With increasing traffic, legacy SONET/SDH-metro rings have mostly been upgraded using point-to-point WDM (PPWDM) transmission. For cost-effective realization, WDM metro networks also employ wavelength-routed optical networking (WRON), where a wavelength is bypassed optically at intermediate nodes. Metro networks are generally split into core and edge rings, with the metro-core ring interfacing with the long-haul backbone and the metro-edge ring interconnecting the metro-core ring with the access segment. The PPWDM/WRON transmission is employed with each wavelength using circuit-switched SONET/SDH transmission, though the metro-edge rings can also use packet-switching to enhance bandwidth utilization with bursty traffic from the access segment. In this chapter, we consider first WDM metro networks using PPWDM/WRON-based rings and present their design methodologies using LP-based and heuristic schemes. We describe some packet-switched WDM ring testbeds and examine the possible improvement in bandwidth utilization therein, as compared to the circuit-switched WRON rings. (143 words)
An ns-3 implementation of a bursty traffic framework for virtual reality sources