| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To guarantee telephone speech quality even if an NGN accommodates an IP-PBX. <P>SOLUTION: When an Sip server 30 receives an Invite message from a caller IP telephone device 10, it relays a band testing-Invite message loaded with a command to allow a called party IP telephone device 20 to respond an address of self-device to an IP-PBX40, calculates telephone call routes for the caller IP telephone device 10 and the called party IP telephone device 20 based on a call location address of the called party IP telephone device 20 obtained from the called party IP telephone device 20 via the IP-PBX40 with the command, determines availability of band guarantee for the calculated telephone call route, and specifies the called party IP telephone device 20 to ring if it determines that the band guarantee is available or notifies the called party IP telephone device 20 of a Cancel message if it determines that the band guarantee is not available. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
