Analyzing Packet Delay in Reactive Networks

Packet delay is among the most important characteristics of networks, since it directly impacts the user satisfaction. Accordingly, it is often used for benchmarking networks. Modern mobile cellular networks handle data streams with complex algorithms, in order to maximize the achievable throughput. Considering that, two question arise: (i) How can latency be measured in such networks? (ii) Are respective concepts from wired networks directly applicable to wireless networks? This thesis provides a self-contained guide on how to measure packet delay in mobile cellular networks. Covered aspects reach from timekeeping on tracing hardware to the design of measurement processes. Measurements in operational networks have evidenced them to be reactive; namely, the experienced latency depends on the injected traffic pattern (including the respective history). Accordingly, involved actions are required to obtain fair delay benchmarks, as outlined in this thesis. Thereby, the design of traffic patterns is regarded as integral part of the measurement methodology. I conclude that several well-known approaches for delay measurements are not sufficient for reactive networks and may produce misleading results. The presented concepts contribute to the topic of latency measurement methodologies, such that they keep pace with the fast evolution of communication technologies.