the user interface  34  and provide the requisite functionality to enable the packet telephone system  32  to facilitate communications with other devices on the packet-switched network  12  directly or indirectly via the proxy server  28 . For the purposes of description, assume that the control system  36  is capable of gathering and providing state information for the packet telephone system  32 . In wireless environments, a wireless packet-switched network (not shown) is necessary to facilitate communications with the packet-switched network  12 . 
     In addition to the telephony-based updates, an unlimited number of devices or systems with which users directly or indirectly interact may be modified to automatically provide state information. The devices and systems may include cable or satellite television systems  38 , internet appliances  40 , wireless telemetry devices  42 , PCs  44 , biometric devices  46 , physical presence detections systems  48 , entertainment systems  50 , and the like. For example, set-top boxes or receivers of cable or satellite systems may be configured to provide state updates to a central location, which forwards the updates to the presence service  20  in association with the user. These devices are normally on disparate networks and configured to communicate various types of information, such as billing information, to a central location. Preferably, a server at the central location will facilitate delivery of state information to the presence system  20 . The server may be configured to monitor the respective devices to determine state changes, or may simply receive state changes generated by the devices. With the proliferation of broadband Internet connectivity, particularly in cable networks, devices of this type could also be directly attached to the packet switched network  12  and provide state updates directly to the presence system  20 . Similarly, internet appliances  40 , such as refrigerators, dishwashers, alarm systems and the like, can readily be configured to send state information relating to user interaction directly or indirectly to the presence system  20 . 
     Wireless telemetry devices  42  may monitor a user&#39;s interaction or location associated with a person or vehicle and provide state information to the presence system  20 . Similarly, biometric devices  46 , which monitor or check biometric data of the user, and physical presence detection systems  48 , which monitor physical presence, may provide state information to the presence system  20 . Entertainment systems  50 , such as home theater systems, gaming consoles, televisions, and the like can sense user activity and provide state updates to the presence system  20 . Any of the devices and systems may be connected directly or indirectly, via a gateway or the like, to the Internet. 
     The presence system  20  may be implemented in one or more systems. With reference to FIG. 2, a logical breakdown of one embodiment of the presence system is illustrated. The presence system  20  includes a control system  52  adapted to implement provisioning logic  54 , subscriber management logic  56 , rules management logic  58 , and device management logic  60 . The device management logic  60  facilitates and controls interaction with the various devices, which are configured to provide state information to the presence service  20  based on user interaction. The subscriber management logic  56  facilitates and controls interaction with the presence applications  24  associated with subscribers. 
     Accordingly, the presence applications  24  will subscribe to the presence service  20  to receive status updates for one or more users via the subscriber management logic  56 . Based on the subscription, the presence service  20  will receive state information from the various devices, evaluate the state information to generate presence information using rules in the rules management logic  58 , and deliver the presence information to the subscribing presence application  24 . The device management logic  60  will control interaction with the various devices providing state information. Such control may include configuring the device to provide the state information in a specified manner and format. The provisioning logic  54  facilitates provisioning of the subscriber management logic  56 , rules management logic  58 , and device management logic  60 . Provisioning may include establishing a profile for the user providing presence information. The profile will typically identify devices and their respective states to monitor, provide rules for evaluating the state information to generate the presence information, and identify individuals, systems, or applications authorized to receive the information. Preferably, categories are defined having different rules for evaluating the state information to provide different views of presence to different subscribers on an individual or group basis. The control system  52  is also associated with a network interface  62  for facilitating communications over the packet-switched network  12 . 
     An exemplary process for initializing the presence system  20  to disseminate user information is outlined in FIG.  3 . Initially, the user must establish an identification for the presence system  20  (step  100 ). The presence system  20  will then receive a profile for the user (step  102 ). Based on the profile, the presence system  20  is provisioned to receive state information from the devices (sources) (step  104 ). Preferably, the device management logic  60  is configured to receive the state information from the provisioned devices. To configure the devices, users may have to interact directly with the devices themselves, or some server or switch that they are attached to, in order to configure the devices to start sending status information to a certain entity associated with the presence system  20  or directly to the presence system  20 . An exemplary model may be for the devices to essentially subscribe to supply information on behalf of a user, who will authorize the devices to provide the status information. Next, the rules for evaluating the state information are established for each presence category (step  106 ). As noted, the categories may be created for a single subscriber via the user&#39;s associated presence application  24  or for a group of subscribers. At this point, the rules management logic  58  and device management logic  60  are configured for a given user. 
