### Contact

Name | Valentin Fitz |
---|---|

Position | Researcher |

Phone | +49-201-183-6361 |

Fax | +49-201-183-4176 |

valentin.fitz@uni-due.de | |

Address | Schützenbahn 70 Building SA 45127 Essen |

Room | SA-327 |

### Research Interest

- Fault Tolerance
- Agreement Protocols
- Distributed Systems

### Education

**Since 10/2014**PhD Student –*University of Duisburg-Essen, Computer Science***2012 – 2014**Master of Science –*University of Duisburg-Essen, Mathematics*– Probability theory**2008 – 2012**Bachelor of Science –*University of Duisburg-Essen, Mathematics*– Probability theory

### Employments

**Since 03/2019**University of Duisburg-Essen, Research Assistant (Networked Embedded Systems)**10/2014 – 02/2019**University of Duisburg-Essen, Research Assistant (Dependability of Computing Systems)**10/2009 – 10/2014**University of Duisburg-Essen, Student Assistant (Dependability of Computing Systems)

### Publications

## 2019 |

Sascha Jungen, Matteo Ceriotti, Valentin Fitz, Alexander Julian Golkowski, Pedro José Marrón: Where are You? Localising Stationary Nodes with Limited Information. In: Proceedings of the IEEE 44th Conference on Local Computer Networks (LCN), Osnabrück, Germany, 2019. (Type: Inproceedings | )@inproceedings{sascha19lcn, |

## 2018 |

Valentin Fitz, Klaus Echtle: General Extension of FABAN and a Topology-based Approach to tolerate any Number of Faults. In: ARCS Workshop 2018; 31th International Conference on Architecture of Computing Systems, pp. 1-8, 2018, ISBN: 978-3-8007-4559-3. (Type: Inproceedings | Abstract)@inproceedings{8385233, FABAN is a fault tolerant atomic broadcast and agreement protocol in bridge-connected networks, which is well understood, precisely analysed and proved for the case with f = 1 faulty bridge. This paper introduces a general extension of FABAN for an arbitrary number f of faulty bridges and specifies the requirements for the underlying bridge-connected topology. The extension is fully compatible to the original protocol description, i.e. is identical in the case f = 1. A topology-based approach is provided as a solution to the problem of tolerating an arbitrary number of faults on the one side and low-cost topologies in regard to a relative small amount of bridges and connections on the other side. Related to this, a rather simple class of network topologies is defined and it is proven, that each network participant can send atomic broadcast messages via FABAN with all benefits the protocol provides. |

## 2016 |

Klaus Echtle, Valentin Fitz: FABAN - Fault-Tolerant Atomic Broadcast and Agreement in Bridge-Connected Networks. In: ARCS 2016; 29th International Conference on Architecture of Computing Systems, pp. 1-10, 2016, ISBN: 978-3-8007-4157-1. (Type: Inproceedings | Abstract)@inproceedings{7499245, FABAN is a new protocol to solve atomic broadcast and Byzantine agreement in a bridge-connected network that provides only f + 1 disjoint paths between any pair of bridges, where f is the number of bridges assumed to be faulty. The case f = 1 with 2 redundant paths is expected to be typical since higher numbers of redundant paths lead to costly networks. In FABAN broadcast messages are signed by the sender and distributed in the network by so-called waves and counterwaves. The three tasks (1) message distribution, (2) message's timeliness checking, and (3) message forwarding are separated between disjoint sets of bridges. As usual, bridges must forward messages according to the topology of the network. Besides this the functionality of bridges is kept as simple as possible. An algorithm for the generation of waves and counterwaves for arbitrary topologies is provided and its completeness formally proven. |