Consensus algorithms in Software Defined Networks  (SDN) for multiple controllers

Λάλου, Σταυρούλα

Αλγόριθμοι Συναίνεσης σε Δίκτυα Ορισμένων Λογισμικών (SDN) για πολλαπλούς ελεγκτές

Doctoral Thesis

Author

Λάλου, Σταυρούλα

Date

2025

Abstract

This doctoral dissertation investigates the application of consensus algorithms to enhance collaboration among multiple controllers in Software Defined Networks (SDN). The research focuses on addressing critical challenges in SDN, such as scalability, fault tolerance, single point of failure, and network state synchronization, by leveraging consensus protocols. Traditional single-controller architectures face limitations in managing large-scale networks, including bottlenecks, overhead, and vulnerability to failures. In contrast, multi-controller architectures offer improved flexibility, scalability, and reliability. However, effective coordination and synchronization among distributed controllers remain essential for optimal network performance. The study conducts a comparative analysis of existing consensus protocols and mechanisms, evaluating their performance under identical simulation environments. A novel consensus mechanism based on the Raft algorithm is proposed, designed to ensure stable, consistent, and efficient network state synchronization across controllers. The mechanism supports high throughput, dynamic view changes, fault tolerance, and controller synchronization, demonstrating superior performance compared to existing alternatives. Additionally, the research explores load balancing techniques to optimize resource utilization in the control plane, addressing challenges such as latency and packet loss during load migration. Furthermore, the dissertation addresses the Controller Placement Problem (CPP), proposing a heuristic greedy algorithm to minimize end-to-end latency and reduce maximum latency between controllers and switches. This approach aims to enhance network performance by strategically positioning controllers and mitigating queuing delays. The study emphasizes the practical implementation of these solutions, providing a comprehensive framework for improving scalability, reliability, and efficiency in SDN architectures. By integrating consensus algorithms, load balancing techniques, and optimized controller placement strategies, this research contributes to advancing SDN management, offering robust solutions for modern network challenges. The findings and proposed mechanism are experimentally validated, demonstrating their effectiveness in achieving stable and high- performing SDN environments.

Department

Σχολή Τεχνολογιών Πληροφορικής και Επικοινωνιών. Τμήμα Ψηφιακών Συστημάτων

Number of pages

113

Language

English

URI

https://dione.lib.unipi.gr/xmlui/handle/unipi/17940

Collections

Τμήμα Ψηφιακών Συστημάτων

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Αναφορά Δημιουργού-Μη Εμπορική Χρήση-Όχι Παράγωγα Έργα 3.0 Ελλάδα