Phan Vĩnh Thu nầComputer Network 1
Ch ng 3:ươ
MÔI TR NG TRUY N D N ƯỜ Ề Ẫ
CHO NETWORKING
Overview
•Copper cable is used in almost every LAN.
Many different types of copper cable are
available, with each type having advantages
and disadvantages. Proper selection of
cabling is key to efficient network operation.
Phan Vĩnh Thu nầComputer Network 2
•Optical fiber is the most frequently used
medium for the longer, high bandwidth, point-to-
point transmissions required on LAN backbones
and on WANs. Using optical media, light is
used to transmit data through thin glass or
plastic fiber. Electrical signals cause a fiber-
optic transmitter to generate the light signals
sent down the fiber. The receiving host receives
the light signals and converts them to electrical
signals at the far end of the fiber. However,
there is no electricity in the fiber-optic cable
itself. In fact, the glass used in fiber-optic cable
is a very good electrical insulator.
Phan Vĩnh Thu nầComputer Network 3
•Physical connectivity allowed an increase in
productivity by allowing the sharing of printers,
servers, and software. Traditional networked
systems require that the workstation remains
stationary permitting moves only within the
limits of the media and office area.
•The introduction of wireless technology
removes these restraints and brings true
portability to the computing world. Currently,
wireless technology does not provide the high-
speed transfers, security, or uptime reliability
of cabled networks. However, flexibility of
wireless has justified the trade off.
Phan Vĩnh Thu nầComputer Network 4
•Administrators often consider wireless when
installing a new network or when upgrading
an existing network. A simple wireless
network could be working just a few minutes
after the workstations are turned on.
Connectivity to the Internet is provided
through a wired connection, router, cable or
DSL modem and a wireless access point
that acts as a hub for the wireless nodes. In
a residential or small office environment
these devices may be combined into a
single unit
Phan Vĩnh Thu nầComputer Network 5
•Students completing this module should
be able to:
–Describe the specifications and
performances of different types of cable.
–Describe coaxial cable and its
advantages and disadvantages over
other types of cable.
–Describe shielded twisted-pair (STP)
cable and its uses.
–Describe unshielded twisted-pair cable
(UTP) and its uses.