This CCNA site has a lot of good links to more information about TCP/IP and the issues with it.
The Cisco Press books are good and most are available as pdf . From the TCP/IP First Step book to the very comprehensive 2 volume ‘Routing TCP/IP’ they cover all aspects, depending on your existing knowledge level.
The <a href=”http://www.tcpipguide.com/free/”>TCP/IP guide online</a> is where I go for a lot of answers to questions. You can get an electronic or hard copy also.