Q: @Jon, But john in the applications where we do not need all 7 layers, only upto the network layer suffice to have a data transfer kind of interface over Ethernet?
A: You don't have to use the whole stack. Something like the User Datagram Protocol (UDP) might suffice. Take a look at: http://en.wikipedia.org/wiki/User_Datagram_Protocol. You can access it at the Transport layer. Also, see: http://cache.freescale.com/files/microcontrollers/doc/app_note/AN2304.pdf.
For industrial control applications, or even a simple assembly line, that machine can go almost 24/7 without a break. But what happens when the task is a little more complex? That’s where the “smart” machine would come in. The smart machine is one that has some simple (or complex in some cases) processing capability to be able to adapt to changing conditions. Such machines are suited for a host of applications, including automotive, aerospace, defense, medical, computers and electronics, telecommunications, consumer goods, and so on. This discussion will examine what’s possible with smart machines, and what tradeoffs need to be made to implement such a solution.