Method of link status reporting using media independent handover

A link state reporting method using an MIH(Media Independent Handover) function is provided to be capable of knowing whether packet loss occurs by congestion or by non-congestion caused by a wireless section and handover, with the use of the MIH function when the packet loss occurs. A client and server of a TCP(Transmission Control Protocol) establishes a link with each other(S1810). The TCP transmits a registration message which requests an MIH entity to deliver an event in the future and to discover whether a correspondent node supports an MIH function(S1820). The MIH entity transmits an MIH_Capability_Discover.request message to a correspondent IP(Internet Protocol) address included in a TCP_Registration.request message(S1830). The MIH entity drives a timer itself(S1840). A TCP of the correspondent node discards the delivered MIH message(S1850), and transmits a message indicating that the correspondent node does not support an MIH function, to the TCP(S1860).