N. B. L. Mathur 
Data Communication And Networking [EPUB ebook] 

This book is well organized, well written, well researched, comprehensive, and is consistently high quality across the board. Data Communications and Networking reads more like a textbook than anything else. This textbook provides a comprehensive coverage of data communications fundamentals, telephone system operation, local area networks, internetworking, and Internet communications. Each chapter in this book contains numerous examples emphasizing the most important concepts presented.