### Abstract

For any non-negative integer K, a K-observer P of a network N is a set of nodes in N such that each message, that travels at least K hops in N, is handled (and so observed) by at least one node in P. A K-observer P of a network N is minimum iff the number of nodes in P is less than or equal the number of nodes in every K-observer of N. The nodes in a minimum K-observer of a network N can be used to monitor the message traffic in network N, detect denial-of-service attacks, and act as firewalls to identify and discard attack messages. This paper considers the problem of constructing a minimum K-observer for any given network. We show that the problem is NP-hard for general networks, and give linear-time algorithms for constructing minimum or near-minimum K-observers for special classes of networks: trees, rings, L-rings, and large grids.

Original language | English (US) |
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Title of host publication | Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) |

Pages | 5-18 |

Number of pages | 14 |

Volume | 6976 LNCS |

DOIs | |

State | Published - 2011 |

Event | 13th International Symposium on Stabilization, Safety, and Security of Distributed Systems, SSS 2011 - Grenoble, France Duration: Oct 10 2011 → Oct 12 2011 |

### Publication series

Name | Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) |
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Volume | 6976 LNCS |

ISSN (Print) | 03029743 |

ISSN (Electronic) | 16113349 |

### Other

Other | 13th International Symposium on Stabilization, Safety, and Security of Distributed Systems, SSS 2011 |
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Country | France |

City | Grenoble |

Period | 10/10/11 → 10/12/11 |

### Fingerprint

### ASJC Scopus subject areas

- Computer Science(all)
- Theoretical Computer Science

### Cite this

*Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)*(Vol. 6976 LNCS, pp. 5-18). (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics); Vol. 6976 LNCS). https://doi.org/10.1007/978-3-642-24550-3_3

**The K-observer problem in computer networks.** / Acharya, H. B.; Choi, Taehwan; Bazzi, Rida; Gouda, Mohamed G.

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

*Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics).*vol. 6976 LNCS, Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), vol. 6976 LNCS, pp. 5-18, 13th International Symposium on Stabilization, Safety, and Security of Distributed Systems, SSS 2011, Grenoble, France, 10/10/11. https://doi.org/10.1007/978-3-642-24550-3_3

}

TY - GEN

T1 - The K-observer problem in computer networks

AU - Acharya, H. B.

AU - Choi, Taehwan

AU - Bazzi, Rida

AU - Gouda, Mohamed G.

PY - 2011

Y1 - 2011

N2 - For any non-negative integer K, a K-observer P of a network N is a set of nodes in N such that each message, that travels at least K hops in N, is handled (and so observed) by at least one node in P. A K-observer P of a network N is minimum iff the number of nodes in P is less than or equal the number of nodes in every K-observer of N. The nodes in a minimum K-observer of a network N can be used to monitor the message traffic in network N, detect denial-of-service attacks, and act as firewalls to identify and discard attack messages. This paper considers the problem of constructing a minimum K-observer for any given network. We show that the problem is NP-hard for general networks, and give linear-time algorithms for constructing minimum or near-minimum K-observers for special classes of networks: trees, rings, L-rings, and large grids.

AB - For any non-negative integer K, a K-observer P of a network N is a set of nodes in N such that each message, that travels at least K hops in N, is handled (and so observed) by at least one node in P. A K-observer P of a network N is minimum iff the number of nodes in P is less than or equal the number of nodes in every K-observer of N. The nodes in a minimum K-observer of a network N can be used to monitor the message traffic in network N, detect denial-of-service attacks, and act as firewalls to identify and discard attack messages. This paper considers the problem of constructing a minimum K-observer for any given network. We show that the problem is NP-hard for general networks, and give linear-time algorithms for constructing minimum or near-minimum K-observers for special classes of networks: trees, rings, L-rings, and large grids.

UR - http://www.scopus.com/inward/record.url?scp=80054706158&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=80054706158&partnerID=8YFLogxK

U2 - 10.1007/978-3-642-24550-3_3

DO - 10.1007/978-3-642-24550-3_3

M3 - Conference contribution

SN - 9783642245497

VL - 6976 LNCS

T3 - Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)

SP - 5

EP - 18

BT - Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)

ER -