i just want to start by saying that I classify my self as a beginner in networking and my only hope is to become very good as you are,so i was reading this book and i didn't understand the term very well a "networking protocol"" and it continue saying that a network has a lot of networking protocols so i just want a simple definition of a protocol. thank you very very much in advance.
A network protocol defines rules and conventions for communication between network devices. Network protocols include mechanisms for devices to identify and make connections with each other, as well as formatting rules that specify how data is packaged into messages sent and received. Some protocols also support message acknowledgment and data compression designed for reliable and/or high-performance network communication.
For understanding protocols, I usually suggestion reading the mail transport protocol first (esp Example 1 of RFC 821), then actually trying it with your own mail servers: it's designed for a person to type it for diagnosing email problems. Then comparing it against something like file transfer FTP (esp example in Section 7 of RFC 959).
Understanding binary protocols and the transport protocols follows naturally from there. It's hard to understand any of the protocols if you don't understand what problem they are solving: hence much easier with sending mail and files.