Patent ID: 6914900
Filing Date: 2005-07-05
Classification: H04L

Abstract:
1. A communication device connection method for connecting a call originating terminal to a call terminating terminal via an IP network, comprising: a first step of setting how to evaluate communication quality; a second step of evaluating communication quality along a route through the IP network from a switching system on an originating side to a switching system on a terminating side when a call originate request has been issued to connect the originating terminal to the terminating terminal via the IP network; a third step of connecting the originating terminal and the terminating terminal if the communication quality is good; and if the communication quality is bad, a fourth step of controlling connection of the communication device in accordance with a command from the caller or controlling connection of the communication device by selecting a route other than the first-mentioned route automatically in accordance with a determination made by a switching system, wherein in a case where said communication quality is evaluated by a pre-call voice-quality measurement mode said second step includes the steps of: sending a test packet from the switching system on the originating side to the switching system on the terminating side via the route through the IP network before a channel is established; sending an ACK packet from the switching system on the terminating side to the switching system on the originating side in response to receipt of the test packet; measuring, at the switching system on the originating side, delay time from sending of the test packet to receipt of the ACK packet; and determining whether communication quality is good or bad based upon a comparison of length of the delay time and length of a set time; and wherein in a case where said communication quality is evaluated by a past-call voice-quality measurement mode, said second step further includes the steps of: storing communication-quality data including packet loss rate that prevailed during a previous call after the previous call ends; and determining whether communication quality is good or bad by referring to the communication-quality data that has been preserved.