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Proposed ad hoc Routing Approaches

Proposed ad hoc Routing Approaches. Conventional wired-type schemes (global routing, proactive): Distance Vector; Link State Proactive ad hoc routing: OLSR, TBRPF On- Demand, reactive routing: DSR (Source routing), MSR AODV (Backward learning) AODV-DFR Scalable routing :

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Proposed ad hoc Routing Approaches

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  1. Proposed ad hoc Routing Approaches • Conventional wired-type schemes (global routing, proactive): • Distance Vector; Link State • Proactive ad hoc routing: • OLSR, TBRPF • On- Demand, reactive routing: • DSR (Source routing), MSR • AODV (Backward learning) • AODV-DFR • Scalable routing : • Hierarchical routing: HSR, Fisheye • OLSR + Fisheye • LANMAR (for teams/swarms) • Geo-routing: • GPSR, GeRaF, etc • Motion assisted routing

  2. DV update Predecessor Data flow Source Sink “Direction” forwarding for mobile, large scale ad hoc networks • Distance Vector not robust to mobility • In Distance Vector Routing (e.g., Bellman Ford, AODV etc.) node keeps pointer to “predecessor” • When the predecessor moves, the path is broken • Alternate paths, even when available, are not used • Proposed solution: direction forwarding

  3. Direction Forwarding • Distance Vector update creates not only “predecessor”, but also “direction” entry • Select “most productive” neighbor in forward direction • If the network is reasonably dense, the path is salvaged

  4. How to compute the “direction” • Need “stable” local orientation system (say, virtual compass) to determine direction of update • Local (rather than global) reference is required; • Local reference system must be refreshed fast enough to track avg local motion • GPS will do (e.g., neighbors exchange (X, Y) coordinates) • If GPS not available, several non-GPS coordinate systems have been recently published • Sextant [Mobihoc ’05]; beacon DV; RFID’s etc

  5. Computing the “direction”(cont) • Compute “direction” to a destination when DV updates are received: • If a DV update packet with a more recent Seq # or smaller hop distance is received: • New “direction” replaces the old one • The “direction” to the predecessor is used as the “direction” to the destination • If multiple DV updates received from different “predecessors” with same hop distance and seq # for the destination • Take vector sum of directions

  6. “Direction” to a destination C A B Computation of the “direction” Suppose node A receives DV update packets from B & C • Compute the “directions” to predecessors node B & C, respectively, Where the polar angle is the radian from the x-axis that is used as the direction of the predecessor node. Directions to predecessors Computation of the “direction” • Unit vectors are used to combine the two “directions”

  7. Direction Forwarding vs Geo routing • Geo-routing: • Direction points to destination • This direction may be unfeasible (holes, etc) • Global geo-coordinates (eg, GPS) • Geo Location Server • Robust to mobility • Direction Forwarding • Direction of updates (always feasible) • Local (not global) position reference system • Advertisements from destination • Robust to mobility

  8. Robust Ad Hoc Routing for Lossy Wireless Environment • Challenges for routing in mobile ad hoc network • Route breakage • High BER • Scalability • The shortcomings of on-demand routing • Not scalable for mobility • The shortcomings of proactive routing • Constant and high routing overhead • The shortcomings of current Geo-routing • Need Geo-Location Service, GLS • “Face routing” is inefficient

  9. Hybrid Routing: AODV-DFR (AODV with Directional Forwarding Routing) • Combines on-demand and proactive routing • When a source starts comm, it first finds the destination as in an on-demand fashion • Once the destination is notified, it initiates periodic routing updates in a proactive fashion • Utilizing an alternate path instantly based on “direction” to the destination if a path fails • resemblance with Georouting in the update message • No location server system is required (not like GPSR)

  10. AODV-DFR • Source initiates route discovery a la AODV • Destination, or any node that has a route, replies • The path is set up • Destination begins proactive advertisements (a la DV) after receiving data pkts from source • Intermediate nodes rebroadcast ads • Only for active connections • Period increases with distance from destination (Fisheye concept) • Packet routing assisted by Direction Forward • The destination stops advertisement if it does not receive pkts for some time

  11. Performance Evaluation • Compare AODV, AODV-DFR, GPSR and ADV (proactive and on-demand Hybrid Routing) • Performance: Delivery ratio, Packet delay, Routing Overhead • Mobile & lossy network: UDP and TCP traffic • Mobility Speed • Packet loss: uniformly distributed on a link • Simulation • 100 nodes randomly moving in 1000x1000m • The traffic pairs are randomly distributed over the network • UDP flows: pkt size 512 bytes, rate 1pkt/sec • TCP flows: NewReno, pkt size 1460 bytes

