Comparison ofSwitching CostforRingOptical Backbone Networks

A point-to-point Wavelength Division Multiplexed (WDM) networkisan optical networkthatuseselectronic routers initsnodesforswitching. On theotherhand,inan Automatically Switched Optical Network(ASON), theswitching isdoneinoptical domain. Electronic switching ismoreexpensive thanoptical switching. Pass-through traffic, whichistraffic that goesthrough anodewithout originating orterminating atthat node,gives ameasureofswitching required ineachnode,and hencethecostofswitching. Inthis paper, wederive expressions forpass-through traffic andswitching costforaringtopology. Usingtheseexpressions, we showthat,intheworstcase, electronic switching inapoint-to-point WDM network isalmost 36times moreexpensive thantheoptical switching inanASON.