Guide To Networking Essentials, 7th Edition Lecture Notes
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Guide to Networking Essentials, Sixth Edition 1-1
Chapter 1
Introduction to Computer Networks
At a Glance
Instructor’s Manual Table of Contents
Overview
Objectives
Teaching Tips
Quick Quizzes
Class Discussion Topics
Additional Projects
Additional Resources
Key Terms
Technical Notes for Hands-On Projects
Using Virtualization for Hands-On Projects
Chapter 1
Introduction to Computer Networks
At a Glance
Instructor’s Manual Table of Contents
Overview
Objectives
Teaching Tips
Quick Quizzes
Class Discussion Topics
Additional Projects
Additional Resources
Key Terms
Technical Notes for Hands-On Projects
Using Virtualization for Hands-On Projects
Guide to Networking Essentials, Sixth Edition 1-1
Chapter 1
Introduction to Computer Networks
At a Glance
Instructor’s Manual Table of Contents
Overview
Objectives
Teaching Tips
Quick Quizzes
Class Discussion Topics
Additional Projects
Additional Resources
Key Terms
Technical Notes for Hands-On Projects
Using Virtualization for Hands-On Projects
Chapter 1
Introduction to Computer Networks
At a Glance
Instructor’s Manual Table of Contents
Overview
Objectives
Teaching Tips
Quick Quizzes
Class Discussion Topics
Additional Projects
Additional Resources
Key Terms
Technical Notes for Hands-On Projects
Using Virtualization for Hands-On Projects
Guide to Networking Essentials, Sixth Edition 1-2
Lecture Notes
Overview
Chapter 1 offers an introduction to basic computer components and operation. Students
learn about the fundamental reasons for networking, as well as how to identify essential
network components. They also learn to compare different types of networks. Students
learn about servers, their role, and the types of servers that are available. Finally, at the
end of the chapter, students are able to describe specialized networks that have recently
gained popularity in the world of networking.
Objectives
Describe basic computer components and operation
Explain the fundamentals of network communication
Define common networking terms
Compare different network models
Identify the functions of various network server types
Describe specialized networks
Teaching Tips
An Overview of Computer Concepts
1. Provide a brief introduction to networking and why it is so important to have a basic
understanding of computer concepts and terminology.
Basic Functions of a Computer
1. Introduce students to the three basic tasks that all computers perform.
a. Input
b. Output
c. Processing
2. Give students an idea of where each of the three basic tasks is utilized. For example, a
keyboard would be used for input, a screen would be used for output.
Teaching
Tip
Students can view a basic breakdown of a computer’s parts and functions at
http://www.howstuffworks.com/pc.htm.
Lecture Notes
Overview
Chapter 1 offers an introduction to basic computer components and operation. Students
learn about the fundamental reasons for networking, as well as how to identify essential
network components. They also learn to compare different types of networks. Students
learn about servers, their role, and the types of servers that are available. Finally, at the
end of the chapter, students are able to describe specialized networks that have recently
gained popularity in the world of networking.
Objectives
Describe basic computer components and operation
Explain the fundamentals of network communication
Define common networking terms
Compare different network models
Identify the functions of various network server types
Describe specialized networks
Teaching Tips
An Overview of Computer Concepts
1. Provide a brief introduction to networking and why it is so important to have a basic
understanding of computer concepts and terminology.
Basic Functions of a Computer
1. Introduce students to the three basic tasks that all computers perform.
a. Input
b. Output
c. Processing
2. Give students an idea of where each of the three basic tasks is utilized. For example, a
keyboard would be used for input, a screen would be used for output.
Teaching
Tip
Students can view a basic breakdown of a computer’s parts and functions at
http://www.howstuffworks.com/pc.htm.
Guide to Networking Essentials, Sixth Edition 1-2
Lecture Notes
Overview
Chapter 1 offers an introduction to basic computer components and operation. Students
learn about the fundamental reasons for networking, as well as how to identify essential
network components. They also learn to compare different types of networks. Students
learn about servers, their role, and the types of servers that are available. Finally, at the
end of the chapter, students are able to describe specialized networks that have recently
gained popularity in the world of networking.
Objectives
Describe basic computer components and operation
Explain the fundamentals of network communication
Define common networking terms
Compare different network models
Identify the functions of various network server types
Describe specialized networks
Teaching Tips
An Overview of Computer Concepts
1. Provide a brief introduction to networking and why it is so important to have a basic
understanding of computer concepts and terminology.
Basic Functions of a Computer
1. Introduce students to the three basic tasks that all computers perform.
a. Input
b. Output
c. Processing
2. Give students an idea of where each of the three basic tasks is utilized. For example, a
keyboard would be used for input, a screen would be used for output.
Teaching
Tip
Students can view a basic breakdown of a computer’s parts and functions at
http://www.howstuffworks.com/pc.htm.
Lecture Notes
Overview
Chapter 1 offers an introduction to basic computer components and operation. Students
learn about the fundamental reasons for networking, as well as how to identify essential
network components. They also learn to compare different types of networks. Students
learn about servers, their role, and the types of servers that are available. Finally, at the
end of the chapter, students are able to describe specialized networks that have recently
gained popularity in the world of networking.
Objectives
Describe basic computer components and operation
Explain the fundamentals of network communication
Define common networking terms
Compare different network models
Identify the functions of various network server types
Describe specialized networks
Teaching Tips
An Overview of Computer Concepts
1. Provide a brief introduction to networking and why it is so important to have a basic
understanding of computer concepts and terminology.
Basic Functions of a Computer
1. Introduce students to the three basic tasks that all computers perform.
a. Input
b. Output
c. Processing
2. Give students an idea of where each of the three basic tasks is utilized. For example, a
keyboard would be used for input, a screen would be used for output.
Teaching
Tip
Students can view a basic breakdown of a computer’s parts and functions at
http://www.howstuffworks.com/pc.htm.
Guide to Networking Essentials, Sixth Edition 1-3
Storage Components
1. Explain the differences between short-term storage and long-term storage.
Personal Computer Hardware
1. Introduce students to the four major PC components.
Computer Boot Procedure
1. Describe the six steps in the typical computer boot procedure.
How the Operating System and Hardware Work Together
1. Explain the critical services provided by a computer’s OS.
The Fundamentals of Network Communication
1. Describe the most basic network as two or more computers connected by some kind of
transmission media.
Network Components
1. Discuss the three components needed in order to “network” a stand-alone computer.
Teaching
Tip
Read an in-depth look at different network media types at
http://www.ciscopress.com/articles/article.asp?p=31276.
Steps of Network Communication
1. Basic steps of a user accessing a network resource
Layers of the Network Communication Process
1. Explain how the steps of network communication are referred to as layers, and the two
models used to describe this process: OSI and TCP/IP.
Storage Components
1. Explain the differences between short-term storage and long-term storage.
Personal Computer Hardware
1. Introduce students to the four major PC components.
Computer Boot Procedure
1. Describe the six steps in the typical computer boot procedure.
How the Operating System and Hardware Work Together
1. Explain the critical services provided by a computer’s OS.
The Fundamentals of Network Communication
1. Describe the most basic network as two or more computers connected by some kind of
transmission media.
Network Components
1. Discuss the three components needed in order to “network” a stand-alone computer.
Teaching
Tip
Read an in-depth look at different network media types at
http://www.ciscopress.com/articles/article.asp?p=31276.
Steps of Network Communication
1. Basic steps of a user accessing a network resource
Layers of the Network Communication Process
1. Explain how the steps of network communication are referred to as layers, and the two
models used to describe this process: OSI and TCP/IP.
Guide to Networking Essentials, Sixth Edition 1-4
Teaching
Tip
Have students review Simulation 1: Layers of the Communication Process on the
book’s CD.
Teaching
Tip
Microsoft has an article on the OSI model that helps explain the workings of a
layered network: http://support.microsoft.com/kb/103884.
How Two Computers Communicate on a LAN: Some Details
1. Introduce students to idea of a computer’s logical and physical address.
2. Use a street address and ZIP code to help explain the difference between a computer’s
two addresses.
Teaching
Tip
Have students review Simulation 2: Communication Between Two Computers
on the book’s CD.
Quick Quiz 1
1. Name the three basic tasks all computers perform:
Answer: Input, Processing, Output.
2. True or False: Random access memory (RAM) is considered long-term storage.
Answer: False – RAM is considered short-term storage because when power to the
computer is turned off, RAM’s contents are gone.
3. A computer’s _______________________ provides a number of critical services,
including a user interface, memory management, a file system, multitasking, and the
interface to hardware devices.
Answer: operating system (OS)
4. What is the name given to software that provides the interface between the OS and
computer hardware?
Answer: device driver
5. What is the physical address assigned to NICs called?
a. Media Address Control
b. Physical Address Control
c. Media Access Control
d. Media Control Access
Teaching
Tip
Have students review Simulation 1: Layers of the Communication Process on the
book’s CD.
Teaching
Tip
Microsoft has an article on the OSI model that helps explain the workings of a
layered network: http://support.microsoft.com/kb/103884.
How Two Computers Communicate on a LAN: Some Details
1. Introduce students to idea of a computer’s logical and physical address.
2. Use a street address and ZIP code to help explain the difference between a computer’s
two addresses.
Teaching
Tip
Have students review Simulation 2: Communication Between Two Computers
on the book’s CD.
Quick Quiz 1
1. Name the three basic tasks all computers perform:
Answer: Input, Processing, Output.
2. True or False: Random access memory (RAM) is considered long-term storage.
Answer: False – RAM is considered short-term storage because when power to the
computer is turned off, RAM’s contents are gone.
3. A computer’s _______________________ provides a number of critical services,
including a user interface, memory management, a file system, multitasking, and the
interface to hardware devices.
Answer: operating system (OS)
4. What is the name given to software that provides the interface between the OS and
computer hardware?
Answer: device driver
5. What is the physical address assigned to NICs called?
a. Media Address Control
b. Physical Address Control
c. Media Access Control
d. Media Control Access
Guide to Networking Essentials, Sixth Edition 1-5
Answer: Media Access Control
Network Terms Explained
1. Explain the importance of learning the “language” of computer networking.
LANs, Internetworks, WANs, and MANs
1. Use Figure 1-13 to show the components of a basic network consisting of computers
interconnected by a hub.
Teaching
Tip
For a list of networks and their scopes, see
http://en.wikipedia.org/wiki/Computer_network#Types_of_networks_based_on_
physical_scope.
