The hierarchical token bucket (HTB) algorithm allows to specify per-flow bitrate guarantees and enables excess bandwidth sharing between flows of the same class. Additionally, it provides capabilities to prioritize the traffic of specific flows, potentially considering their delay demands. HTB hence constitutes a powerful mechanism to enforce QoS requirements hierarchically and on a fine granular per-flow level, making it an appropriate choice in numerous use-cases. In this paper, we present HTBQueue, our implementation of a compound module for HTB support in the discrete event simulator OMNeT++. We validate HTBQueue's functionality in terms of rate conformance and fair bandwidth sharing behavior between competing flows. We furthermore demonstrate its support for flow prioritization.

Published in: M. Marek, G. Nardini, V. Vesely (Eds.), Proceedings of the 8th OMNeT++ Community Summit, Virtual Summit, September 8-10, 2021