| 摘要 |
<p>A callback system performs callback to notify a call available state, when a network bandwidth becomes wide enough to secure the call quality in an Internet phone which receives call admission through an admission control server. An originating Internet phone sends an admission request message for requesting admission of a necessary network bandwidth to the admission control server using a user interface. Upon receipt of the admission request message from the originating Internet phone, an admission control server determines whether the requested network bandwidth is acceptable or not, and sends an admission reject message to the originating Internet phone, when the admission-requested bandwidth is not acceptable. Upon receipt of the admission reject message, the originating Internet phone sends a callback request message to the admission control server. Upon receipt of a callback request message from the originating Internet phone, the admission control server sends a callback message to the originating Internet phone when the network bandwidth requested by the originating Internet phone is secured. <IMAGE></p> |