Packets and Frames
1. Briefly discuss how data is segmented into packets and then encapsulated into frames
for transmission
a. IP addressing information exists in packets
b. MAC addressing added in frames
Clients and Servers
1. Explain the different uses of the term client in relation to software / software suites /
OS
2. “Server” can also be ambiguous, cover different definitions in relation to service-based
software, server operating systems, and server computers.
Network Models
1. Discuss the two major types of network models: peer-to-peer and server-based.
Peer-to-Peer/Workgroup Model
1. Peer-to-peer networking model as it relates to client PCs
a. Cover the benefits (cost) of a peer-to-peer network model versus the
disadvantages (scalability).
b. Members are all simultaneously servers and clients for whichever resources they
may host.
Server/Domain-Based Model
Answer: Media Access Control
Network Terms Explained
1. Explain the importance of learning the “language” of computer networking.
LANs, Internetworks, WANs, and MANs
1. Use Figure 1-13 to show the components of a basic network consisting of computers
interconnected by a hub.
Teaching
Tip
For a list of networks and their scopes, see
http://en.wikipedia.org/wiki/Computer_network#Types_of_networks_based_on_
physical_scope.
Packets and Frames
1. Briefly discuss how data is segmented into packets and then encapsulated into frames
for transmission
a. IP addressing information exists in packets
b. MAC addressing added in frames
Clients and Servers
1. Explain the different uses of the term client in relation to software / software suites /
OS
2. “Server” can also be ambiguous, cover different definitions in relation to service-based
software, server operating systems, and server computers.
Network Models
1. Discuss the two major types of network models: peer-to-peer and server-based.
Peer-to-Peer/Workgroup Model
1. Peer-to-peer networking model as it relates to client PCs
a. Cover the benefits (cost) of a peer-to-peer network model versus the
disadvantages (scalability).
b. Members are all simultaneously servers and clients for whichever resources they
may host.
Server/Domain-Based Model
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Guide to Networking Essentials, Sixth Edition 1-6
1. Explain what it means to be a part of a domain-based network architecture and how it
affects user accounts and resource access
a. Advantages in relation to peer-to-peer (centralization, scalability).
b. Services that are related and most likely part of a domain architecture should
also be mentioned, such as naming services, or e-mail services.
Teaching
Tip
Microsoft Active Directory hasn't always been the only directory services
product. Take a look at Novell's older solution, eDirectory:
http://www.novell.com/products/edirectory/fsd/comparison.html.
Quick Quiz 2
1. An _________________ is a networked collection of LANs tied together by devices
such as routers.
Answer: internetwork
2. What is the more well-known term for chunks of data sent across the network?
Answer: Packet ( Frame is another term that is often used)
3. What is the difference between a client and a server, in networking terms?
Answer: A client can be a workstation that requests network resources from a server. A
server provides a network service to client computers.
4. Networks fall into two major types: peer-to-peer and client/server (also called
____________________).
Answer: server-based
5. On a Windows-based peer-to-peer network, all computers are members of a:
a. Domain
b. Workgroup
c. Server network
d. WAN
Answer: Workgroup
Teaching
Tip
You can find a comparison of various operating systems at
http://en.wikipedia.org/wiki/Comparison_of_operating_system.
Network Servers
1. Discuss common services found on network servers in various sized networks.
1. Explain what it means to be a part of a domain-based network architecture and how it
affects user accounts and resource access
a. Advantages in relation to peer-to-peer (centralization, scalability).
b. Services that are related and most likely part of a domain architecture should
also be mentioned, such as naming services, or e-mail services.
Teaching
Tip
Microsoft Active Directory hasn't always been the only directory services
product. Take a look at Novell's older solution, eDirectory:
http://www.novell.com/products/edirectory/fsd/comparison.html.
Quick Quiz 2
1. An _________________ is a networked collection of LANs tied together by devices
such as routers.
Answer: internetwork
2. What is the more well-known term for chunks of data sent across the network?
Answer: Packet ( Frame is another term that is often used)
3. What is the difference between a client and a server, in networking terms?
Answer: A client can be a workstation that requests network resources from a server. A
server provides a network service to client computers.
4. Networks fall into two major types: peer-to-peer and client/server (also called
____________________).
Answer: server-based
5. On a Windows-based peer-to-peer network, all computers are members of a:
a. Domain
b. Workgroup
c. Server network
d. WAN
Answer: Workgroup
Teaching
Tip
You can find a comparison of various operating systems at
http://en.wikipedia.org/wiki/Comparison_of_operating_system.
Network Servers
1. Discuss common services found on network servers in various sized networks.
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Guide to Networking Essentials, Sixth Edition 1-7
Domain Controller/Directory Servers
1. Explain the use of directory services to centralize account management and unified
resource access.
Teaching
Tip
Give students the chance to take an in-depth look at Windows Server 2008
Active Directory Domain Services at http://technet.microsoft.com/en-
us/library/cc770946%28WS.10%29.aspx.
File and Print Servers
1. File and print servers provide a single point of access for storage and printers, as well as
additional features such as fault tolerance and load balancing.
Application Servers
1. Explain that an application server takes most of the responsibility for processing and
data storage, while a client (such as a Web browser) does considerably less work.
a. Common examples of application servers are web-based platforms.
Communication Servers
1. Emphasize the use of communication servers and their ability to service remote users
with network resources that would not be available otherwise.
E-Mail/Fax Servers
1. E-mail servers handle and deliver e-mail using a variety of different protocols, while fax
servers consolidate incoming and outgoing faxes.
a. SMTP is used to send e-mail
b. POP3 is used to deliver e-mail
Web Servers
1. Web servers host Web pages for access by Web browsers such as Internet Explorer or
Firefox.
a. Web servers often provide additional services such as FTP for remote file
access.
Additional Network Services
1. Discuss the importance of DNS and DHCP to the functionality of domain services as
well as their importance outside of domain environments.
Server Hardware Requirements
Domain Controller/Directory Servers
1. Explain the use of directory services to centralize account management and unified
resource access.
Teaching
Tip
Give students the chance to take an in-depth look at Windows Server 2008
Active Directory Domain Services at http://technet.microsoft.com/en-
us/library/cc770946%28WS.10%29.aspx.
File and Print Servers
1. File and print servers provide a single point of access for storage and printers, as well as
additional features such as fault tolerance and load balancing.
Application Servers
1. Explain that an application server takes most of the responsibility for processing and
data storage, while a client (such as a Web browser) does considerably less work.
a. Common examples of application servers are web-based platforms.
Communication Servers
1. Emphasize the use of communication servers and their ability to service remote users
with network resources that would not be available otherwise.
E-Mail/Fax Servers
1. E-mail servers handle and deliver e-mail using a variety of different protocols, while fax
servers consolidate incoming and outgoing faxes.
a. SMTP is used to send e-mail
b. POP3 is used to deliver e-mail
Web Servers
1. Web servers host Web pages for access by Web browsers such as Internet Explorer or
Firefox.
a. Web servers often provide additional services such as FTP for remote file
access.
Additional Network Services
1. Discuss the importance of DNS and DHCP to the functionality of domain services as
well as their importance outside of domain environments.
Server Hardware Requirements
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Guide to Networking Essentials, Sixth Edition 1-8
1. Emphasize that hardware requirements between client operating systems and server
operating systems differ due to the tasks they’re expected to complete.
a. Servers require increasingly more resources depending on load and services
provided.
b. Client operating system hardware requirements have increased, while server
operating systems have remained relatively the same.
Specialized Networks
1. Discuss various non-computer-centric networks.
Storage Area Networks
1. A SAN provides access to large amounts of networked storage.
a. SANs typically use Fibre Channel or iSCSI.
Wireless Personal Area Networks
1. WPANs help to connect mobile devices to other devices but typically have short range.
a. IEEE 802.15 is the standard for WPANs.
Quick Quiz 3
1. What is the role of an application server?
Answer: Application servers supply the server side of client/server applications, and often
the data that goes along with them, to network clients.
2. What is the role of a communication server?
Answer: Communication servers provide a mechanism for users to access a network’s
resources remotely.
3. What is the name of the network service that provides name resolution services that
allow users to access both local and Internet servers by name rather than address?
Answer: DNS – Domain Name System
4. A ____________________ is a short-range networking technology designed to connect
personal devices to exchange information.
Answer: wireless personal area network (WPAN)
Class Discussion Topics
1. Have any of the students installed/configured a LAN before? If so, ask them to briefly
discuss their experiences.
1. Emphasize that hardware requirements between client operating systems and server
operating systems differ due to the tasks they’re expected to complete.
a. Servers require increasingly more resources depending on load and services
provided.
b. Client operating system hardware requirements have increased, while server
operating systems have remained relatively the same.
Specialized Networks
1. Discuss various non-computer-centric networks.
Storage Area Networks
1. A SAN provides access to large amounts of networked storage.
a. SANs typically use Fibre Channel or iSCSI.
Wireless Personal Area Networks
1. WPANs help to connect mobile devices to other devices but typically have short range.
a. IEEE 802.15 is the standard for WPANs.
Quick Quiz 3
1. What is the role of an application server?
Answer: Application servers supply the server side of client/server applications, and often
the data that goes along with them, to network clients.
2. What is the role of a communication server?
Answer: Communication servers provide a mechanism for users to access a network’s
resources remotely.
3. What is the name of the network service that provides name resolution services that
allow users to access both local and Internet servers by name rather than address?
Answer: DNS – Domain Name System
4. A ____________________ is a short-range networking technology designed to connect
personal devices to exchange information.
Answer: wireless personal area network (WPAN)
Class Discussion Topics
1. Have any of the students installed/configured a LAN before? If so, ask them to briefly
discuss their experiences.
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Guide to Networking Essentials, Sixth Edition 1-9
2. Do students have previous experience configuring servers? If so, ask them to briefly
discuss their experiences.
Additional Projects
1. Students can research a list of operating systems (client or server) and detail their
hardware requirements. Have them look at Microsoft and non-Microsoft solutions, and
compare benefits of either solution in relation to hardware requirements.
2. Give students the chance to look at network comparisons of small, home peer-to-peer
networks versus a larger domain-based server network. Ask them to identify what
services they have in common (DHCP, DNS)
Additional Resources
1. Computer Networking:
http://en.wikipedia.org/wiki/Computer_network
2. Linux Networking-Concepts HOWTO:
www.netfilter.org/documentation/HOWTO/networking-concepts-HOWTO.html
3. Networking Glossary:
www.nextecsystems.com/networking-glossary.html
4. Client-server:
http://en.wikipedia.org/wiki/Client-server
5. How Home Networking Works:
http://computer.howstuffworks.com/home-network.htm
Key Terms
application server A computer that supplies the server side of client/server
applications, and often the data that goes along with them, to network clients.
bus A collection of wires that carry data from one place to another on a computer’s
motherboard.
client Can be used to describe: an operating system designed mainly to access network
resources; a computer’s primary role in a network which is that of running user
applications and accessing network resources; software that requests network resources
from servers.
communication server A computer that provides a mechanism for users to access a
network’s resources remotely.
core a core is an instance of a processor inside a single CPU chip. See multicore CPU.
