发明名称 Packet-switched telephony with circuit-switched backup
摘要 A packet voice switch 60 and method for its operation are disclosed. The switch comprises a network switching means, preferably implemented within its host processor 78, that allows calls to be routed between a circuit-switched connection at circuit-switched interface 74 and either another circuit-switched connection at interface 74 or a packet-switched connection at packet-switched interface 76. The network switching means selects call routing for calls based on a comparison of the current quality of service for the call over the packet-switched connection vs. the extra cost of connecting the call over the circuit-switched connection. Preferably, the comparison can be adjusted for call distance, the user's own quality of service preference, and current system load.In a preferred embodiment, switch 60 communicates with a similar packet voice switch (handling the other end of the same call) in order to initiate a mid-call network switch that is transparent to the calling and called parties. This embodiment provides a guaranteed minimum quality of service for packet voice applications, and provides a reliable backup in case of a packet data route failure.In a second embodiment, users may initiate network switching themselves if they desire higher quality, by entering an appropriate sequence on their DTMF keypad.
申请公布号 US6781983(B1) 申请公布日期 2004.08.24
申请号 US19990304032 申请日期 1999.05.03
申请人 CISCO TECHNOLOGY, INC. 发明人 ARMISTEAD R. ASHBY
分类号 H04L12/28;H04L12/64;H04M7/00;(IPC1-7):H04L12/56 主分类号 H04L12/28
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