Size and Scalability Three specifications determine the size and scalability of networking media: maximum nodes per segment, maximum segment length, and maximum network length. A network can include two types of segments: populated and unpopulated. o Populated segment: is a part of a network that contains end nodes. For example, a switch connecting users in a classroom is part of a populated segment. o Unpopulated segment: also known as a link segment , is a part of the network that does not contain end nodes, but simply connects two networking devices such as routers. Connectors and Media Converters Connectors are the pieces of hardware that connect the wire to the network device, be it a server, workstation, switch, or printer. A media converter is a piece of hardware that enables networks or segments running on different media to interconnect and exchange signals. For example, suppose a segment leading from your company’s data center to a group of workstations uses fiber-optic cable, but the workgroup hub can only accept twisted pair (copper) cable. In that case, you could use a media converter to interconnect the hub with the fiber-optic cable Coaxial Cable Coaxial cable consists of a central metal core (often copper) surrounded by an insulator, a braided metal shielding, called braiding or shield , and an outer cover, called the sheath or jacket.
Because of its shielding, most coaxial cable has a high resistance to noise. It can also carry signals farther than twisted pair cabling before amplification of the signals becomes necessary (although not as far as fiber-optic cabling). On the other hand, coaxial cable is more expen- sive than twisted pair cable because it requires significantly more raw materials to manufacture. Coaxial cabling comes in hundreds of specifications, although you are likely to see only two or three types of coax in use on data networks. o RG-6—A type of coaxial cable that is characterized by an impedance of 75 ohms and contains an 18 AWG conducting core. The core is usually made of solid copper. RG-6 coaxial cables are used, for example, to deliver broadband cable Internet service and cable TV, particularly over long distances. If a service provider such as Comcast or Charter supplies you with Internet service, the cable entering your home is RG-6. o RG-8—A type of coaxial cable characterized by a 50-ohm impedance and a 10 AWG core. RG-8 provided the medium for the first Ethernet networks, known as Thicknet. You will never find Thicknet on new networks, but you might find it on older networks. o RG-58—A type of coaxial cable characterized by a 50-ohm impedance and a 24 AWG core. RG-58 was a popular medium for Ethernet LANs in the 1980s. With a smaller diameter than RG-8, RG-58 is more flexible and easier to handle and install. Its core is typically made of several thin strands of copper. The Ethernet standard that relies on RG-58 coax is called Thinnet because it is thinner than Thicknet cables. Like Thicknet, Thinnet is almost never used on modern
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- Twisted pair, Coaxial cable, Twisted Pair Cable, fiber-optic cable