     The rules typically define how to evaluate the state information and deliver the resultant presence information for each presence category. For each presence category, a user may establish rules to control how they should be contacted based on the state of one or more associated devices. For example, the following hierarchy may be implemented for a first presence category: 
     if the user&#39;s office PC is in use and the office telephone is on-hook, send presence information indicating the user is available in the office and directing subscribing presence applications to contact the user for voice conversations using the office telephone; 
     if the user&#39;s office PC is in use and the office telephone is off-hook, send presence information indicating the user is in the office but unavailable for voice conversations and directing subscribing presence applications to contact the user via instant message or office email; 
     if the user&#39;s mobile telephone is on and in a meeting mode, send presence information indicating the user is in a meeting and not readily available and directing subscribing applications to contact the user via a pager if urgent, otherwise via email; 
     if the user&#39;s office PC is off and the user&#39;s mobile telephone is on and not engaged in a call, send presence information indicating the user is out of the office but available if necessary and directing subscribing applications to contact the user via the mobile telephone; 
     if the user is driving a vehicle (telemetry), send presence information indicating the user is in transit and directing subscribing applications to contact the user via the mobile telephone; and 
     if the user is interacting with an internet appliance or home entertainment system, send presence information indicating the user is at home and directing subscribing applications to contact the user via the user&#39;s home telephone. 
     For a second presence category, the following hierarchy may be implemented: 
     if the users&#39;s office PC is in use, send presence information indicating the user is available in the office and directing subscribing presence applications to contact the user for voice conversations using the office telephone; and 
     if the user&#39;s office PC is not in use, send presence information indicating the user is out of the office but will periodically check email. 
     For a third presence category, the following hierarchy may be implemented: 
     if the user is driving a vehicle (telemetry), send presence information indicating the user is in transient and directing subscribing applications to contact the user via the mobile telephone; 
     if the user is interacting with an internet appliance or home entertainment system, send presence information indicating the user is at home and directing subscribing applications to contact the user via the user&#39;s home telephone; and 
     otherwise, send presence information to contact the user at work via telephone or email. 
     Alternatively, the presence information may simply estimate the user&#39;s availability, and potentially location, rather than providing the level of granularity illustrated above, and allow the subscriber to choose how to process the information and contact the user, if desired. 
     Those skilled in the art will recognize limitless variations in profile and rule constructions for evaluating state information for the presence categories of subscribers and generating presence information to send to subscribing presence applications. Further, any combination of current and past device state information may be used to determine the presence information. Preferably, the presence information is automatically updated for each presence category, if necessary, when state changes are detected. Depending on the presence rules, a state change from a given device may or may not impact the presence information. If the presence information does not change, then there may not be a need to update the subscribing presence applications  24 . 
     FIG. 4 provides an exemplary process for subscribing to presence updates for a user through the presence system  20 . Initially, a subscriber, via their presence application  24 , will send a request to subscribe to the presence system  20 . The subscription management logic  56  of the presence system  20  will receive the request for presence information from the presence application  24  (step  200 ). The presence service  20  will authorize the request (step  202 ), and, if authorized, provide initial presence information for the given presence category to the subscribing presence application  24  (step  204 ). The initial presence information may be default presence information or that based on current states of the devices as evaluated by the rules. Once subscribed, the presence system  20  will provide presence information to the presence application  24  as state information from the devices changes in a manner warranting a presence update (step  206 ). 
     FIG. 5 illustrates an exemplary process for evaluating state information from the provisioned devices. The process continuously receives state information from all provisioned devices (step  300 ) and applies the rules for each presence category based on the user profile (step  302 ). Notably, the presence application  24  or subscriber associated therewith can also provide a profile to configure or otherwise filter the types of presence information requested. Finally, the rules management logic  58  will evaluate the state changes and create presence information for each presence category, if necessary, to send to the subscribing presence applications  24  (step  304 ). 
