Abstract
We consider the problem of Rendezvous or gathering of multiple autonomous entities (called mobile agents) moving in an unlabelled environment (modelled as a graph). The problem is usually solved using randomization or assuming distinct identities for the agents, such that they can execute different protocols. When the agents are all identical and deterministic, and the environment itself is symmetrical (e.g. a ring) it is difficult to break the symmetry between them unless, for example, the agents are provided with a token to mark the nodes. We consider fault-tolerant protocols for the problem where the tokens used by the agents may disappear unexpectedly. If all tokens fail, then it becomes impossible, in general, to solve the problem. However, we show that with any number of failures (less than a total collapse), we can always solve the problem if the original instance of the problem was solvable. Unlike previous solutions, we can tolerate failures occurring at arbitrary times during the execution of the algorithm. Our solution can be applied to any arbitrary network even when the topology is unknown.
Access provided by Autonomous University of Puebla. Download to read the full chapter text
Chapter PDF
Similar content being viewed by others
Keywords
References
Alpern, S., Gal, S.: The Theory of Search Games and Rendezvous. Kluwer, Dordrecht (2003)
Angluin, D.: Local and global properties in networks of processors. In: Proc. of 12th Symposium on Theory of Computing (STOC 1980), pp. 82–93 (1980)
Barrière, L., Flocchini, P., Fraigniaud, P., Santoro, N.: Can we elect if we cannot compare? In: Proc. Fifteenth Annual ACM Symp. on Parallel Algorithms and Architectures (SPAA 2003), pp. 324–332 (2003)
Baston, V., Gal, S.: Rendezvous search when marks are left at the starting points. Naval Research Logistics 38, 469–494 (1991)
Boldi, P., Shammah, S., Vigna, S., Codenotti, B., Gemmell, P., Simon, J.: Symmetry breaking in anonymous networks: Characterizations. In: Proc. 4th Israel Symp. on Th. of Comput. and Syst., pp. 16–26 (1996)
Chalopin, J., Das, S., Santoro, N.: Rendezvous of Mobile Agents in Unknown Graphs with Faulty Links. In: Pelc, A. (ed.) DISC 2007. LNCS, vol. 4731, pp. 108–122. Springer, Heidelberg (2007)
Das, S.: Mobile Agent Rendezvous in a Ring using Faulty Tokens. In: Rao, S., Chatterjee, M., Jayanti, P., Murthy, C.S.R., Saha, S.K. (eds.) ICDCN 2008. LNCS, vol. 4904, pp. 292–297. Springer, Heidelberg (2008)
Das, S., Flocchini, P., Nayak, A., Santoro, N.: Effective elections for anonymous mobile agents. In: Asano, T. (ed.) ISAAC 2006. LNCS, vol. 4288, pp. 732–743. Springer, Heidelberg (2006)
De Marco, G., Gargano, L., Kranakis, E., Krizanc, D., Pelc, A., Vaccaro, U.: Asynchronous deterministic rendezvous in graphs. Theor. Comput. Sci. 355(3), 315–326 (2006)
Dessmark, A., Fraigniaud, P., Kowalski, D.R., Pelc, A.: Deterministic Rendezvous in Graphs. Algorithmica 46(1), 69–96 (2006)
Flocchini, P., Kranakis, E., Krizanc, D., Luccio, F.L., Santoro, N., Sawchuk, C.: Mobile Agents Rendezvous When Tokens Fail. In: Kralovic, R., Sýkora, O. (eds.) SIROCCO 2004. LNCS, vol. 3104, pp. 161–172. Springer, Heidelberg (2004)
Flocchini, P., Kranakis, E., Krizanc, D., Santoro, N., Sawchuk, C.: Multiple mobile agent rendezvous in a ring. In: Farach-Colton, M. (ed.) LATIN 2004. LNCS, vol. 2976, pp. 599–608. Springer, Heidelberg (2004)
Flocchini, P., Roncato, A., Santoro, N.: Computing on anonymous networks with sense of direction. Theor. Comput. Sci. 301, 1–3 (2003)
Klasing, R., Markou, E., Pelc, A.: Gathering asynchronous oblivious mobile robots in a ring. Theor. Comput. Sci. 390(1), 27–39 (2008)
Kosowski, A., Klasing, R., Navarra, A.: Taking Advantage of Symmetries: Gathering of Asynchronous Oblivious Robots on a Ring. In: Baker, T.P., Bui, A., Tixeuil, S. (eds.) OPODIS 2008. LNCS, vol. 5401, pp. 446–462. Springer, Heidelberg (2008)
Kowalski, D.R., Pelc, A.: Polynomial Deterministic Rendezvous in Arbitrary Graphs. In: Fleischer, R., Trippen, G. (eds.) ISAAC 2004. LNCS, vol. 3341, pp. 644–656. Springer, Heidelberg (2004)
Kranakis, E., Krizanc, D., Markou, E.: Mobile Agent Rendezvous in a Synchronous Torus. In: Correa, J.R., Hevia, A., Kiwi, M. (eds.) LATIN 2006. LNCS, vol. 3887, pp. 653–664. Springer, Heidelberg (2006)
Norris, N.: Universal covers of graphs: isomorphism to depth n − 1 implies isomorphism to all depths. Discrete Applied Math 56, 61–74 (1995)
Sawchuk, C.: Mobile agent rendezvous in the ring. PhD Thesis, Carleton University (2004)
Yamashita, M., Kameda, T.: Computing on anonymous networks: Parts I and II. IEEE Trans. on Parallel and Distributed Systems 7(1), 69–96 (1996)
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2008 Springer-Verlag Berlin Heidelberg
About this paper
Cite this paper
Das, S., Mihalák, M., Šrámek, R., Vicari, E., Widmayer, P. (2008). Rendezvous of Mobile Agents When Tokens Fail Anytime. In: Baker, T.P., Bui, A., Tixeuil, S. (eds) Principles of Distributed Systems. OPODIS 2008. Lecture Notes in Computer Science, vol 5401. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-540-92221-6_29
Download citation
DOI: https://doi.org/10.1007/978-3-540-92221-6_29
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-540-92220-9
Online ISBN: 978-3-540-92221-6
eBook Packages: Computer ScienceComputer Science (R0)