Patent Application
20060112177
The described technology relates generally to controlling access to presence information.
Real-time conversations between conversation participants via their computer systems are becoming increasingly common. A real-time conversation requires that the participants be present at their computer system (e.g., personal digital assistant) and able to respond when a communication is received. The most common form of real-time conversations is provided by instant messaging services. An instant messaging service allows participants to send messages and have them received within a second or two by the other participants in the conversation. The receiving participants can then send responsive messages to the other participants in a similar manner. To be effective, a real-time conversation relies on the participants becoming aware of, reviewing, and responding to received messages very quickly. This quick response is in contrast to conventional electronic mail systems in which the recipients of electronic mail messages respond to messages at their convenience.
When an initiating participant wants to start a real-time conversation, that participant needs to know whether the intended participants are available to respond in real time to a message. If not, then communications via conventional electronic mail, voice mail, or some other mechanism may be more appropriate. For example, if the computers of the intended participants are currently powered off, then a real-time conversation would not be possible. Moreover, if their computers are currently powered on, but the intended participants are away from their computers, a real-time conversation would also not be possible. The initiating participant would like to know the availability of the intended participants so that an appropriate decision on the form of communication can be made.
The availability status of an entity such as a computer system or a user associated with that computer system is referred to as “presence information.” Users make their presence information available so that other users can decide how best to communicate with them. For example, the presence information may indicate whether a user is logged on (“online”) with an instant messaging server or is logged off (“offline”). Presence information may also provide more detailed information about the availability of the user. For example, even though a user is online, that user may be away from their computer in a meeting. In such a case, the presence information may indicate “online” and “in a meeting.”
In an instant messaging context, a publishing user (“publisher”) may provide their presence information to a presence server that then provides the presence information to subscribing users (“subscribers”). Thus, a presence server may use a subscriber/publisher model to provide the presence information for the users of the presence service. Whenever the presence information of a user changes, the presence server is notified of the change by that user's computer system and in turn notifies the subscribing users of the change. A subscribing user can then decide whether to initiate an instant messaging conversation based on the presence information of the intended participants.
To protect the privacy of users, presence servers allow users to specify access control rights to their presence information. For example, a user may provide the presence server with a list of those other users who are authorized to access the presence information of that user. When a user who is not on the list requests to subscribe to the presence information of that user, the presence server denies the request.
A difficulty with the enforcement of access control rights to presence information via a presence server is that the storage and computation requirements of the server become a bottleneck. The bottleneck results from the need of the server to store the access control information for each user of the presence server and to check the access control information whenever a subscribe request is received and possibly whenever presence information of a user changes. As communications via real-time conversations become even more popular, there will be a need to store the access control information for tens of millions of users. Thus, the server needs to grow to accommodate increasing numbers of users and subscription requests.
Another difficulty with storage and enforcement of access control rights is that a presence server typically has a predefined set of presence states to describe the availability of an entity. These predefined sets of presence states may not, however, effectively describe the presence state of a user in many situations. For example, the presence states that are appropriate for a business person may not be appropriate for a college student. Also, a person may have different presence states depending on their current context. For example, a person at work may have very different presence states from when at leisure.
It would be desirable to have a real-time communications architecture that would avoid this bottleneck at a presence server and allow flexibility in specifying presence states.
A presence information system allows access to presence information of a publishing entity to be controlled by the publishing entity and enforced by a computer system of that publishing entity on a peer-to-peer basis, rather than by a presence server. A subscribing entity can send to the publishing entity on a peer-to-peer basis a request to subscribe to the presence information of the publishing entity. When the publishing entity receives the request to subscribe to its presence information, the presence information system of the publishing computer system can allow or deny the request based on access rights associated with the subscribing entity. If the request is allowed, then the publishing entity notifies the subscribing entity of its current presence state and new presence states. The presence information system may also allow a publishing entity to define its own presence model that indicates the presence states of the publishing entity.
A method and system for controlling access to presence information on a peer-to-peer basis is provided. In one embodiment, the presence information system allows access to presence information of a publishing entity to be controlled by the publishing entity and enforced by the computer system of that publishing entity on a peer-to-peer basis, rather than by a presence server. Once a subscribing entity locates the address of the computer system of a publishing entity, for example, using a presence server, the subscribing entity can send to the publishing entity on a peer-to-peer basis, using the located address, a request to subscribe to the presence information of the publishing entity. When the publishing entity receives the request to subscribe to its presence information, the presence information system of the publishing computer system can allow or deny the request based on access rights associated with the subscribing entity. If the request is allowed, then the publishing entity notifies the subscribing entity of its current presence state and its new presence state when it changes. Because the publishing computer systems, rather than a presence server, maintain and enforce the access rights of their subscribing entities, the presence server is relieved of the overhead of doing so and the number of entities accessing presence information can increase without placing a heavy burden on the presence server.
