The OSI model is used as the reference model for networking, IT professionals know it like the back of their hand and it's regularly used to describe various hardware capabilities such as a 'layer two switch' for example. 

Knowledge of the OSI will immediately give you more confidence with networking. You will quickly learn exactly where IP lives in the process of sending a data packet from host to host, and it will also give you a far better understanding of how to troubleshoot basic networking problems. 

This short course is your gateway to networking and as an AV professional you should know it's structure and you should be able to reference it when needed.