Post on 02-Nov-2021
transcript
Institute of Telematics
OverSimA Flexible Overlay Network Simulation
Framework
Ingmar Baumgart, Bernhard Heep, Stephan Krause
IEEE Global Internet Symposium 2007, Anchorage, AK, USA
OverSim, GI07, Anchorage, AK, USAStephan Krause Institute of TelematicsUniversität Karlsruhe (TH) www.tm.uka.de
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Requirements
OverlayFlexibility Scalability
UnderlayHeterogeneityTerminal MobilityBackbone simulation
OverSim, GI07, Anchorage, AK, USAStephan Krause Institute of TelematicsUniversität Karlsruhe (TH) www.tm.uka.de
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Additional Requirements
InteroperabilityPlanetLabexperimentsNetwork emulation
Debugging and Overlay visualization
OverSim, GI07, Anchorage, AK, USAStephan Krause Institute of TelematicsUniversität Karlsruhe (TH) www.tm.uka.de
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State of the Art
No established standard overlay simulatorMost promising: P2PSim, OverlayWeaver and PlanetSimP2PSim (http://pdos.csail.mit.edu/p2psim/)☺ Many implemented overlay protocols
No real world interconnection, no visualizationOverlayWeaver (http://overlayweaver.sourceforge.net/)☺ Real world interconnection
No simulation of underlying network, not scalablePlanetSim (http://planet.urv.es/planetsim/)☺ Flexible and scalable
Only very simplistic model of underlying network
OverSim, GI07, Anchorage, AK, USAStephan Krause Institute of TelematicsUniversität Karlsruhe (TH) www.tm.uka.de
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Outline
How to implement all required features?Overlay layer: Flexibility, scalabilityUnderlay model: Heterogeneity, terminal mobility, backbone simulationInteroperability, network emulationDebugging and overlay visualization
Featured Overlays and Applications
Performance Evaluation and Validation
OverSim, GI07, Anchorage, AK, USAStephan Krause Institute of TelematicsUniversität Karlsruhe (TH) www.tm.uka.de
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Flexibility
Modular architectureBased on OMNeT++
Layered architectureUnderlying networkOverlay layerApplication layer
Consistent interfacesbetween layers
UDP between network and overlayCommon API between overlay and applicationExchange of one component is transparent to all
other components
Application Layer
Common API Interface
Overlay Layer
UDP Interface
Underlying Network
OverSim, GI07, Anchorage, AK, USAStephan Krause Institute of TelematicsUniversität Karlsruhe (TH) www.tm.uka.de
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Scalability
Tradeoff: Level of detail vs. simulation speedMaximum scalability SimpleUnderlayPackets are exchanged directly between nodes
Minimizes number of eventsSimple scenario: Constant delayFor more realistic delays:
Place nodes in Euclidian spaceDelay is proportional to distanceNo additional events needed Still scalable
OverSim, GI07, Anchorage, AK, USAStephan Krause Institute of TelematicsUniversität Karlsruhe (TH) www.tm.uka.de
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Heterogeneity and Mobility
Extension of the synthetic coordinate modelNodes are assigned to an “access net” with specific bandwidth and delay characteristicsCalculated packet delay:
Mobility: Move node to new coordinate, change access net characteristics and IP address
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OverSim, GI07, Anchorage, AK, USAStephan Krause Institute of TelematicsUniversität Karlsruhe (TH) www.tm.uka.de
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Backbone Simulation
For detailed simulation of the underlying network: INETUnderlayBased on INET framework for OMNeT++Simulates a complete IP backboneAccess routers attached to backbone routers
Simulates all effects of heterogeneous access networks
Bandwidth, Delay, Packet loss, Queuing effects
Mobility is simulated by moving a node from one access router to another
OverSim, GI07, Anchorage, AK, USAStephan Krause Institute of TelematicsUniversität Karlsruhe (TH) www.tm.uka.de
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Interoperation
For PlanetLab experiments and interconnecting with real world implementations:Emulated nodes inreal networks Event scheduler runs at real timeLinux TUN device forexchanging packetswith a real networkExternal applications canbe connected to the simulation
OverSim, GI07, Anchorage, AK, USAStephan Krause Institute of TelematicsUniversität Karlsruhe (TH) www.tm.uka.de
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Network Emulation
For demonstrational purposes:Real nodes in emulated networksEmulate overlay networkwith INETUnderlayAdd a gateway node
This router features a TUN interface
External devices can communicate with simulated overlay
OverSim, GI07, Anchorage, AK, USAStephan Krause Institute of TelematicsUniversität Karlsruhe (TH) www.tm.uka.de
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Visualization and Debugging
Topologyvisualization
Messagevisualization
Node statedebugging
OverSim, GI07, Anchorage, AK, USAStephan Krause Institute of TelematicsUniversität Karlsruhe (TH) www.tm.uka.de
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Overlay Protocols
Implemented overlay protocolsStructured: Chord, Pastry, Koorde, BrooseUnstructured: GIAGaming protocols/Multicast: VAST
Base class for structured overlays to facilitate implementation of new overlay protocols
Overlay message handling (RPC, statistics)Generic lookup functionBootstrapping supportOverlay topology visualization
OverSim, GI07, Anchorage, AK, USAStephan Krause Institute of TelematicsUniversität Karlsruhe (TH) www.tm.uka.de
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OverSim Performance Evaluation
Compare simulation speed with P2PSimUnderlay model:
P2PSim and OverSim/SimpleUnderlay:Constant delay of 50 msec
OverSim/INETUnderlay:Randomly generated backbone (40 routers)
Number of nodes: 1,000, 10,000 and 100,000Simulated time period: 1,000 secondsOverlay: Chord
Stabilize interval: 20 secFix fingers interval: 120 secEach node sends a query every 10 sec
OverSim, GI07, Anchorage, AK, USAStephan Krause Institute of TelematicsUniversität Karlsruhe (TH) www.tm.uka.de
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Performance Evaluation Results
OverSim is faster even with greater level of detail
OverSim, GI07, Anchorage, AK, USAStephan Krause Institute of TelematicsUniversität Karlsruhe (TH) www.tm.uka.de
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Validation: Chord Results
Simulation results are comparable to P2PSim’s
OverSim, GI07, Anchorage, AK, USAStephan Krause Institute of TelematicsUniversität Karlsruhe (TH) www.tm.uka.de
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Conclusion & Future Work
OverSim is a new, modular overlay simulatorFocus on scalability and flexibilityVarious underlay models for maximum speed, maximum precision or real network useMany implemented overlay protocolsEasily extendable
Future work:New overlay protocols and applications
Kademlia, Scribe, i3, P2PSIPImport models from topology generatorsImport datasets from internet latency measurements
Institute of Telematics
http://www.oversim.org/
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