TCP/IP is very close to OSI but in a few ways there are differences. In the network layer, TCP/IP delivers data in datagrams of 64k length. OSI however, uses CLNS for communication. In TCP/IP, the datagrams can sometimes get mixed up or lost.

     The OSI consists of 7 layers while TCP/IP has only 4. TCP/IP is simpler since it has fewer layers. The layers of TCP/IP are very broad in scope.

www.cellsoft.de/telecom/tcpiposi.htm

http://www.scribd.com/doc/14206202/Difference-Between-OSI-and-TCPIP-Models

www.buzzle.com/articles/tcpip-model-vs-osi-model.html