     Accordingly, the present invention gathers state information and evaluates the state information by a rules-based presence system  20  that takes into account relatively static preferences supplied directly by the user wishing to project an indication of presence along with optional positional data associated with the devices. The evaluation of the state information may differ based on the presence category to allow the user to provide unique views of presence to different subscribers or groups of subscribers via the corresponding presence applications  24 . Those skilled in the art will recognize that manually provided state information may be used by the rules logic management  58  in combination with those initiated from naturally occurring interactions. 
     Although many communication protocols may be used to facilitate communications, including delivery of state and presence information between the various devices, the Session Initiation Protocol (SIP) or the SIP for Instant Messaging and Presence Leveraging Extensions (SIMPLE) protocol is implemented in one embodiment of the present invention. The specification for SIP is provided in the Internet Engineering Task Force&#39;s RFC 2543: Session Initiation Protocol Internet Draft, which is incorporated herein by reference in its entirety. 
     In general, a SIP proxy, such as may be provided by the proxy server  28 , may facilitate media sessions between any number of endpoints, which represent the devices communicating with each other. These endpoints may support any one or combination of data, audio, and voice media sessions, depending on the configuration of the respective endpoints. In addition to traditional SIP endpoints, endpoints for the present invention may take the form of the switch  14 , the registrar  26 , the presence system  20 , the device running the presence application  24 , and the like. 
     A SIP endpoint is generally capable of running an application, which is generally referred to as a user agent (UA), and is capable of facilitating media sessions using SIP. User agents register their ability to establish sessions with a SIP proxy, such as proxy server  28 , by sending “REGISTER” messages to the SIP proxy. The REGISTER message informs the SIP proxy of the SIP universal resource locator (URL) that identifies the user agent to the SIP network. The REGISTER message also contains information about how to reach specific user agents over the SIP network, by providing the Internet Protocol (IP) address and port that the user agent will use for SIP sessions. 
     A “SUBSCRIBE” message may be used to subscribe to an application or service provided by a SIP endpoint. Further, “NOTIFY” messages may be used to provide information between SIP endpoints in response to various actions or messages, including REGISTER and SUBSCRIBE messages. 
     When a user agent wants to establish a session with another user agent, the user agent initiating the session will send an INVITE message to the SIP proxy and specify the targeted user agent in the TO header of the INVITE message. Identification of the user agent takes the form of a SIP URL. In its simplest form, the URL is represented by a number or “&lt;username&gt;@&lt;domain&gt;,” such as “janedoe@nortelnetworks.com.” The SIP proxy will use the SIP URL in the TO header of the message to determine if the targeted user agent is registered with the SIP proxy. Generally, the user name is unique within the name space of the specified domain. 
     If the targeted user agent has registered with the SIP proxy, the SIP proxy will forward the INVITE message directly to the targeted user agent. The targeted user agent will respond with a 200 OK message, and a session between the respective user agents will be established as per the message exchange required in the SIP specification. Media capabilities are passed between the two user agents of the respective endpoints as parameters embedded within the session setup messages, such as the INVITE, 200 OK, and acknowledgement (ACK) messages. The media capabilities are typically described using the Session Description Protocol (SDP). Once respective endpoints are in an active session with each other and have determined each other&#39;s capabilities, the specified media content may be exchanged during an appropriate media session. 
     The following example illustrates detailed message flows related to telephony devices, which are in one particular class of devices that can provide state information. Other classes of devices, including but not limited to those previously discussed, may have their own unique message flows to achieve similar results. Those skilled in the art will recognize there are many implementation methods possible for associating devices with the presence system  20 . This SIP-based example provides a relatively simple to describe explanation of relevant message flows. 
     An exemplary message flow for providing state information relating to a telephony device  16  on the circuit-switched network  10  is illustrated in FIG.  6 . Although the SIP protocol is used for illustration, those skilled in the art will recognize the general functionality of the described messages and their applicability to other protocols. Further, the switch  14  is preferably configured to monitor states resulting from user interactions or other events and provide corresponding state information to the presence system. For example, the user interaction could be the user selecting a mode of operation, such as ring, meeting (off or vibrate), or actually participating in a call. 
