The difference between IEC 101 vs IEC 104 Protocol Communication

The difference between IEC 101 vs IEC 104 Communication Protocol

IEC 101 and IEC 104 are protocols used for communication between Supervisory Control and Data Acquisition (SCADA) systems and Remote Terminal Units (RTUs). However, they differ in several key aspects. Here is the general key between the two types of protocol:

IEC 60870-5-101

Cyclic data transfer: IEC 101 uses a cyclic data transfer mechanism, meaning the master (SCADA) periodically polls the slaves (RTUs) for data.

Limited security: IEC 101 has limited security features, making it vulnerable to attacks.

Older protocol: IEC 101 is an older protocol, developed in the 1970s.

IEC 60870-5-104

Event-driven data transfer: IEC 104 uses an event-driven data transfer mechanism, meaning data is only transferred when there is a change in the status of the remote equipment.

Enhanced security: IEC 104 has enhanced security features, including encryption and authentication.

Modern protocol: IEC 104 is a more modern protocol, developed in the 1990s.

Feature	IEC 101	IEC 104
Data transfer mechanism	Cyclic	Event-driven
Security	Limited	Enhanced
Age	Older	Modern

When to choose IEC 101 or IEC 104:

IEC 101: Suitable for smaller, less complex SCADA systems, especially if security is not a major concern.

IEC 104: Suitable for larger, more complex SCADA systems, especially where security is a critical requirement and efficient data transfer is essential.

In conclusion, IEC 104 is generally considered a more advanced and secure protocol compared to IEC 101. However, the choice between the two depends on the specific needs and requirements of the SCADA system.

IEC 60870-101

IEC 60870-101 is a widely used protocol for communication between supervisory control and data acquisition (SCADA) systems and remote terminal units (RTUs). It is particularly common in the energy industry, including power generation, transmission, and distribution.

Key features and components of IEC 101:

1. Asynchronous serial communication: It uses asynchronous serial communication, which is a common method for transmitting data over serial lines, such as RS-232 or RS-485.
2. Master-slave architecture: The protocol follows a master-slave architecture, where the SCADA system acts as the master and controls the RTUs, which are the slaves.
3. Cyclic data transfer: IEC 101 uses a cyclic data transfer mechanism, where the master periodically polls the slaves for data. This ensures that the SCADA system has up-to-date information about the status of the remote equipment.
4. Message types: IEC 101 defines various message types for different functions, including:
5. Initialization messages: Used to establish communication between the master and slaves.
6. Control messages: Used to send control commands to the slaves, such as starting or stopping equipment.
7. Data messages: Used to transmit measurement data from the slaves to the master.
8. Status messages: Used to report the status of the slaves and their connected equipment.
9. Error detection and correction: IEC 101 includes mechanisms for error detection and correction, such as parity checking and cyclic redundancy checks (CRCs), to ensure data integrity.
10. Security features: While IEC 101 does not have built-in encryption, it can be used in conjunction with other security measures to protect data transmission.

IEC 60870-104

IEC 60870-104 is a modern and more advanced protocol compared to IEC 101. It is designed to address the limitations of IEC 101, such as its security vulnerabilities and performance limitations.

Key features and components of IEC 104:

1. Asynchronous serial communication: Similar to IEC 101, IEC 104 uses asynchronous serial communication for data transmission.
2. Master-slave architecture: It also follows a master-slave architecture, where the SCADA system is the master and controls the RTUs.
3. Event-driven data transfer: Unlike IEC 101, IEC 104 uses an event-driven data transfer mechanism. This means that data is only transmitted when there is a change in the status of the remote equipment, rather than periodically. This improves efficiency and reduces network traffic.
4. Message types: IEC 104 defines various message types for different functions, including:
5. Initialization messages: Used to establish communication between the master and slaves.
6. Control messages: Used to send control commands to the slaves.
7. Data messages: it is used to transmit measurement data from the slaves to the master.
8. Status messages: Used to report the status of the slaves and their connected equipment.
9. Error detection and correction: IEC 104 includes mechanisms for error detection and correction, similar to IEC 101.
10. Security features: IEC 104 incorporates security features, such as; encryption and authentication, to protect data transmission.

Overall, IEC 104 is a superior protocol to IEC 101, offering improved performance, security, and scalability. It is particularly suitable for large and complex SCADA systems that require high levels of reliability and data integrity. However, its complexity and higher costs may be factors to consider when making a decision.