2. Do students have previous experience configuring servers? If so, ask them to briefly
discuss their experiences.
Additional Projects
1. Students can research a list of operating systems (client or server) and detail their
hardware requirements. Have them look at Microsoft and non-Microsoft solutions, and
compare benefits of either solution in relation to hardware requirements.
2. Give students the chance to look at network comparisons of small, home peer-to-peer
networks versus a larger domain-based server network. Ask them to identify what
services they have in common (DHCP, DNS)
Additional Resources
1. Computer Networking:
http://en.wikipedia.org/wiki/Computer_network
2. Linux Networking-Concepts HOWTO:
www.netfilter.org/documentation/HOWTO/networking-concepts-HOWTO.html
3. Networking Glossary:
www.nextecsystems.com/networking-glossary.html
4. Client-server:
http://en.wikipedia.org/wiki/Client-server
5. How Home Networking Works:
http://computer.howstuffworks.com/home-network.htm
Key Terms
application server A computer that supplies the server side of client/server
applications, and often the data that goes along with them, to network clients.
bus A collection of wires that carry data from one place to another on a computer’s
motherboard.
client Can be used to describe: an operating system designed mainly to access network
resources; a computer’s primary role in a network which is that of running user
applications and accessing network resources; software that requests network resources
from servers.
communication server A computer that provides a mechanism for users to access a
network’s resources remotely.
core a core is an instance of a processor inside a single CPU chip. See multicore CPU.
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Guide to Networking Essentials, Sixth Edition 1-10
credentials The username and password or other form of identity used to access a
computer.
device driver Software that provides the interface between the OS and computer
hardware.
directory service The software that manages centralized access and security in a server-
based network.
domain controller A computer running a Windows server OS on which the directory
service role called Active Directory is installed. A domain controller maintains a
database of user and computer accounts as well as network access policies in a
Windows domain. See directory service.
domain A collection of users and computers in a server-based network whose accounts
are managed by Windows servers called domain controllers. See domain controller.
encapsulation The process of adding header and trailer information to chunks of data.
file and print server A computer that provide secure centralized file storage and
sharing and access to networked printers.
frame A packet with the source and destination MAC addresses added to it. In addition,
an error-checking code is added to the back end of the packet. Frames are generated by
and processed by the network interface. See also packet.
header Information added to the front end of a chunk of data so that the data can be
properly interpreted and processed by network protocols.
internetwork A networked collection of LANs tied together by devices such as routers.
See also local area network (LAN).
local area network (LAN) A small network limited to a single collection of machines
and connected by one or more interconnecting devices in a small geographic area.
mail servers A computer that handles sending and receiving e-mail messages for
network users.
metropolitan area network (MAN) An internetwork that is confined to a geographic
region such as a city or county. Uses third-party communication providers to provide
connectivity among locations. See also internetwork.
multicore CPU A CPU that contains two or more processing cores. See core.
multitasking An operating system’s capability to run more than one application or
process at the same time.
name server A computer that stores the names and addresses of computers on a
network allowing other computers to use computer names rather than addresses to
communicate with one another.
network client software The application or operating system service that can request
information stored on another computer.
Network Information Service (NIS) A Linux-supported directory service that supports
centralized logon.
network model Defines how and where resources are shared and how access to these
resources is regulated.
credentials The username and password or other form of identity used to access a
computer.
device driver Software that provides the interface between the OS and computer
hardware.
directory service The software that manages centralized access and security in a server-
based network.
domain controller A computer running a Windows server OS on which the directory
service role called Active Directory is installed. A domain controller maintains a
database of user and computer accounts as well as network access policies in a
Windows domain. See directory service.
domain A collection of users and computers in a server-based network whose accounts
are managed by Windows servers called domain controllers. See domain controller.
encapsulation The process of adding header and trailer information to chunks of data.
file and print server A computer that provide secure centralized file storage and
sharing and access to networked printers.
frame A packet with the source and destination MAC addresses added to it. In addition,
an error-checking code is added to the back end of the packet. Frames are generated by
and processed by the network interface. See also packet.
header Information added to the front end of a chunk of data so that the data can be
properly interpreted and processed by network protocols.
internetwork A networked collection of LANs tied together by devices such as routers.
See also local area network (LAN).
local area network (LAN) A small network limited to a single collection of machines
and connected by one or more interconnecting devices in a small geographic area.
mail servers A computer that handles sending and receiving e-mail messages for
network users.
metropolitan area network (MAN) An internetwork that is confined to a geographic
region such as a city or county. Uses third-party communication providers to provide
connectivity among locations. See also internetwork.
multicore CPU A CPU that contains two or more processing cores. See core.
multitasking An operating system’s capability to run more than one application or
process at the same time.
name server A computer that stores the names and addresses of computers on a
network allowing other computers to use computer names rather than addresses to
communicate with one another.
network client software The application or operating system service that can request
information stored on another computer.
Network Information Service (NIS) A Linux-supported directory service that supports
centralized logon.
network model Defines how and where resources are shared and how access to these
resources is regulated.
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Guide to Networking Essentials, Sixth Edition 1-11
network protocols The software on a computer that defines the rules and formats a
computer must use when sending information across the network.
network server software The software that allows a computer to share its resources by
fielding requests generated by network clients.
packet A chunk of data with source and destination IP addresses (as well as other IP
protocol information) added to it. Packets are generated by and processed by the
network protocol.
peer-to-peer network The network model in which all computers can function as
clients or servers as necessary and in which there is no centralized control over network
resources.
server Can be used to describe: an operating system designed mainly to share network
resources; when a computer’s primary role is to give client computers access to network
resources; the software that responds to requests for network resources from client
computers.
server-based network The network model in which server computers take on
specialized roles to provide client computers with network services and to provide
centralized control over network resources.
stand-alone computer A computer that does not have the necessary hardware or
software to communicate on a network.
storage area network (SAN) A specialized network that uses high-speed networking
technologies to provide servers with fast access to large amounts of disk storage.
trailer Information added to the back end of a chunk of data so that the data can be
properly interpreted and processed by network protocols.
Web server A computer running software that allows users to access HTML and other
document types using a Web browser.
wide area networks (WANs) An internetwork that is geographically dispersed and uses
third-party communication providers to provide connectivity among locations. See also
internetwork.
wireless personal area network (WPAN) A short-range networking technology
designed to connect personal devices to exchange information.
Technical Notes for Hands-On Projects
All projects in this book that use the Sharing and Security option for folders assume that the
Use simple file sharing option has been disabled.
Hands-On Project 1-1: This project requires the NET HELP and NET VIEW utilities.
Hands-On Project 1-2: This project requires Windows Explorer and the NET VIEW utility.
Hands-On Project 1-3: This project requires Internet access and a Web browser.
network protocols The software on a computer that defines the rules and formats a
computer must use when sending information across the network.
network server software The software that allows a computer to share its resources by
fielding requests generated by network clients.
packet A chunk of data with source and destination IP addresses (as well as other IP
protocol information) added to it. Packets are generated by and processed by the
network protocol.
peer-to-peer network The network model in which all computers can function as
clients or servers as necessary and in which there is no centralized control over network
resources.
server Can be used to describe: an operating system designed mainly to share network
resources; when a computer’s primary role is to give client computers access to network
resources; the software that responds to requests for network resources from client
computers.
server-based network The network model in which server computers take on
specialized roles to provide client computers with network services and to provide
centralized control over network resources.
stand-alone computer A computer that does not have the necessary hardware or
software to communicate on a network.
storage area network (SAN) A specialized network that uses high-speed networking
technologies to provide servers with fast access to large amounts of disk storage.
trailer Information added to the back end of a chunk of data so that the data can be
properly interpreted and processed by network protocols.
Web server A computer running software that allows users to access HTML and other
document types using a Web browser.
wide area networks (WANs) An internetwork that is geographically dispersed and uses
third-party communication providers to provide connectivity among locations. See also
internetwork.
wireless personal area network (WPAN) A short-range networking technology
designed to connect personal devices to exchange information.
Technical Notes for Hands-On Projects
All projects in this book that use the Sharing and Security option for folders assume that the
Use simple file sharing option has been disabled.
Hands-On Project 1-1: This project requires the NET HELP and NET VIEW utilities.
Hands-On Project 1-2: This project requires Windows Explorer and the NET VIEW utility.
Hands-On Project 1-3: This project requires Internet access and a Web browser.
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Guide to Networking Essentials, Sixth Edition 1-12
Hands-On Project 1-4: This project requires Internet access and a Web browser.
Hands-On Project 1-5: This project assumes students are using Windows XP Professional as
the operating system, but the tasks can be accomplished in other operating systems.
Students also use a word processor or a simple text editor.
Using Virtualization for Hands-On Projects
The following Hands-On Projects/Challenge Labs have been identified as those that students
can do using virtual machines rather than physical machines.
Hands-On Project 1-1
Hands-On Project 1-2
Hands-On Project 1-3
Hands-On Project 1-4
Hands-On Project 1-5
Hands-On Project 1-4: This project requires Internet access and a Web browser.
Hands-On Project 1-5: This project assumes students are using Windows XP Professional as
the operating system, but the tasks can be accomplished in other operating systems.
Students also use a word processor or a simple text editor.
Using Virtualization for Hands-On Projects
The following Hands-On Projects/Challenge Labs have been identified as those that students
can do using virtual machines rather than physical machines.
Hands-On Project 1-1
Hands-On Project 1-2
Hands-On Project 1-3
Hands-On Project 1-4
Hands-On Project 1-5
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Guide to Networking Essentials, Sixth Edition 2-1
Chapter 2
Network Hardware Essentials
At a Glance
Instructor’s Manual Table of Contents
Overview
Objectives
Teaching Tips
Quick Quizzes
Class Discussion Topics
Additional Projects
Additional Resources
Key Terms
Technical Notes for Hands-On Projects
Using Virtualization for Hands-On Projects
Chapter 2
Network Hardware Essentials
At a Glance
Instructor’s Manual Table of Contents
Overview
Objectives
Teaching Tips
Quick Quizzes
Class Discussion Topics
Additional Projects
Additional Resources
Key Terms
Technical Notes for Hands-On Projects
Using Virtualization for Hands-On Projects
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Guide to Networking Essentials, Sixth Edition 2-2
Lecture Notes
Overview
Chapter 1 offers an introduction to the basic operation of network repeaters and hubs.
