ON THE EFFICIENCY OF GO-BACK-N : The impact of noise and Transmission Window on the efficiency of Go-Back-N

Abstract: Reliable data transfer is one of the more important issues contained within computer networking. In order for data transfer to be reliable there need to exist protocols and mechanisms to combat the potential problems that could occur, such as corrupted data or loss of data. One of these protocols is Go-Back-N which is one the more fundamental protocols [8, Chapter 3]. Th‘e reason for loss of data or data corruption could for example be a consequence of a noisy channel. For this reason this study has focused on the impact noise will have on the overall transmission efficiency and if the transmission window (which is a component in Go-Back-N) could be used to mitigate the potential loss in efficiency. ‘The results that were gathered using a Go-Back-N emulator showcased that the major loss inefficiency occured  when noise (or packet error ratio) moved towards 4% packet corruption. ‘There were also major diff‚erences between diff‚erent transmission speeds. Higher transmission speeds were more prone towards major decreases in efficiency compared to lower transmission speeds, and the reason is because a higher transmission speed requires a larger transmission window (more allowed data at any given time) which causes a drop in efficiency. It could also be shown that, given the proposed theoretical models, that selecting the required transmission window relied heavily on the delay-bandwidth and that deviating from it caused drops in efficiency.