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Frame Aggregation
Frame aggregation is a feature that allows communicating on a shared link or channel, typically a TDM shared channel, with a minimum time slot that for efficiency reasons benefits from filling the time slot with data, i.e. sending two or more data frames in a single transmission. The feature is an important part of the IEEE 802.11e, 802.11n and 802.11ac wireless LAN standards that increases throughput with frame aggregation. The MoCA protocol used for communication over coaxial networks also implements frame aggregation for the same reason. In protocol standards and implementations, the frame aggregation is usually combined with segmentation and reassembly of frames so that the time slots can be filled to 100%. E.g., an aggregation MAC PDU can be filled with 3.5 frames to ensure the time slot is utilized to 100% and in the next time slot the rest of the fragmented frame is sent together with any additional complete frames. The article uses IEEE 802.11 as a basis for explan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Frame (networking)
A frame is a digital data transmission unit in computer networking and telecommunications. In packet switched systems, a frame is a simple container for a single network packet. In other telecommunications systems, a frame is a repeating structure supporting time-division multiplexing. A frame typically includes frame synchronization features consisting of a sequence of bits or symbols that indicate to the receiver the beginning and end of the payload data within the stream of symbols or bits it receives. If a receiver is connected to the system during frame transmission, it ignores the data until it detects a new frame synchronization sequence. Packet switching In the OSI model of computer networking, a frame is the protocol data unit at the data link layer. Frames are the result of the final layer of encapsulation before the data is transmitted over the physical layer. A frame is "the unit of transmission in a link layer protocol, and consists of a link layer header follo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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IEEE
The Institute of Electrical and Electronics Engineers (IEEE) is an American 501(c)(3) organization, 501(c)(3) public charity professional organization for electrical engineering, electronics engineering, and other related disciplines. The IEEE has a corporate office in New York City and an operations center in Piscataway, New Jersey. The IEEE was formed in 1963 as an amalgamation of the American Institute of Electrical Engineers and the Institute of Radio Engineers. History The IEEE traces its founding to 1884 and the American Institute of Electrical Engineers. In 1912, the rival Institute of Radio Engineers was formed. Although the AIEE was initially larger, the IRE attracted more students and was larger by the mid-1950s. The AIEE and IRE merged in 1963. The IEEE is headquartered in New York City, but most business is done at the IEEE Operations Center in Piscataway, New Jersey, opened in 1975. The Australian Section of the IEEE existed between 1972 and 1985, after which it s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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IEEE 802
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. The IEEE 802 standards are restricted to computer networks carrying variable-size packets, unlike cell relay networks, for example, in which data is transmitted in short, uniformly sized units called cells. Isochronous signal networks, in which data is transmitted as a steady stream of octet (computing), octets, or groups of octets, at regular time intervals, are also outside the scope of the IEEE 802 standards. The number 802 has no significance: it was simply the next number in the sequence that the IEEE used fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Wireless LAN
A wireless LAN (WLAN) is a wireless computer network that links two or more devices using wireless communication to form a local area network (LAN) within a limited area such as a home, school, computer laboratory, campus, or office building. This gives users the ability to move around within the area and remain connected to the network. Through a Gateway (telecommunications), gateway, a WLAN can also provide a connection to the wider Internet. Wireless LANs based on the IEEE 802.11 standards are the most widely used computer networks in the world. These are commonly called Wi-Fi, which is a trademark belonging to the Wi-Fi Alliance. They are used for home and small office networks that link together laptop computers, printer (computing), printers, smartphones, Web TVs and gaming devices through a Wireless router, wireless network router, which in turn may link them to the Internet. Hotspot (Wi-Fi), Hotspots provided by routers at restaurants, coffee shops, hotels, libraries, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Multimedia Over Coax Alliance
The Multimedia over Coax Alliance (MoCA) is an international standards consortium that publishes specifications for networking over coaxial cable. The technology was originally developed to distribute IP television in homes using existing cabling, but is now used as a general-purpose Ethernet link where it is inconvenient or undesirable to replace existing coaxial cable with optical fiber or twisted pair cabling. MoCA 1.0 was approved in 2006, MoCA 1.1 in April 2010, MoCA 2.0 in June 2010, and MoCA 2.5 in April 2016. The most recently released version of the standard, MoCA 3.0, supports speeds of up to . This technology is not yet available in customer premises equipment. Membership The Alliance currently has 45 members including pay TV operators, OEMs, CE manufacturers, and IC vendors. MoCA's board of directors consists of Arris, Comcast, Cox Communications, DirecTV, Echostar, Intel, InCoax, MaxLinear and Verizon. Technology Within the scope of the Internet protocol s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Segmentation And Reassembly
