Computer network or data network is a telecommunications network that allows computers to exchange data. The physical connection between networked computing devices is established using either cable media or wireless media. The best-known computer network is the Internet. This tutorial has been prepared for the computer science graduates to help them understand the basic to advanced concepts related to Data Communication and Computer Networking. After completing this tutorial you will find yourself at a moderate level of expertise in Data Communication and Computer Networking from where you can take yourself to next levels.
Before you start, I'm making an assumption that you are already aware about basic computer concepts like what is keyboard, mouse, monitor, input, output, primary memory and secondary memory etc. If you are not well aware of these concepts then I will suggest to go through any tutorial on Computer Fundamentals. These notes will help you at Gradaute level and IIT GATE.