LAN 101: Networking Basics

Network Architecture Overview

The architecture on which you choose to base your network is the single most important decision you make when setting up a LAN. The architecture defines the speed of the network, the medium access control mechanism it uses (for example, collision detection, token passing, and so on), the types of cables you can use, the network interface adapters you must buy, and the adapter drivers you install.

The Institute of Electrical and Electronic Engineers (IEEE) has defined and documented a set of standards for the physical characteristics of both collision-detection and token-passing networks. These standards are known as IEEE 802.3 (Ethernet) and IEEE 802.5 (Token-Ring), respectively. IEEE 802.11 (Wi-Fi) defines wireless versions of Ethernet.

Note: Be aware, however, that the colloquial names Ethernet and Token-Ring actually refer to earlier versions of these architectures, on which the IEEE standards were based. Minor differences exist between the frame definitions for true Ethernet and true IEEE 802.3. In terms of the standards, IBM’s 16 Mb/s Token-Ring products are an extension of the IEEE 802.5 standard.

New Token-Ring installations are rare today and are not covered here.

The most common choice today for new networks is Ethernet (both wired and wireless). In rare cases, you may encounter a Token-Ring or ARCnet network. Network data-link architectures you might encounter are summarized in the following table. The abbreviations used for the cable types are explained in the following sections.