Modern digital and industrial systems depend on communication. Files are transferred, sensors report measurements, logs flow to monitoring systems, and business applications interact with machines. Each of these actions uses a protocol, which is essentially the language that defines how data moves between systems.
At first glance, the protocol landscape looks overwhelming: FTP, SMB, NTP, SMTP, Modbus, OPC, REST APIs, and many more. This variety did not happen overnight. It is the result of decades of evolution in both IT and OT, shaped by different priorities, different life cycles, and different vendor ecosystems.
The central argument of this article is simple: The large number of protocols is not the core problem. The real challenge is connecting IT and OT safely now that these once-separate worlds are becoming increasingly interconnected.
Why do so many protocols exist?
There is no single protocol that can serve every purpose. OT systems require predictable timing and reliability. IT systems require scalability and interoperability. Governments need a structured, controlled file exchange. Industrial systems need real-time control of physical processes.
For that reason, different types of communication emerged for different tasks:
- File transfer focuses on moving data.
- File shares focus on collaboration.
- Time synchronization ensures accurate logs and consistency.
- Email protocols distribute notifications and alerts.
- Logging protocols support monitoring and security.
- Industrial protocols control machines and sensors.
- API protocols allow applications to communicate.
- Database replication maintains business continuity.
Each of these functions demands its own approach, which naturally results in a diverse protocol landscape, as seen in the table below:
Two different worlds with different priorities
The diversity becomes clearer when comparing IT and OT.
OT priorities:
- Stable real-time control
- Predictable performance
- Long hardware life cycles
- Vendor-specific ecosystems such as Siemens, Rockwell, Honeywell
- A preference for keeping things unchanged when they work reliably
IT priorities:
- Scalability
- Interoperability
- Security
- Standardization
- Frequent refresh cycles and updates
OT protocols are often older and optimized for control. IT protocols are modern, secure, and designed for software interoperability. These two areas evolved separately, which is why their ‘languages’ look so different today.
Why does this matter today?
For many years, IT and OT remained in separate domains. Today, organizations want:
- Predictive maintenance
- Cloud-based analytics
- Remote monitoring
- Integration with security monitoring platforms
- Dashboards that combine operational and business data
This brings two previously isolated technological worlds together. OT protocols were never designed for exposure to external networks. Many have no authentication, no encryption, and very limited visibility. IT systems expect structured, secure communication. The number of protocols becomes a concern only when these systems need to interact.
Aggregation and interfaces: using the DataDiode and replicators to control complexity
The real challenge is not eliminating protocol diversity but managing it in a controlled and secure way. This is where two components become essential: the DataDiode and its replicators.
The DataDiode sits at the critical boundary between OT and IT and enforces a strict one-way flow of information. It ensures that operational networks can send data outward for monitoring or analysis without any possibility of commands or traffic flowing back in. This breaks the attack path while still allowing higher layers to access the information they need.
This approach prevents protocol complexity from spreading upward, maintains strong separation between domains, and enables safe IT/OT integration without redesigning industrial systems.
Conclusion: the number of protocols is not the problem; the boundary is
The wide variety of protocols we see today is the logical result of decades of IT and OT evolving for different purposes. These systems were never meant to speak the same language, and that diversity will not disappear. It also does not need to. What matters is how these worlds meet.
The real risk lies at the point where OT connects to IT. That boundary must be controlled, predictable, and secure. This is precisely what the DataDiode and the protocol replicators provide. The goal is not to simplify OT by removing protocols. The goal is to contain OT, protect it, and translate it safely. When the interface is strong, the complexity below no longer matters.