Students learn about the purpose of network switches as well as how to summarize the
operation of wireless access points. They will also be able to describe the basic
operation of network interface cards. At the end of the chapter, students learn about the
very important function of routers in a network.
Objectives
Describe the basic operation of network repeaters and hubs
Explain the purpose of network switches
Summarize the operation of wireless access points
Describe the basic operation of network interface cards
Explain the function of routers
Teaching Tips
Network Repeaters and Hubs
1. Describe how repeaters take a weakened signal and repeat it at its original strength.
2. Show students that many networking devices, such as hubs, switches, and bridges, act
as repeaters.
3. Discuss the purpose of a repeater, or why a device might be used as a repeater.
a. Most often repeaters are used to connect PCs over several hundred feet, where
signal would normally degenerate.
4. Explain the purpose of a hub.
a. Network hubs serve as a connection point to a single network segment.
b. All network devices connected to the hub share the same media and must take turns
when using the network.
Multiport Repeaters and Hubs
1. Explain that a multiport repeater, or hub, will clean a signal as well as regenerate it.
2. Show that hubs come in a variety of sizes, from 4 ports to 24 ports most commonly
Hubs and Network Bandwidth
1. Explain why when devices are connected to a hub, they must wait their turn to
communicate.
Lecture Notes
Overview
Chapter 1 offers an introduction to the basic operation of network repeaters and hubs.
Students learn about the purpose of network switches as well as how to summarize the
operation of wireless access points. They will also be able to describe the basic
operation of network interface cards. At the end of the chapter, students learn about the
very important function of routers in a network.
Objectives
Describe the basic operation of network repeaters and hubs
Explain the purpose of network switches
Summarize the operation of wireless access points
Describe the basic operation of network interface cards
Explain the function of routers
Teaching Tips
Network Repeaters and Hubs
1. Describe how repeaters take a weakened signal and repeat it at its original strength.
2. Show students that many networking devices, such as hubs, switches, and bridges, act
as repeaters.
3. Discuss the purpose of a repeater, or why a device might be used as a repeater.
a. Most often repeaters are used to connect PCs over several hundred feet, where
signal would normally degenerate.
4. Explain the purpose of a hub.
a. Network hubs serve as a connection point to a single network segment.
b. All network devices connected to the hub share the same media and must take turns
when using the network.
Multiport Repeaters and Hubs
1. Explain that a multiport repeater, or hub, will clean a signal as well as regenerate it.
2. Show that hubs come in a variety of sizes, from 4 ports to 24 ports most commonly
Hubs and Network Bandwidth
1. Explain why when devices are connected to a hub, they must wait their turn to
communicate.
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Guide to Networking Essentials, Sixth Edition 2-3
a. Because the media must be shared among all connected devices, the average
bandwidth available per machine when communicating is much less than whatever
speed the hub is rated for.
2. Discuss the additional cost to bandwidth for the time lost due to network collisions.
a. If two machines try to use the media on the hub at the same time, a collision will
occur. All machines must then wait for a period of time before trying again to use
the media.
b. Try to demonstrate this with an actual hub and several connected devices generating
traffic.
3. Explain that all devices connected to a hub will see any traffic passed through the hub.
a. While protocol analyzers aren’t covered until much later, this can be demonstrated
using Wireshark. Try to connect to a service that passes information in cleartext,
such as Telnet, to illustrate how traffic on a hub will work.
4. You should emphasize the limitations of hubs.
a. Devices on a hub operate in half-duplex mode, meaning that they can only send or
receive, not both at the same time.
5. If you have old hubs available, demonstrate the collision process. Many hubs have an
indicator light to show that a collision has occurred or is occurring on the network.
Have students review Simulation 3—Basic Operation of a Hub on the book’s CD.
Teaching
Tip
For additional information about shared traffic on hubs, see
http://wiki.wireshark.org/HubReference.
Network Switches
1. Explain the benefits of using a switch versus a hub.
Basic Switch Operation
1. Illustrate how switches separate connections into individual network segments. In other
words, a switch eliminates the possibility of a collision caused by multiple transmitting
machines.
a. Use the fact that each port is a separate collision domain as a talking point.
2. Explain how a switch directs traffic to the correct port by using a MAC address.
a. When a switch powers on, it begins collecting MAC addresses into a switching
table, which it then uses as a map to reach specific network devices.
b. MAC addresses are 12 hexadecimal digits long, or 48 bits.
3. Describe the process of a network transaction with a switch.
a. When a switch receives a frame, it records the sender’s MAC address on the
port it was received in the switching table. If the destination MAC address is
unknown to the switch, it broadcasts the frame to all connected ports except the
original sending port.
b. You can demonstrate this if you have three machines on an isolated network
switch, with Wireshark running as you plug all three machines in.
a. Because the media must be shared among all connected devices, the average
bandwidth available per machine when communicating is much less than whatever
speed the hub is rated for.
2. Discuss the additional cost to bandwidth for the time lost due to network collisions.
a. If two machines try to use the media on the hub at the same time, a collision will
occur. All machines must then wait for a period of time before trying again to use
the media.
b. Try to demonstrate this with an actual hub and several connected devices generating
traffic.
3. Explain that all devices connected to a hub will see any traffic passed through the hub.
a. While protocol analyzers aren’t covered until much later, this can be demonstrated
using Wireshark. Try to connect to a service that passes information in cleartext,
such as Telnet, to illustrate how traffic on a hub will work.
4. You should emphasize the limitations of hubs.
a. Devices on a hub operate in half-duplex mode, meaning that they can only send or
receive, not both at the same time.
5. If you have old hubs available, demonstrate the collision process. Many hubs have an
indicator light to show that a collision has occurred or is occurring on the network.
Have students review Simulation 3—Basic Operation of a Hub on the book’s CD.
Teaching
Tip
For additional information about shared traffic on hubs, see
http://wiki.wireshark.org/HubReference.
Network Switches
1. Explain the benefits of using a switch versus a hub.
Basic Switch Operation
1. Illustrate how switches separate connections into individual network segments. In other
words, a switch eliminates the possibility of a collision caused by multiple transmitting
machines.
a. Use the fact that each port is a separate collision domain as a talking point.
2. Explain how a switch directs traffic to the correct port by using a MAC address.
a. When a switch powers on, it begins collecting MAC addresses into a switching
table, which it then uses as a map to reach specific network devices.
b. MAC addresses are 12 hexadecimal digits long, or 48 bits.
3. Describe the process of a network transaction with a switch.
a. When a switch receives a frame, it records the sender’s MAC address on the
port it was received in the switching table. If the destination MAC address is
unknown to the switch, it broadcasts the frame to all connected ports except the
original sending port.
b. You can demonstrate this if you have three machines on an isolated network
switch, with Wireshark running as you plug all three machines in.
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Guide to Networking Essentials, Sixth Edition 2-4
4. Discuss the advantages inherent in using switches compared to a hub.
a. Switch-based networks do not suffer from the same bandwidth drawbacks as
hubs do. Network devices connected to a switch can operate in full-duplex
mode, allowing them to transmit while also receiving.
b. Devices connected to a switch do not see each others traffic, unlike a hub. They
will only see broadcasted traffic and traffic intended for that device. There are a
few exceptions to this, namely the situation described in #3-a. A switch will also
simply flood all packets to all connected devices if it finds itself out of memory.
Under most normal conditions, however, this shouldn’t happen.
Have students review Simulation 4—Basic Operation of a Switch on the book’s CD.
Teaching
Tips
Switches also have the ability to perform more advanced tasks such as link
aggregation, or port bonding, to increase link speeds.
Teaching
Tip
For a visual guide in explaining how a MAC address is structured, see
http://upload.wikimedia.org/wikipedia/commons/9/94/MAC-48_Address.svg.
Quick Quiz 1
1. What does a repeater do?
Answer: It receives bit signals generated by NICs and other devices, strengthens them, and
then sends them along or repeating them to other parts of the network.
2. A multiport repeater is often referred to as a _________________.
a. Switch
b. Bridge
c. Hub
d. Network Interface Card
Answer: c. hub
3. The amount of data that can be transferred on a network during a specific interval is
called the ________________________________.
a. Network bandwidth
b. Network speed rating
c. Line speed rating
d. Duplexing speed
Answer: network bandwidth
4. True or False: A switch operates just like a hub?
4. Discuss the advantages inherent in using switches compared to a hub.
a. Switch-based networks do not suffer from the same bandwidth drawbacks as
hubs do. Network devices connected to a switch can operate in full-duplex
mode, allowing them to transmit while also receiving.
b. Devices connected to a switch do not see each others traffic, unlike a hub. They
will only see broadcasted traffic and traffic intended for that device. There are a
few exceptions to this, namely the situation described in #3-a. A switch will also
simply flood all packets to all connected devices if it finds itself out of memory.
Under most normal conditions, however, this shouldn’t happen.
Have students review Simulation 4—Basic Operation of a Switch on the book’s CD.
Teaching
Tips
Switches also have the ability to perform more advanced tasks such as link
aggregation, or port bonding, to increase link speeds.
Teaching
Tip
For a visual guide in explaining how a MAC address is structured, see
http://upload.wikimedia.org/wikipedia/commons/9/94/MAC-48_Address.svg.
Quick Quiz 1
1. What does a repeater do?
Answer: It receives bit signals generated by NICs and other devices, strengthens them, and
then sends them along or repeating them to other parts of the network.
2. A multiport repeater is often referred to as a _________________.
a. Switch
b. Bridge
c. Hub
d. Network Interface Card
Answer: c. hub
3. The amount of data that can be transferred on a network during a specific interval is
called the ________________________________.
a. Network bandwidth
b. Network speed rating
c. Line speed rating
d. Duplexing speed
Answer: network bandwidth
4. True or False: A switch operates just like a hub?
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Guide to Networking Essentials, Sixth Edition 2-5
Answer: False: Instead of simply regenerating incoming bit signals and repeating them to
all other ports, a switch actually reads data in the message, determines which port the
destination device is connected to, and forwards the message to only that port
5. How long are MAC addresses?
a. 42 bits
b. 16 hexadecimal characters
c. 4 octets
d. 12 hexadecimal characters
Answer: d. 12 hexadecimal characters
Wireless Access Points
1. Explain the use of access points as means of wireless distribution.
Basic AP Operation
1. Make a comparison of access points to hubs.
a. All wireless clients must share the access media (the air), and multiple machines
cannot transmit at the same time. They must all share the bandwidth of the access
point.
