150 likes | 370 Views
TCP/IP Performance across Optical Packet-Switched (OPS) Networks. Jingyi He ( Co-supervised by Dr. Gary Chan and Dr. Danny Tsang ) Apr. 25, 2002. Outline. The perspective of OPS networks Special features of OPS networks (our research motivations) Deflection routing Packet aggregation
E N D
TCP/IP Performance across Optical Packet-Switched (OPS) Networks Jingyi He (Co-supervised by Dr. Gary Chan andDr. Danny Tsang) Apr. 25, 2002
Outline • The perspective of OPS networks • Special features of OPS networks (our research motivations) • Deflection routing • Packet aggregation • Simulation model and results • Conclusions
Towards the Optical Internet… • Current Internet • Point-to-Point WDM links • Electronic routers (switches) O/E/O conversion Electronic bottleneck • Near-term Solution: Wavelength-Routed Networks
Wavelength-Routed Networks • Electronic routers Wavelength-routing switches • Lightpaths • Problem: circuit switching low bandwidth efficiency
Optical Burst-Switched Networks • A compromise between circuit-switching and packet-switching • A control packet is first sent to set up the “connection” for a burst, which is released as soon as the burst is sent • Bandwidth is reserved for a shorter time than circuit-switching higher bandwidth efficiency
The Eventual Solution…may be OPS Networks! • Large capacity • High bandwidth efficiency • Rich routing functionalities • Great flexibility and reliability
Special Features • Deflection Routing • A contention resolution scheme in case of no optical buffer • Packet Aggregation • To relieve the optical packet switches of the heavy burden of processing each individual (small) packet • Possible schemes: mixed-flow, per-flow
Motivations of Our Research • Deflection routing Out-of-order delivery of packets • Packet aggregation In case of deflection or packet dropping, the effect may be magnified What’s their impact on TCP/IP performance?
Simulation • Simulator: ns-2 • Simulation model:
Performance Metrics • TCP throughput (goodput) • TCP fairness among the flows • Jain’s Fairness Index: • f (0, 1], with f =1 meaning perfect fairness
Conclusions • Deflection routing significantly improves the TCP fairness • Mixed-flow aggregation outperforms per-flow aggregation in terms of both TCP throughput and fairness Q & A