Abstract: A method and apparatus for quickly determining the status of a network device in a network communicates status inquiry messages over the forwarding plane of one network device to at least one neighboring network device. The status inquiry messages indicate the connectivity status with at least one neighboring network device.

Abstract: A method and apparatus for quickly determining the status of a network device in a network communicates status inquiry messages over the forwarding plane of one network device to at least one neighboring network device. The status inquiry messages indicate the connectivity status with at least one neighboring network device.

Abstract: A method and apparatus for quickly determining the status of a network device in a network communicates status inquiry messages over the forwarding plane of one network device to at least one neighboring network device. The status inquiry messages indicate the connectivity status with at least one neighboring network device.

Abstract: A method and apparatus for quickly determining the status of a network device in a network communicates status inquiry messages over the forwarding plane of one network devise to at least one neighboring network device. The status inquiry messages indicate the connectivity status with at least one neighboring network device.

Abstract: A method and apparatus for quickly determining the status of a network device in a network communicates status inquiry messages over the forwarding plane of one network device to at least one neighboring network device. The status inquiry messages indicate the connectivity status with at least one neighboring network device.

Abstract: A method and apparatus for quickly determining the status of a network device in a network communicates status inquiry messages over the forwarding plane of one network device to at least one neighboring network device. The status inquiry messages indicate the connectivity status with at least one neighboring device. The status inquiry messages are transmitted periodically to the at least one neighboring device. In addition, the network device may communicate an advertisement message over the control plane to discover the at least one neighboring network device prior to the communication of the status inquiry messages over the forwarding plane. The network devices may negotiate communication parameters for the exchange of status inquiry messages with the at least one network device.

Abstract: A system, device, and method for receiver access control in an interne television system uses a push mechanism to distribute access control information from a distribution device to an access device. The access device uses the access control information to make receiver access control decisions for a subsequently received request from a host to join a television channel multicast group.

Abstract: A system, device, and method for distributing link state information in a communication network combines a link state routing protocol with a sliding window mechanism in order to efficiently distribute link state information. The sliding window mechanism permits a predetermined number of unacknowledged link state advertisement protocol messages to be outstanding at any given time. Unacknowledged link state advertisement protocol messages are retransmitted after a predetermined timeout period.

Abstract: A system, device, and method for controlling access in a multicast communication network uses a distributed host authentication scheme to prevent unauthorized hosts from joining a shared multicast distribution tree. An authorized host is provided with access information for accessing the shared tree. Certain access information is also distributed to at least a designated device associated with the host, although the access information may be distributed to other devices as well. The designated device uses the access information to authenticate the host and establish a security agreement with the host. Other devices may use the access information to authenticate the host in the event that the designated device is unable to authenticate the host. An authenticated host is added to the shared tree, while a host that cannot be authenticated is prevented from joining the shared tree.

Abstract: A system, device, and method for distributing link state information in a communication network combines a link state routing protocol with a sliding window mechanism in order to efficiently distribute link state information. The sliding window mechanism permits a predetermined number of unacknowledged link state advertisement protocol messages to be outstanding at any given time. Unacknowledged link state advertisement protocol messages are retransmitted after a predetermined timeout period.

Abstract: A system, device, and method for sending keep-alive messages in a communication network involves determining a reliability factor for communicating with a neighbor and setting the frequency for sending keep-alive messages to the neighbor based upon the reliability factor. The reliability factor is determined based upon the reliability of the neighbor as well as the reliability of the communication link to the neighbor. The frequency for sending keep-alive messages to the neighbor is relatively high if the reliability factor is low. The frequency for sending keep-alive messages to the neighbor is relatively low if the reliability factor is high. The frequency for sending keep-alive messages to the neighbor is dynamically adjusted based upon an updated reliability factor.

Abstract: An apparatus and method of communicating messages between a first application and a second application establishes a path between the first application and the second application. At least one channel is defined within the path, where each of the at least one channels is designated as forwarding a single type of message between the first application and the second application. A handler is assigned to each channel. In preferred embodiments, the handler processes messages in its assigned channel in a uniform manner.

