IEEE 802-2001 pdf download IEEE Standard for Local and Metropolitan Area Networks: Overview and Architecture
Although primarily aimed at deployment on the scale of a large building or a campus, LANs are alsofrequently applied in smaller areas, such as small offices or single laboratories, and increasingly in homesAt the small-scale application level, a LAN is different from the type of network, such as a data bus orbackplane bus, that is optimized for the interconnection of devices on a desktop or of components within asingle piece of equipment However, desktop-scale applications of LANs are also possible, particularlywhere the nature of the application is more suited to peer-to-peer communication among autonomouscomponents, as opposed to a system structure with more centralized control.
The original IEEE 802 LAN technologies used shared-medium communication, with information broadcasifor all stations to receive. That approach has beenvaried and augmented subsequently, but in ways that pre.serve the appearance of simple peer-to-peer communications behavior for end stations. In particular, the useof bridges (see 6.3.2) for interconnecting LANs is now widespread. These devices allow the construction olnetworks with much larger numbers of LAN end stations, and much higher aggregate throughput, thanwould be achievable with a single shared-medium LAN. End stations attached to such a bridged LAN cancommunicate with each other just as though they were attached to a single shared-medium LAN (howeverthe ability to communicate with other stations can be limited by use of management facilities in the bridges.particularly where broadcast or multicast transmissions are involved). A further stage in this evolution hasled to the use of point-to-point full duplex communication in LANs, cither between an end station and abridge or as a typically high-speed link between a pair of bridges.
The basic communications capabilities provided by all LANs and MANs are packet-based, as opposed toeither cel-based or isochronous. That is, the basic unit of transmission is a sequence of data octets, whichcan be of any length within a range that is dependent on the type of LAN, for all LAN types, the maximumlength is in excess of 1000 octets. (By contrast, cell-based communication transmits data in shorterixed-length units: isochronous communication transmits data as a steady stream of octets, or groups oloctets, at equal time intervals.)
An optional function that may be offered by a LAN or a MAN is the provision of local networking ofisochronous bearer services that are compatible with. or higher speed versions of, Integrated Services DigitalNetworks (ISDN) as defined by the ITU-T I-series Recommendations, to support voice, video, and datadevices and terminals. These services are based on the use of end-user to end-user isochronous bearers thatwill span the supporting Integrated Services LAN (SLAN) or MAN and an intervening ISDN-conformantWAN. Typically, the information streams for packet and isochronous services are multiplexed over the samcphysical media. In addition, capabilities are specified for a single integrated management of these variousstreamns.
1.3 Application and support
The networks are intended to have wide applicability in many environments. The primary aim is to providefor moderate-cost devices and networks, suitable for commercial, educational, governmental, and industrialapplications. Low-cost alternatives are possible for some networks, and application in other environments isnot precluded. The following lists are intended to show some applications and devices and, as such, are notintended to be exhaustive. nor do they constitute a set of required itemms:
File transfer
Graphics
IEEE 802-2001 pdf download
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