The most popular copper cable type is Unshielded Twisted Pair (UTP). This consists of two unshielded wires that are twisted around each other. Because of its low cost, UTP cabling is used extensively throughout LANs and for telephone connections.
The problem with UTP cabling is it does not offer as high a bandwidth as fiber, nor does it offer protection from interference like coaxial cable or fiber can. If the network operates at 100 Mbps or higher, the general recommendation is to use Cat5 or Cat6 UTP cabling throughout the network environment.
UTP cabling is generally used to connect end devices, such as servers, workstations, laptops, printers, or IP telephones that are no more than 100 meters away from the LAN switch or the Access Layer switch. The connection from the Access Layer switch to the multilayer switch usually requires more bandwidth, so it is recommended that you use MM fiber.
If you want to connect two buildings that are less than 10 km from each other, you can use standard SM fiber. When dealing with distances greater than 10 km, you should consider using special categories of SM fiber or other emerging WAN/radio technologies, eventually using the ISP’s infrastructure. The concept of physical cabling is illustrated in Figure 4.6 below:
Figure 4.6 – Physical Cabling