This paper presents the expected transmission count metric (ETX), which finds high-throughput paths on multi-hop wireless networks. ETX minimizes the expected total number of packet transmissions (including retransmissions) required to successfully deliver a packet to the ultimate destination. The ETX metric incorporates the effects of link loss ratios, asymmetry in the loss ratios between the two directions of each link, and interference among the successive links of a path. In contrast, the minimum hop-count metric chooses arbitrarily among the different paths of the same minimum length, regardless of the often large differences in throughput among those paths, and ignoring the possibility that a longer path might offer higher throughput.
This paper describes the design and implementation of ETX as a metric for the DSDV and DSR routing protocols, as well as modifications to DSDV and DSR which allow them to use ETX. Measurements taken from a 29-node 802.11b test-bed demonstrate the poor performance of minimum hop-count, illustrate the causes of that poor performance, and confirm that ETX improves performance. For long paths the throughput improvement is often a factor of two or more, suggesting that ETX will become more useful as networks grow larger and paths become longer.
Unable to display preview. Download preview PDF.
- B. Awerbuch, D. Holmer and H. Rubens, High throughput route selection in multi-ratead hoc wireless networks, Technical report, Johns Hopkins University, Computer Science Department (March 2003). Version 2.Google Scholar
- H. Balakrishnan, V.N. Padmanabhan, S. Seshan and R.H. Katz, A comparison of mechanisms for improving TCP performance of wireless links, IEEE/ACM Transactions on Networking 6(5) (1997).Google Scholar
- B. Bensaou, Y. Wang and C.C. Ko, Fair medium access in 802.11 based wireless ad-hoc networks, in: First Annual IEEE and ACM International Workshop on Mobile Ad Hoc Networking and Computing (MobiHoc) (August 2000).Google Scholar
- J. Broch, D.A. Maltz, D.B. Johnson, Y.-C. Hu and J. Jetcheva, A performance comparison of multi-hop wireless ad hoc network routing protocols, in: Proc. ACM/IEEE MobiCom (October 1998) pp. 85–97.Google Scholar
- S. Chen and K. Nahrstedt, Distributed quality-of-service routing in ad hoc networks, IEEE Journal on Selected Areas in Communcations 17(8) (Aug. 1999).Google Scholar
- T.-W. Chen, J.T. Tsai and M. Gerla, QoS routing performance in multihop, multimedia, wireless networks, in: Proceedings of IEEE ICUPC’97 (1997).Google Scholar
- K.-W. Chin, J. Judge, A. Williams and R. Kermode, Implementation experience with MANET routing protocols, ACM SIGCOMM Computer Communications Review 32(5) (2002).Google Scholar
- B.H. Davies and T.R. Davies, The application of packet switching techniques to combat net radio, in: Proceedings of the IEEE 75(1) (1987).Google Scholar
- R. Dube, C.D. Rais, K.-Y. Wang and S.K. Tripathi, Signal stability-based adaptive routing (SSA) for ad hoc mobile networks, IEEE Personal Communications (Feb. 1997).Google Scholar
- T. Goff, N.B. Abu-Ghazaleh, D.S. Phatak and R. Kahvecioglu, Preemptive routing in ad hoc networks, in: Proc. ACM/IEEE MobiCom (July 2001).Google Scholar
- W.R. Heinzelman, A. Chandrakasan and H. Balakrishnan, Energy-efficient communication protocols for wireless microsensor networks, in: Proceedings of the Hawaiian International Conference on Systems Science (Jan. 2000).Google Scholar
- Y.-C. Hsu, T.-C. Tsai, Y.-D. Lin and M. Gerla, Bandwidth routing in multi-hop packet radio environment, in: Proceedings of the 3rd International Mobile Computing Workshop (1997).Google Scholar
- Y.-C. Hu and D.B. Johnson, Design and demonstration of live audio and video over multihop wireless ad hoc networks, in: Proceedings of the MILCOM 2002 (2002).Google Scholar
- D.B. Johnson, Routing in ad hoc networks of mobile hosts, in: Proc. of the IEEE Workshop on Mobile Computing Systems and Applications (Dec. 1994). pp. 158–163.Google Scholar
- D.B. Johnson, D.A. Maltz and Y.-C. Hu, The dynamic source routing protocol for mobile ad hoc networks (DSR), Internet draft (work in progress), IETF (April 2003). http://www.ietf.org/internet-drafts/draft-ietf-manet-dsr-09.txt.
