Conference on Future InternetCommunications 2013Guaranteed Greedy Routing inOverlay NetworksDragan Milic and Torsten Braun...
Overview> Introduction— Motivation— Greedy Routing in Virtual Spaces— Greedy Routing Failure> Overlay Network Construction...
Motivation> Overlay network construction does often not considerunderlying network topology.> Overlay network routing prot...
CFIC, Coimbra, May 16, 2013Torsten Braun: Guaranteed Greedy Routing in Overlay Networks4Positioning Hosts in a Virtual Spa...
Greedy Routing in Virtual Spaces> Next hop =neighbour with minimaldistance to destinationCFIC, Coimbra, May 16, 2013Torste...
Greedy Routing Failure> Problem— There might not always bea neighbour closer to thedestination.> Solutions— For geographic...
Overlay Network Constructionfor Greedy RoutingCFIC, Coimbra, May 16, 2013Torsten Braun: Guaranteed Greedy Routing in Overl...
Nearest Neighbours Convex Set (NNCS)> Construct half spacesfor all neighbours of a node> NNCS— is a convex setdefined by i...
Algorithm for NNCS MaintenanceCFIC, Coimbra, May 16, 2013Torsten Braun: Guaranteed Greedy Routing in Overlay Networks9
NNCS Robustness> Problem— In case of churns orfailures, NNCS may lead torouting failures or isolatednodes.> Solution— Add ...
Routing OptimizationCFIC, Coimbra, May 16, 2013Torsten Braun: Guaranteed Greedy Routing in Overlay Networks11> Problem— NN...
Applications> Building of Multicast Trees> Service Discovery> Spatially Bound Query Flooding> Network Optimization / QoSCF...
Building of Multicast Trees> Reverse path multicast routing> Node R forwards a receivedmulticast message to allnodes that ...
Service DiscoveryCFIC, Coimbra, May 16, 2013Torsten Braun: Guaranteed Greedy Routing in Overlay Networks14> Problem— Servi...
Spatially Bound Query Flooding> Queries can easily boundwithin a certain area, e.g.,a hyper ball, to ensure RTTbetween que...
Network Optimization / QoS> Paths fulfilling RTT / QoSrequirements must be withinan ellipsoid around sourceand destination...
Relative Path Stretch> NNCS evaluation using OMNET++> Different data sets— PlanetLab data for 217 overlay nodes— KING data...
Conclusions> NNCS enables greedy routing in overlay networks usingvirtual space embedding.> Various applications can take ...
Thanks for your Attention !> cds.unibe.ch> slideshare.net/torstenbraun> braun@iam.unibe.chTorsten Braun: Guaranteed Greedy...
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Guaranteed Greedy Routing in Overlay Networks

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Guaranteed Greedy Routing in Overlay Networks

