  More and more industrial devices are connected to IP-based networks, as this
is essential for the success of Industry 4.0. However, this interconnection
also results in an increased attack surface for various network-based attacks.
One of the easiest attacks to carry out are DoS attacks, in which the attacked
target is overloaded due to high network traffic and corresponding CPU load.
Therefore, the attacked device can no longer provide its regular services. This
is especially critical for devices, which perform real-time operations in
industrial processes. To protect against DoS attacks, there is the possibility
of throttling network traffic at the perimeter, e.g. by a firewall, to develop
robust device architectures. In this paper, we analyze various concepts for
secure device architectures and compare them with regard to their robustness
against DoS attacks. Here, special attention is paid to how the control process
of an industrial controller behaves during the attack. For this purpose, we
compare different schedulers on single-core and dual-core Linux-based systems,
as well as a heterogeneous multi-core architecture under various network loads
and additional system stress.
