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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).
The second conclusion resulted in the formation of six subcommittees to look into various alternatives. Today there are twelve subcommittees, including:
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:
In addition, three technical advisory groups were established802.7, 802.8, and 802.9to 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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