| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an automatic exchange system for fault alternation on a PNNI network by which the efficiency of data transfer can be prevented from being lowered even when a circuit fault occurs. SOLUTION: When a call is disconnected by a current fault during communication between a caller terminal 1 and a caller terminal 2 on an optimum route 6 and call setting is performed for an alternate route 7, call setting information and a route designation list used for call setting are preserved. When the recovery of the circuit fault is detected from a change in PNNI topology information, the weight of a circuit to the alternate route 7 and the optimum route 6, where the fault of the circuit is recovered, is compared. When it is judged that the optimum route 6 is optimum, call setting is performed to the optimum route 6, then the optimum route 6 and the detour route 7 are switched to/from each other. After the circuit fault is recovered, the circuit is automatically switched to the line of the optimum route 6.</p> |
