To solve the problem that a bypass is required, an autonomous and small-scale routing table is required and it becomes necessary to immediately deal with the change of a communication path caused by power-on and power-off since the communication path is cut when the computer of each node is powered off in a neighboring network where routing selection is performed by directly connecting computers of nodes without installing an IP router nor a management server.

The system for packet communication in the neighboring network comprises: a means for connecting an arriving packets to all other outgoing paths, other than an outgoing path of the arriving packet at its incoming path side, when a computer is turned off; a means for using a small-scale routing table for collating the address of an adjacent node with the outgoing path; and a means for performing autonomous routing by using a neighboring packet, search packet, response packet, carrier packet, emergency packet, single completed packet and broadcast distribution packet having different roles.