Apparatus and method for performing cyclic redundancy check (CRC) on partial protocol data units (PDUS)
First Claim
1. An apparatus for performing CRC operations on protocol data units (PDUs), the apparatus comprising:
- a queue manager and scheduler capable of managing a plurality of queues, wherein each of queues comprise a plurality of memory object descriptors (MODs);
a CRC controller capable of performing said CRC operations;
a plurality of processing nodes capable of controlling said CRC operations;
a transmit handler capable of calculating said CRC values of segments flow to a network;
a first memory for maintaining at least said partial PDUs; and
, a second memory for maintaining at least said plurality of MODs and partial CRC values;
whereby said apparatus is designed to off-load the CRC calculation for PDUs transmitted or received from a host computer.
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Abstract
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.
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Citations
17 Claims
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1. An apparatus for performing CRC operations on protocol data units (PDUs), the apparatus comprising:
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a queue manager and scheduler capable of managing a plurality of queues, wherein each of queues comprise a plurality of memory object descriptors (MODs);
a CRC controller capable of performing said CRC operations;
a plurality of processing nodes capable of controlling said CRC operations;
a transmit handler capable of calculating said CRC values of segments flow to a network;
a first memory for maintaining at least said partial PDUs; and
,a second memory for maintaining at least said plurality of MODs and partial CRC values;
whereby said apparatus is designed to off-load the CRC calculation for PDUs transmitted or received from a host computer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method for generating a CRC for a partial PDU comprising the steps of:
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identifying the color of the MOD respective of said partial PDU;
waiting for MOD color change if MOD color is red and then proceeding with the following steps;
calculating the CRC if the MOD color is not blue;
otherwise,performing the following steps;
inserting CRC result in trailer;
resetting the CRC channel;
writing CRC result to memory. - View Dependent Claims (15, 16, 17)
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Specification