Flow-Based Network Creation Games

TL;DR

This paper introduces Flow-Based Network Creation Games where agents strategically create links to maximize bandwidth, addressing the need for robust, high-capacity networks in decentralized settings, and analyzes their equilibrium properties.

Contribution

It is the first to study bandwidth-focused network creation games, proving existence of equilibria, providing algorithms, and analyzing efficiency bounds.

Findings

Pure Nash equilibria exist in the model.

An optimal network creation algorithm is provided.

Price of Stability is 1, and Price of Anarchy is at most 2.

Abstract

Network Creation Games(NCGs) model the creation of decentralized communication networks like the Internet. In such games strategic agents corresponding to network nodes selfishly decide with whom to connect to optimize some objective function. Past research intensively analyzed models where the agents strive for a central position in the network. This models agents optimizing the network for low-latency applications like VoIP. However, with today's abundance of streaming services it is important to ensure that the created network can satisfy the increased bandwidth demand. To the best of our knowledge, this natural problem of the decentralized strategic creation of networks with sufficient bandwidth has not yet been studied. We introduce Flow-Based NCGs where the selfish agents focus on bandwidth instead of latency. In essence, budget-constrained agents create network links to maximize their minimum or average network flow value to all other network nodes. Equivalently, this can also be understood as agents who create links to increase their connectivity and thus also the robustness of the network. For this novel type of NCG we prove that pure Nash equilibria exist, we give a simple algorithm for computing optimal networks, we show that the Price of Stability is 1 and we prove an (almost) tight bound of 2 on the Price of Anarchy. Last but not least, we show that our models do not admit a potential function.