Internet service providers (ISPs) have a variety of quality attributes that determine their attractiveness for data transmission, ranging from quality-of-service metrics such as jitter to security properties such as the presence of DDoS defense systems. ISPs should optimize these attributes in line with their profit objective, i.e., maximize revenue from attracted traffic while minimizing attribute-related cost, all in the context of alternative offers by competing ISPs. However, this attribute optimization is difficult not least because many aspects of ISP competition are barely understood on a systematic level, e.g., the multi-dimensional and cost-driving nature of path quality, and the distributed decision making of ISPs on the same path. In this paper, we improve this understanding by analyzing how ISP competition affects path quality and ISP profits. To that end, we develop a game-theoretic model in which ISPs (i) affect path quality via multiple attributes that entail costs, (ii) are on paths together with other selfish ISPs, and (iii) are in competition with alternative paths when attracting traffic. The model enables an extensive theoretical analysis, surprisingly showing that competition can have both positive and negative effects on path quality and ISP profits, depending on the network topology and the cost structure of ISPs. However, a large-scale simulation, which draws on real-world data to instantiate the model, shows that the positive effects will likely prevail in practice: If the number of selectable paths towards any destination increases from 1 to 5, the prevalence of quality attributes increases by at least 50%, while 75% of ISPs improve their profit.

翻译：互联网服务提供商（ISP）具有多种决定其数据传输吸引力的质量属性，涵盖从抖动等服务品质指标到DDoS防御系统等安全特性。ISP应根据利润目标优化这些属性，即在吸引流量的收入最大化与属性相关成本最小化之间取得平衡，同时需考虑竞争对手提供的替代方案。然而，这种属性优化面临严峻挑战，原因之一在于ISP竞争的诸多方面在系统层面的认知仍相当有限，例如路径质量的多维性与成本驱动特性，以及同一路径上各ISP的分布式决策机制。本文通过分析ISP竞争如何影响路径质量与ISP利润来深化这一认知。为此，我们建立了一个博弈论模型，其中ISP能够：(i)通过多种产生成本的属性影响路径质量，(ii)与其他自私的ISP共存于同一路径，(iii)在吸引流量时与替代路径展开竞争。该模型支持广泛的理论分析，并出人意料地揭示：竞争对路径质量和ISP利润可能产生正面或负面影响，具体取决于网络拓扑结构与ISP的成本结构。然而，基于真实世界数据实例化模型的大规模仿真表明，正面效应在实践中更可能占据主导：当通向任意目的地的可选路径数量从1条增至5条时，质量属性的普及率至少提升50%，同时75%的ISP实现利润改善。