Patent ID: 8473591

Claim:
An information processing system comprising: an information processor; a server; and a communication processor for performing processing on communications between said information processor and said server; said information processor including: a history packet transmitter for transmitting via a plurality of ports of said communication processor a plurality of history packets as packets for determining a reference time of measuring a port keeping time of the communication processor; a request packet transmitter for transmitting to said server, via a port different from a plurality of history ports as the ports of the communication processor where said history packets have passed, a plurality of request packets as packets for requesting transmission of a return packet as a packet to be transmitted from said server, the plurality of request packets transmitted after a predetermined time has elapsed since transmitting the history packets; a packet transmission controller for controlling transmission of request packets by said request packet transmitter; a return packet receiver for receiving a return packet transmitted from said server via said history port; and a port keeping time detector for detecting the port keeping time of said communication processor based on reception of a return packet by said return packet receiver; said server including: a request packet receiver for receiving said request packet; and a return packet transmitter for transmitting said return packet to a history port corresponding to the request packet received by said request packet receiver among the plurality of history ports upon reception of request packets by said request packet receiver, wherein said port keeping time detector detects said port keeping time based on a wait time during which said return packet receiver has successfully received a return packet that reached the history port of said communication processor at the end of a wait time among the wait times, wherein wait time is an amount of time from a point in time a return packet reached the history port of said communication processor to a point in time a packet passed through the history port just before, wherein a packet that passes through said history port at the beginning of said wait time is said history packet and said packet transmission controller controls transmission of said request packet as well as controls transmission of a history packet by said history packet transmitter at the beginning of said wait time, wherein said port keeping time detector detects the port keeping time of said communication processor also based on transmission of a history packet by said history packet transmitter, and wherein in said port keeping time detector, a point in time a packet passed through said history port as the beginning of said wait time is a point in time said history packet was transmitted.