Network+ Online Course
Lesson 3 - The Physical Network
Introduction
Synopsis
This chapter deals with the physical aspects of the network and broadly corresponds to issues
found at the physical layer of the OSI model. It covers transmission media, both cable and
wireless, and the connectors and other miscellaneous hardware it takes to connect everything
together. It also covers network topologies, which is the layout of the network.
Lesson Index
A. Cable concepts
B. Cable types
C. Wireless technology
D. Topologies
E. Cable hardware
F. Troubleshooting
Review and Final Exercise
Lesson Objectives
Upon completion of this section, students will:
- Be able to explain the benefits of various cable types including coaxial cable, twisted
pair and fiber optic, as well as of wireless technology such as radio, infrared, microwave
and satellite. The student will be able to select the appropriate media for various
situations taking into account cost, distance limitations and number of nodes.
- Understand the topology of networks and how the computers are connected together. The
topologies include the linear bus, ring and star.
- Be able to identify the various connectors and other hardware that the cable systems
require.
- Be able to select the appropriate topology for various Token-ring and Ethernet networks.
- Be able to describe the characteristics and purpose of the media used in IEEE 802.3 and
IEEE 802.5 standards.
Discussion
As a network designer, you must grapple with issues such as “how shall I lay out the network”
and “what type of cable should I use.” In reality, many of these decisions are taken out of
your hands as soon as you decide on a network technology. Small Ethernet LANs have a standard
star topology and use category 5 UTP cable. Token Ring LANs use a star-wired ring topology
and also use category 5 UTP cable. Does this mean that the information found in this chapter
is useless? Clearly not. There will be situations when you will need to extrapolate from a
standard network to solve particular problems. Here are a few examples.
- The cable is too short to reach a particular computer.
- Buildings in a campus setting must be connected together.
- The cable is picking up interference from an electrical source or is interfering with an
electrical device.
- Laptop users come to the office but there is no network connections for them.
Network+ test objectives covered in this lesson
1.1 Recognize the following logical or physical network topologies given a diagram, schematic
or description – Star, bus, mesh, ring.
1.4 Recognize the following media connectors and describe their uses – RJ-11, RJ-45, F-Type,
ST, SC, IEEE 1394, Fiber LC, MT-RJ, USB.
1.5 Recognize the following media types and describe their uses: Cat 3, 5, 5e & 6, UTP, STP,
coaxial cable, single mode and multimode fiber optic cable.
2.15 Identify the basic characteristics of the following Internet access technologies —
satellite, wireless.
3.3 Identify the appropriate tool for a given wiring task (e.g. wire crimper, media tester,
punch down tool or tone generator).
4.3 Given a network scenario interpret visual indicators (e.g. link & collision LEDs) to
determine the nature of a stated problem.
4.7 Given a troubleshooting scenario involving a network with a particular physical topology
(i.e., bus, star, mesh, or ring) and including a network diagram, identify the network area
affected and the cause of the stated failure.
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