| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To economically improve the reliability against communication failures of a provider communication network. <P>SOLUTION: A packet transfer device 1 converts a packet to be transferred to a packet transfer device 2 into a format for the provider communication network to be a current communication path between the packet transfer device 1 and the packet transfer device 2. The packet transfer device 1 periodically confirms whether a failure occurs in a communication path via respective provider communication networks PNW1, PNW2 and PNW3 for each provider communication network between the packet transfer device 1 and the packet transfer device 2 for respective provider communication networks. When it is determined that a failure occurs in the current communication path, the packet transfer device 1 performs communication path switching that makes a communication path via a provider communication network determined to have no failure occurrence to be a current communication path. <P>COPYRIGHT: (C)2004,JPO&NCIPI</p> |
