ICS is including supervisory control and data acquisition (SCADA) systems, DCS, and other control system configuration such as skid-mounted PLC which often found in industrial control. ICS are generally used in industries such as oil and natural gas, water and wastewater, electric, chemical, transportation, pharmaceutical, pulp and paper etc.
SCADA systems are usually used to control dispersed asset using centralized and data acquisition and supervising control. DCS are typically used to control the system of production within a local area such as factory using supervisory and regulatory control. PLCs are usually used for discrete control for specific applications and generally provide regulatory control.
These control systems are very vital and important to the operation of critical infrastructures that are often highly interconnected and mutually dependent systems. Firstly, ICS had little resemblance to traditional of information technology (IT) systems. In that ICS were isolated systems running proprietary control protocols using specialized software and hardware. Low cost Internet protocol devices are replacing proprietary solutions now, it makes increasing the possibility of cyber security vulnerabilities and incidents.
ICS are adopting IT solutions to promote corporate business systems remote and connectivity access capabilities, and are being designed and implemented using operating systems, standard computers and network protocols.
Network Components of ICS
There are different network characteristics for each layer within a hierarchy of control system. Network topologies across different ICS implementations vary with modern system using enterprise integration strategies and internet based IT. Control networks have merged with corporate networks to allow control engineers to control and monitor systems from outside of the network of control system. Below is a list of the major components of an ICS network:
• Fieldbus Network. The fieldbus network links sensors and other devices to a PLC, use of fieldbus technologies eliminates the need wiring point to point between controller and each device.
• Control network. The control network connects the supervisory to lower level control module.
• Communication routers. A router is the communicating device that transfer messages, it can be LAN or WAN.
• Firewall. A firewall protects device on the network by controlling and monitoring communication packets using predefined filtering policies.
• Modems. A modem is device used to convert serial data digital and a signal suitable for transmission to allow devices to communicate. Modem is often used in SCADA systems to enable serial communication between remote field devices and MTUs.
• Remote Access point. Remote access points are distinct areas, devices and locations of a control network for remotely accessing process data and configuring control systems.