Abstract
We study adaptive routing algorithms in a round-based model. Suppose we are given a network equipped with load-dependent latency functions on the edges and a set of commodities each of which is defined by a collection of paths (represented by a DAG) and a flow rate. Each commodity is controlled by an agent which aims at balancing its traffic among its paths such that all used paths have the same latency. Such an allocation is called a Wardrop equilibrium.
In recent work, it was shown that an infinite population of users each of which carries an infinitesimal amount of traffic can attain approximate equilibria in a distributed and concurrent fashion quickly. Interestingly, the convergence time is independent of the underlying graph and depends only mildly on the latency functions. Unfortunately, a direct simulation of this process requires to maintain an exponential number of variables, one for each path.
The focus of this work lies on the distributed and efficient computation of the adaptation rules by a finite number of agents. In order to guarantee a polynomial running time, every agent computes a randomised path decomposition in every communication round. Based on this decomposition, agents remove flow from paths with high latency and reassign it proportionally to all paths. This way, our algorithm can handle exponentially large path collections in polynomial time.
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References
Ahuja, R.K., Magnanti, T.L., Orlin, J.B.: Network flows: Theory, algorithms and applications. Prentince-Hall, Englewood Cliffs (1993)
Awerbuch, B., Khandekar, R.: Greedy distributed optimization of multi-commodity flows. In: Proc. 26th Ann. Symp. on Principles of Distributed Computing (PODC) (2007)
Awerbuch, B., Khandekar, R., Rao, S.: Distributed algorithms for multicommodity flow problems via approximate steepest descent framework. In: Proc. 18th Ann. Symp. on Discrete Algorithms (SODA) (2007)
Awerbuch, B., Kleinberg, R.D.: Adaptive routing with end-to-end feedback: Distributed learning and geometric approaches. In: Proc. 36th Ann. Symp. on Theory of Comput. (STOC), pp. 45–53 (2004)
Beckmann, M., McGuire, C.B., Winsten, C.B.: Studies in the Economics of Transportation. Yale University Press, New Haven and London (1956)
Berenbrink, P., Friedetzky, T., Goldberg, L.A., Goldberg, P., Hu, Z., Martin, R.: Distributed selfish load balancing. In: Proc. 17th Ann. Symp. on Discrete Algorithms (SODA) (2006)
Bertsekas, D.P.: Network Optimization: Continuous and Discrete Models. Athena Scientific (1998)
Blum, A., Even-Dar, E., Ligett, K.: Routing without regret: On convergence to Nash equilibria of regret-minimizing algorithms in routing games. In: Proc. 25th Ann. Symp. on Principles of Distributed Computing (PODC), pp. 45–52. ACM, New York (2006)
Cole, R., Dodis, Y., Roughgarden, T.: How much can taxes help selfish routing? In: Proc. 4th Conf. on Electronic Commerce, pp. 98–107 (2003)
Cominetti, R., Correa, J.R., Moses, N.E.S.: Network games with atomic players. In: Bugliesi, M., Preneel, B., Sassone, V., Wegener, I. (eds.) ICALP 2006. LNCS, vol. 4052, pp. 525–536. Springer, Heidelberg (2006)
Even-Dar, E., Mansour, Y.: Fast convergence of selfish rerouting. In: Proc. 16th Ann. Symp. on Discrete Algorithms (SODA), pp. 772–781 (2005)
Fischer, S., Räcke, H., Vöcking, B.: Fast convergence to Wardrop equilibria by adaptive sampling methods. In: Proc. 38th Symposium on Theory of Computing (STOC), pp. 653–662. ACM, New York (2006)
Fischer, S., Vöcking, B.: Adaptive routing with stale information. In: Aguilera, M.K., Aspnes, J. (eds.) Proc. 24th Symp. on Principles of Distributed Computing (PODC), pp. 276–283. ACM, New York (2005)
Fleischer, L.: Linear tolls suffice: New bounds and algorithms for tolls in single source networks. In: Díaz, J., Karhumäki, J., Lepistö, A., Sannella, D. (eds.) ICALP 2004. LNCS, vol. 3142, pp. 544–554. Springer, Heidelberg (2004)
Goldberg, P.W.: Bounds for the convergence rate of randomized local search in a multiplayer, load-balancing game. In: Proc. 23rd Symp. on Principles of Distributed Computing (PODC), pp. 131–140. ACM, New York (2004)
Hagerup, T., Rüb, C.: A guided tour of Chernoff bounds. Information Processing Letters 33, 305–308 (1990)
Roughgarden, T.: How unfair is optimal routing? In: Proc. 13th Ann. Symp. on Discrete Algorithms (SODA), pp. 203–204 (2002)
Roughgarden, T., Tardos, É.: How bad is selfish routing? J. ACM 49(2), 236–259 (2002)
Wardrop, J.G.: Some theoretical aspects of road traffic research. In: Proc. of the Institute of Civil Engineers, Pt. II, vol. 1, pp. 325–378 (1952)
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Fischer, S., Olbrich, L., Vöcking, B. (2007). Approximating Wardrop Equilibria with Finitely Many Agents . In: Pelc, A. (eds) Distributed Computing. DISC 2007. Lecture Notes in Computer Science, vol 4731. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-540-75142-7_20
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DOI: https://doi.org/10.1007/978-3-540-75142-7_20
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