Effect of Using Header Compression Method in TCP/IP Protocol Over HDLC in SCADA System


Most of the header information remains constant over the life-time of the connection. For TCP connection many fields are constant and others change with small values. To initiate compression of the headers of a packet stream, a full header is transmitted over the link. The compressor and decompressor store most fields of this full header as reference. The reference consists of the fields of the headers whose values are constant and thus need not be sent over the link at all, or change little between consecutive headers so that it uses fewer bits to send the difference from the previous value compared to sending the absolute value. To improve interactive response time and to decrease the header overhead on the system we used the method of Compressing Protocol Headers (TCP/IP). Also it is used to compress the HDLC header. The simulated communication protocols have been tested between two PCs and the time delay, throughput and utilization have been measured.