A method for providing seamless on-demand application service using DPI in IP network

This paper provides a method of providing a seamless on-demand service using a Deep Packet Inspection (DPI) function. A system for providing an on-demand service may include: a switch to recognize a signature of media, and to convert a resolution of media based on information associated with a resolution of media included in the recognized signature, a terminal resolution of a terminal held by a user, and a user requirement; an authentication management server to perform a terminal authentication or a user authentication; and a policy control server to set a path based on a terminal function, a media characteristic, and the user requirement.