In order to solve the problem of using the passage resource insufficiently and loading imbalance in passage plan of SDH bidirectional multiplexing section protection ring
a new passage plan algorithm based on shortest path splitting loading is presented in this paper. This algorithm combine advantage of shortest path loading algorithm with balance loading algorithm can satisfactorily meet the requirements of eco- nomical efficiency
security etc. in SDH network engineering design. By using the algorithm
an example optimizing SDH ring networks passage plan has achieved obvious effect.