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Chapter 1, Introduction to Networking
Chapter 1, Lesson 1
What Is a Network?
1.
The Concept of Networking
A.
B.
2.
Introducing Computer Networking
A.
B.
C.
3.
Stand-Alone Environment
The Sneakernet
A Simple Computer Network
Why Use a Computer Network?
A.
B.
C.
4.
Network is defined as a system in which a number of independent
computers are linked together to share data and peripherals, such as
hard disks and printers.
Sharing is the purpose of computer networking.
Sharing Information (or Data)
1.
Documents (memos, spreadsheets, invoices, and so on)
2.
E-mail messages
3.
Illustrations, photographs, videos, and audio files
4.
Live audio and video broadcasts
Sharing Hardware and Software
1.
Word-processing software
2.
Project-tracking software
3.
Printers
4.
Fax machines
5.
Modems
6.
CD-ROM drives and other removable drives, such as Zip and Jaz drives
7.
Hard drives
Centralizing Administration and Support
1.
Networking computers can simplify support tasks.
2.
Consistency in software across the network increases support efficiency.
Two Major Types of Networks: LANs and WANs
A.
B.
Local Area Network (LAN)
1.
Basic building block of any network.
2.
Confined to a limited geographical area.
Wide Area Network (WAN)
1.
Number of interconnected LANs.
2.
No geographical limit.
3.
Ultimate WAN is the Internet.
Chapter 1, Lesson 2
Network Configuration
1.
Overview
A.
B.
2.
Peer-to-Peer Networks
A.
B.
C.
D.
E.
2
Components, functions, and features in common:
1.
Servers: Computers that provide shared resources to network users.
2.
Clients: Computers that access shared network resources provided by a
server.
3.
Media: The wires that make the physical connections.
4.
Shared Data: Files provided to clients by servers across the network.
5.
Shared Printers and Other Peripherals: Additional resources provided by
servers.
6.
Resources: Any service or device, such as files, printers, or other items,
made available for use by members of the network.
Type of network will depend on the following:
1.
Size of organization
2.
Level of security required
3.
Type of business
4.
Level of administrative support available
5.
Amount of network traffic
6.
Needs of the network users
7.
Network budget
Size
1.
Also called workgroups
2.
Typically ten or fewer computers
Cost
1.
Relatively simple
2.
Less expensive than server-based networks
3.
No central server
Operating Systems
1.
Servers do not function as clients.
2.
Peer-to-peer networking built into many operating systems.
Implementation
1.
Computers located at user’s desk.
2.
User determines the data to be shared and is also responsible for the
security of the data.
3.
Simple, visible cabling system.
Where a Peer-to-Peer Network is Appropriate:
1.
Ten or fewer users.
2.
Users share resources, such as files and printers, but no specialized
servers exist.
3.
Security is not an issue.
Outline, Chapter 1
Networking Essentials Plus, Third Edition
4.
F.
3.
Organization and the network will experience only limited growth
within the foreseeable future.
Peer-to-Peer Network Considerations
1.
Administration
a.
Managing users and security
b.
Making resources available
c.
Maintaining applications and data
d.
Installing and upgrading application and operating system software
2.
Sharing Resources
a.
Users share resources (directories, printers, fax cards, and so forth).
b.
Users control the manner in which these resources are shared.
3.
Server Requirements
a.
Use a large percentage of its resources to support the user at the
computer, known as the local user.
b.
Use additional resources such as hard disk space and memory, to
support the user's accessing resources on the network, known as the
remote user.
4.
Security
a.
Limited to resource password security.
b.
Each resource has its own password.
c.
Very little control over peer-to-peer networks.
5.
Training
a.
Users need training before they are able to function properly as both
users and administrators of their computers.
b.
Users require more training than those in a server-based network.
Server-Based Networks
A.
B.
C.
Specialized Server(s)
1.
File and Print Servers
2.
Application Servers
3.
Mail Servers
4.
Fax Servers
5.
Communication Servers
6.
Directory Services Servers
Role of Software
1.
Network server hardware and its operating system work together as a
unit.
2.
Advanced server operating systems from Novell and Microsoft are
designed to take advantage of the most advanced server hardware.
3.
No matter how powerful a server might be, it is useless without an
operating system that can take advantage of its physical resources.
Advantages
1.
Sharing Resources: Centrally administered and controlled.
2.
Security: Access to resources can be limited to specific users.
Outline, Chapter 1
Networking Essentials Plus, Third Edition
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3.
4.
5.
D.
Backup: Can be scheduled to occur automatically.
Redundancy: All data can be duplicated and kept online.
Number of Users: Can support a larger number of users and a larger
network.
Hardware Considerations
1.
Limited to the needs of the user.
2.
Typical client has 32 MB of RAM.
Chapter 1, Lesson 3
Network Topology
1.
Designing Network Topology
A.
B.
C.
2.
Standard Topologies
A.
4
Definition of Network Topology:
1.
Arrangement or physical layout of computers, cables, and other
components.
2.
Standard term that most network professionals use for the network’s
basic design.
Network topology determines the following:
1.
