Size and scalability three specifications determine

 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