Over the past two decades, a desire to reduce transit cost, improve control over routing and performance, and enhance the quality of experience for users, has yielded a more densely connected, flat network with fewer hops between sources and destinations. The shortening of paths in terms of the number of hops or links has also meant, for what is at the end an infrastructure-bound network, the lengthening of many of these links. In this paper, we focus on an important aspect of the evolving logical connectivity of the Internet that has received little attention to date: intercontinental long-haul links. We develop a methodology and associated processing system for identifying long haul links in traceroute measurements. We apply this system to a large corpus of traceroute data and report on multiple aspects of long haul connectivity including country-level prevalence, routers as international gateways, preferred long-haul destinations, and the evolution of these characteristics over a 7 year period. We identify over 9K layer 3 links that satisfy our definition for intercontinental long haul with many of them terminating in a relatively small number of nodes. An analysis of connected components shows a clearly dominant one with a relative size that remains stable despite a significant growth of the long-haul infrastructure.

翻译：过去二十年间，为降低传输成本、优化路由及性能控制、提升用户体验质量，催生了连接更密集、跃点更少的扁平化网络，使得源与目的地之间的跃点数量减少。然而，对于本质上依附于物理基础设施的网络而言，路径（以跃点或链路数衡量）的缩短也意味着众多链路的距离被拉长。本文聚焦于互联网逻辑连接演进中一个迄今鲜受关注的重要方面：跨大陆长途链路。我们开发了一套方法论及配套处理系统，用于从traceroute测量数据中识别长途链路，并将其应用于大规模traceroute数据集。我们从国家层面占比、作为国际网关的路由器、首选长途目的地等多个维度报告长途连接特性，并揭示这些特性在七年时间跨度内的演变规律。我们识别出超过9000条满足跨大陆长途定义的第三层链路，其中多数终止于相对少量的节点。连通分量分析显示存在一个显著的主导性分量，其相对规模在长途基础设施显著扩张的情况下仍保持稳定。