| 摘要 |
PROBLEM TO BE SOLVED: To quickly switch communication routes when a communication route has abnormality.SOLUTION: In a designated router 20a, a writing unit 40 writes information indicating that a relay target packet has passed through the designated route 20a in an option part of an IP header of the packet. In a router 20, a monitoring unit 50 monitors an option part of an IP header of a received packet whether the information indicating that the packet has passed through the designated router 20a is written, and a reconstruction unit 55 reconstructs a route on the basis of a monitoring result by the monitoring unit 50 if not receiving the number of packets in which the information indicating that the packet has passed through the designated router 20a is written, the number being equal to or more than a predetermined threshold. |