Abstract: A technique for expediting an operation in a computer system involves raising the priority level of an operating system task from a low priority level to a high priority level in order to perform the operation at the high priority level and lowering the priority level of the operating system task back to the low priority level upon completion of the operation. Task priority control logic causes the operating system task to execute at the low priority level as a default priority level. The task priority control logic monitors for a trigger condition indicating that the operation is to be performed. Upon detecting the trigger condition, the task priority control logic raises the operating system task to the high priority level, and begins monitoring for completion of the operation. Upon determining that the operation is complete, the task priority control logic lower the operating system task back to the low priority level.

Abstract: A system, device, and method for receiver access control in a multicast communication network uses a policy service to determine whether a subscriber device can be admitted to a multicast group. The subscriber device accesses the multicast communication network via an access device. The access device uses a policy service to obtain a policy decision from a policy server, where the policy decision indicates whether or not the subscriber device can be admitted to the multicast group. The access device enforces the policy decision by admitting the subscriber device to the multicast group if and only if the policy decision indicates that the subscriber device can be admitted to the multicast group.

Abstract: A system, device, and method for receiver access control in a multicast communication network treats each subscriber location as a separate subnetwork having one and only one multicast receiver. An access device is situated at each subscriber location. Each access device connects to a separate port of a multicast distribution device. Each subscriber device accesses the multicast network through the access device that is situated at its subscriber location. Each access device acts as a proxy for its respective subscriber devices by joining and leaving multicast groups on behalf of the subscriber devices and acting as the sole multicast receiver for the subscriber location. The access devices run a multicast group management protocol for joining and leaving various multicast groups, and therefore the access devices appear to the multicast distribution device as the ultimate multicast receivers for multicast information.

Abstract: A system, device, and method for receiver access control in a multicast communication network uses a policy service to determine whether a subscriber device can be admitted to a multicast group. The subscriber device accesses the multicast communication network via an access device. The access device uses a policy service to obtain a policy decision from a policy server, where the policy decision indicates whether or not the subscriber device can be admitted to the multicast group. The access device enforces the policy decision by admitting the subscriber device to the multicast group if and only if the policy decision indicates that the subscriber device can be admitted to the multicast group.

Abstract: In a technique for priority forwarding, an upper layer protocol that requires priority forwarding includes a priority function that is invoked by a lower layer protocol in order to obtain the priority for a message. The upper layer protocol provides the priority function to the lower layer protocol when the upper layer protocol is installed in the protocol stack. The lower layer protocol invokes the priority function before passing a message to the upper layer protocol in order to determine a priority for the message. The lower layer protocol places the message in the appropriate queue based upon the priority indicator obtained from the upper layer protocol's priority function.

Abstract: A system, device, and method for receiver access control in a multicast communication network uses a policy service to determine whether a subscriber device can be admitted to a multicast group. The subscriber device accesses the multicast communication network via an access device. The access device uses a policy service to obtain a policy decision from a policy server, where the policy decision indicates whether or not the subscriber device can be admitted to the multicast group. The access device enforces the policy decision by admitting the subscriber device to the multicast group if and only if the policy decision indicates that the subscriber device can be admitted to the multicast group.

Abstract: An application programming interface for use in a network device includes at least one control module that is capable of controlling a forwarding plane of the network device. In particular, the network device forwards packets across a network, and includes the forward plane for processing data packets. The application programming interface includes an input module that receives function calls, at least one control module (mentioned above) that receives input control data via the function calls, and an output module that forwards output control data from the control module. The control module produces the output control data based upon the input control data. The output control data is capable of controlling execution of the forwarding plane.

Abstract: An apparatus and method of maintaining a route table within a network device lists data identifying specific routes of interest that have changed. The routes of interest may be within a given set of routes. Specifically, after the given set of routes are registered with the apparatus, it is determined if any of the routes in the given set has changed. Data identifying each route in the given set of routes that has been determined to change then is listed.