Physical layout of the network
2.
Design of the network (for example, star, bus, ring, and mesh)
3.
Diagram of the network
4.
Map of the network
Choice of topology influences the following:
1.
Type of equipment the network needs
2.
Capabilities of the network
3.
Future growth of the network
4.
Network management
Bus
1.
Communication on the Bus
a.
Single trunk (backbone/segment) connects all computers in a single
line.
b.
Computers communicate by addressing data to a particular computer
and sending out that data on the cable as electronic signals.
2.
Sending the Signal
a.
Addressed data is put on network in the form of electronic signals.
b.
Signal goes to all computers on the bus.
c.
Information is accepted only by the computer with the correct
address.
d.
Only one computer can send data at a time.
e.
If one computer fails, it does not affect the rest of the network.
3.
Signal Bounce
Outline, Chapter 1
Networking Essentials Plus, Third Edition
a.
4.
5.
6.
B.
C.
D.
If the signal is allowed to continue uninterrupted, it will keep
bouncing back and forth along the cable and prevent other computers
from sending signals.
b.
The signal must be stopped after it has had a chance to reach the
proper destination address.
Terminator
a.
Terminator required at each end of bus.
b.
Signal could bounce up and down the cable forever.
c.
"Break" in cable creates nonterminated ends.
Disrupting Network Communication
a.
Break in the bus cable can bring down the network.
b.
Computers can still function as stand-alone computers, but they
cannot communicate with each other.
Network Expansion
a.
Lengthen cable using BNC barrel connectors.
b.
Use a repeater to boost the signal.
Star
1.
Computers are connected by cable segments to a hub; signals are
transmitted from sending computer through the hub to all computers on
the network.
2.
If a hub fails, all computers on that hub fail; but if a line from the hub to
the computer is broken, only that computer is down. Remainder of
network stays up.
3.
If one computer fails, remainder of network stays up.
4.
More cable is required with a star than a bus.
Ring
1.
Ring topology connects computers on a single circle of cable.
a.
No terminated ends.
b.
Signals travel around the loop in one direction and pass through each
computer.
2.
Token Passing.
a.
Computers are connected on a single circle of cable in a ring or loop.
Given that the cable is connected in a ring, no termination is required.
b.
The signal, or token, travels from computer to computer around the
loop in one direction only until it reaches the destination computer
with the address that matches the address on the data. Each computer
boosts the signal and sends it on its way to the next computer. Upon
delivery, a verification message is sent to the sender. The data is
stripped from the signal and a new free signal is created by sender.
c.
Just as in the bus topology, one failed computer can affect the entire
network if the physical topology is a ring.
d.
Token travels at approximately speed of light.
Mesh
1.
Each computer is connected to every other computer by separate
cabling.
Outline, Chapter 1
Networking Essentials Plus, Third Edition
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2.
3.
3.
Hubs
A.
B.
4.
B.
C.
Star Bus
1.
Bus backbone connects several star topologies in a linear fashion.
2.
If one computer goes down, it will not affect the rest of the network.
Star Ring
1.
Hubs all feed back to a main hub.
2.
The main hub contains the ring.
Peer-to-Peer
1.
Configured as either a physical star or bus topology.
2.
All computers on the network are equal.
Selecting a Topology
A.
B.
6
Three types of Hubs:
1.
Active Hub: Acts like a repeater by regenerating and retransmitting a
signal (also called multiport repeaters)
2.
Passive Hub: A connecting point or switching station like a block
3.
Hybrid Hub: Supports different cable types
Hub Considerations
1.
Hubs segment the network; a break in any of the cables attached to the
hub would bring only that segment down. The remainder of the network
will continue to work.
2.
Wiring systems can be changed or expanded as needed.
3.
Different ports can be used to accommodate a variety of cabling types.
4.
Monitoring of network activity and traffic can be centralized.
Variations on the Standard Topologies
A.
5.
Superior redundancy and reliability.
Expensive to install because they use a lot of cabling.
Bus
1.
Advantages
a.
Cable is economical.
b.
Media is inexpensive and easy to use.
c.
Simple to set up.
d.
Easy to extend.
2.
Disadvantages
a.
Network can slow down in heavy traffic.
b.
Problems are difficult to isolate.
c.
Cable break can affect many users.
Ring
1.
Advantages
a.
System provides equal access for all computers.
b.
Performance is even despite many users.
2.
Disadvantages
a.
Failure of one computer can impact the rest of the network.
Outline, Chapter 1
Networking Essentials Plus, Third Edition
b.
c.
C.
D.
Problems are hard to isolate.
Network reconfiguration disrupts operation.
Star
1.
Advantages
a.
Modifying system and adding new computers is easy.
b.
Centralized monitoring and management are possible.
c.
Failure of one computer does not affect the rest of the network.
2.
Disadvantages
a.
If the central point fails, the network fails.
Mesh
1.
Advantages
a.
Provides increased redundancy and reliability as well as ease of
troubleshooting.
2.
Disadvantages
a.
Expensive to install because it uses a lot of cabling.
Outline, Chapter 1
Networking Essentials Plus, Third Edition
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