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Ordering in Time: A New Routing Approach for Wireless Networks. Stephen Dabideen and J.J. Garcia-Luna-Aceves Department of Computer Engineering University of California, Santa Cruz. MASS 2010. Outline. Introduction Related Work TORP(Time-Based Ordering for On-Demand Loop-Free Routing)
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Ordering in Time:A New Routing Approach for Wireless Networks Stephen Dabideen and J.J. Garcia-Luna-Aceves Department of Computer Engineering University of California, Santa Cruz MASS 2010
Outline • Introduction • Related Work • TORP(Time-Based Ordering for On-Demand Loop-Free Routing) • Performance • Conclusion
Introduction • Many routing approaches have been proposed for routing in wireless networks over the past 40 years • Most has focused on the ordering of nodes with respect to destinations using spatial information, such as • Distances to destinations, • Absolute location of nodes, • Relative location with respect to special nodes • While shortest path routing works well in wired networks, it is not very efficient in wireless networks especially in the face of mobility.
Related Work [18] C. E. Perkins and E. Royer. Ad hoc on-demand distance vector routing. In Proceedings of the 2nd IEEE Workshop on Mobile Computing Systems and Applications, pages 90–100, February 1999. [17] C. E. Perkins and P. Bhagwat. Highly dynamic destination-sequenced distance-vector routing (dsdv) for mobile computers. In Proceedings SIGCOMM ’94, pages 234–244, August 1994. • Spatial ordering • AODV [18] , DSDV [17] D • Link quality • Distance • Network congestion A B C • Multiple paths • Delivery ratio S
Related Work [6] D. D. Couto, D. Aguayo, J. Bicket, and R. Morris. A high-throughput path metric for multi-hop wireless routing. Proc. MobiCom, 2003. • Spatial ordering • ETX [6] Hop count =0 D Hop count =1 Hop count =1 Hop count =1 A B C Heavy load and low mobility. S Hop count =2
Related Work [10] B. Karp and H. Kung. Greedy perimeter stateless routing for wireless networks. Proceedings of the Sixth Annual ACM/IEEE International Conference on Mobile Computing and Networking, pages 243–254, August 2000. • Spatial ordering • GPSR [10] D Hop count =1 Hop count =1 A B C S Local minima Knowing the position of the destination beforehand remains a critical assumption
The Temporal Ordering Routing • We advocate the use of a temporal ordering as an alternative to the spatial orderings used in most routing protocols. • We propose the use of ordering of nodes based on time rather than space • Without the need to establish any clock synchronization among nodes.
TORP • Time-Based Ordering for On-Demand Loop-Free Routing • Route Request Phase • Route Replay Phase RREP D A B RREQ S
TORP • Route Request Phase Definition 1: Node A is a successor of Node B on a path to destination C ifor if A is the destination. RA RB TA TB A B RREQ is the local time node B received a RREQ from 𝐴 is the local time at which node 𝐵 retransmitted the RREQ. as an upper bound on the transmission and propagation delay
TORP Definition 1: Node A is a successor of Node B on a path to destination C ifor if A is the destination. • Route Request Phase RB TD RA D RS RA TB RD RS TA RB RD A B RREQ TS RA RB S
TORP Definition 2: The Reply Acceptance Condition (RAC): A node can only accept and process a RREP if it is received from a successor, as defined in Definition 1. • Route Replay Phase RREP D D B A B C RREQ A B S
TORP • Route Maintenance • When a link fails, a node can route data through any of its neighbors as long as they are successors • As long as the destination is receiving packets, it periodically initiates proactive updates D A B S
TORP • Adjustable Ordering and Mobility in TORP • Nodes attempt to adjust the ordering of their neighbors so that they have almost equal number of successors and predecessors. • This is done by adjusting the time at which they retransmit RREQs. A
TORP • The advantages of time-based temporal ordering over spatial ordering in the design of routing protocols, such as • Allowing more paths, • Factoring in network conditions implicitly, • To be efficient under heavy load and high mobility.
Performance • The simulations were performed using the Qualnet 4.5 network simulator.
Conclusion • We introduced the Time Ordered Routing Protocol (TORP) as an example of the potential of this new type of ordering • We have described the inherent advantages of temporal ordering over spatial ordering in the design of routing protocols • We showed that it performs better than the traditional approaches based on spatial ordering.