IEEE 802.2 is the original name of the ISO/IEC 8802-2 standard which defines logical link control (LLC) as the upper portion of the data link layer of the OSI Model. The original standard developed by the Institute of Electrical and Electronics Engineers (IEEE) in collaboration with the American National Standards Institute (ANSI) was adopted by the International Organization for Standardization (ISO) in 1998, but it remains an integral part of the family of IEEE 802 standards for local and metropolitan networks.
In computer networking, multicast is a type of group communication where data transmission is addressed to a group of destination computers simultaneously. Multicast can be one-to-many or many-to-many distribution. Multicast differs from physical layer point-to-multipoint communication.
In computer networking, the User Datagram Protocol (UDP) is one of the core communication protocols of the Internet protocol suite used to send messages to other hosts on an Internet Protocol (IP) network. Within an IP network, UDP does not require prior communication to set up communication channels or data paths.
Connectionless communication, often referred to as CL-mode communication, is a data transmission method used in packet switching networks, using data packets that are frequently called datagrams, in which each data packet is individually addressed and routed based on information carried in each packet, rather than in the setup information of a prearranged, fixed data channel as in connection-oriented communication. Connectionless protocols are usually described as stateless protocols, the Internet Protocol (IP) and User Datagram Protocol (UDP) are examples.
In the IEEE 802 reference model of computer networking, the logical link control (LLC) data communication protocol layer is the upper sublayer of the data link layer of the seven-layer OSI model. The LLC sublayer acts as an interface between the medium access control (MAC) sublayer and the network layer.
In computer networking, the transport layer is a conceptual division of methods in the layered architecture of protocols in the network stack in the Internet protocol suite and the OSI model. The protocols of this layer provide end-to-end communication services for applications. It provides services such as connection-oriented communication, reliability, flow control, and multiplexing.
IEC 61850 is an international standard defining communication protocols for intelligent electronic devices at electrical substations. It is a part of the International Electrotechnical Commission's (IEC) Technical Committee 57 reference architecture for electric power systems. The abstract data models defined in IEC 61850 can be mapped to a number of protocols. Current mappings in the standard are to Manufacturing Message Specification (MMS), GOOSE [see section 3, Terms and definitions, term 3.65 on page 14], SV or SMV, and soon to web services. In the previous version of the standard, GOOSE stood for "Generic Object Oriented Substation Event", but this old definition is still very common in IEC 61850 documentation. These protocols can run over TCP/IP networks or substation LANs using high speed switched Ethernet to obtain the necessary response times below four milliseconds for protective relaying.
The Precision Time Protocol (PTP) is a protocol used to synchronize clocks throughout a computer network. On a local area network, it achieves clock accuracy in the sub-microsecond range, making it suitable for measurement and control systems. PTP is employed to synchronize financial transactions, mobile phone tower transmissions, sub-sea acoustic arrays, and networks that require precise timing but lack access to satellite navigation signals.
Distributed Network Protocol 3 (DNP3) is a set of communications protocols used between components in process automation systems. Its main use is in utilities such as electric and water companies. Usage in other industries is not common. It was developed for communications between various types of data acquisition and control equipment. It plays a crucial role in SCADA systems, where it is used by SCADA Master Stations, Remote Terminal Units (RTUs), and Intelligent Electronic Devices (IEDs). It is primarily used for communications between a master station and RTUs or IEDs. ICCP, the Inter-Control Center Communications Protocol, is used for inter-master station communications. Competing standards include the older Modbus protocol and the newer IEC 61850 protocol.
Retransmission, essentially identical with automatic repeat request (ARQ), is the resending of packets which have been either damaged or lost. Retransmission is one of the basic mechanisms used by protocols operating over a packet switched computer network to provide reliable communication.
Packet loss occurs when one or more packets of data travelling across a computer network fail to reach their destination. Packet loss is either caused by errors in data transmission, typically across wireless networks, or network congestion. Packet loss is measured as a percentage of packets lost with respect to packets sent.
The Common Information Model (CIM) is an electric power transmission and distribution standard developed by the electric power industry. It aims to allow application software to exchange information about an electrical network. It has been officially adopted by the International Electrotechnical Commission (IEC).
A protocol converter is a device used to convert standard or proprietary protocol of one device to the protocol suitable for the other device or tools to achieve the desired interoperability. Protocols are software installed on the routers, which convert the data formats, data rate and protocols of one network into the protocols of the network in which data is navigating. There are varieties of protocols used in different fields like power generation, transmission and distribution, oil and gas, automation, utilities, and remote monitoring applications. The major protocol translation messages involve conversion of data messages, events, commands, and time synchronization.
System Configuration description Language formerly known as Substation Configuration description Language (SCL) is the language and representation format specified by IEC 61850 for the configuration of electrical substation devices. This includes representation of modeled data and communication services specified by IEC 61850–7–X standard documents. The complete SCL representation and its details are specified in IEC 61850-6 standard document. It includes data representation for substation device entities; its associated functions represented as logical nodes, communication systems and capabilities. The complete representation of data as SCL enhances the different devices of a substation to exchange the SCL files and to have a complete interoperability.
IEC 60870 part 6 in electrical engineering and power system automation, is one of the IEC 60870 set of standards which define systems used for telecontrol in electrical engineering and power system automation applications. The IEC Technical Committee 57 have developed part 6 to provide a communication profile for sending basic telecontrol messages between two systems which is compatible with ISO standards and ITU-T recommendations.
IEC 62351 is a standard developed by WG15 of IEC TC57. This is developed for handling the security of TC 57 series of protocols including IEC 60870-5 series, IEC 60870-6 series, IEC 61850 series, IEC 61970 series & IEC 61968 series. The different security objectives include authentication of data transfer through digital signatures, ensuring only authenticated access, prevention of eavesdropping, prevention of playback and spoofing, and intrusion detection.
High-availability Seamless Redundancy (HSR) is a network protocol for Ethernet that provides seamless failover against failure of any single network component. PRP and HSR are independent of the application-protocol and can be used by most Industrial Ethernet protocols in the IEC 61784 suite. HSR does not cover the failure of end nodes, but redundant nodes can be connected via HSR.
IEC 60870 part 5 is one of the IEC 60870 set of standards which define systems used for telecontrol in electrical engineering and power system automation applications. Part 5 provides a communication profile for sending basic telecontrol messages between two systems, which uses permanent directly connected data circuits between the systems. The IEC Technical Committee 57 have developed a protocol standard for telecontrol, teleprotection, and associated telecommunications for electric power systems. The result of this work is IEC 60870-5. Five documents specify the base IEC 60870-5:
NACK-Oriented Reliable Multicast (NORM) is a transport layer Internet protocol designed to provide reliable transport in multicast groups in data networks. It is formally defined by the Internet Engineering Task Force (IETF) in Request for Comments (RFC) 5740, which was published in November 2009.
Industrial automation systems consisting of several distributed controllers need a precise synchronization for commands, events and process data. For instance, motors for newspaper printing are synchronized within some 5 microseconds to ensure that the color pixels in the different cylinders come within 0.1 mm at a paper speed of some 20 m/s. Similar requirements exist in high-power semiconductors and in drive-by-wire vehicles. This synchronisation is provided by the communication network, in most cases Industrial Ethernet. Many ad-hoc synchronization schemes exist, so IEEE published a standard Precision Time Protocol IEEE 1588 or "PTP", which allows sub-microsecond synchronization of clocks. PTP is formulated generally, so concrete applications need a stricter profile. In particular, PTP does not specify how the clocks should operate when the network is duplicated for better resilience to failures.
