| 摘要 |
<p>PURPOSE:To effectively select a trunk line and to evade the selection of a line of inferior line quality hy providing the line selection system with a mechanism which evaluates the line quality level of the line periodically, and employing its evaluation result as one condition of the line selection. CONSTITUTION:Packet exchanges 11, 12, and 13 are connected by lines 21, 22, and 23 to obtain triangular constitution. The packet exchanges select trunk lines, but sequential selection or rate selection is determined according to predetermined data. Further, the adequacy of the line is decided by using a line quality level table to select the line. Here, a quality decision mechanism changes decisions of the line quality level table. The line selection system has a sequential selecting mechanism 2 and a rate selecting mechanism 3, which include line selecting mechanisms 5 and also have line quality decision mechanisms 1 respectively. The line quality decision mechanism 1 is actuated periodically to output the latest data to the line quality level table 4 through an information gathering means for line error information, a quality decision means for line error quality, and a line quality level table, for each line, thereby updating the table.</p> |
