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Introduction to Networks
Lesson 1
Objectives
Exam Objective Matrix
Technology Skill Covered
Exam Objective
Exam Objective Number
Basic Definitions
Describe different network topologies.
•Peer-to-peer
•Client-server
3.5
Basic Network Topologies
Describe different network topologies.
•Point-to-point
•Point-to-multipoint
•Ring
•Star
•Mesh
•Bus
•Hybrid
3.5
Basic Network Configuration in Windows
A Brief History of Networking
• First networks called “sneaker nets”
– Transferred files between computers on
floppy disks
• Mainframe computers and dumb terminals
• Defense Advanced Research Projects
Agency (DARPA) created ARPAnet
– Became Internet
• Mid 1980s
– PCs common in workplace
A Brief History of Networking (Continued)
• Late 1980s
– Businesses commonly networked PCs
• July/August 1989
– BryanNet at William Jennings Bryan College
– First general use high speed network
– Through put speeds of 2.5 mbps (megabits
per second)
– Token ring
– Client/server
A Brief History of Networking (Continued)
• Mid 1990s
– World Wide Web established as a viable
entity on the Internet
Internet
World
Wide Web
• Hardware and software
infrastructure
• Service, or software,
that runs on top of the
infrastructure of the
Internet
Local Area Network (LAN)
• A network limited to a local area
• Usually limited to one building, or several
buildings near one another
• Sometimes limited to certain rooms in a
building
Local Area Network (LAN) (Continued)
• Peer-to-peer network
– Each computer acts independently but can
share data and resources, such as printers
– Best used with 10 or fewer computers
• Client/server
– One main computer is server or domain
controller
– User accounts and resources available on
one or more servers
Wide Area Network (WAN)
• A very large network that can stretch across
large geographical areas
– Internet is biggest WAN in existence
• Enterprise network
– WANs in a company’s offices or buildings in
widely dispersed areas that connect facilities
and employees
Metropolitan Area Network (MAN)
• A single network larger than a LAN but
slightly too small to be considered a WAN
• Is generally 50 kilometers maximum
• Links college campuses or stretches across
cities
• Privately owned by an organization or
publicly owned by a municipality
• Term “MAN” falling out of usage, usually
referred to as WAN or enterprise network
Basic Network Topologies
• Shape of network = topology
– Bus
– Star
– Ring
– Mesh
– Point-to-Point
– Point-to-Multipoint
– Hybrid
Bus Topology
• All computers in network are connected by
one main cable, called a backbone
• Advantages
– Easy to build and requires minimal amount of
cable
• Disadvantages
– If cable breaks, networked computers cannot
communicate
– Signal collisions
Bus Network Topology
Star Topology
• Most commonly used networking topology
• Several workstations connected via one
central device such as a hub or a switch
• Advantage
– If cable to one computer goes bad, only that
computer is affected
• Disadvantage
– If central connecting device goes bad, entire
network does not work
Star Network Topology
Ring Topology
• Backbone cable is formed into a ring to
connect all computers
• Advantage
– Use of token avoids data collisions
• Disadvantages
– If backbone breaks, entire network goes
down
– Network becomes very slow when large
amounts of data are being sent
Ring Topology Network
Mesh Topology
• Every computer or building is connected
directly to every other computer or building
• Most commonly used in a WAN environment
• Number of connections: n (n–1) /2
• Advantages
– Reliability, redundancy, high availability
• Disadvantage
– Number of connections grows quickly
Mesh Topology Network
Point-to-Point Topology
• Only one computer is directly connected to
one other computer or device
• Primarily a WAN type topology
• Most commonly used when a computer
outside the network needs to remotely
connect to a computer or server inside a
network
Point-to-Multipoint Topology
• A variation on the point-to-point topology but
commonly used in both LANs and WANs
• One device connects to several other
devices
• Most often used to connect one switch or
router to multiple switches, routers,
computers, or other network devices
Point-to-Multipoint Topology Network
Hybrid Topology
• A hybrid or combination of several network
topologies
• Most networks are hybrid
Hybrid Topology Network
Physical vs. Logical Topologies
• Physical topology
– The shape of the wires
• Logical topology
– The shape of the path the data follows as it
moves through the network.
Physical Star Topology Using a Logical Bus
Topology
Physical Star Topology Using a Logical Ring
Topology
Basic Network Configuration in Windows
• User Account Control
– A feature of Windows Vista and Windows 7
– Requires confirmation, and sometimes
administrative passwords, to allow certain
actions to be taken on a Windows Vista or
Windows 7 computer, even when the person
attempting the actions has administrative
rights
– Can become bothersome
Basic Network Configuration in Windows
(Continued)
To turn off UAC in Windows Vista:
1. Open Control Panel.
2. Double-click the Security icon.
3. In the Security dialog box, turn off UAC in
the Other security settings section.
TIP: It’s best to leave UAC enabled for general
users. Professionals may turn off UAC temporarily
when maintaining PCs.
Windows Vista Security Dialog Box
Basic Network Configuration in Windows
(Continued)
• Network and Sharing applet in Windows 7
and Windows Vista
• All issues related to networking and sharing
of files, folders, media, and so on are
located here
Windows Vista Network and Sharing Center
Dialog Box
Summary
• In organizations, PCs were common by the mid
1980s and networked PCs by the late 1980s.
• The Internet is the hardware and software
infrastructure on which the World Wide Web (a
service or program) runs.
• A LAN is a local network. A MAN is a campus or citywide network. A WAN covered a wide geographic
area.
• All computers are “equal” on a peer-to-peer
network.
Summary (Continued)
• A client/server network has a server or domain
controller to which users connect and access
shared resources.
• Network topologies include bus, star, ring, mesh,
point-to-point, point-to-multipoint, and hybrid.
• Physical topology refers to the shape of a network’s
wires; logical topology is the shape of the path the
data follows as it moves through a network.
• In Windows 7 and Windows Vista, most networking
configurations are performed in the Network and
Sharing Center.