Abstract: The problem of dynamically establishing dependable connections in wavelength division multiplexing (WPM) mesh networks with traffic grooming capabilities was investigated. A disjoint routing scheme under shared risk link groups (SRLG) constraints was proposed. It was called multi-granularity shared sub-path protection (MSSP) scheme. The scheme searches a primary path for each connection request firstly, and then segments the path into several equal length sub-paths, and calculates their SRLG-disjoint backup paths. In order to obtain the optimal spare capacity, MSSP makes use of the backup multiplexing technology to share backup bandwidth among different backup paths if their corresponding primary sub-paths are SRLG-disjoint. Based on dynamic traffic with different load, the performance of MSSP was investigated via simulations. MSSP can improve the performance of the network significantly and make the tradeoffs between the resource utilization and recovery times.