Rerouting of packet exchanges by a mobile terminal is controlled so as to be optimized on a real time basis to prevent network resources from being wasted by redundant routing. In an initial state a route of data from a mobile communication terminal M to a CN 8, which is a communication partner, is a route R5. Then, an access router (AR) 72 acquires the number of hops of data received from the CN 8 by the mobile communication terminal M. As the mobile communication terminal M now performs a handover to under the command of the AR 73, the route will change to a route R9. Then the AR 73 detects that the route becomes redundant by the fact that the number of hops acquired after the shift is greater than the pre-shift number of hops received from the AR 72, and invokes control to reroute to a route R7, which provides the optimal routing.