  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.