2. Explain that although access points are wireless distributors, they still commonly
connect to a wired network connection.
3. Discuss the limitations of wireless, as well as advantages/disadvantages of using a
wireless connection.
a. Bandwidth available on a wireless network is often half what is advertised due to
overhead in establishing and maintaining the connection.
Teaching
Tip
Widely available consumer home routers that provide wireless access are actually
several devices combined into one, including an access point. It might be helpful
to point out some wireless router models as access points.
Network Interface Cards
1. Discuss how network interface cards use different types of media, but all have similar
functions and methods of working with operating systems.
NIC Basics
1. Describe the process by which a NIC turns a frame into transmittable signals for
whatever media type it is made for.
Answer: False: Instead of simply regenerating incoming bit signals and repeating them to
all other ports, a switch actually reads data in the message, determines which port the
destination device is connected to, and forwards the message to only that port
5. How long are MAC addresses?
a. 42 bits
b. 16 hexadecimal characters
c. 4 octets
d. 12 hexadecimal characters
Answer: d. 12 hexadecimal characters
Wireless Access Points
1. Explain the use of access points as means of wireless distribution.
Basic AP Operation
1. Make a comparison of access points to hubs.
a. All wireless clients must share the access media (the air), and multiple machines
cannot transmit at the same time. They must all share the bandwidth of the access
point.
2. Explain that although access points are wireless distributors, they still commonly
connect to a wired network connection.
3. Discuss the limitations of wireless, as well as advantages/disadvantages of using a
wireless connection.
a. Bandwidth available on a wireless network is often half what is advertised due to
overhead in establishing and maintaining the connection.
Teaching
Tip
Widely available consumer home routers that provide wireless access are actually
several devices combined into one, including an access point. It might be helpful
to point out some wireless router models as access points.
Network Interface Cards
1. Discuss how network interface cards use different types of media, but all have similar
functions and methods of working with operating systems.
NIC Basics
1. Describe the process by which a NIC turns a frame into transmittable signals for
whatever media type it is made for.
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Guide to Networking Essentials, Sixth Edition 2-6
a. In the case of Ethernet, the frame is transmitted electrically. A fiber-optic NIC,
however, transmits using light.
2. Explain why NICs are assigned MAC addresses.
a. These addresses must be unique, or communication on the network no longer
works properly.
b. MAC addresses are divided into two parts: the 24-bit organizationally unique
identifier (OUI) assigned to the manufacturer and the remaining 24 bits used for
a serial number to identify the specific NIC.
3. Demonstrate the broadcast MAC address.
a. A MAC address of FF:FF:FF:FF:FF:FF is reserved for broadcasts and cannot be
used by any NIC.
b. A frame using this broadcast MAC as its destination will be seen by all
connected devices.
Have students review Simulation 5—How a NIC Works on the book’s CD.
Selecting a NIC
1. Discuss with students that when selecting a NIC to install in a computer there are a
number of factors to consider:
a. What bus type should be used? Several are available, such as PCI and PCIe.
Some network cards are available for USB as well.
b. Is the NIC compatible with your operating system? Not all NICs have drivers
available for the latest operating systems.
c. How fast should the NIC be? Workstations won’t require a NIC as fast as a
server, but faster NICs have become cheap and widely available.
NIC Drivers
1. Students should learn that NIC drivers in most cases will be automatically installed or
already available to modern operating systems.
Wireless NICs
1. Discuss the prevalence of wireless NICs in mobile devices.
a. This makes it difficult or impossible to replace NICs on anything but desktop
PCs, but eliminates the need to hunt for drivers as well.
2. Talk about the use of wireless standards and how it affects wireless transmission speeds
as well as compatibility.
a. Keep in mind that several wireless standards exist, such as 802.11b and 802.11g.
Even though these two standards are backwards compatible, they are not
compatible with 802.11a, which uses a different frequency.
b. Another common issue during recent years involved “Draft N” devices that were
built by various manufacturers. These devices may or may not work with other
“Draft N” devices from other manufacturers.
3. Discuss what information is needed in order to connect to a wireless network.
a. In the case of Ethernet, the frame is transmitted electrically. A fiber-optic NIC,
however, transmits using light.
2. Explain why NICs are assigned MAC addresses.
a. These addresses must be unique, or communication on the network no longer
works properly.
b. MAC addresses are divided into two parts: the 24-bit organizationally unique
identifier (OUI) assigned to the manufacturer and the remaining 24 bits used for
a serial number to identify the specific NIC.
3. Demonstrate the broadcast MAC address.
a. A MAC address of FF:FF:FF:FF:FF:FF is reserved for broadcasts and cannot be
used by any NIC.
b. A frame using this broadcast MAC as its destination will be seen by all
connected devices.
Have students review Simulation 5—How a NIC Works on the book’s CD.
Selecting a NIC
1. Discuss with students that when selecting a NIC to install in a computer there are a
number of factors to consider:
a. What bus type should be used? Several are available, such as PCI and PCIe.
Some network cards are available for USB as well.
b. Is the NIC compatible with your operating system? Not all NICs have drivers
available for the latest operating systems.
c. How fast should the NIC be? Workstations won’t require a NIC as fast as a
server, but faster NICs have become cheap and widely available.
NIC Drivers
1. Students should learn that NIC drivers in most cases will be automatically installed or
already available to modern operating systems.
Wireless NICs
1. Discuss the prevalence of wireless NICs in mobile devices.
a. This makes it difficult or impossible to replace NICs on anything but desktop
PCs, but eliminates the need to hunt for drivers as well.
2. Talk about the use of wireless standards and how it affects wireless transmission speeds
as well as compatibility.
a. Keep in mind that several wireless standards exist, such as 802.11b and 802.11g.
Even though these two standards are backwards compatible, they are not
compatible with 802.11a, which uses a different frequency.
b. Another common issue during recent years involved “Draft N” devices that were
built by various manufacturers. These devices may or may not work with other
“Draft N” devices from other manufacturers.
3. Discuss what information is needed in order to connect to a wireless network.
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Guide to Networking Essentials, Sixth Edition 2-7
a. You must know the service set identifier (SSID). Most wireless routers available
for home consumers have default SSIDs configured out of the box, such as
“linksys”, “default”, or “2WIRE”.
Teaching
Tip
If you have a wireless device, or preferably a workstation/laptop with wireless,
try doing a wireless survey around your area. Show students just how prevalent
wireless technology is! Netstumbler is a common tool for doing a wireless
survey, and can be found at www.netstumber.com.
Quick Quiz 2
1. What is the main difference between a wireless access point and a hub?
Answer: Signals don’t travel through a physical medium; they travel through the airwaves
as radio signals.
2. Before a computer can transmit data to the AP, it must first send a short
________________________message to let the AP know it intends to transmit data.
a. Broadcast
b. Request to Send (RTS)
c. Beacon
d. SSID
Answer: b. request to send (RTS)
3. What is the name of the address that is part of a NIC?
Answer: Media Access Control or MAC address
4. A frame with a destination MAC address composed of all binary 1s or FF-FF-FF-FF-
FF-FF in hexadecimal is a ____________________.
a. Unicast frame
b. Anycast frame
c. Multicast frame
d. Broadcast frame
Answer: d. broadcast frame
5. In order to connect to a wireless network, you need to have the __________.
a. Name of the switch
b. SSID
c. MAC address of the router
d. MAC address of the switch
Answer: b. SSID
a. You must know the service set identifier (SSID). Most wireless routers available
for home consumers have default SSIDs configured out of the box, such as
“linksys”, “default”, or “2WIRE”.
Teaching
Tip
If you have a wireless device, or preferably a workstation/laptop with wireless,
try doing a wireless survey around your area. Show students just how prevalent
wireless technology is! Netstumbler is a common tool for doing a wireless
survey, and can be found at www.netstumber.com.
Quick Quiz 2
1. What is the main difference between a wireless access point and a hub?
Answer: Signals don’t travel through a physical medium; they travel through the airwaves
as radio signals.
2. Before a computer can transmit data to the AP, it must first send a short
________________________message to let the AP know it intends to transmit data.
a. Broadcast
b. Request to Send (RTS)
c. Beacon
d. SSID
Answer: b. request to send (RTS)
3. What is the name of the address that is part of a NIC?
Answer: Media Access Control or MAC address
4. A frame with a destination MAC address composed of all binary 1s or FF-FF-FF-FF-
FF-FF in hexadecimal is a ____________________.
a. Unicast frame
b. Anycast frame
c. Multicast frame
d. Broadcast frame
Answer: d. broadcast frame
5. In order to connect to a wireless network, you need to have the __________.
a. Name of the switch
b. SSID
c. MAC address of the router
d. MAC address of the switch
Answer: b. SSID
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Guide to Networking Essentials, Sixth Edition 2-8
Teaching
Tip
To see more information about the latest 802.11 wireless standard, 802.11n, visit
http://en.wikipedia.org/wiki/IEEE_802.11n-2009.
Routers
1. Discuss the role of routers in delivering packets or information to other non-locally
connected networks.
Have students review Simulation 6—Router Operation in a Simple Internetwork on the book’s
CD.
Routers Connect LANs
1. Explain that in order to communicate between two LANs or networks with different
addressing schemes, you need a router.
a. A router is configured to know or find the paths to other networks, either
through directly connected interfaces or via other routers.
Teaching
Tip
An easy way to explain the idea of how routers handle traffic is to use the postal
analogy. To see how this works, read
http://cs.gmu.edu/cne/itcore/internet/tcpip/tcpip.html.
Routers Create Broadcast Domains
1. Detail how and why a router will create broadcast domains.
a. Also discuss the benefits of creating broadcast domains and how broadcast
traffic can affect network performance on large scales.
Routers Work with IP Addresses and Routing Tables
1. Describe how a router maintains a table of addresses to direct networking traffic.
a. While a switch uses a MAC address to move traffic, a router uses an IP address
to route traffic.
b. An IP address is 32 bits long and is separated into four base 256 octets, such as
192.168.1.1.
2. Briefly discuss what a subnet is and how it works.
a. The network address for a given IP is determined by a subnet mask. Subnet
masks, while similar in appearance to IP addresses, use bits to designate the
network portion of an address and separate it from the host portion of an
address. For example, if the IP address 192.168.1.1 had a subnet mask of
255.255.255.0, then the network address would be 192.168.1.0.
Teaching
Tip
To see more information about the latest 802.11 wireless standard, 802.11n, visit
http://en.wikipedia.org/wiki/IEEE_802.11n-2009.