     The flow begins when a user initially requests activation of the telephony device  16  through a local exchange carrier or like entity, which controls access and communications for the telephony device  16 . Typically, the telephony device  16  is provisioned by providing provisioning information from the provisioning database  18  to the switch  14  (step  400 ). The traditional provisioning information is supplemented with information indicating whether the user of telephony device  16  wishes to subscribe to the presence service provided by the presence system  20 . Accordingly, the switch  14  will receive the provisioning information from the provisioning database  18  and provision the telephony device  16 , as well as store information that correlates the relationship between the telephony device  16  and a presence ID, which is used by the presence system  20  for determining the state of the telephony device  16 . The telephony device  16  is typically identified on the circuit-switched network  10  using a directory number, caller identification, or similar designation. Alternatively, a user may be able to dynamically provision a device from the device, without requiring the network operator to take action. 
     Once the provisioning of telephony device  16  is complete, the switch  14  will send a REGISTER message to the proxy server  28  (step  402 ). Preferably, the switch  14  registers as a user agent, and the proxy server  28  acts as a SIP proxy server. The REGISTER message effectively registers the ability of the switch  14  to provide presence information with the SIP proxy  28 . In particular, the REGISTER message informs the proxy server  28  of the SIP URL that identifies the user agent of the switch  14  to the (SIP) packet-switched network  12 . The REGISTER message may also contain information about how to reach the user agent over the packet-switched network  12 , typically by providing the Internet Protocol (IP) address and port that the user agent will use for SIP sessions. Preferably, the REGISTER message will also include an initial state of the telephony device  16  and identification indicia for the telephony device  16 . The identification indicia in a SIP environment is preferably a SIP ID, which is the logical address associated with the telephony device  16  as represented on the packet-switched network  12 . 
     In response to this initial REGISTER message, the proxy server  28  will send a like REGISTER message to the registrar  26  to register the telephony device  16  with the registrar  26  (step  404 ). Further, the proxy server  28  may also forward the REGISTER message to the presence system  20  (step  406 ). At this point, the presence system  20  has registered the telephony device  16  and has associated an initial state for the telephony device  16 . All other devices used to determine presence information of the user will register in the same or similar fashion. 
     The presence system  20  consolidates and/or transforms device data into the state associated with a logical or user identification and provides relevant state information to the presence application  24 . Subsequently, the presence application  24  will subscribe to the presence service provided by the presence system  20  to receive presence state information based on state changes associated the various devices of the user. Accordingly, the presence application  24  will send a SUBSCRIBE message, which includes identification information (SIP ID) of the user or telephony device  16 , to the proxy server  28  (step  408 ), which will forward the SUBSCRIBE message to the presence system  20  (step  410 ). In response, the presence system  20  will use the SIP ID provided in the SUBSCRIBE message to identify the user or devices for which presence information is requested. Once the presence system  20  has evaluated the state of the telephony device  16 , a NOTIFY message, including presence information for the user of the telephony device  16 , is sent to the proxy server  28  (step  412 ), which forwards the NOTIFY message to the presence application  24  (step  414 ). At this point, the presence application  24  has subscribed to the presence service  20  for the user and has received the initial presence information for the user, and perhaps the state of the telephony device  16  and other devices, if so provisioned. Thus, the presence application  24  may react as necessary in response to receiving the presence information for the user and awaits state change notifications for the user. 
     Assume that the telephony device  16  changes state, such as being placed on-hook, going off-hook, initiating a hold function, going out of service, initiating a service activation, changing modes, or the like. In essence, a change of state of the device may be configured to trigger an event, which is sent to the switch  14  in traditional fashion (step  416 ). In addition to normal processing of the event, the switch  14  will recognize that the telephony device  16  has been provisioned to alert the presence service of state changes, and will send a REGISTER message identifying the telephony device  16  (preferably using the SIP ID) and including the current state to the proxy server  28  (step  418 ), which represents the presence system  20  to the switch  14 . Proxy server  28  will then send a REGISTER message to register the new state in association with the identified telephony device  16  with the presence system  20  (step  420 ). The presence system  20  will then process the state information to create the presence information for the user and send a NOTIFY message, if necessary, to the proxy server  28  to provide the updated presence information (step  422 ). The proxy server  28  will forward the NOTIFY message, which includes the presence information, to the presence application  24  (step  424 ), which can then take appropriate action based on the state information (step  426 ). As noted above, the state information may be associated with location information in an appropriately configured wireless communication system. 