  12. Mobile Network: Delivery Ratio 80 UDP flows

  13. Mobile Network: Packet delay 80 UDP flows

  14. Mobile Network: Routing Overhead 80 UDP flows

  15. Mobile & Lossy Network: Delivery Ratio UDP Flow number: 80 Mobility Speed: 10 m/s

  16. Mobile & Lossy Network: Routing Overhead UDP Flow number: 80 Mobility Speed: 10 m/s

  17. TCP in Mobile Network 40 TCP flows

  18. TCP in Mobile & Lossy Network TCP flow number: 40 Mobility: 10 m/s

  19. AODV-DFR Contributions • A hybrid routing: proactive + on-demand • Robust to mobility and packet loss • Utilize location information for directional forwarding with only local updates. • Low overhead • Provide better performance than AODV and GPSR • Enhances AODV • Competitive with GPSR (does not require “global” positioning such as GPS) • Ongoing work: local coordinate system; integration of local and global coordinates (indoor+outdoor)

  20. Robust Ad Hoc Routing for Lossy Wireless EnvironmentCS 218 Fall 08 UCLA: Jiwei Chen, Yeng-Zhong Lee, Mario Gerla TJU: He Zhou, Yantai Shu Milcom 2006

  21. Introduction • Challenges for routing in mobile ad hoc network • Route breakage • High BER • Scalability • The shortcomings of on-demand routing • Not scalable for mobility • The shortcomings of proactive routing • Constant and high routing overhead • The shortcomings of current Geo-routing • Need Geo-Location Service, GLS • “Face routing” is inefficient ENTER AODV-DFR!

  22. Related Work • Proactive Routing • OLSR, DSDV • On-demand Routing • AODV, DSR • Geographic Routing • GPSR and several others • greedy + face algorithm • GLS (geo location service) • Hybrid Routing • ZRP, SHARP, LANMAR zone and group concept • ADV, proactive and on-demand • DREAM, proactive and geo-routing • AODV-DFR

  23. AODV-DFR • Source initiates route discovery a la AODV • Destination, or any node that has a route, replies • The path is set up • Destination begins periodic advertisements (a la Distance Vector) after receiving data packets from source • Intermediate nodes rebroadcast advertisements - interval increases with distance from destination (Fisheye concept) • Packet routing assisted by Direction Forwarding • The destination stops advertisement if it does not receive packets for some time.

  24. Proactive Advertising in AODV-DFR • Only for active connections • “Fisheye” updating frequency

  25. Direction Forwarding • Distance Vector update creates not only “predecessor”, but also “direction” entry DV update Predecessor Data flow Source Sink “Direction” to Sink • “Predecessor only” forwarding fails • DFR selects “most productive” neighbor in right direction • If the network is reasonably dense, the path is salvaged

  26. Directional Forwarding • Each node remembers the local advertised directional • Only local coordinates needed • Direction is computed by the aggregation of local updates • “Multiple hop” direction can also be available. • Next node with min-hop and minimal deviation from the direction is selected.

  27. Routing Tables at a Node • Neighbor Table • Direction to all neighbors • Routing table • Routes to all active destinations

  28. Performance Evaluation • Compare AODV, AODV-DFR, ADV, and GPSR (without charge for GLS overhead). • Performance in mobile network • Delivery ratio • Routing Overhead • Performance in mobile & lossy network • Packet loss: uniformly distributed on a link • UDP and TCP traffic

  29. Simulation Environment • 100 nodes randomly moving in a 1000x1000m space • The traffic pairs are randomly distributed over the network. • UDP flows: pkt size 512 bytes, rate 1pkt/sec • TCP flows: data pkt size 1460 bytes, NewReno

  30. Mobile Network: Delivery Ratio 80 UDP flows

  31. Mobile Network: Routing Overhead 80 UDP flows

  32. Mobile & Lossy Network: Delivery Ratio UDP Flow number: 80 Mobility Speed: 10 m/s

  33. TCP in Mobile Network 40 TCP flows

  34. AODV-DFR Contributions • A hybrid routing: proactive + on-demand • Robust to mobility and packet loss • Utilize location information for directional forwarding with only local updates. • Low overhead • Enhances AODV • Competitive with GPSR: • not affected by GLS and by face routing issues; • does not require “global” positioning such as GPS • Ongoing work: local coordinate system; integration of local and global coordinates (indoor+outdoor)

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