This paper investigates the self-adaptive transmission control architectures (SATCA) in impairment-aware transparent WDM networks. Two approaches are proposed for the implementation of SATCA. Simulations are conducted to evaluate the benefits obtained by applying SATCA.
In the transparent WDM networks, the control plane based on GMPLS protocols introduces connection intelligence into the optical networks. However, since dynamic setup/teardown of connection or fast re-route may introduce unpredictable physical impairments(i.e., fluctuation of optical power and residual dispersion) into the lightpath and in all-optical networks these physical impairments will accumulate along the lightpath, the optical signal quality and service survivablity can not be guaranteed. Therefore, the future optical networks should also have self-adaptive optical transmission ability to guarantee the physical quality of connections.
Two proposed approaches to implement SATCA separately introduce extensions to routing protocols (routing-based approach) and signalling protocols (signaling-based approach) of GMPLS. For both approaches, the lightpath quality estimation (LQE) module, which is applied to evaluate the lightpath's QOT and make the compensation budgets, should be added to the optical control plane.
The purpose of the simulations is to research the effect of SATCA approaches on the lightpath performance. We suppose that if OSNR or RD is out of the acceptable range, the lightpath is refused. So the blocking probability can be used for comparison among the signaling-based approach,routing-based approach and the traditional approach which is without considering physical impairments. Since the lightpath performance can be improved in the SATCA approach, the quality of lightpath is greatly guaranteed.