In some data communication standards, a time unit (TU) is equal to 1024 microseconds. [1] This unit of time was originally introduced in IEEE 802.11-1999 standard [2] and continues to be used in newer issues of the IEEE 802.11 standard. [1]
In the 802.11 standards, periods of time are generally described as integral numbers of time units. The unit allows for maintaining intervals that are easy to implement in hardware that has a 1 MHz clock (by dividing the clock signal in half ten times, rather than operating a phase-locked loop or digital divider to divide such a clock signal by 1000).
One time unit is equal to one millionth of a kibisecond (1 TU = 10−6 Kis).
A binary prefix is a unit prefix that indicates a multiple of a unit of measurement by an integer power of two. The most commonly used binary prefixes are kibi (symbol Ki, meaning 210 = 1024), mebi (Mi, 220 = 1048576), and gibi (Gi, 230 = 1073741824). They are most often used in information technology as multipliers of bit and byte, when expressing the capacity of storage devices or the size of computer files.
IEEE 802 is a family of Institute of Electrical and Electronics Engineers (IEEE) standards for local area networks (LANs), personal area networks (PANs), and metropolitan area networks (MANs). The IEEE 802 LAN/MAN Standards Committee (LMSC) maintains these standards. The IEEE 802 family of standards has had twenty-four members, numbered 802.1 through 802.24, with a working group of the LMSC devoted to each. However, not all of these working groups are currently active.
IEEE 802.11 is part of the IEEE 802 set of local area network (LAN) technical standards, and specifies the set of medium access control (MAC) and physical layer (PHY) protocols for implementing wireless local area network (WLAN) computer communication. The standard and amendments provide the basis for wireless network products using the Wi-Fi brand and are the world's most widely used wireless computer networking standards. IEEE 802.11 is used in most home and office networks to allow laptops, printers, smartphones, and other devices to communicate with each other and access the Internet without connecting wires. IEEE 802.11 is also a basis for vehicle-based communication networks with IEEE 802.11p.
10BASE2 is a variant of Ethernet that uses thin coaxial cable terminated with BNC connectors to build a local area network. During the mid to late 1980s, this was the dominant 10 Mbit/s Ethernet standard.
In computer networking, Gigabit Ethernet is the term applied to transmitting Ethernet frames at a rate of a gigabit per second. The most popular variant, 1000BASE-T, is defined by the IEEE 802.3ab standard. It came into use in 1999, and has replaced Fast Ethernet in wired local networks due to its considerable speed improvement over Fast Ethernet, as well as its use of cables and equipment that are widely available, economical, and similar to previous standards. The first standard for faster 10 Gigabit Ethernet was approved in 2002.
IEEE 802.11e-2005 or 802.11e is an approved amendment to the IEEE 802.11 standard that defines a set of quality of service (QoS) enhancements for wireless LAN applications through modifications to the media access control (MAC) layer. The standard is considered of critical importance for delay-sensitive applications, such as voice over wireless LAN and streaming multimedia. The amendment has been incorporated into the published IEEE 802.11-2007 standard.
The Attachment Unit Interface (AUI) is a physical and logical interface defined in the IEEE 802.3 standard for 10BASE5 Ethernet and the earlier DIX standard. The physical interface consists of a 15-pin D-subminiature connector that links an Ethernet node's physical signaling to the Medium Attachment Unit (MAU), sometimes referred to as a transceiver. An AUI cable can extend up to 50 metres, though often the MAU and data terminal equipment's (DTE) medium access controller (MAC) are directly connected, bypassing the need for a cable. In Ethernet implementations where the DTE and MAU are combined, the AUI is typically omitted.
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The media-independent interface (MII) was originally defined as a standard interface to connect a Fast Ethernet medium access control (MAC) block to a PHY chip. The MII is standardized by IEEE 802.3u and connects different types of PHYs to MACs. Being media independent means that different types of PHY devices for connecting to different media can be used without redesigning or replacing the MAC hardware. Thus any MAC may be used with any PHY, independent of the network signal transmission medium.
The Precision Time Protocol (PTP) is a protocol for clock synchronization throughout a computer network with relatively high precision and therefore potentially high accuracy. In a local area network (LAN), accuracy can be sub-microsecond – making it suitable for measurement and control systems. PTP is used 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.
IEEE 802.11n-2009, or 802.11n, is a wireless-networking standard that uses multiple antennas to increase data rates. The Wi-Fi Alliance has also retroactively labelled the technology for the standard as Wi-Fi 4. It standardized support for multiple-input multiple-output (MIMO), frame aggregation, and security improvements, among other features, and can be used in the 2.4 GHz or 5 GHz frequency bands.
IEEE 1541-2002 is a standard issued in 2002 by the Institute of Electrical and Electronics Engineers (IEEE) concerning the use of prefixes for binary multiples of units of measurement related to digital electronics and computing. IEEE 1541-2021 revises and supersedes IEEE 1541–2002, which is 'inactive'.
The physical-layer specifications of the Ethernet family of computer network standards are published by the Institute of Electrical and Electronics Engineers (IEEE), which defines the electrical or optical properties and the transfer speed of the physical connection between a device and the network or between network devices. It is complemented by the MAC layer and the logical link layer. An implementation of a specific physical layer is commonly referred to as PHY.
In computer networking, an Ethernet frame is a data link layer protocol data unit and uses the underlying Ethernet physical layer transport mechanisms. In other words, a data unit on an Ethernet link transports an Ethernet frame as its payload.
IEEE 802.11 – or more correctly IEEE 802.11-1997 or IEEE 802.11-1999 – refer to the original version of the IEEE 802.11 wireless networking standard released in 1997 and clarified in 1999. Most of the protocols described by this early version are rarely used today.
This timeline of binary prefixes lists events in the history of the evolution, development, and use of units of measure that are germane to the definition of the binary prefixes by the International Electrotechnical Commission (IEC) in 1998, used primarily with units of information such as the bit and the byte.
IEEE 802.11ac-2013 or 802.11ac is a wireless networking standard in the IEEE 802.11 set of protocols, providing high-throughput wireless local area networks (WLANs) on the 5 GHz band. The standard has been retroactively labelled as Wi-Fi 5 by Wi-Fi Alliance.
IEEE 802.11ah is a wireless networking protocol published in 2017 called Wi-Fi HaLow as an amendment of the IEEE 802.11-2007 wireless networking standard. It uses 900 MHz license-exempt bands to provide extended-range Wi-Fi networks, compared to conventional Wi-Fi networks operating in the 2.4 GHz, 5 GHz and 6 GHz bands. It also benefits from lower energy consumption, allowing the creation of large groups of stations or sensors that cooperate to share signals, supporting the concept of the Internet of things (IoT). The protocol's low power consumption competes with Bluetooth, LoRa, and Zigbee, and has the added benefit of higher data rates and wider coverage range.
Wi-Fi 6, or IEEE 802.11ax, is an IEEE standard from the Wi-Fi Alliance, for wireless networks (WLANs). It operates in the 2.4 GHz and 5 GHz bands, with an extended version, Wi-Fi 6E, that adds the 6 GHz band. It is an upgrade from Wi-Fi 5 (802.11ac), with improvements for better performance in crowded places. Wi-Fi 6 covers frequencies in license-exempt bands between 1 and 7.125 GHz, including the commonly used 2.4 GHz and 5 GHz, as well as the broader 6 GHz band.
Audio Video Bridging (AVB) is a common name for a set of technical standards that provide improved synchronization, low latency, and reliability for switched Ethernet networks. AVB embodies the following technologies and standards:
time unit (TU): A measurement of time equal to 1024 μs.
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