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SELECTIVE COMPRESSION ALGORITHM BASED ON KNOWN LOWER LAYER MINIMUM TRANSMISSION UNIT SIZES

IP.com Disclosure Number: IPCOM000009005D
Original Publication Date: 1999-Jan-01
Included in the Prior Art Database: 2002-Jul-31
Document File: 2 page(s) / 88K

Publishing Venue

Motorola

Related People

Robert Boxall: AUTHOR [+3]

Abstract

Many peer-to-peer protocols improve efficiency by using compression algorithms to reduce the amount of data that is required to be transmitted. This reduction implies that less bandwidth is required for transmission, which improves band- width efficiency and protocol performance. However, compression algorithm performance is dependent on a few factors, including algorithm complexity, data redundancy and dictionary size. Real-time compression ratios can also vary based on how often the algorithm is reset. In some cases, application of compression causes the datagram size to actually increase as a result of these factors.

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MoloRoLA Technical Developments

SELECTIVE COMPRESSION ALGORITHM BASkD ON KNOWN LOWER LAYER MINIMUM TRANSMISSION UNIT SIZES

by Robert Boxall, Mark Nowak and John Monson

PROBLEM DESCRIPTION

  Many peer-to-peer protocols improve efficiency by using compression algorithms to reduce the amount of data that is required to be transmitted. This reduction implies that less bandwidth is required for transmission, which improves band- width efficiency and protocol performance. However, compression algorithm performance is dependent on a few factors, including algorithm complexity, data redundancy and dictionary size. Real-time compression ratios can also vary based on how often the algorithm is reset. In some cases, application of compression causes the datagram size to actually increase as a result of these factors.

  Many lower layer protocols impose a minimum transmission unit (MTU) size. If the compression algorithm at a higher layer does not reduce the data- gram size by at least one MTU, datagram compres- sion is not necessary. If compression is performed anyway, unnecessary loading is required by the compression and decompression entities. In the worst case, if the number of MTUs increases, band- width would be wasted in addition to the extra processing.

DESCRIPTION OF INVENTION

  The invention proposes to utilize the MTU information in determining whether application of compression to a datagram is necessary. The algo- rithm has one input, the datagram size, and one out- put, compression ON or compression OFF. The algorithm must be aware of the system MTU size.

Application of the algorithm at the transmitter is as follows:

MIb~SIZE = MTU size;

/*Don't bother compressing if datagram is smaller than one MTU*/

IF (datagran-size < MIN-SIZE)

Compression = OFF;

ELSE/* Datag...