In the SDH transmission system and the SDH transmission system the transmission path choice manner

摘要

PROBLEM TO BE SOLVED: To select a path by calculating a propagation delay without considering an actual path length and an actual node delay. ;SOLUTION: On the occurrence of the necessity of switching from an active path 61 to a bypass due to any reason in a transmission line network where a plurality of communication paths are in existence, a path 62 is selected as the bypass. Multi-frame decode sections 81, 82 decode a multi-frame signal to establish synchronization of multi-frame, and a phase difference detector 15 obtains the phase difference of signals through the active path 61 and the bypass 62 to obtain the transmission delay of the bypass 62 with respect to the active path 61. A controller 11 controls a selector 12 to select the bypass 62 when the transmission delay is within a set value. Thus, the propagation delay of the bypass 62 can be measured without knowing the actual path length and the actual node delay.;COPYRIGHT: (C)2000,JPO