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IEEE 802 STANDARDS

Efforts to create standard LAN frameworks have been under way for many years, and the complete IEEE specifications have received the endorsements of several government, industry, and international organizations. Many of these groups are actively working to create a standard framework for LANs. the consensus decision has been to confine LAN protocols defined by the IEEE to the lowest two layers (i.e., physical and link layers) of the OSI reference model.

The IEEE 802 working groups were chartered to create standards by which devices could communicate over LANs. The committees’ objectives were to define a LAN standard that ensures compatibility of multivendor equipment such that efficient data communications between devices and systems require minimal effort on the part of end users, equipment users, and network designers.

The IEEE 802 committee established two important premises. First, the task of communication across the LAN is complex and thus needs to be broken down into more manageable subtasks. Second, a single technical solution cannot meet the requirements of various applications.

The result of the first decision was the creation of the following flexible framework for LANs spanning the lower two OSI levels as well as network management of those layers (see Exhibit 1-1-2).

  Physical layer.
  Media access control sublayer of the data link layer.
  Logical link control sublayer of the data link layer.
  Network management.


Exhibit 1-1-2.  IEEE 802 LAN Standards

The second conclusion resulted in the formation of six subcommittees to look into various alternatives. Today there are twelve subcommittees, including:

  IEEE 802.1: Higher-layer interface. Chartered to make recommendations regarding internetworking and higher-layer interfaces and several network management functions.
  IEEE 802.2: Logical link control. Concerned with establishing, maintaining, and terminating a logical link between communicating stations.
  IEEE 802.3: Carrier-sense multiple access with collision detection (CSMA/CD). Standard based on bus topology with a decentralized control structure.
  IEEE 802.3u: 100Base-T. Introduces Fast Ethernet 100Base-T with a bit rate of 100M bps.
  IEEE 802.7: Broadband local area networks. Specifies the cable medium for IEEE 802.3b, IEEE Std. 802.4, video, and RF modems.
  IEEE 802.8: Optical fiber technology. Standard covering the fiber distributed data interface (FDDI).
  IEEE 802.9: Integrated voice and data applications. Includes ISDN.
  IEEE 802.9a. Introduces iso-Ethernet, a 100M bps mode.
  IEEE 802.10: Interoperable LAN security.
  IEEE 802.11 Wireless LANs.
  IEEE 802.12: Demand priority LAN. Introduces 100VG-AnyLAN.
  IEEE 802.14: Hybrid fiber coaxial systems. This committee, a spin-off from 802.6, began work in 1995 on standards for providing broadband access to users.

Several different standards now offer bit rates in the 100M bps range. Among them are the IEEE 802.3u Fast Ethernet, the IEEE 802.12 100VG-AnyLAN, and:

  IEEE 802.4: Token bus. Standard based on token passing technology over a bus topology.
  IEEE 802.5: Token ring. Standard also based on the token passing access method, but over a ring topology.
  IEEE 802.6: Metropolitan area network (MAN). Capable of providing high-speed switched connection over distances of at least 50 km.

In addition, three technical advisory groups were established—802.7, 802.8, and 802.9—to study and make recommendations about, respectively, broadband networks (e.g., techniques for broadband LAN frequency allocation), optical fiber technology (e.g., development of FDDI), and integrated voice and data applications (e.g., ISDN). These topics are not within the scope of this chapter.

The IEEE has also established Committee 802.10, with a charter to develop standards for interoperable LAN security. The last several years have seen the introduction of wireless and high-speed LANs. New standards for these areas are being developed by two new IEEE standards committees: the 802.11 Wireless LAN (WLAN) Working Group and the 802.12 Demand Priority LAN (DPLAN) Working Group, respectively.

The remainder of this chapter is divided into two major sections. First, each of the IEEE 802 standards that defines services and protocols for operating within a LAN or MAN (i.e., 802.2 through 802.6) is described in depth. This section is followed by a discussion of standards and technologies for interconnecting multiple 802 LANs.


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