Go-Back-N

An implementation of Go-Back-N protocol.This is a teamwork with kennch. An article about interesting issues during our implementing process can be found here.

Feature

Cycler array is used to store packet window, making it compatible for transfering unlimited larget file.
Dynamically swtiching window size among 1,2, and 4 based on TIMEOUT event. When all ACKs received, switch to larger window size, but when there is ACK loss, slow down to size 1 window

Usage

create input file with name , it can be of any type: pdf, jpeg, etc.
make
launch receiver
./receiver <port> <output-file>
launch sender
./sender 127.0.0.1 <port> <input file>

C Standard

We use C99 for this lab.

External source

The logger used in this lab is credited to rxi/log.c

Play with it

Change packet loss rate and corrupt rate in file gbn.h, they are configured by LOSS_PROB and CORR_PROB.

Enable Logger Output

The logger for this lab is disabled by default, in order to optimize its performance. To enable logging output, go to gbn.c, and find gbn_init().

log_set_quiet(1);
log_set_level(LOG_DEBUG);

Changing log_set_quiet(1) to log_set_quiet(0) enables logging output. You can also change the logging level by modifying log_set_level(LOG_DEBUG). For more usages, you can have a reference on rxi/log.c