Algorithm 1. Details of the proposed AR-ISA algorithm.

AR-ISA Algorithm

1: Compute K shortest-paths for each node pair in the network 2: Set a MISR for the algorithm 3: while network is running do 4: When a service R arrives 5:  Select K pre-computed paths for R as its candidate paths 6:  Calculate the modulate level and the amount of the needed FSs on each candidate path for R 7:  for one path p in the K candidate paths do 8:   Calculate the ISR along p 9:   If the calculated ISR is larger than pre-set MISR then 10:    Postpone R according to the time interval between two successive services 11: end if 12:   Find available FSs on P for R 13: if available FSs are found on p then 14: Allocate the found FSs to R 15:   end if 16: break 17: end for 18:  If spectrum allocation for R is unsuccessful then 19:   Do spectrum fragmentation for the existing services 20: for one path pin the K candidate paths do 21: Find available FSs on P for R 22: if available FSs are found on p then 23: Allocate the found FSs to R 24: end if 25:  break 26: end for 27: end if 28:  If spectrum allocation for R is unsuccessful then 29:   Block R 30:  end if 31:  Update the network 32: end while