The TCP/IP protocol stack is the foundation of the internet and, more generally, network communication. Operating at various physical and logical layers, these protocols are the language that allow computers to communicate with each other. While most IT professionals don't work at the protocol level regularly, there are times when a clear understanding of what's going at the network level can be invaluable. This is the book to give that grounding and to act as a definitive reference when needed. This book covers in detail the Open System Interconnection (OSI) reference model and the TCP/IP protocols that operate that different layers. Its coverage includes various application protocols. The authors explain in an easy-to-read style networking concepts and protocols, with examples that make the book a practical guide in addition to its coverage of theory.