CertiGuide to Network+  9  Chapter 0001:  LAN Cabling

II  Connections 1 IV  Coaxial Cable (Coax)

Adding to a legacy network (an existing network) involves a balancing act. You must maintain compatibility with the existing network while minimizing future bandwidth limitations, or at least delaying your encounter with the bandwidth brick wall as long as possible, while keeping an eye on other factors such as capital outlay. The discussion begins with physical cabling topologies, sometimes unofficially titled “layer 0’, which is a reference to the OSI network model, reviewed later in this course. Of course, in the actual model there is no ‘layer 0’ – that’s just what we call it to indicate that it exists below the functionality described by the OSI model.

Legacy physical cable topologies or types include 10Base2 and 10Base5 coax cable (similar to that used for cable TV) technologies. These are discussed below, along with current and state-of-the-art technologies. Since these are, relatively speaking, ancient history, you may think, why become familiar with them? As noted earlier, once installed, network cabling tends to be used for many years. So unless you’re walking into a brand new site, you’re likely to run into one or more of these older technologies.

II  Connections 1 IV  Coaxial Cable (Coax)