- J. Jubin and J.D. Tornow, The DARPA packet radio network protocols, in: Proceedings of the IEEE 75(1) (1987).Google Scholar
- E.-S. Jung and N. Vaidya, A power control MAC protocol for ad hoc networks, in: Proc. ACM/IEEE MobiCom (Sept. 2002).Google Scholar
- E. Kohler, R. Morris, B. Chen, J. Jannotti and M.F. Kaashoek, The Click modular router, ACM Transactions on Computer Systems 18(4) (2000).Google Scholar
- J. Li, C. Blake, D. S.J. De Couto, H.I. Lee and R. Morris, Capacity of ad hoc wireless networks, in: Proceedings of the 7th ACM International Conference on Mobile Computing and Networking, (Rome, Italy, July 2001) pp. 61–69.Google Scholar
- C.R. Lin, On-demand QoS routing in multihop mobile networks, in: Proc. IEEE Infocom (April 2001).Google Scholar
- H. Lundgren, E. Nordström and C. Tschudin, Coping with comunication gray zones in IEEE 802.11b based ad hoc networks, in: 5th ACM International Workshop on Wireless Mobile Multimedia (WoWMoM 2002) (September 2002).Google Scholar
- A. Michail and A. Ephremides, Algorithms for routing session traffic in wireless ad-hoc networks with energy and bandwidth limitations, in: Proceedings of 12th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (2001).Google Scholar
- C. Parsa and J.J. Garcia-Luna-Aceves, TULIP: A link-level protocol for improving TCP over wireless links, in: Proc. IEEE Wireless Communications and Networking Conference 1999 (WCNC 99), (Sept. 1999).Google Scholar
- C.E. Perkins and P. Bhagwat, Highly dynamic destination-sequenced distance-vector routing (DSDV) for mobile computers, in: Proc. ACM SIGCOMM Conference (SIGCOMM ‘94) (Aug. 1993) pp. 234–244.Google Scholar
- C.E. Perkins and E.M. Royer, Ad hoc on-demand distance vector routing, in: Proceedings of the 2nd IEEE Workshop on Mobile Computing Systems and Applications (1999).Google Scholar
- R.J. Punnoose, P.V. Nitkin, J. Broch and D.D. Stancil, Optimizing wireless network protocols using real-time predictive propagation modeling, in: Radio and Wireless Conference (RAWCON) (August 1999).Google Scholar
- R. Ramanathan and R. Rosales-Hain, Topology control of multihop wireless networks using transmit power adjustment, in: Proc. IEEE Infocom (March 2000).Google Scholar
- Rice Monarch Project, Wireless and mobility extensions to ns-2. http://www.monarch.cs.rice.edu/cmu-ns.html.
- S.H. Shah and K. Nahrstedt, Predictive location-based QoS routing in mobile ad hoc networks, in: Proceedings of IEEE International Conference on Communications (2002).Google Scholar
- P. Sinha, R. Sivakumar and V. Bharghavan, CEDAR: A core-extraction distributed ad hoc routing algorithm, in: Proc. IEEE Infocom (March 1999).Google Scholar
- The Network Simulator—ns-2 (2003). http://www.isi.edu/nsnam/ns.
- A. Tornquist, Modular and adaptive ad hoc routing in Click, Master’s thesis, University of Colorado (2001).Google Scholar
- M. Yarvis, W.S. Conner, L. Krishnamurthy, J. Chhabra, B. Elliott and A. Mainwaring, Real-world experiences with an interactive ad hoc sensor network, in: Proceedings of the International Workshop on Ad Hoc Networking (August 2002).Google Scholar
- C. Zhu and M.S. Corson, QoS routing for mobile ad hoc networks, in: Proc. IEEE Infocom (June 2001).Google Scholar