1. Corporate Research Center - page 1 IP over ATM t IP over everything,..., PoS, PoATM, Ethernet, … t IP will be transported over whatever L1/L2 technology is best suited t ATM will be a player in the Internet arena, but will not dominate t Complexity t OC-48c+ SAR non-existent, while OC-48c PoS interfaces exist t Efficiency t cell tax, duplication of functions t Scalability t VP/VC space, payload size doesn’t scale with link speed t ATM’s prime qualities t Virtual connectivity: VPNs, multi-CoS networks t Installed base, QoS? t Co-existence with other, non-IP services

2. Corporate Research Center - page 2 IP over SONET t Higher utilization compared to IP/ATM (Sprint IP network) t Problems with SONET framing t TDM, designed mainly for voice service, not transparent to IP packets t Scrambling t Designers of new link technology are catering to the specific requirements of IP t Basic functions of SONET are still needed t Synchronization t performance monitoring t protection switching t Path protection switching at L3 ?

3. Corporate Research Center - page 3 IP over WDM t The capacity of a DWDM fiber is already beyond 160 Gbps, may well exceed 1 Tbps t Transmission systems t Virtual connectivity t Role in Metropolitan Area Networks t Optical packet/burst WDM networks t Natural move ? t To circumvent potential bottleneck of electronic processing t Challenges: t Synchronization, burst mode receiver, replace SONET functionality t Provide QoS due to lack of optical RAM t Optical WDM layer protection/restoration may still needed t Coarse, fast restoration