  Time-Sensitive Networking (TSN) enables the transmission of multiple traffic
types within a single network. While the performance of high-priority traffic
has been extensively studied in recent years, the performance of low-priority
traffic varies significantly between different TSN forwarding algorithms. This
paper provides an overview of existing TSN forwarding algorithms and discusses
their impact on best-effort traffic. The effects are quantified through
simulations of synthetic and realistic networks. The considered forwarding
mechanisms are Strict Priority (SP), Asynchronous Traffic Shaper (ATS),
Credit-Based Shaper (CBS), Enhanced Transmission Selection (ETS), and
Time-Aware Shaper (TAS).
  The findings indicate that ATS, CBS, and ETS can significantly reduce queuing
delays and queue lengths for best-effort traffic when compared to SP and TAS.
This effect is enhanced when the reserved bandwidth for high priority queues -
using CBS, ATS, or ETS - is reduced to the lowest possible value, within the
reserved rate and latency requirements. Specifically, the simulations
demonstrate that the choice of forwarding algorithm can improve the performance
of low-priority traffic by up to twenty times compared to the least effective
algorithm. This study not only provides a comprehensive understanding of the
various TSN forwarding algorithms but can also serve as guidance at networks'
design time to improve the performance for all types of traffic.
