enip

ENIP, short for EtherNet/IP, is an industrial automation protocol that maps the Common Industrial Protocol (CIP) onto Ethernet networks. It enables real-time exchange of I/O data, control information, and configuration between industrial devices such as PLCs, safety controllers, HMIs, sensors, actuators, and drives over standard Ethernet infrastructure. ENIP is standardized by the ODVA and is widely used in manufacturing, packaging, and process industries.

Technically, EtherNet/IP relies on the CIP object model, which defines a set of standard and vendor-specific objects that devices expose for interoperability. Two primary messaging modes are used: Explicit messaging, which carries configuration and non-time-critical data over a TCP-based transport; and Implicit messaging, which handles real-time I/O data through a dedicated, connection-oriented channel designed for cyclic updates. This combination allows both flexible data access and predictable, low-latency I/O communication.

Network design and topology in ENIP deployments typically use conventional Ethernet hardware, including switches and routers, with industrial features such as QoS, VLANs, and redundancy options to improve reliability and determinism. ENIP networks often integrate with other CIP-enabled networks and support interoperability across many vendors, aiding system integration and scalability. The protocol also supports safety extensions, such as CIP Safety, to enable dependable exchange of safety-related information across the same network.

Security considerations for ENIP include network segmentation, access controls, and the use of CIP Security where applicable. While ENIP provides interoperability and ease of integration, securing EtherNet/IP deployments requires standard industrial cybersecurity practices and, where possible, dedicated, isolated network zones.