| 摘要 |
PROBLEM TO BE SOLVED: To realize restoration to initial delay quantity margin, without a hit in a signal under service provision, and to expand a route length fluctuation range for securing the state of enabling hit-less switching. SOLUTION: In respect to a change in the write phase of a 1-system VC frame to a delay buffer 111, due to a change in the route length of a 1-system transmission line 1D under operation, a phase delayed from the changed write phase of the 1-system VC frame to the delay buffer 111 by a delay quantity Δt2 (initial delay quantity margin) is defined as the read phase of the 1-system VC frame, and a phase delayed from the write phase of a 0-system VC frame to the delay buffer 110 by a delay quantity Δt3, obtained by adding the delay quantity Δt2 to a phase difference Δd' between the write phase of the 0-system VC frame and the changed write phase of the 1-system VC frame is defined as the read phase of the 0-system VC frame. In this case, the read phase is changed, by repeating stuff control in a fixed cycle. |
