SYSTEM FOR SUPPLYING AN INSTANT MESSENGER AND A PUSH-TO-TALK SERVICE IN WIRELESS IP NETWORK, CONCERNED WITH REDUCING A DELAY TIME OF PTT AND IM(INSTANT MESSAGING) FUNCTIONS WHILE IMPROVING PERFORMANCE OF PROGRAM

摘要

PURPOSE: A system for supplying an instant messenger and a PTT(Push-To-Talk) service in a wireless IP network is provided to reduce or remove a time for setting a wireless channel, and to select an access network optimal to an application program, thereby reducing a delay time of PTT and IM(Instant Messaging) functions while improving performance of the program. CONSTITUTION: When an MS(Mobile Station)(108) is powered on, the MS(108) forms a PPP connection with a PDSN(103) to perform a packet data process. When a simple IP is used, the PDSN(103) assigns an IP address to the MS(108). A PTT system supports various "presence" information of subscribers. The MS(108) registers the IP address in a home SIP server(100) whenever the self IP address is changed. If someone tries to send data, the SIP server(100) searches the current IP address of the MS(108). The MS(108) is in dormant state at which a dedicated channel is not assigned, when data is not transmitted.