| 摘要 |
<P>PROBLEM TO BE SOLVED: To reduce the processing load of a network and eliminate a processing delay when multiple data transfers are performed between the same terminal devices in a SIP based TCP connection. <P>SOLUTION: Edge routers 3a, 3b hold a NAT control purpose IP address space and a NAPT control purpose IP address space therein separately one from the other. For a communication method which reserves a communication path whose port numbers used in TCP are undetermined, NAT conversion is set to exert NAT control; for other communications, NAPT conversion is set to exert NAPT control. This makes it possible to reduce the processing load of a network without entailing a session change by a SIP signal, and, even when a terminal device 4a changes a port number to reestablish a TCP connection, the problem of a Time Wait state can be avoided without involving port number conversion in the edge routes 3a, 3b. <P>COPYRIGHT: (C)2012,JPO&INPIT |
