Abstract: A method and apparatus for scheduling packets using a pre-sort deficit round-robin method. Scheduling decisions for packets are made when packets are received, and entries for the received packets are stored in a pre-sorted scheduling array. A packet is transmitted by dequeuing the packet from the pre-sorted scheduling array.

Abstract: A method and apparatus for scheduling packets using a pre-sort scheduling array having one or more smoothing registers. The scheduling array includes a number of round buffers, each round buffer having an associated smoothing register. To schedule a packet for transmission, the packet's transmission round and relative position within that round are determined, and an identifier for the packet is placed at the appropriate position within the scheduling array. A bit of the associated smoothing register is set, the set bit corresponding to the entry receiving the packet identifier. During transmission, the set bits of the smoothing register associated with a current round buffer are read to identify packets that are to be dequeued.

Abstract: A scheduling mechanism to control transmission of data units, such as variable size packets or fixed size cells, to ports of a network device such as a switching fabric system. The scheduling mechanism maintains scheduling data structures, including an array storing information for available queues of ports and circular buffers representing nonempty port queues of the available port queues according to classes of service. The scheduling mechanism uses the data structures to make scheduling decisions concerning the scheduling of data units in the nonempty port queues for transmission to the ports.

Abstract: A method that includes streaming video content at a given bit-rate from a computing platform through a wireless access point and to a digital media adaptor that decodes the video content for display. A communication channel used to stream the video content to the digital media adaptor is monitored and information associated with the communication channel as at least a portion of the video content is streamed from the computing platform to the digital media adaptor is collected. Available bandwidth for the communication channel is determined based on the collected information. An adjustment to the given bit-rate that another portion of the video content is streamed from the computing platform is made based on the available bandwidth.

Abstract: In-band flow control data may be received from a switch fabric at a first network processor. The received in-band flow control data may be transmitted to a second network processor using a flow control bus. The second network processor may determine which receive queues in the switch fabric exceed a predetermined overflow threshold based on the in-band flow control data. The second processor may transmit data to the receive queues in the switch fabric determined not to exceed the predetermined overflow threshold.

Abstract: A method and apparatus for scheduling packets using one or more pre-sort scheduling arrays. Scheduling decisions for packets are made when packets are received, and entries for the received packets are stored in a pre-sorted scheduling array. Packets may be scheduled according to a non-work conserving technique, or packets may be scheduled according to a work conserving technique. A packet is transmitted by dequeuing the packet from a pre-sorted scheduling array.

Abstract: A method and apparatus for scheduling packets using a pre-sort scheduling array having one or more smoothing registers. The scheduling array includes a number of round buffers, each round buffer having an associated smoothing register. To schedule a packet for transmission, the packet's transmission round and relative position within that round are determined, and an identifier for the packet is placed at the appropriate position within the scheduling array. A bit of the associated smoothing register is set, the set bit corresponding to the entry receiving the packet identifier. During transmission, the set bits of the smoothing register associated with a current round buffer are read to identify packets that are to be dequeued.

Abstract: Techniques for optimizing queuing performance include passing, from a ring having M slots, one or more enqueue requests and one or more dequeue requests to a queue manager, and determining whether the ring is full, and if the ring is full, sending only an enqueue request to the queue manager when one of the M slots is next available, otherwise, sending both an enqueue request and a dequeue request to the queue manager.

Abstract: A scheduling mechanism to control transmission of data units, such as variable size packets or fixed size cells, to ports of a network device such as a switching fabric system. The scheduling mechanism maintains scheduling data structures, including an array storing information for available queues of ports and circular buffers representing nonempty port queues of the available port queues according to classes of service. The scheduling mechanism uses the data structures to make scheduling decisions concerning the scheduling of data units in the nonempty port queues for transmission to the ports.

Abstract: A method and apparatus for scheduling packets using a pre-sort deficit round-robin method. Scheduling decisions for packets are made when packets are received, and entries for the received packets are stored in a pre-sorted scheduling array. A packet is transmitted by dequeuing the packet from the pre-sorted scheduling array.

Abstract: A system is disclosed for determining whether an imaging system is in a proper operating condition. In an embodiment, the system includes an illumination modulator for providing a desired modulated illumination field at an image surface, a detection unit including a slit opening for receiving a portion of the modulated illumination field, an average power sample unit and a variation power sample unit. The average power sample unit is for determining the average power sample value of the modulated illumination field as the modulated illumination field is moved with respect to the slit opening and for determining whether the average power sample value has changed significantly since a previous scan. The variation power sample unit is for determining the variation in power sample values of the modulated illumination field as the modulated illumination field is moved with respect to the slit opening and for determining whether the variation in power sample values has changed significantly since a previous scan.

Abstract: In general, in one aspect, the disclosure describes a method of enqueuing and dequeuing queue entries for protocol data units. The method includes assigning a queue from a set of queues to a received protocol data unit, determining a queue from the set of queues to dequeue based on a scheduling policy, and adjusting a count of entries of the queue to dequeue and the queue assigned to the protocol data unit. After the adjusting, the method includes enqueuing an entry for the received protocol data unit in the assigned queue and dequeueing an entry in the queue to dequeue.

Abstract: In-band flow control data may be received from a switch fabric at a first network processor. The received in-band flow control data may be transmitted to a second network processor using a flow control bus. The second network processor may determine which receive queues in the switch fabric exceed a predetermined overflow threshold based on the in-band flow control data. The second processor may transmit data to the receive queues in the switch fabric determined not to exceed the predetermined overflow threshold.

Abstract: An instrument and a method for identifying active channels in a communications system, especially a system operating according to the asynchronous transfer mode (ATM) protocol in which data cells are associated with virtual channels (VCs) and virtual paths (VPs). The instrument includes an ATM module with a VP/VC filter that permits capture of only those ATM cells corresponding to any selected set of VCs for a particular VP. The module also includes a processor that executes software that controls the VP/VC filter to scan through VP/VCs using a combination of slow and fast scan sequences such that channels with heavy traffic are identified quickly and channels with low bandwidth traffic are also identified, although not necessarily as quickly. To identify active VCs on a particular VP, the VP/VC filter is initially set to capture cells on all channels; as active channels are identified, those channels are disabled in the filter.