International Business Machines Corporation

Brocade Communications Systems, Inc.

Brocade Communication Systems LLC

Kevin Gerard Plotz

Gary Scott Delp

Jonathan W Byrn

Philip Lynn Leichty

Albert Alfonse Slane

Mark William Branstad

Jeffrey James Lynch

John Handley Shaffer

Oran Uzrad-Nali

Lee Anton Sendelbach

Todd Edwin Leonard

Gary Paul McClannahan

John Emery Nordman

Fadi-Christian E Safi

Phil L Leichty

Baiju V Patel

Frank Andre Schaffa

Marc Hubert Willebeek-LeMair

David William Davenport

Phillip L Leichty

The present invention discloses an apparatus and method for performing cyclic redundancy check (CRC) on partial protocol data units (PDUs). The disclosed apparatus is designed to off-load the CRC calculation for transmit or receive from a host computer. According to the disclosed method, when generating CRC for partial PDUs, for each such PDUs a decision is made to determine whether a CRC action is required, i.e., if CRC should be calculated, checked or placed in the outgoing byte stream. When partial CRC calculation is performed the intermediate value is saved into memory and later is used for calculating the CRC for a consecutive partial PDU. In accordance with a preferred embodiment of the invention, the need to re-calculate the CRC in a case of a re-transmit request is eliminated.

Apparatus and method for performing cyclic redundancy check (CRC) on partial protocol data units (PDUs)

A method for accelerating storage access in a network. The method comprises receiving a data record having a plurality of data segments. The data segments are stored in a local memory of a network controller (NC). A virtual write buffer (VWB) entry is assigned for the incoming data record in the NC local memory. The data segments of said data record are reassemble using the VWB. The data record is sent from the network controller directly to an I/O controller of a storage device.

Virtual write buffers for accelerated memory and storage access

Apparatus and method for performing cyclic redundancy check (CRC) on partial protocol data units (PDUS)

A method and apparatus are provided for implementing communications in a communications network. The apparatus for implementing communications includes a system interface to the communications network. A scheduler schedules enqueued cells and enqueued frames to be transmitted. A segmenter segments frames and cells in into cells or frames applied to a media adaptation block for transmission in a selected one of multiple modes.

Communications adapter for implementing communications in a network and providing multiple modes of communications

A method and Gigabit Ethernet communications adapter are provided for implementing communications in a communications network. A transmission queue is defined of data to be transmitted. A transmission rate is set for the transmission queue. Data to be transmitted are enqueued on the transmission queue. The transmission queue can be subdivided into multiple priority queues, for example, using time wheels, and a transmission rate is set for each transmission queue.

Communications methods and gigabit ethernet communications adapter providing quality of service and receiver connection speed differentiation

A method and apparatus are provided for scheduling the transmission of cells and frames in a communications network. The transmission of cells and frames are scheduled utilizing a selected scheduling algorithm. The cell/frame scheduling algorithm includes the step of identifying a frame or cell transmission type. Responsive to the identified frame or cell transmission type, a frame multiplier value is identified. A target transmission time is calculated for the frame or cell transmission type utilizing the identified frame multiplier value. A method and apparatus optionally are provided for scheduling the transmission of packet pairs.

Cell/frame scheduling method and communications cell/frame scheduler

A method and apparatus are provided for implementing cyclic redundancy check (CRC) calculation for data communications in a communications system. CRC calculation apparatus includes a CRC tree structure receiving a first CRC input, a data input of N&minus;1 data input bytes; and a length input. The CRC tree structure includes a series of CRC trees. Each of the CRC trees has a seed CRC input, a fixed size data input and provides a CRC result output. The series of CRC trees are arranged in cascade with increasing data size inputs. A multiplexer control logic responsive to the length input selectively couples predefined data input bytes to predefined ones of the series of the CRC trees. The multiplexer control logic responsive to the length input couples the first CRC input to a selected one of the CRC trees; couples predefined CRC result outputs to predefined ones of the CRC trees; and utilizes a selected CRC tree to provide the overall CRC result.

Method and apparatus for implementing cyclic redundancy check calculation for data communications

A rate based mechanism for determining which data to replace in a cache when the cache is full. The computer system processes data, which are associated with multiple channels or processes. These channels or processes have different, cyclic rates. When the cache is full, the system chooses the data to replace by selecting the data block in the cache that has the lowest rate and is the most recently used.

Rate based memory replacement mechanism for replacing cache entries when

A method and apparatus for implementing virtual memory having multiple selected page sizes are provided. A virtual address includes a map index and a frame offset. A selector mechanism receives the virtual address frame offset and generates an offset and index. A frame map table indexes the virtual address map index and the selector generated index and generates a base address. The frame map table generated base address and the selector generated offset are combined to provide a physical address.

Method and apparatus for implementing virtual memory having multiple

Method and apparatus are provided for segmenting a multiple program multimedia digital data stream for transmission over a distribution communications network. Each program multimedia digital data stream includes sequential transport system (TS) packets with program clock references (PCRs) at a set time interval and a program identification (PID) associated with the PCRs. The multiple program multimedia digital data stream is received. The TS packets are decoded to identify the program clock references (PCRs). A selected number N of TS packets are identified. The multimedia digital data stream into frames responsive to both the identified number N of TS packets and the identified PCRs. A program identification (PID) associated with one of the PCRs is selected for timing the transmission of segmented multiple program multimedia digital data stream. A time interval following an identified PCR associated with the selected program identification PID is identified and compared with the set time interval between the program clock references (PCRs). Responsive to the identified time interval being greater than the set time interval, a new program identification (PID) is selected for timing the transmission of segmented multiple program multimedia digital data stream.

Apparatus and method for segmentation and time synchronization of the

Method and apparatus are provided for transmitting a stream of multimedia digital data over a distribution communications network. A multimedia stream server segments the multimedia digital data stream into data blocks on a first boundary and a second boundary. The first boundary is a set number of transport system data packets and the second boundary is a transport system data packet including a timestamp. A scheduler schedules the segmented data blocks for transmission. The multimedia stream server decodes the segmented data blocks to locate the timestamps and matches the transmission of the located timestamp data block with a time value indicated by the timestamp. The set number of transport system data packets can be determined at connection setup and is not a predetermined value for all sessions. At the receiver, batch processing of received multimedia data can be provided.

apparatus and method for segmentation and time synchronization of the

A method and apparatus for scheduling the transmission of a number of data streams over a common communications link, where each of the data streams conforms to a corresponding set of flow control parameters. Each of the data streams to be transmitted on the communications link is stored in a corresponding queue. The status of each queue is maintained, and a target transmission time is calculated for each queue. Signals are then generated for each queue at a time at least after the target transmission time, and these signals are used to indicate to a corresponding queue that is can transmit a cell on the link. Upon reception of a corresponding signal, a queue then transmits at least one cell onto the communications link.

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Byron, MN, United States of America

Kevin Gerard Plotz