In order to address the problem of spectrum allocation for time-varying services in flexgrid optical networks
this paper proposes a novel scheme of spectrum allocation
which is mainly based on Non-Contiguous Virtual Connections(NCVC).In this scheme
new non-contiguous spectrum blocks can be allocated to satisfy the increased bandwidth requirement of the service transmission without changing the already allocated spectrum blocks.Simulations are performed on the simulation platform built by using the OMNeT++ software and the numerical results show that this scheme can effectively reduce the network blocking probability and improve the utilization efficiency of network spectrum sources.