Available Bandwidth vs. Achievable Throughput Measurements in 4G Mobile Networks

摘要

Mobile broadband (MBB) networks are being increasingly used worldwide, and they are planned to steadily evolve to support new services, bigger user base, and booming machine-to-machine communications. In this scenario, performance measurements on deployed networks becomes crucial. In particular, being aware of the achievable throughput has multiple important uses ranging from path and server selection, to root-cause analysis. Throughput estimation suffers from high intrusiveness and dependence on transport and application protocol, while Available Bandwidth is a network-layer metric characterizing the spare capacity of path, not suffering from any of these shortcomings. However, ABw estimation tools have been mainly developed focusing on wired networks, with limited attention to mobile and wireless scenarios, multi-homed mobile nodes, and their peculiarities.In this work, we analyze ABw estimates and TCP achievable throughput measurements on a real 3G/4G testbed (the MONROE platform) performing tests with different providers from countries across Europe. The two metrics are compared for results and in terms of measurement intrusiveness and time cost, highlighting the non-trivial relationship between them. In particular, results show that in suitable conditions ABw estimates can be used as a proxy for TCP achievable throughput measurements, while generating much lower traffic volumes (a critical asset on MBB networks), and that policies enforced by service providers may significantly alter the difference between the two estimated metrics. Future research on how to exploit these findings is discussed as well. We published as open data packet traces and logs of the measurements.