Research

Internet Measurement

Carrier Grade NAT detection: We performed a large-scale measurement study of the deployment and behavior of Carrier Grade NAT (CGN) in ISP networks. As one measurement methodology we integrated a traceroute-like approach for stateful middlebox detection into the Netalyzr network troubleshooting tool. We found a large variability in the dimensioning, configuration, and placement of CGNs and observe that CGN deployments have a larger impact on connectivity compared to CPE NAT devices.

Browser-based network measurement: With the implementation of WebRTC all major web browsers now come with powerful networking functionality built-in. We want to find out if we can utilize web browsers for crowd-sourced measurement of network connectivity, performance, and middleboxes on different layers and also evaluate how reliable these measurements are. Currently, we are beta-testing a browser-based demo of the Netalyzr network troubleshooting tool.

TLS proxy detection: Previous measurement studies of TLS interception found a non-negligible percentage of TLS interception. We implemented a measurement tool that performs a range of different TLS handshakes to detect and analyze TLS proxies. Our approach goes beyond the state-of-the-are in that it varies the TLS handshake (e.g. SNI value) aiming to trigger selective TLS proxies.

Content Distribution

Akamai operates a global, highly distributed, and well-connected serving infrastructure. In our paper (to appear) we analyze the AS-level connectivity fabric of Akamai's platform paying special attention to deployments in guest networks that host Akamai machines. In addition, we examine performance data from Akamai's server-side logs and find a that peering decisions matter for performance.

Performance of Software-based Packet Processing

Performance measurements of networking devices only represent a current snapshot of a specific configuration. We built tools to improve and automate network performance testing such that we can easily repeat measurements and explore large parameter spaces. This includes documentation of our hardware setup and software configuration, such that other researchers can reproduce our measurements.