SSPP firstly computes a minimum hop primary path for each connection request, and it follows to compute two SRLG disjoint and minimum cost backup paths for each sub-path on the primary path.

• 共享子通路保护为每条业务请求计算一条最短的工作路由，并为工作路由上每段子通路各计算两条共享风险链路组分离且代价最小的保护路由。