Network Constraints. WSON Route Calculation Key Technology Research

In the 21st century, with the development of internet technology such as peer-to-peer services, the world networks band width demand's yearly rate reaches as high as 50%-100%. The next transport networks drove by broadband data services are evolving to high speed, large capacity, ultra long distance and intelligent network is the trend. WSON (Wavelength Switched Optical Networks) is the intelligent WDM (Wavelength Division Multiplexing) networks standard in the core transport networks of OTN (Optical Transport Networks) and the third all-optical networks advocated by IETF group which is also named of ASON (Automatically Switched Optical Network) based on WDM transport networks.In the WSON's optical layer, the cross connection is lambda which is different with circuit layer cross connection in switching. On the one hand, wavelength continuity constrains the optical control plane routing and wavelength allocation (RWA) due to unmature all-optical wavelength conversation. On the other hand, due the lack of 3R regeneration, optical signal quality may degrade seriously in long-haul transmission systems. So it is needed for WSON networks to develop novel impairment-aware RWA (IA-RWA) algorithm. In order to slove the above problems, the key technologies about two types of constrain routing computation are analyzed in GMPLS-based (Generalized Multiprotocol Label Switching) distributed control plane and PCE-based (Path Computation Element) centralized control plane.The main innovative contributions are listed as follows.Firstly, in order to solve the network blocking problem caused by inaccurate traffic engineering (TE) based on routing strategy in GMPLS-based distributed control plane, a novel PCE-based RWA algorithm and wavelength reservation strategy are proposed in the article. In the novel RWA model, the failures in forward wavelength reservation are degraded due to the centralized PCE-based wavelength reservation strategy by global TE belong to PCE. The TE synchronization time is decreased by extending the PCEP (PCE Communication Protocol) to synchronize TED (TE Database). The path setup delay is decreased by once signaling message. Meanwhile, in order to degrade the collision probability in backward wavelength reservation based on signaling strategy, a novel backward-recursive PCE-based RWA algorithm model is proposed in the article which can detect valiable wavelength by backward-recurision based on PCE.Secondly, the traditional distributed control plane is hard to reroute accurately for multi-failure in mutli-area networks due to the distributed routing computation. A novel PCE-based fast reroute algorithm model with rerouting message buffer and centralized computation function is proposed in the article which can effectively decrease the wavelength collision when rerouting multi-path caused by multi-failure and can improve the networks survivability consequently.Thirdly, in view of the different control plane bandwidth the OSPF-TE convergence is compared and analyzed under great quantity physical impairment advertisements in real networks. As a result, a novel synchronization physical parameter database (PPD) schema by extending PCEP to advertise physical impairments is proposed in the article which can decrease the physical impairment advertisement numbers. In addition, a novel physical impairment advertisement schema using data lossless compression is proposed which can eleviate the physical impairment adverstisements size. Through the above two schemas, the infection of physical impairment advertisement can be eleviate in limited bandwidth control plane networks. In addition, in order to support the impairment-aware optical control plane, the standard GMPLS routing protocol OSPF-TE and PCE protocol are extended based on previous study.Forthly, according to the standard of ASON/WSON/PCE/GMPLS, WSON simulation software is developed and its architecture is introduced in the article. The agile software architecture can be easily extended to multi-layer multi-area optical networks simulation.Fifthly, because control plane networks are distributed, it has to cost more fees to setup experimental networks using one PC to simulate one control plane node. A novel VM-based (Virtual Machine) experimental networks method using one PC to simulate many control plane nodes is proposed in the article which can effectively decrease experimental cost.