  1. 1. Conference on Future InternetCommunications 2013Guaranteed Greedy Routing inOverlay NetworksDragan Milic and Torsten BraunUniversität Bern, Switzerlandbraun@iam.unibe.ch, cds.unibe.ch
  2. 2. Overview> Introduction— Motivation— Greedy Routing in Virtual Spaces— Greedy Routing Failure> Overlay Network Construction for Greedy Routing— Nearest Neighbours Convex Set (NNCS)— Algorithm for NNCS Maintenance— NNCS Robustness— Routing Optimization> NNCS Applications— Building of Multicast Trees— Service Discovery— Spatially Bound Query Flooding— Network Optimization / QoS> Evaluation: Relative Path Stretch> ConclusionsCFIC, Coimbra, May 16, 2013Torsten Braun: Guaranteed Greedy Routing in Overlay Networks2
  3. 3. Motivation> Overlay network construction does often not considerunderlying network topology.> Overlay network routing protocols— optimize number of hops along the path, but— disregard paths’ RTT stretch= actual RTT on the path through the overlay networkRTT along the optimal path in the underlying network> Proposal: apply greedy routing in virtual spaces,where distance between nodes is proportional to their RTTCFIC, Coimbra, May 16, 2013Torsten Braun: Guaranteed Greedy Routing in Overlay Networks3
  4. 4. CFIC, Coimbra, May 16, 2013Torsten Braun: Guaranteed Greedy Routing in Overlay Networks4Positioning Hosts in a Virtual SpaceHost 1Host 2Host 8Host 3Host 5Host 7Host 4Host 6Physical NetworkVirtual SpaceHost 1Host 8Host 2Host 3Host 7Host 4Host 5Host 6xy
  5. 5. Greedy Routing in Virtual Spaces> Next hop =neighbour with minimaldistance to destinationCFIC, Coimbra, May 16, 2013Torsten Braun: Guaranteed Greedy Routing in Overlay Networks5
  6. 6. Greedy Routing Failure> Problem— There might not always bea neighbour closer to thedestination.> Solutions— For geographical routing inmobile ad-hoc networks:backup routing modes,e.g., using right-hand rulein GPSR— For overlay networks:construct an overlaynetwork that ensures tohave always a neighbourcloser to the destinationCFIC, Coimbra, May 16, 2013Torsten Braun: Guaranteed Greedy Routing in Overlay Networks6
  7. 7. Overlay Network Constructionfor Greedy RoutingCFIC, Coimbra, May 16, 2013Torsten Braun: Guaranteed Greedy Routing in Overlay Networks7> Delaunay triangulation— can ensure existence ofcloser neighbours towardsdestination,— but distributed approach iscomplex.> Solution— Nearest NeighborsConvex Set (NNCS)is based on dividing thevirtual space into half spaces.Current NodeNeighbour NodeHalf Space
  8. 8. Nearest Neighbours Convex Set (NNCS)> Construct half spacesfor all neighbours of a node> NNCS— is a convex setdefined by intersection ofall half spaces.— guarantees thatgreedy routing makesprogress at each node.CFIC, Coimbra, May 16, 2013Torsten Braun: Guaranteed Greedy Routing in Overlay Networks8Current NodeNeighbour NodeOther NodesHalf Space
  9. 9. Algorithm for NNCS MaintenanceCFIC, Coimbra, May 16, 2013Torsten Braun: Guaranteed Greedy Routing in Overlay Networks9
  10. 10. NNCS Robustness> Problem— In case of churns orfailures, NNCS may lead torouting failures or isolatednodes.> Solution— Add second NNCS layer byconstructing a NNCS withoutconsidering the nodes in thefirst layer of the NNCSCFIC, Coimbra, May 16, 2013Torsten Braun: Guaranteed Greedy Routing in Overlay Networks10
  11. 11. Routing OptimizationCFIC, Coimbra, May 16, 2013Torsten Braun: Guaranteed Greedy Routing in Overlay Networks11> Problem— NNCS selects closeneighbours, which leads to manyhops.— Fisheye overlay network with amix of close and distantneighbours, but greedy routingusing a Fisheye overlay networkdoes not guarantee progress.> Solution— maintain NNCS and Fisheyeoverlay network sets— select next hop making mostprogress from both node setsD. Milic, T. Braun: “Fisheye: Topology awarechoice of peers for overlay networks”,34th IEEE Local Computer Networks, 2009
  12. 12. Applications> Building of Multicast Trees> Service Discovery> Spatially Bound Query Flooding> Network Optimization / QoSCFIC, Coimbra, May 16, 2013Torsten Braun: Guaranteed Greedy Routing in Overlay Networks12
  13. 13. Building of Multicast Trees> Reverse path multicast routing> Node R forwards a receivedmulticast message to allnodes that would use Rfor routing a unicastmessage to the sourceCFIC, Coimbra, May 16, 2013Torsten Braun: Guaranteed Greedy Routing in Overlay Networks13
  14. 14. Service DiscoveryCFIC, Coimbra, May 16, 2013Torsten Braun: Guaranteed Greedy Routing in Overlay Networks14> Problem— Service discovery isusually based on flooding.— Efficient floodingmechanisms> Solution— Forwarding of querymessage along reverse pathQuery SourceEnd Systemswith Query Sourcein their NNCSOther NodesFlooding Path
  15. 15. Spatially Bound Query Flooding> Queries can easily boundwithin a certain area, e.g.,a hyper ball, to ensure RTTbetween query source andserver.CFIC, Coimbra, May 16, 2013Torsten Braun: Guaranteed Greedy Routing in Overlay Networks15Query SourceEnd Systemswith Query Sourcein their NNCSOther NodesFlooding Path
  16. 16. Network Optimization / QoS> Paths fulfilling RTT / QoSrequirements must be withinan ellipsoid around sourceand destination.> Ellipsoid as bounding areafor path to be selected.CFIC, Coimbra, May 16, 2013Torsten Braun: Guaranteed Greedy Routing in Overlay Networks16
  17. 17. Relative Path Stretch> NNCS evaluation using OMNET++> Different data sets— PlanetLab data for 217 overlay nodes— KING data for 462 overlay nodes> Comparison of NNCS using differentvirtual space dimensions with PastryCFIC, Coimbra, May 16, 2013Torsten Braun: Guaranteed Greedy Routing in Overlay Networks17
  18. 18. Conclusions> NNCS enables greedy routing in overlay networks usingvirtual space embedding.> Various applications can take advantage of NNCS.> NNCS based approach outperforms Pastry.CFIC, Coimbra, May 16, 2013Torsten Braun: Guaranteed Greedy Routing in Overlay Networks18
  19. 19. Thanks for your Attention !> cds.unibe.ch> slideshare.net/torstenbraun> braun@iam.unibe.chTorsten Braun: Guaranteed Greedy Routing in Overlay NetworksCFIC, Coimbra, May 16, 2013 19

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