On Understanding the Internet Via Edge Measurement

Résumé du livre

The design philosophy of the Internet enables the transmission of packets between "smart" network edges via a "dumb" middle, or core portion of the network. Core networks are ultimately responsible for the single task of routing packets between hosts that are not physically connected. They do so by operating at the network layer of the Open System Interconnection model using the Internet Protocol. Routing requires no understanding of what type of traffic is being transmitted, but only of where a packet is ultimately destined. Whereas the core network's primary job is to correctly route packets, edge networks have additional "smarts" as they contain myriad end point devices each responsible for implementing network protocols and applications. Common tasks like transmitting email, streaming video, or visiting web pages must all be implemented by end point devices. Thus, edge networks and the devices they contain are largely responsible for the evolution of overall network characteristics. In this dissertation we examine several changes edge networks have undergone recently and leverage empirical measurements to understand how edge network evolution has affected various network characteristics. We begin by studying traffic characterization and connection performance on a residential Fiber-To-The-Home network. We then shift our attention to the Transmission Control Protocol (TCP) and how its performance has been affected by a mismatch between the protocol specification and packet round trip times on the modern network. Next, we examine ways network applications drive sending patterns in TCP connections and how these patterns affect overall TCP performance. We conclude with two studies focusing on security related topics for edge networks. First, we develop and test a methodology that aims to broadly understand the port filtering policies in place throughout the network through passive traffic observation. Finally, we undertake a study of Internet Group Management Protocol (IGMP) traffic characteristics and demonstrate how IGMP traffic can be used to launch several attacks from edge networks. The list of topics we tackle is by no means exhaustive, but each topic does represent important work that allows us to keep our understanding of edge network behaviors up-to-date.