End-to-end principle of Network System Design

The principle, called the end-to-end argument,
suggests that functions placed at low levels of a system may be redundant or of little
value when compared with the cost of providing them at that low level.

http://web.mit.edu/Saltzer/www/publications/endtoend/endtoend.pdf
or same paper at http://citeseer.ist.psu.edu/did/83743

"(Certain functions) can completely and correctly be implemented only with the knowledge and help of the application standing at the end points of the communication system. Therefore, providing the questioned function as a feature of the communication system itself is not possible."

http://www.acm.org/crossroads/columns/connector/may2001.html

http://en.wikipedia.org/wiki/End-to-end_principle