OutlineOptical Flow Switching MotivationOFS Motivation (cont)Optical Flow Switching StudyConnection Setup InvestigationMethodologyIdeal Approach IllustrationTell-and-Go Approach IllustrationReverse Reservation Approach IllustrationSimulation DescriptionSimulation TopologyLatency-free Control Network Results (1sec flows)PowerPoint PresentationInteresting PhenomenonScheduled OFS in ONRAMPScheduling in ONRAMPONRAMP Connection SetupAlgorithm TimelineUtilizing Link CapacityExperimental SetupOFS PerformanceCurrent Performance LimitationsCurrent Performance Limitations(cont.)LIDSMITOutline•Motivation•Simulation Study•Scheduled OFS•Experimental Results•DiscussionLIDSMITOptical Flow Switching MotivationIP router IP router IP routerWDM WDM WDMIP router IP router IP routerWDM WDM WDMIP router IP router IP routerWDM WDM WDMWithout flow switchingRouter initiated flowsEnd-end flows•OFS reduces the amount of electronic processing by switching long sessions at the WDM layer–Lower costs, reduced delays, increased switch capacity–Provide specific QoS for advanced servicesLIDSMITOFS Motivation (cont)Flow Size1KB 1MB 100MB10MBNumber of FlowsTotal BytesFlow Size1MB 100MB10MB1KBOptical DomainElect. Domain Optical DomainElect. Domain-Internet displays a “heavy-tail” distribution of connections-More efficient optics => more transactions in optical domain (red line moves left)LIDSMITOptical Flow Switching Study•Short-duration optical connections –Access area–Wide area•Network architecture issues–Connection setup–Route/wavelength assignment–Goal: efficient use of network resources I.e. high throughput•Previous work: “probabilistic” approaches–Difficulty: high-arrival rate leads to high blocking probability–Problem: lack of timely network state information•Our proposed solution: Use of timing information in network–Schedule connections–Gather timely network state information•This demonstration–Demonstrate flow switching–Demonstrate viability of timing and scheduling connections–Investigate key sources of overhead–High efficiencyLIDSMITConnection Setup Investigation•Key issue:–How to learn optical resource availability?–Distribution problem–“Wavelength continuity” problem makes it worse •Previous work–Addresses issues one at a time–Assumes perfect network state information–Will these results be useful for ONRAMP, WAN implementation?•This work–Assesses effects of distributed network state information–Models some current proposals MP-lambda-S ASONLIDSMITMethodology•Design distributed approaches –Combined routing, wavelength assignment–Connection setup•Baseline flow switching architecture–Requested flows from user to user–Durations on order of seconds–All-optical•Simulate approaches on WAN topology–End-to-end latency (“time of flight” only)–Approaches: Ideal, Tell-and-Go, Reverse Reservation•Assess performance versus idealized approach–Blocking probabilityLIDSMITIdeal Approach IllustrationA C BD-Changers-Changers-Changers-ChangersA C BDBidirectionalMulti-fiber LinkNetwork Infrastructure“Tell”cntl packetLLR Routing, Connection SetupOptical FlowAssume: Flow Requested from A->BLIDSMITTell-and-Go Approach IllustrationA C BDLink-stateUpdatesAvailable : 1,2,3Available : 1,2Available : 2,3 Available : 2,3,4Link-State ProtocolA C BDOptical FlowConnection Setup“Tell” Packet - Single wavelengthAssume: Flow Requested from A->BLIDSMITReverse Reservation Approach IllustrationA C BDInformation PacketsA C BDRoute DiscoveryRoute Chosen by BReservationPacketAssume: Flow Requested from A->BRoute, Wavelength ReservationLIDSMITSimulation Description•Results shown as Blocking Probability vs. Traffic Intensity–Uniform, Poisson flow traffic per node•Fixed WAN topology•Parameters:–F = Number of fibers/link–L = Number of channels/link–K = Number of routes considered for routing decisions–U = Update interval (seconds) = Average service rate for flows (flows/second) = Average arrival rate of flows (flows/second) = Traffic intensity. Equal to / not utilization factorLIDSMITSimulation TopologyLIDSMITLatency-free Control Network Results (1sec flows)RR: F=1, L=16, K=10 TG: F=1, L=16, K=10Title:Creator:gnuplotPreview:This EPS picture was not savedwith a preview included in it.Comment:This EPS picture will print to aPostScript printer, but not toother types of printers.LIDSMITControl Network With Latency Results (1sec flows)Title:Creator:gnuplotPreview:This EPS picture was not savedwith a preview included in it.Comment:This EPS picture will print to aPostScript printer, but not toother types of printers.TG, RR: U=0.1, F=1, L=16, K=10LIDSMITInteresting Phenomenon•Why is TG performance better than RR?–1 sec flows and large rho => small inter-arrival times Smaller than round trip time–Thus, with high probability, successive flows will see same state (at least locally)–Increases chance of collision Effect of distribution (latency)•Why is Rand better than FF?–This is exactly opposite of analytical papers’ claim–Combination of reasons Nodes have imperfect information FF makes them compete for same wavelengths (false advertisement)–Not seen in analysis because distribution was ignoredLIDSMITScheduled OFS in ONRAMP•Inaccurate information hurts performance–In this case: Simple speed of light–Biggest problem: Core network resources wasted•Our proposal: Use of timing information to schedule flows–Deliver network information on time to make decisions–Exchange flow-based information–Maximize utilization of core network–Possible small delay for user•Issues–Can timing be implemented cheaply, scaled?–Can schedules be implemented?–Must make use of current/future optical devices–Low cost•ONRAMP OFS–Demonstration of scheduled OFS in access-area network–One example of an implementationLIDSMITFixed XponderTunable XponderAccess Node #2OXCRouterGE GEIPFLOWIPControlXmitter (X)Fixed XponderTunable XponderAccess Node #1RouterOXCGE GEIP FLOWIPControlIntermediate NodeOXCOXCRouterRouter•Receiver (R )Fixed XponderTunable XponderAccess Node #2OXCGE GEIPFLOWIPControl)Fixed XponderTunable XponderAccess Node #1RouterOXCGE GEIP FLOWIPControlIntermediate NodeOXCOXCRouterRouterX-R-OXC Sched OXC SchedOXC SchedScheduling in ONRAMPLIDSMIT•Uses timeslotting and schedules for lightpaths•X => i busy on output