Routers
1. Discuss the role of routers in delivering packets or information to other non-locally
connected networks.
Have students review Simulation 6—Router Operation in a Simple Internetwork on the book’s
CD.
Routers Connect LANs
1. Explain that in order to communicate between two LANs or networks with different
addressing schemes, you need a router.
a. A router is configured to know or find the paths to other networks, either
through directly connected interfaces or via other routers.
Teaching
Tip
An easy way to explain the idea of how routers handle traffic is to use the postal
analogy. To see how this works, read
http://cs.gmu.edu/cne/itcore/internet/tcpip/tcpip.html.
Routers Create Broadcast Domains
1. Detail how and why a router will create broadcast domains.
a. Also discuss the benefits of creating broadcast domains and how broadcast
traffic can affect network performance on large scales.
Routers Work with IP Addresses and Routing Tables
1. Describe how a router maintains a table of addresses to direct networking traffic.
a. While a switch uses a MAC address to move traffic, a router uses an IP address
to route traffic.
b. An IP address is 32 bits long and is separated into four base 256 octets, such as
192.168.1.1.
2. Briefly discuss what a subnet is and how it works.
a. The network address for a given IP is determined by a subnet mask. Subnet
masks, while similar in appearance to IP addresses, use bits to designate the
network portion of an address and separate it from the host portion of an
address. For example, if the IP address 192.168.1.1 had a subnet mask of
255.255.255.0, then the network address would be 192.168.1.0.
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Guide to Networking Essentials, Sixth Edition 2-9
3. Break down and describe what happens when a router receives a packet addressed to
another network
a. First, it checks its routing table for a match.
b. If a match is found for the specific network, the packet is forwarded to the
destination.
c. If no match is found, and the router has a default route, the router forwards the
packet to the default route.
d. If no match is found and no default route is configured, the packet is dropped.
Usually a router will respond to the sender of the packet with a Network
Unreachable message.
Quick Quiz 3
1. True or False: Routers are devices that enable multiple LANs to communicate with one
another by forwarding packets from one LAN to another.
Answer: True
2. The scope of devices to which broadcast frames are forwarded is called a
_________________.
Answer: broadcast domain
3. What is another name for a port on routers?
Answer: Interface
4. The __________________ tells a router where to send a packet with a destination
network that can’t be found in the routing table.
Answer: default route
Class Discussion Topics
1. Discuss the potential reasons for choosing a hub versus a switch, whether it be cost,
speed, security, or other.
2. What might prevent wireless from being used extensively in an enterprise? Ask students
to consider how adding a wireless infrastructure might affect a hospital or large credit
card company.
Additional Projects
1. If Cisco equipment is available, set up two switches with connections to each other,
then connect one PC to each switch. After setting up networking on both PCs, show
what the MAC address table of each switch looks like.
3. Break down and describe what happens when a router receives a packet addressed to
another network
a. First, it checks its routing table for a match.
b. If a match is found for the specific network, the packet is forwarded to the
destination.
c. If no match is found, and the router has a default route, the router forwards the
packet to the default route.
d. If no match is found and no default route is configured, the packet is dropped.
Usually a router will respond to the sender of the packet with a Network
Unreachable message.
Quick Quiz 3
1. True or False: Routers are devices that enable multiple LANs to communicate with one
another by forwarding packets from one LAN to another.
Answer: True
2. The scope of devices to which broadcast frames are forwarded is called a
_________________.
Answer: broadcast domain
3. What is another name for a port on routers?
Answer: Interface
4. The __________________ tells a router where to send a packet with a destination
network that can’t be found in the routing table.
Answer: default route
Class Discussion Topics
1. Discuss the potential reasons for choosing a hub versus a switch, whether it be cost,
speed, security, or other.
2. What might prevent wireless from being used extensively in an enterprise? Ask students
to consider how adding a wireless infrastructure might affect a hospital or large credit
card company.
Additional Projects
1. If Cisco equipment is available, set up two switches with connections to each other,
then connect one PC to each switch. After setting up networking on both PCs, show
what the MAC address table of each switch looks like.
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Guide to Networking Essentials, Sixth Edition 2-10
Additional Resources
1. http://en.wikipedia.org/wiki/Broadcast_domain.
2. http://en.wikipedia.org/wiki/Collision_domain.
Key Terms
access point (AP) A wireless device that serves as the central connection point of a
wireless LAN. An AP mediates communication between wireless computers.
bandwidth sharing A network design in which the interconnecting devices allow only one
connected device to transmit data at a time, thus requiring the devices to share the available
bandwidth the interconnecting device provides.
broadcast domain The scope of devices to which broadcast frames are forwarded. Router
interfaces delimit broadcast domains because they do not forward broadcasts whereas
switches and hubs do forward broadcasts.
broadcast frame A network message that is intended to be processed by all devices on the
LAN. A broadcast frame carries a destination address of FF:FF:FF:FF:FF:FF.
clear to send (CTS) A signal generated by an access point in response to a request to send
(RTS) signal. A CTS indicates that the computer that sent an RTS may transmit data. See
also request to send and access point.
dedicated bandwidth A property of switches in which the bandwidth of each port is
dedicated to the device or devices connected to the port. This differs from a hub in which
the bandwidth of a port is shared among all the devices connected to the hub.
default gateway The address configured in a computer’s IP address settings that is set to
the address of a router to which the computer can send all packets destined for other
networks.
default route An entry in a router’s routing table that tells a router where to send a packet
with a destination network address that can’t be found in the routing table.
full-duplex mode A communication mode in which a device can simultaneously transmit
and receive data on the same cable connection. Switches can operate in full-duplex mode
but hubs cannot.
half-duplex mode A communication mode in which a device can send or receive data but
cannot do both simultaneously. Hubs can only operate in half-duplex mode, whereas
switches can operate in both half-duplex and full-duplex modes.
hub A network device that performs the same function as a repeater but has several ports to
connect a number of devices. Sometimes called a multiport repeater. See also repeater.
network bandwidth The amount of data that can be transferred on a network during a
specific interval, usually measured in bits per second.
network interface card (NIC) A device that creates and mediates the connection between
a computer and the network medium.
Additional Resources
1. http://en.wikipedia.org/wiki/Broadcast_domain.
2. http://en.wikipedia.org/wiki/Collision_domain.
Key Terms
access point (AP) A wireless device that serves as the central connection point of a
wireless LAN. An AP mediates communication between wireless computers.
bandwidth sharing A network design in which the interconnecting devices allow only one
connected device to transmit data at a time, thus requiring the devices to share the available
bandwidth the interconnecting device provides.
broadcast domain The scope of devices to which broadcast frames are forwarded. Router
interfaces delimit broadcast domains because they do not forward broadcasts whereas
switches and hubs do forward broadcasts.
broadcast frame A network message that is intended to be processed by all devices on the
LAN. A broadcast frame carries a destination address of FF:FF:FF:FF:FF:FF.
clear to send (CTS) A signal generated by an access point in response to a request to send
(RTS) signal. A CTS indicates that the computer that sent an RTS may transmit data. See
also request to send and access point.
dedicated bandwidth A property of switches in which the bandwidth of each port is
dedicated to the device or devices connected to the port. This differs from a hub in which
the bandwidth of a port is shared among all the devices connected to the hub.
default gateway The address configured in a computer’s IP address settings that is set to
the address of a router to which the computer can send all packets destined for other
networks.
default route An entry in a router’s routing table that tells a router where to send a packet
with a destination network address that can’t be found in the routing table.
full-duplex mode A communication mode in which a device can simultaneously transmit
and receive data on the same cable connection. Switches can operate in full-duplex mode
but hubs cannot.
half-duplex mode A communication mode in which a device can send or receive data but
cannot do both simultaneously. Hubs can only operate in half-duplex mode, whereas
switches can operate in both half-duplex and full-duplex modes.
hub A network device that performs the same function as a repeater but has several ports to
connect a number of devices. Sometimes called a multiport repeater. See also repeater.
network bandwidth The amount of data that can be transferred on a network during a
specific interval, usually measured in bits per second.
network interface card (NIC) A device that creates and mediates the connection between
a computer and the network medium.
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Guide to Networking Essentials, Sixth Edition 2-11
promiscuous mode An operational mode of a NIC in which all frames are read and
processed rather than only broadcast and unicast frames addressed to the NIC. Protocol
analyzer software sets a NIC to promiscuous mode so that all network frames can be read
and analyzed.
repeater A network device that takes incoming signals and regenerates, or repeats, them to
other parts of the network.
request to send (RTS) A signal used in wireless networks indicating that a computer has
data ready to send on the network.
router A device that enables multiple LANs to communicate with one another by
forwarding packets from one LAN to another. They also forward packets from one router to
another when LANs are separated by multiple routers. Routers have multiple interfaces and
each interface communicates with a LAN.
service set identifier (SSID) The name assigned to a wireless network so that wireless
clients can distinguish between wireless networks when more than one is detected.
switch A network device that reads the destination MAC address of incoming frames to
determine out which port to forward the frame.
switching table A table used by switches that contains MAC address and port pairs. The
table is used by the switch to determine which port to forward frames it receives to reach
the destination computer.
unicast frame A network message that is addressed to only one computer on the LAN.
uplink port A designated port on a hub or switch used to connect to another hub or switch
without using a crossover cable.
Technical Notes for Hands-On Projects
Hands-On Project 2-1: This project requires regular classroom computers or virtual machines
with a connection to the Internet, or the instructor can provide the Wireshark setup program
on a network share.
Hands-On Project 2-2: This project requires three computers (minimum) with Ethernet NICs
installed; 10/100 Mbps or 10/100/1000 NICs are preferable, but 10 Mbps NICs will also
work.
Hands-On Project 2-3: This project requires three computers (minimum) with Ethernet NICs
installed; 10/100 Mbps or 10/100/1000 NICs are preferable, but 10 Mbps NICs will also
work. Three patch cables and a 10/100 switch, although a single-speed switch or Gigabit
switch will also work.