     Those skilled in the art will recognize that the use of REGISTER messages is only one implementation. In general, the switch  14  or some other device that provides autonomous state change information can use a REGISTER message or some other undefined message to notify the presence service. If the presence system  20  subscribes to the information on the switch  14 , which changes the role of the switch  14  to that of a presence user agent, it would allow the use of NOTIFY messages to communicate the presence data to the presence system  20 . 
     The switch  14  may be configured to provide a table, which correlates the identification of the telephony device  16  on the circuit-switched network  10  with a presence identity, which is preferably a SIP address or URL. Using this table, the switch  14  can identify state changes for the telephony device  16 , process the changes based on the rules management logic  58 , and send updated state information indirectly or directly to the presence system  20 . For example, assume that a user has registered for an automatic presence service from a cellular communication operator. Part of the registration process will provision a presence address and correlate it with a registered mobile telephone  16 B, based either upon the mobile identification number, a SIM card identification, the telephone number, or like designation. 
     Whenever the user&#39;s mobile telephone  16 B is on and in reach of the mobile network, the home location register (HLR) is made aware of this fact as part of the normal course of cellular telephone operation. The HLR can register on-line status on behalf of the user&#39;s presence identification based on this information. As noted, the state information may include location identification in addition to traditional state information. Those skilled in the art will recognize the application of the present invention to both traditional time division multiplexing (TDM) switching systems and more recent innovations, such as IP public branch exchanges, or telephony clients, such as SIP user agents, H.323 endpoints, Microsoft NetMeeting, or real-time communication clients. Network resources, such as SIP proxies or H.323 gatekeepers, may also apply this technology if they retain call status information on the endpoints or user agents they manage. 
     Turning now to FIG. 7, a block representation of a switch  14  is illustrated. The switch  14  is represented generically and is intended to cover the logical functionality of land-based and mobile switching systems, which include all control for call server-based functions. These switches may be implemented in a variety of ways using different equipment types, such as Nortel Networks Limited&#39;s DMS-100 local switching system. The switch  14  typically includes a switching fabric module  64 , a computing module  66  including storage software  68 , a subscriber/base station interface  70 , a network interface  72 , an operations/administration and maintenance (OA &amp; M) module  74  and a packet interface  76 . The switching fabric  64  may comprise logical and physical switches for interconnecting the subscriber/base station interface  70  with the remainder of the circuit-switched network  10  through the network interface  72 . Depending on a land-based or wireless embodiment, the subscriber/base station interface  70  will either directly support subscribers through subscriber lines or will support base stations, which facilitate wireless communications with mobile devices. As illustrated, the computing module  66  controls circuit-switched communications via the switching fabric  64  and is capable of providing traditional intelligent network monitoring and functions. Further, the computing module  66  may cooperate with the provisioning database  18  as described above. As noted above, the functionality of the switch  14  may be provided in various levels of integration. 
     In operation, the software  68  of the computing module  66  is modified to recognize state changes associated with supported telephony devices  16  and to provide the state information via the packet interface  76  either directly or indirectly to the presence system  20  on the packet-switched network  12 . As noted, the messages sent to the presence system  20  will include identification of the associated telephony device  16 , relative state information, and perhaps location information derived from a mobile telephone  1   6 B or from elsewhere in the system. Preferably, the computing module  66  will cooperate with the provisioning database  18  to store information indicating that the particular telephony device  16  is subscribing to the presence service and providing an address for sending state change messages directly or indirectly to the presence system  20 . The other devices providing state information are similarly configured to trigger delivery of state information upon recognizing the occurrence of an event bearing on the availability of the user. 
     Current presence technology standards and systems are provided for in references from the Internet Engineering Task Force (IETF). Presence technology protocol-related publications hereby incorporated by reference include: Day, M., Aggarwal, S. and Vincent, J., “Instant Messaging/Presence Protocol Requirements,” Request for Comment (RFC) 2779, February 2000; Day, M., Rosenberg, J. and Sugano, H., “A Model for Presence and Instant Messaging,” RFC 2778, February 2000; Rosenberg, J. and Schulzrinne, H., “SIP caller preferences and caller capabilities,” (work in progress), November 2000; Crocker, D. et al., “A Common Profile for Instant Messaging (CPIM),” (work in progress), February 2001. 
     Those skilled in the art will recognize improvements and modifications to the preferred embodiments of the present invention. All such improvements and modifications are considered within the scope of the concepts disclosed herein and the claims that follow.