  Network calculus (NC), particularly its min-plus branch, has been extensively
utilized to construct service models and compute delay bounds for
time-sensitive networks (TSNs). This paper provides a revisit to the
fundamental results. In particular, counterexamples to the most basic min-plus
service models, which have been proposed for TSNs and used for computing delay
bounds, indicate that the packetization effect has often been overlooked. To
address, the max-plus branch of NC is also considered in this paper, whose
models handle packetized traffic more explicitly. It is found that mapping the
min-plus models to the max-plus models may bring in an immediate improvement
over delay bounds derived from the min-plus analysis. In addition, an
integrated analytical approach that combines models from both the min-plus and
the max-plus NC branches is introduced. In this approach, the max-plus
$g$-server model is extended and the extended model, called $g^{x}$-server, is
used together with the min-plus arrival curve traffic model. By applying the
integrated NC approach, service and delay bounds are derived for several
settings that are fundamental in TSNs.
