Learning TCP/IP

I have been spending the past couple of days reading information on the TCP/IP protocol suite. I want the key concepts and ideas to be knowledge in my mind. See I believe that there is a point when learning where; the things that you are reading, studying and thinking about, become things that you know, and the knowledge is secured into you mind.
It can take a while for this to happen, with somethings, yet eventually the knowledge becomes Your knowledge.

I started out by studying the following RFC's:
RFC 790 - Assigned numbers
RFC 791 - Internet Protocol:
RFC 793 - Transmission Control Protocol
RFC 1122 - Requirements for Internet Hosts - Communication Layers
RFC 1123 - Requirements for Internet Hosts - Application and Support
RFC 1180 - TCP/IP tutorial
Also if you are looking for a really good explanation of the OSI reference Model then wikipedia has one here: OSI model From Wikipedia

I started reading The TCP/IP Guide; from chapter: Networking Fundamentals. This is a very fully on book about TCP/IP. I am enjoying reading it, even though at times it feels a little flowery, and I think that some of the explanations could have been a little clearer. Yet I understand how hard it is to make a complex subject manageable.
I hope to continue reading through this guide today. It will take me a while to get through I imagine.