Intel Corporation

Hewlett-Packard Company

David Romano

Gilbert M Wolrich

Sanjeev Jain

John Wishneusky

Mark B Rosenbluth

Prashant R Chandra

Donald F Hooper

Sridhar Lakshmanamurthy

Alok Kumar

Uday Ramakrishna Naik

Hugh M Wilkinson, Iii

Yim Pun

Richard J Brody

Raymond Ng

Lawrence B Huston

Ameya S Varde

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.

Method and apparatus for scheduling packets

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.

Method for optimizing queuing performance

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.

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.

Circular link list scheduling

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.

Method and apparatus to communicate flow control information in a duplex network processor system

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.

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Cumberland, RI, United States of America

David Romano