Hands-On Project 2-4: This project requires three computers (minimum) with Ethernet NICs
installed; 10/100 Mbps or 10/100/1000 NICs are preferable, but 10 Mbps NICs will also
promiscuous mode An operational mode of a NIC in which all frames are read and
processed rather than only broadcast and unicast frames addressed to the NIC. Protocol
analyzer software sets a NIC to promiscuous mode so that all network frames can be read
and analyzed.
repeater A network device that takes incoming signals and regenerates, or repeats, them to
other parts of the network.
request to send (RTS) A signal used in wireless networks indicating that a computer has
data ready to send on the network.
router A device that enables multiple LANs to communicate with one another by
forwarding packets from one LAN to another. They also forward packets from one router to
another when LANs are separated by multiple routers. Routers have multiple interfaces and
each interface communicates with a LAN.
service set identifier (SSID) The name assigned to a wireless network so that wireless
clients can distinguish between wireless networks when more than one is detected.
switch A network device that reads the destination MAC address of incoming frames to
determine out which port to forward the frame.
switching table A table used by switches that contains MAC address and port pairs. The
table is used by the switch to determine which port to forward frames it receives to reach
the destination computer.
unicast frame A network message that is addressed to only one computer on the LAN.
uplink port A designated port on a hub or switch used to connect to another hub or switch
without using a crossover cable.
Technical Notes for Hands-On Projects
Hands-On Project 2-1: This project requires regular classroom computers or virtual machines
with a connection to the Internet, or the instructor can provide the Wireshark setup program
on a network share.
Hands-On Project 2-2: This project requires three computers (minimum) with Ethernet NICs
installed; 10/100 Mbps or 10/100/1000 NICs are preferable, but 10 Mbps NICs will also
work.
Hands-On Project 2-3: This project requires three computers (minimum) with Ethernet NICs
installed; 10/100 Mbps or 10/100/1000 NICs are preferable, but 10 Mbps NICs will also
work. Three patch cables and a 10/100 switch, although a single-speed switch or Gigabit
switch will also work.
Hands-On Project 2-4: This project requires three computers (minimum) with Ethernet NICs
installed; 10/100 Mbps or 10/100/1000 NICs are preferable, but 10 Mbps NICs will also
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Guide to Networking Essentials, Sixth Edition 2-12
work. Four patch cables and a crossover cable, 10/100 hubs with uplink switch, and a
10/100 switch.
Hands-On Project 2-5: This project requires two or more computers with 802.11 wireless NICs
installed. One wireless AP or wireless router configured with the service set identifier
(SSID, the name for a wireless network) “NetEss.” The 802.11 standard supported doesn’t
matter as long as the AP is compatible with the NICs. Windows 7 is the preferred OS, but
some steps can be changed to accommodate other OSs. The computers shouldn’t be
connected to a hub or switch.
Hands-On Project 2-6: This project requires a classroom computer; no other tools or equipment
are required. Windows 7 is the assumed OS, but this project can also be done in Windows
Vista or Windows XP.
Hands-On Project 2-7: This project requires three workstations, two hubs or switches, a router,
and five patch cables. The router can be the same router/AP you used for Hands-On Project
2-5. Assuming you’re using a typical home network router/AP such as a Linksys
WRT54GL, the router should be set up so that the WAN interface is assigned the address
192.168.2.1 with subnet mask 255.255.255.0, and the LAN interface is left as the default
192.168.1.1 address.
Hands-On Project 2-8: This project requires a classroom computer, access to the Internet, and a
valid DNS server.
Challenge Lab 2-1: This project requires a classroom computer with Wireshark installed; the IP
address of another classroom computer or device.
Challenge Lab 2-2: This project requires a computer with Wireshark installed; access to the
Internet.
Using Virtualization for Hands-On Projects
The following Hands-On Projects/Challenge Labs have been identified as those that
students can do using virtual machines rather than physical machines.
Hands-On Project 2-1
Hands-On Project 2-6
Hands-On Project 2-8
Challenge Lab 2-1
Challenge Lab 2-2
work. Four patch cables and a crossover cable, 10/100 hubs with uplink switch, and a
10/100 switch.
Hands-On Project 2-5: This project requires two or more computers with 802.11 wireless NICs
installed. One wireless AP or wireless router configured with the service set identifier
(SSID, the name for a wireless network) “NetEss.” The 802.11 standard supported doesn’t
matter as long as the AP is compatible with the NICs. Windows 7 is the preferred OS, but
some steps can be changed to accommodate other OSs. The computers shouldn’t be
connected to a hub or switch.
Hands-On Project 2-6: This project requires a classroom computer; no other tools or equipment
are required. Windows 7 is the assumed OS, but this project can also be done in Windows
Vista or Windows XP.
Hands-On Project 2-7: This project requires three workstations, two hubs or switches, a router,
and five patch cables. The router can be the same router/AP you used for Hands-On Project
2-5. Assuming you’re using a typical home network router/AP such as a Linksys
WRT54GL, the router should be set up so that the WAN interface is assigned the address
192.168.2.1 with subnet mask 255.255.255.0, and the LAN interface is left as the default
192.168.1.1 address.
Hands-On Project 2-8: This project requires a classroom computer, access to the Internet, and a
valid DNS server.
Challenge Lab 2-1: This project requires a classroom computer with Wireshark installed; the IP
address of another classroom computer or device.
Challenge Lab 2-2: This project requires a computer with Wireshark installed; access to the
Internet.
Using Virtualization for Hands-On Projects
The following Hands-On Projects/Challenge Labs have been identified as those that
students can do using virtual machines rather than physical machines.
Hands-On Project 2-1
Hands-On Project 2-6
Hands-On Project 2-8
Challenge Lab 2-1
Challenge Lab 2-2
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Guide to Networking Essentials, Sixth Edition 3-1
Chapter 3
Network Topologies and Technologies
At a Glance
Instructor’s Manual Table of Contents
Overview
Objectives
Teaching Tips
Quick Quizzes
Class Discussion Topics
Additional Projects
Additional Resources
Key Terms
Technical Notes for Hands-On Projects
Using Virtualization for Hands-On Projects
Chapter 3
Network Topologies and Technologies
At a Glance
Instructor’s Manual Table of Contents
Overview
Objectives
Teaching Tips
Quick Quizzes
Class Discussion Topics
Additional Projects
Additional Resources
Key Terms
Technical Notes for Hands-On Projects
Using Virtualization for Hands-On Projects
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Guide to Networking Essentials, Sixth Edition 3-2
Lecture Notes
Overview
Chapter 3 offers an introduction to the basic primary physical networking topologies in
common use. Students also learn about the primary logical networking topologies. They
will be able to describe the major LAN networking technologies found in many
networks today.
Objectives
Describe the primary physical networking topologies in common use
Describe the primary logical networking topologies in common use
Describe major LAN networking technologies
Teaching Tips
Physical Topologies
1. Explain the differences between topologies, and weigh the advantages/disadvantages of
each one.
2. Emphasize that a physical topology is different from a logical topology, where the
layout of a network could appear completely different.
Physical Bus Topology
1. Describe the limits of a physical bus topology and how these limits contributed to it
becoming a legacy technology.
a. Limit of 30 computers per cable segment
b. Any break in the bus brings down entire network
c. Limited to 10 Mbps half-duplex communication
2. It is worth mentioning that although this technology is now legacy, the Ethernet
standards were born on the physical bus topology.
3. Students should be told the methods by which signals were passed between machines,
especially when only a single cable connected all devices. Signal propagation and signal
bounce should be discussed, albeit briefly.
Physical Star Topology
1. Discuss the use of a central device for connecting machines on a network.
2. Compare the advantages of a physical star topology to the disadvantages of older legacy
topologies.
a. Creates a single point of administration
b. Allows for faster network speeds
Lecture Notes
Overview
Chapter 3 offers an introduction to the basic primary physical networking topologies in
common use. Students also learn about the primary logical networking topologies. They
will be able to describe the major LAN networking technologies found in many
networks today.
Objectives
Describe the primary physical networking topologies in common use
Describe the primary logical networking topologies in common use
Describe major LAN networking technologies
Teaching Tips
Physical Topologies
1. Explain the differences between topologies, and weigh the advantages/disadvantages of
each one.
2. Emphasize that a physical topology is different from a logical topology, where the
layout of a network could appear completely different.
Physical Bus Topology
1. Describe the limits of a physical bus topology and how these limits contributed to it
becoming a legacy technology.
a. Limit of 30 computers per cable segment
b. Any break in the bus brings down entire network
c. Limited to 10 Mbps half-duplex communication
2. It is worth mentioning that although this technology is now legacy, the Ethernet
standards were born on the physical bus topology.
3. Students should be told the methods by which signals were passed between machines,
especially when only a single cable connected all devices. Signal propagation and signal
bounce should be discussed, albeit briefly.
Physical Star Topology
1. Discuss the use of a central device for connecting machines on a network.
2. Compare the advantages of a physical star topology to the disadvantages of older legacy
topologies.
a. Creates a single point of administration
b. Allows for faster network speeds
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Guide to Networking Essentials, Sixth Edition 3-3
c. Easily expandable (into extended star)
3. In contrast to those benefits, be sure to make note that this also creates a central point of
failure. While easy to troubleshoot, sometimes having a single point of failure is too big
of a risk.
4. To leverage the single point of failure inherent with plain physical star topologies,
students should learn that the most commonly used network topology is now the
extended star.
a. The extended star can provide a hierarchical topology structure for easy
management
b. Provides easy expandability
c. Does not necessarily eliminate single point of failure concerns, but can be
designed for redundancy
Teaching
Tip
Physical cabling has come a long way from what was used on some of these
legacy topologies. Students may find some of the Thicknet images on
http://en.wikipedia.org/wiki/Thicknet interesting.
Physical Ring Topology
1. Explain that a physical ring topology is similar to a bus in cabling structure.
2. Because of their similarities, physical ring also suffers some of the same
disadvantages.
a. A failure of a PC or node on the network brings the whole ring down
3. Students should be introduced to the idea of a network backbone. Physical ring was
most commonly used in connecting LANs to FDDI.
Point-to-Point Topology
1. Describe the point-to-point topology and where it is most prevalent: WANs.
2. Students should also be aware that point-to-point topologies are also used to bridge
wireless networks together when physical cabling isn’t an option.
Teaching
Tip
For a simplified look at some of these topologies, point your students to
http://learn-networking.com/network-design/a-guide-to-network-topology.
Mesh Topology
1. Discuss the use of mesh topology as a means of redundancy and fault tolerance.
a. Leverage this benefit with the disadvantage of cost, which in a full mesh
topology can be exponential with expansion.
b. Partial mesh is a valid solution that helps alleviate cost.
c. Easily expandable (into extended star)
3. In contrast to those benefits, be sure to make note that this also creates a central point of
failure. While easy to troubleshoot, sometimes having a single point of failure is too big
of a risk.