Segmentation and reassembly (SAR) is the process used to fragment and reassemble variable length Network packet, packets into fixed length cells so as to allow them to be transported across Asynchronous Transfer Mode (ATM) networks or other cell based infrastructures. Since ATM's payload is only 48 bytes, nearly every packet from any other protocol has to be processed in this way. Thus, it is an essential process for any ATM node. It is usually handled by a dedicated chip, called the SAR. The process is conceptually simple: an incoming packet from another protocol to be transmitted across the ATM network is chopped up into segments that fit into 48-byte chunks carried as ATM cell payloads. At the far end, these chunks are fitted back together to reconstitute the original packet. The process is analogous to the IP fragmentation, fragmentation of IP packets on reaching an interface with a maximum transmission unit (MTU) less than the packet size and the subsequent reassembly of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Protocol Data Unit
In telecommunications, a protocol data unit (PDU) is a single unit of information transmitted among peer entities of a computer network. It is composed of protocol-specific control information and user data. In the layered architectures of communication protocol stacks, each layer implements protocols tailored to the specific type or mode of data exchange. For example, the Transmission Control Protocol (TCP) implements a connection-oriented transfer mode, and the PDU of this protocol is called a ''segment'', while the User Datagram Protocol (UDP) uses datagrams as protocol data units for connectionless communication. A layer lower in the Internet protocol suite, at the Internet layer, the PDU is called a packet, irrespective of its payload type. Packet-switched data networks In the context of packet switching data networks, a protocol data unit (PDU) is best understood in relation to a service data unit (SDU). The features or services of the network are implemented in d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Header (computing)
In information technology, header is supplemental data placed at the beginning of a block of data being stored or transmitted. In data transmission, the data following the header is sometimes called the ''Payload (computing), payload'' or ''HTML element#body, body''. It is vital that header composition follows a clear and unambiguous specification or format, to allow for parsing. Examples * E-mail header: The text (body) is preceded by header lines indicating sender, recipient, subject, sending time stamp, receiving time stamps of all intermediate and the final mail transfer agents, and much more. * Similar headers are used in Usenet (NNTP) messages, and HTTP headers. * In a data packet sent via the Internet, the data (payload) are preceded by header information such as the sender's and the recipient's IP addresses, the Communications protocol, protocol governing the format of the payload and several other formats. The header's format is specified in the Internet Protocol, see IP h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Media Access Control
In IEEE 802 LAN/MAN standards, the medium access control (MAC), also called media access control, is the layer that controls the hardware responsible for interaction with the wired (electrical or optical) or wireless transmission medium. The MAC sublayer and the logical link control (LLC) sublayer together make up the data link layer. The LLC provides flow control and multiplexing for the logical link (i.e. EtherType, 802.1Q VLAN tag etc), while the MAC provides flow control and multiplexing for the transmission medium. These two sublayers together correspond to layer 2 of the OSI model. For compatibility reasons, LLC is optional for implementations of IEEE 802.3 (the frames are then "raw"), but compulsory for implementations of other IEEE 802 physical layer standards. Within the hierarchy of the OSI model and IEEE 802 standards, the MAC sublayer provides a control abstraction of the physical layer such that the complexities of physical link control are invisible to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Bandwidth (computing)
In computing, bandwidth is the maximum rate of data transfer across a given path. Bandwidth may be characterized as network bandwidth, data bandwidth, or digital bandwidth. This definition of ''bandwidth'' is in contrast to the field of signal processing, wireless communications, modem data transmission, digital communications, and electronics, in which ''bandwidth'' is used to refer to the signal bandwidth measured in hertz, meaning the frequency range between lowest and highest attainable frequency while meeting a well-defined impairment level in signal power. The actual bit rate that can be achieved depends not only on the signal bandwidth but also on the noise on the channel. Network capacity The term ''bandwidth'' sometimes defines the net bit rate ''peak bit rate'', ''information rate'', or physical layer ''useful bit rate'', channel capacity, or the maximum throughput of a logical or physical communication path in a digital communication system. For example, bandwi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Ethernet
Ethernet ( ) is a family of wired computer networking technologies commonly used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN). It was commercially introduced in 1980 and first standardized in 1983 as IEEE 802.3. Ethernet has since been refined to support higher bit rates, a greater number of nodes, and longer link distances, but retains much backward compatibility. Over time, Ethernet has largely replaced competing wired LAN technologies such as Token Ring, FDDI and ARCNET. The original 10BASE5 Ethernet uses a thick coaxial cable as a shared medium. This was largely superseded by 10BASE2, which used a thinner and more flexible cable that was both less expensive and easier to use. More modern Ethernet variants use Ethernet over twisted pair, twisted pair and fiber optic links in conjunction with Network switch, switches. Over the course of its history, Ethernet data transfer rates have been increased from the original to the lates ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |