| 摘要 |
<p>PROBLEM TO BE SOLVED: To enable routing switching based on a congestion without prolonging the communication disable time of an IP packet and unnecessarily increasing a traffic. SOLUTION: An L2 frame (IP packet (IPP)) is received by the first or second L2 control part 4 (L2), the state of a route transferring this frame is investigated by a routing control part 6 and when the state is abnormal, this route is deleted from a virtual routing table 10 (VRTBL) by a routing topology managing part 8. Then, the next route is retrieved from the VRTBL by a transmission destination IP address(IPAD) and this IPP is transmitted from L2 of the retrieved route. Besides, when the route of transfer is normal, the next route is retrieved from a routing table 9 by the IPAD, the state of the retrieved next route is investigated and when the state is normal, this IPP is transmitted but when the state is abnormal, the next route is retrieved from the VRTBL by the IPAD. Then, this IPP is transmitted from L2 of this retrieved next route.</p> |
