Hi! can any one explain me what is mean of protocol stack? Regards
This is the point where we quibble about whether or not a cell phone or telco switch is a "computer"... (I think so, at least for this purpose. But of course you can counter-quibble that there exist protocols that don't involve computers -- say, Morse code, or semaphore, and the address that sends the telegram on beyond the receiving telegraph station; or proper etiquette when "calling CQ" or "breaking" into a CB channel.)