To help a publishing entity control its privacy, the presence information system may allow a publishing entity to define access rights for a subscribing entity at various levels of detail of presence information. For example, a publishing entity may specify that a subscribing entity has the right to know whether the publishing entity is online or offline, but does not have the right to know any further details when the publishing entity is online. The publishing entity may, however, specify that another subscribing entity has the right to know further details such as whether the publishing entity is in a meeting or out to lunch when the publishing entity is online. Moreover, the presence information system may allow an entity to define a presence model for their presence information, rather than rely on a predefined set of presence states. A presence model may define a hierarchy of presence states. For example, one publishing entity may define a presence model that specifies the presence states of “at home” or “at work” within the “online” state, whereas another publishing entity may specify the presence states of “on the East Coast” or “on the West Coast” within the “online” state. The presence information system allows a publishing entity to define access rights of a subscribing entity based on its own presence model. The presence information system may also allow a publishing entity to define multiple presence models and to expose different presence models to the different subscribing entities. For example, a publishing entity may provide a presence model to their spouse that is different from that provided to a coworker. In this way, the presence information system allows a publishing entity to define a presence model that is customized based on the context of the publishing entity and allows a publishing entity to provide different presence models to different subscribing entities.
In one embodiment, each presence state in a presence model may have an associated access control list that defines the access rights of subscribing entities to presence information associated with that state. When a publishing entity changes to a new presence state, the presence information system notifies the subscribing entities that have the appropriate access right of the new presence state. In general, a subscribing entity is notified of the nearest ancestor presence state of the new presence state (including the new presence state itself) to which the subscribing entity has access rights. For example, an employee may give their supervisor access rights to the “at work” and “in a meeting” presence states but not give access rights to their “on the phone” and “at lunch” presence state. When the employee leaves a meeting and goes to lunch, the presence information system notifies the supervisor that the employee is currently “at work,” which is the nearest ancestor present state to which the supervisor has access. The same employee may give their secretary access rights to their “on the phone” and “at lunch” presence state. When the employee goes to lunch, the presence information system notifies their secretary that the employee is currently “at lunch.” When the employee returns from lunch to start talking on the phone, the presence information system notifies their secretary that the employee is currently “on the phone.” The presence information system, however, does not notify the supervisor because the supervisor was already notified that the employee was “at work” and the supervisor does not have access rights to the “on the phone” presence state. Each subscribing entity, thus, can be considered to have a different view into the presence model that is defined by their access rights. The presence information system may only notify those subscribing entities of a change in the presence state that is within their view.
The computing device on which the presence information system is implemented may include a central processing unit, memory, input devices (e.g., keyboard and pointing devices), output devices (e.g., display devices), and storage devices (e.g., disk drives). The memory and storage devices are computer-readable media that may contain instructions that implement the presence information system. In addition, the data structures and message structures may be stored or transmitted via a data transmission medium, such as a signal on a communications link. Various communication links may be used, such as the Internet, a local area network, a wide area network, a point-to-point dial-up connection, a cell phone network, and so on.
Embodiments of the presence information system may be implemented in various operating environments that include personal computers, server computers, hand-held or laptop devices, multiprocessor systems, microprocessor-based systems, programmable consumer electronics, digital cameras, network PCs, minicomputers, mainframe computers, distributed computing environments that include any of the above systems or devices, and so on. The computer systems may be cell phones, personal digital assistants, smart phones, personal computers, programmable consumer electronics, digital cameras, and so on.
The presence information system may be described in the general context of computer-executable instructions, such as program modules, executed by one or more computers or other devices. Generally, program modules include routines, programs, objects, components, data structures, and so on that perform particular tasks or implement particular abstract data types. Typically, the functionality of the program modules may be combined or distributed as desired in various embodiments.
From the foregoing, it will be appreciated that specific embodiments of the presence information system have been described herein for purposes of illustration, but that various modifications may be made without deviating from the spirit and scope of the invention. One skilled in the art will appreciate that the users associated with an enterprise (e.g., a corporation) may have their presence models stored on and/or enforced by a server of the enterprise. Thus, such a server would act as a proxy for the computer system of the users. Accordingly, the invention is not limited except as by the appended claims.
