| 摘要 |
According to one embodiment, a communication control method of a communication system which connects an IP network to plural networks including IP communication devices through routers provided for respective networks, which communicates between the IP communication devices of the different networks through the IP network with IP-packetized data, and which contains plural relay servers including a first and second relay servers, the method includes: determining whether peer-to-peer communication between the IP communication devices can be conducted by using a test packet through the first and second relay servers and the router; relaying the IP packet by the first or second relay server between the IP communication devices determined that the peer-to-peer communication cannot be conducted; and sequentially switching a relay server to relay the IP packet according to a state of the first relay server, from the first relay server to a relay server other than the first relay server. |
