| 摘要 |
<p>A telephone network redirects calls intended for an Internet Service Provider (ISP) to one of a plurality of available Internet Protocol (IP) gateways operated by the ISP. A call is received by the telephone network at an originating switch from a subscriber's calling terminal, the call directed to a toll-free-number or a central number (TFN) for the subscriber's ISP. The originating switch interacts with the signaling network via a coupled service switching point (SSP) to request a Dialed Number (DN) corresponding to the TFN. In one operation, the destination switch (or a Private Branch Exchange "PBX" coupled to the destination switch), instead of completing the call, redirects the call to a new IP gateway coupled to a new destination switch or coupled PBX. In redirecting the call, the destination switch provides a CAUSE INDICATOR, the new called number (CLD) of the selected IP gateway, the Destination Point Code (DPC) of the new destination switch and the IP address to use at the new IP gateway. The destination switch then releases the call to the telephone network. The call is routed between the originating switch and the new destination switch via a lowest point in the traffic network so that a minimum set of resources of the traffic network are consumed. The call is then setup between the subscriber's calling terminal and the new IP gateway via the originating switch and the new destination switch. An Internet session is then setup and serviced between the new IP gateway and the subscriber's calling terminal. The call may be first routed to a PBX operated by the ISP that couples to the destination switch and the PBX redirects the call to a new IP gateway via a new destination switch. The signaling network may redirect the call to a new IP gateway before the call is routed to the destination switch. The call may be terminated to the ISP facility (e.g., IP gateway) via the destination switch before the call is redirected to the new IP gateway via the new destination switch. The destination switch (or PBX) may also make a call to the new IP gateway to ensure its availability. Once the call to the new IP gateway is completed via the destination switch, the call is released back into the telephone network for rerouting via a lowest point. <IMAGE></p> |
