## 1 Introduction  
OT devices and thus communication protocols are widely being adopted into networked applications [1]. This is being expanded with the increasing adoption of Industrial IoT (IIoT) networks, driven by the demand for greater automation, data sharing, and remote monitoring [2]. These networks may also rely on time-sensitive applications that may impact the safety of workers, for example, to shut down a production line when an incident is detected, or to protect energy grid systems in the event of a fault. Previously, delivery of communication over serial networks had limited distances to travel and set maximum delays for communication. As a result, these protocols were ideally suited for safety-critical applications. However, the translation to TCP/IP-based networked communication to better integrate and coexist with existing IT protocols has introduced additional latency and cybersecurity concerns for these communication networks. In many cases, a complete retrofit of existing OT device deployments is not feasible due to the cost, complexity, and potential disruptions associated with upgrading legacy equipment. As a result, there is a growing reliance on solutions that bridge the gap between older OT systems and modern IT networks. Protocol gateways, which act as translators between different communication protocols, have become a common solution in these scenarios. These gateways facilitate the integration of OT systems that use legacy communication protocols, such as Modbus/RTU [3], with more modern network infrastructures using more sophisticated OT protocols, such as DNP3 [4], by mapping protocol values through shared memory within the gateway device. However, while these gateways offer flexibility and interoperability, they also introduce new vulnerabilities into OT networks by making communication more accessible to external threats. The security and timely communication of OT systems are critical, as vulnerabilities in communication protocols can have far-reaching consequences on both operational uptime and worker safety. OT protocols are often designed with limited security features and are sometimes not updated to address modern cybersecurity threats. These vulnerabilities are often mitigated through a defense-in-depth strategy, which involves multiple layers of protection, including network segmentation, firewalls, and intrusion detection systems. However, these measures may not always prevent all vulnerabilities, especially those inherent in a device's protocol implementation [5]. The need to monitor and control OT systems across vast geographic areas has further complicated this issue. An example is the utilization of renewable energy resources and decentralized power grids, which requires the deployment of monitoring devices and sensors interconnected over a large geographical footprint. Remote monitoring, often achieved via wireless networks [6; 7], is becoming essential for maintaining operational efficiency and system resilience. However, this shift introduces new challenges, particularly when communication failures occur between devices located at remote sites. These failures can lead to significant disruptions in system performance, delayed responses to critical events, and increased downtime. In our previous works, we implemented both physical and emulated testbeds to evaluate the performance of specific OT protocols and their on-device implementations [8]. These studies revealed significant variability in the performance of the same protocol across different devices, highlighting the potential for device-specific implementation flaws to cause system-wide failures. In some cases, mismanagement of key protocol functions, such as flag handling or message synchronization, led to complete communication breakdowns. Given the critical need for reliable communication in OT systems, it is essential to address the vulnerabilities introduced by integrating legacy OT protocols with modern IT infrastructure.