The internet is a very large and general term. It comprises millions of servers, routers, generally includes things like web browsers, http, etc.

TCP is just one protocol of the thousands of protocols used for the internet, typically to carry other protocols. UDP is also used on the internet.

"not all the logic" means that this implementation is not a full implementation of the TCP protocol.

Check out: http://en.wikipedia.org/wiki/Internet_protocol_suite http://en.wikipedia.org/wiki/OSI_model