|
IEEE 802.11d
IEEE 802.11d-2001 is an amendment to the IEEE 802.11 specification that adds support for "additional regulatory domains". This support includes the addition of a country information element to beacons, probe requests, and probe responses. The country information elements simplifies the creation of 802.11 wireless access points and client devices that meet the different regulations enforced in various parts of the world. The amendment has been incorporated into the published IEEE 802.11-2012 standard. 802.11d is a wireless specification for operation in additional regulatory domains. This supplement to the 802.11 specifications defines the physical layer requirements: * Channelization * Hopping patterns * New values for current MIB attributes * Future requirements to extend the operation of 802.11 WLANs to new regulatory domains (countries). The current 802.11 standard defines operation in only a few regulatory domains (countries). This supplement adds the requirements and def ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IEEE 802
IEEE 802 is a family of Institute of Electrical and Electronics Engineers (IEEE) standards for local area networks (LAN), personal area network (PAN), and metropolitan area networks (MAN). 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 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 for standards projects. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beacon Frame
Beacon frame is one of the management frames in IEEE 802.11 based WLANs. It contains all the information about the network. Beacon frames are transmitted periodically, they serve to announce the presence of a wireless LAN and to synchronise the members of the service set. Beacon frames are transmitted by the access point (AP) in an infrastructure basic service set (BSS). In IBSS network beacon generation is distributed among the stations. For the 2.4 GHz spectrum, when having more than 15 SSIDs on non-overlapping channels (or more than 45 in total), beacon frames start to consume significant amount of air time and degrade performance even when most of the networks are idle. Components Beacon frames consist of an 802.11 MAC header, body and FCS. Some of the fields in the body are listed below. * * * * SSID * Supported rates * Frequency-hopping (FH) Parameter Set * Direct-Sequence (DS) Parameter Set * Contention-Free (CF) Parameter Set * IBSS Parameter Set * Traffic indi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Probe Request
IEEE 802.11 is part of the IEEE 802 set of local area network (LAN) technical standards, and specifies the set of media 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 IEEE 802.11p. The standards are created and maintained by the Institute of Electrical and Electronics Engineers (IEEE) LAN/MAN Standards Committee (IEEE 802). The base version of the standard was released in 1997 and has had subsequent amendments. While each amendment is officially revoked when it is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wireless Access Point
In computer networking, a wireless access point (WAP), or more generally just access point (AP), is a networking hardware device that allows other Wi-Fi devices to connect to a wired network. As a standalone device, the AP may have a wired connection to a router, but, in a wireless router, it can also be an integral component of the router itself. An AP is differentiated from a hotspot which is a physical location where Wi-Fi access is available. Connections An AP connects directly to a wired local area network, typically Ethernet, and the AP then provides wireless connections using wireless LAN technology, typically Wi-Fi, for other devices to use that wired connection. APs support the connection of multiple wireless devices through their one wired connection. Wireless data standards There are many wireless data standards that have been introduced for wireless access point and wireless router technology. New standards have been created to accommodate the increasing n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of WLAN Channels
Wireless LAN (WLAN) channels are frequently accessed using IEEE 802.11 protocols, and equipment that does so is sold mostly under the trademark Wi-Fi. Other equipment also accesses the same channels, such as Bluetooth. The radio frequency (RF) spectrum is vital for wireless communications infrastructure. The 802.11 standard provides several distinct radio frequency bands for use in Wi-Fi communications: 900 MHz, 2.4 GHz, 3.6 GHz, 4.9 GHz, 5 GHz, 5.9 GHz, 6 GHz and 60 GHz. Each range is divided into a multitude of channels. In the standards, channels are numbered at 5 MHz spacing within a band (except in the 60 GHz band, where they are 2.16 GHz apart), and the number linearly relates to the centre frequency of the channel. Although channels are numbered at 5 MHz spacing, transmitters generally occupy at least 20 MHz, and standards allow for channels to be bonded together to form wider channels for higher throughput. Co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frequency-hopping Spread Spectrum
Frequency-hopping spread spectrum (FHSS) is a method of transmitting radio signals by rapidly changing the carrier frequency among many distinct frequencies occupying a large spectral band. The changes are controlled by a code known to both transmitter and receiver. FHSS is used to avoid interference, to prevent eavesdropping, and to enable code-division multiple access (CDMA) communications. The available frequency band is divided into smaller sub-bands. Signals rapidly change ("hop") their carrier frequencies among the center frequencies of these sub-bands in a predetermined order. Interference at a specific frequency will affect the signal only during a short interval. FHSS offers four main advantages over a fixed-frequency transmission: # FHSS signals are highly resistant to narrowband interference because the signal hops to a different frequency band. # Signals are difficult to intercept if the frequency-hopping pattern is not known. # Jamming is also difficult if the p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Management Information Base
A management information base (MIB) is a database used for managing the entities in a communication network. Most often associated with the Simple Network Management Protocol (SNMP), the term is also used more generically in contexts such as in OSI/ISO Network management model. While intended to refer to the complete collection of management information available on an entity, it is often used to refer to a particular subset, more correctly referred to as MIB-module. Objects in the MIB are defined using a subset of Abstract Syntax Notation One (ASN.1) called "Structure of Management Information Version 2 (SMIv2)" . The software that performs the parsing is a MIB compiler. The database is hierarchical (tree-structured) and each entry is addressed through an object identifier (OID). Internet documentation RFCs discuss MIBs, notably , "Structure and Identification of Management Information for TCP/IP based internets", and its two companions, , "Management Information Base for N ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
