Research of Applying Random Early Blocking strategy to 应用随机早期阻断策略研究课件.ppt

The Research of Applying Random Early Blocking strategy to Dynamic Lightpath Routing Outline Background Related works SCP, WSCP, EWSCP Layered-Graph model Simulation of routing strategies Random Early Blocking (REB) Simulation results Conclusion Background Communication service More bandwidth is needed by customs The poplar services Internet, cell-phone…… Background WDM (Wavelength Division Multiplex) Wavelengths are carried on a fiber Bandwidth grows much Background WDM network routing strategies Fixed routing Alternative routing Adaptive routing Routing Wavelength Assignment (RWA) Wavelength continuous constrain Wavelength conversion Converter placement The adaptive routing strategies To search lightpath as calls coming in Routing information Distance vector (RIP) Link state (OSPF) Adaptive routing – Related works Shortest Cost Path (SCP) The path cost function Equal-weighted link cost Disadvantage Some links may be heavy traffic load Higher blocking probability Adaptive routing – Related works Weighted Shortest Cost Path (WSCP) Distributing traffic load Better network utilization Lower blocking probability The path cost function Liner link cost function assignment Adaptive routing – Related works Exponential Weighted Shortest Cost Path (EWSCP) Light load? shortest path Medium load? load balance Heavy load? avoid exhaust all wavelength on a link Link cost function Layered-graph model Physical network topology N(R,L,W) R is the set of routing nodes L is the set of links W is the set of wavelengths per link Layered-graph model – logical network Layered-graph model – logical network N’(V,E,X) V is the set of routing nodes E is the set of links X is the set of wavelengths per link R’ is the set of routing nodes with conversion Number of V is : Number of E Simulation parameters W=32 per network link Full converter, sparse converter, non-converter Different network topologies Network traffic : Link congestion index : Network topology Network top