| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a packet relay device and a semiconductor chip by which a real time performance can easily be assured so that technology of Ethernet (R) and TCP/IP can be applied to a control system in an automation field or the like. <P>SOLUTION: The packet relay device 101 has a timer 141 which counts the present time, preliminarily counts predicted arrival time to a destination node which may be a candidate and holds it in an arrival time table 142. When a packet including time information is received, a transmission queue control and time calculation part 131 calculates allowed time from the present time, the time information included in the packet and the predicted arrival time and gives priority to a packet with less allowed time. Furthermore, the transmission queue and time calculation part 131 calculates the allowed time from the present time, the time information included in the packet, the predicted arrival time and time required for transmitting other packets, when temporal violation is recognized, a packet buffer control and exception packet processing part 121 transmits an exception packet corresponding to the temporal violation. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
