## Abstract

Gathering data from nodes in a network is at the heart of many distributed applications, most notably, while performing a global task. We consider information spreading among n nodes of a network, where each node v has a message m(v) which must be received by all other nodes. The time required for information spreading has been previously upper-bounded with an inverse relationship to the conductance of the underlying communication graph. This implies high running times for graphs with small conductance. The main contribution of this paper is an information spreading algorithm which overcomes communication bottlenecks and thus achieves fast information spreading for a wide class of graphs, despite their small conductance. As a key tool in our study we use the recently defined concept of weak conductance, a generalization of classic graph conductance which measures how well-connected the components of a graph are. Our hybrid algorithm, which alternates between random and deterministic communication phases, exploits the connectivity within components by first applying partial information spreading, after which messages are sent across bottlenecks, thus spreading further throughout the network. This yields substantial improvements over the best known running times of algorithms for information spreading on any graph that has a large weak conductance, from polynomial to poly logarithmic number of rounds. We demonstrate the power of fast information spreading in accomplishing global tasks on the leader election problem, which lies at the core of distributed computing. Our results yield an algorithm for leader election that has a scalable running time on graphs with large weak conductance, improving significantly upon previous results.

Original language | English |
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Title of host publication | Proceedings of the 22nd Annual ACM-SIAM Symposium on Discrete Algorithms, SODA 2011 |

Pages | 440-448 |

Number of pages | 9 |

State | Published - 2011 |

Event | 22nd Annual ACM-SIAM Symposium on Discrete Algorithms, SODA 2011 - San Francisco, CA, United States Duration: 23 Jan 2011 → 25 Jan 2011 |

### Publication series

Name | Proceedings of the Annual ACM-SIAM Symposium on Discrete Algorithms |
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### Conference

Conference | 22nd Annual ACM-SIAM Symposium on Discrete Algorithms, SODA 2011 |
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Country/Territory | United States |

City | San Francisco, CA |

Period | 23/01/11 → 25/01/11 |

## Keywords

- Distributed computing
- Information spreading
- Leader election
- Randomized algorithms
- Weak conductance

## All Science Journal Classification (ASJC) codes

- Software
- General Mathematics