| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To obtain an IP address of a connection object terminal required for the Internet VPN without extending a function for an expensive dedicated line and a dynamic DNS support if there is a connectivity of an SIP. <P>SOLUTION: An SIP terminal A101 supported by an SIP protocol has only a public SIP address. The SIP terminal A101 sends a first SIP method containing a keyword to urge an IP address information notice to an SIP terminal B103 directed by the public SIP address. The SIP terminal B103 which has received the first SIP method checks up the keyword (602) and sends a second SIP method by using its own address as IP address information. The SIP terminal A101 which has received the second SIP method extracts the IP address of the SIP terminal B103 from the second SIP method containing the IP address information (609). <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
