Fig. 1. Flow chart of CODS-RSA algorithm

Fig. 2. Preliminary calculation control model of CODS-RSA algorithm

Fig. 3. Service request response time of preliminary calculation control model in CODS-RSA algorithm

Fig. 4. Diagram of link spectrum allocation in network

Fig. 5. Flow chart of optimal allocation algorithm

Fig. 6. Simulation results. (a) Average establishment delay of optical path; (b) blocking rate; (c) spectrum utilization