An important aspect of any LAN implementation is the cabling infrastructure over which it will run. Over the years, many changes have occurred as to the best practices of the time. Original implementations of technologies, such as Ethernet and Token Ring, were very much based on specific cable types with design rules that reflected the transmission properties of that medium. These days, many organizations are installing more generic cabling systems known as Structured Cabling Systems, which have become supported as the technologies mature. The purpose of this section is to investigate the cabling infrastructures supported by the LAN technologies discussed in this book. This starts with a discussion of original implementations (still very much supported, if not widely implemented), in this chapter, and followed by a more detailed discussion of Structured Cabling Systems in chapter 39.