Several international standards for asynchronous data compression are available today. In 1993 the International Telecommunication Union (ITU) started to research possible ways to compress synchronous data. Special attention was given to compatibility with previous asynchronous standards, namely V.42bis. In September 1993 a proposal for modification of the V.42bis standard to make it applicable to synchronous data was published. In this paper a prototype of a synchronous data link layer protocol based on the ITU proposals is described. The protocol chosen is HDLC based. The V.42bis compression standard is adapted to serve the needs of a synchronous protocol. A functional model is designed followed by a performance analysis of the protocol. The analysis shows a decrease of the compression ratio due to the adaption of the compression algorithm.
Asynchronous communication,Computer science,Data link layer,Computer network,Error detection and correction,High-Level Data Link Control,Coding (social sciences),Compression ratio,Data compression,Data link