Sequential switching of relay servers according to server state

Abstract

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.

Description

[0001] Cross References to Related Applications [0002] This application is based on and claims priority from Japanese Patent Application No. 2005-316379 filed on October 31, 2005, the entire contents of which are incorporated herein by reference. technical field [0003] An embodiment of the present invention relates to a communication control method in a communication system that performs information communication through an IP (Internet Protocol) network and includes a router having a conversion function of a private address and a global address. Background technique [0004] In recent years, a system for transmitting IP-packetized data (IP-packetized data) such as voice, video, modem, facsimile, etc. through an IP network has been widely used. In the IP network, a router is a key device. Routers route IP packets based on destination and source addresses. [0005] This type of communication system can be constructed using multiple networks through routers. In such a s...

AI Technical Summary

Problems solved by technology

However, signal paths need to be established between the address resolution server and all terminals in advance, and point-to-point communication between terminals cannot be performed

[0009] As described above, when a NAT router is set in a communication system via an IP network, the NAT router may restrict communication between terminals on different networks

To prepare for such situations, a relay server is set up, but the load on this relay server increases with the traffic

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