4. To leverage the single point of failure inherent with plain physical star topologies,
students should learn that the most commonly used network topology is now the
extended star.
a. The extended star can provide a hierarchical topology structure for easy
management
b. Provides easy expandability
c. Does not necessarily eliminate single point of failure concerns, but can be
designed for redundancy
Teaching
Tip
Physical cabling has come a long way from what was used on some of these
legacy topologies. Students may find some of the Thicknet images on
http://en.wikipedia.org/wiki/Thicknet interesting.
Physical Ring Topology
1. Explain that a physical ring topology is similar to a bus in cabling structure.
2. Because of their similarities, physical ring also suffers some of the same
disadvantages.
a. A failure of a PC or node on the network brings the whole ring down
3. Students should be introduced to the idea of a network backbone. Physical ring was
most commonly used in connecting LANs to FDDI.
Point-to-Point Topology
1. Describe the point-to-point topology and where it is most prevalent: WANs.
2. Students should also be aware that point-to-point topologies are also used to bridge
wireless networks together when physical cabling isn’t an option.
Teaching
Tip
For a simplified look at some of these topologies, point your students to
http://learn-networking.com/network-design/a-guide-to-network-topology.
Mesh Topology
1. Discuss the use of mesh topology as a means of redundancy and fault tolerance.
a. Leverage this benefit with the disadvantage of cost, which in a full mesh
topology can be exponential with expansion.
b. Partial mesh is a valid solution that helps alleviate cost.
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Guide to Networking Essentials, Sixth Edition 3-4
Quick Quiz 1
1. What is the difference between physical topology and logical topology?
Answer: The arrangement of cabling and how the cables connect one device to another
in a network is considered the network’s physical topology, and the path data travels
between computers on a network is considered the network’s logical topology.
2. True or False: Any break in a physical star topology causes the entire network to go
down.
Answer: true
3. The physical star topology uses a ___________________ to interconnect computers in
a LAN.
a. Central device
b. Bus cable
c. Access point
d. FDDI backbone
Answer: a. Central device, such as a hub or switch
4. What is the name of the most widely used physical topology in networks today?
Answer: extended star
5. How many links would you need in a full mesh configuration if you had 4 nodes?
a. 4
b. 5
c. 6
d. 7
Answer: c. 6
Logical Topologies
1. Focus on the idea that the logical topology, while partially determined by physical
topology, may not be similar to the physical topology itself. Mention the following for
students:
a. For example, there are physical star topologies that act as a bus logically, such
as a star topology that makes use of a hub.
b. Another example is wireless LANs. While the technology may appear to be a
star, it is in fact a logical bus.
c. Star topologies can also have a logical ring topology when using a multistation
access unit (MAU).
d. Refer students to Figures 3-7 to 3-9 for a visual representation.
Quick Quiz 1
1. What is the difference between physical topology and logical topology?
Answer: The arrangement of cabling and how the cables connect one device to another
in a network is considered the network’s physical topology, and the path data travels
between computers on a network is considered the network’s logical topology.
2. True or False: Any break in a physical star topology causes the entire network to go
down.
Answer: true
3. The physical star topology uses a ___________________ to interconnect computers in
a LAN.
a. Central device
b. Bus cable
c. Access point
d. FDDI backbone
Answer: a. Central device, such as a hub or switch
4. What is the name of the most widely used physical topology in networks today?
Answer: extended star
5. How many links would you need in a full mesh configuration if you had 4 nodes?
a. 4
b. 5
c. 6
d. 7
Answer: c. 6
Logical Topologies
1. Focus on the idea that the logical topology, while partially determined by physical
topology, may not be similar to the physical topology itself. Mention the following for
students:
a. For example, there are physical star topologies that act as a bus logically, such
as a star topology that makes use of a hub.
b. Another example is wireless LANs. While the technology may appear to be a
star, it is in fact a logical bus.
c. Star topologies can also have a logical ring topology when using a multistation
access unit (MAU).
d. Refer students to Figures 3-7 to 3-9 for a visual representation.
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Guide to Networking Essentials, Sixth Edition 3-5
Teaching
Tip
Students may find
http://www.cisco.com/iam/unified/ipt701/ENT/Network_Topology_Diagrams.htm
helpful in documenting network topology diagrams. However, students may
require a guided look.
Network Technologies
1. Discuss with students what network technology is, namely how it applies to what data
link layer protocols are in use.
a. Explain how this might define frame format and which media types are
available.
Network Technologies and Media
1. Show students a strand of unshielded twisted-pair (UTP) cable. While showing the
cable, illustrate the various speeds capable over UTP and discuss the meaning of
categories for UTP.
2. Next, show students some fiber-optic cabling if available to contrast the size difference.
Students should learn where fiber is most commonly used.
3. When detailing coaxial cable, make mention that this is most commonly used for cable-
based ISPs, such as Comcast or Cablevision. Briefly explain why coaxial became
obsolete for LANs.
4. Explain to students the difference between baseband and broadband, and give an
example of which network technologies use either method of signal transmission.
a. Ethernet uses baseband, while cable TV/modem access uses broadband.
Ethernet Networks
1. Detail how Ethernet has scaled to various connection speeds over time, and how it will
scale in the future.
2. Explain that despite how the speed of the interface may change, the underlying Ethernet
protocol remains essentially the same.
Ethernet Addressing
1. Review some of the information discussed in Chapter 2 about MAC addressing: why
every NIC needs a unique MAC address, and what the broadcast MAC address is used
for.
Ethernet Frames
1. Teach students some of the different kinds of frame types, and then explain that frame
type has no affect on the attributes of a frame.
2. Students should know the size of a frame can vary between 64 bytes and 1518 bytes.
Discuss the common frame headers and fields.
Teaching
Tip
Students may find
http://www.cisco.com/iam/unified/ipt701/ENT/Network_Topology_Diagrams.htm
helpful in documenting network topology diagrams. However, students may
require a guided look.
Network Technologies
1. Discuss with students what network technology is, namely how it applies to what data
link layer protocols are in use.
a. Explain how this might define frame format and which media types are
available.
Network Technologies and Media
1. Show students a strand of unshielded twisted-pair (UTP) cable. While showing the
cable, illustrate the various speeds capable over UTP and discuss the meaning of
categories for UTP.
2. Next, show students some fiber-optic cabling if available to contrast the size difference.
Students should learn where fiber is most commonly used.
3. When detailing coaxial cable, make mention that this is most commonly used for cable-
based ISPs, such as Comcast or Cablevision. Briefly explain why coaxial became
obsolete for LANs.
4. Explain to students the difference between baseband and broadband, and give an
example of which network technologies use either method of signal transmission.
a. Ethernet uses baseband, while cable TV/modem access uses broadband.
Ethernet Networks
1. Detail how Ethernet has scaled to various connection speeds over time, and how it will
scale in the future.
2. Explain that despite how the speed of the interface may change, the underlying Ethernet
protocol remains essentially the same.
Ethernet Addressing
1. Review some of the information discussed in Chapter 2 about MAC addressing: why
every NIC needs a unique MAC address, and what the broadcast MAC address is used
for.
Ethernet Frames
1. Teach students some of the different kinds of frame types, and then explain that frame
type has no affect on the attributes of a frame.
2. Students should know the size of a frame can vary between 64 bytes and 1518 bytes.
Discuss the common frame headers and fields.
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Guide to Networking Essentials, Sixth Edition 3-6
a. There are exceptions to the 1518 maximum byte frame size, but this generally
requires all hardware to be compatible with whatever extension is being used.
Ethernet Media Access
1. Discuss the Carrier Sense Multiple Access with Collision Detection (CSMA/CD)
access method, and explain when it is used.
a. Explain how the network responds to collisions with this method, how the method
changes when hubs versus switches are used (switches eliminate collisions).
Teaching
Tip Have students review Simulation 7—The CSMA/CD Process on the book’s CD.
Collisions and Collision Domains
1. Emphasize that collisions are only possible when Ethernet is used on shared media.
a. (FYI) This technically includes the current wireless networks based on 802.11, but
the method of access is significantly different; CSMA/CA (Collision Avoidance)
attempts to prevent a collision altogether, rather than respond to one after the fact.
b. Explain that although a switch will eliminate collisions on segments it is connected
to, this will not provide collision domains to a hub if connected. The hub-connected
devices will be on shared media, and a collision will be possible for these devices
only.
c. Briefly mention that a collision on a switch is technically possible, but only under
certain circumstances that are highly unlikely and almost entirely dependent on
configuration.
Ethernet Error Handling
1. Discuss Ethernet’s best effort delivery system.
a. Students should understand that reliable delivery is left to higher-level protocols to
ensure.
b. Make students aware that while 1-a means Ethernet makes no effort to retransmit a
bad frame (in most cases; see 1-c), it is capable of detecting whether a frame is bad
using a Cyclic Redundancy Check (CRC) that is added to the frame trailer.
c. If a collision is detected, Ethernet will retransmit a frame after the backoff period.
Half-Duplex Versus Full-Duplex Communication
1. Describe how half-duplex communication compares to full-duplex.
a. How does half-duplex affect speeds? Access methods?
b. How does full-duplex affect speeds? Access methods?
Ethernet Standards
a. There are exceptions to the 1518 maximum byte frame size, but this generally
requires all hardware to be compatible with whatever extension is being used.
Ethernet Media Access
1. Discuss the Carrier Sense Multiple Access with Collision Detection (CSMA/CD)
access method, and explain when it is used.
a. Explain how the network responds to collisions with this method, how the method
changes when hubs versus switches are used (switches eliminate collisions).
Teaching
Tip Have students review Simulation 7—The CSMA/CD Process on the book’s CD.
Collisions and Collision Domains
1. Emphasize that collisions are only possible when Ethernet is used on shared media.
a. (FYI) This technically includes the current wireless networks based on 802.11, but
the method of access is significantly different; CSMA/CA (Collision Avoidance)
attempts to prevent a collision altogether, rather than respond to one after the fact.
b. Explain that although a switch will eliminate collisions on segments it is connected
to, this will not provide collision domains to a hub if connected. The hub-connected
devices will be on shared media, and a collision will be possible for these devices
only.
c. Briefly mention that a collision on a switch is technically possible, but only under
certain circumstances that are highly unlikely and almost entirely dependent on
configuration.
Ethernet Error Handling
1. Discuss Ethernet’s best effort delivery system.
a. Students should understand that reliable delivery is left to higher-level protocols to
ensure.
b. Make students aware that while 1-a means Ethernet makes no effort to retransmit a
bad frame (in most cases; see 1-c), it is capable of detecting whether a frame is bad
using a Cyclic Redundancy Check (CRC) that is added to the frame trailer.
c. If a collision is detected, Ethernet will retransmit a frame after the backoff period.
Half-Duplex Versus Full-Duplex Communication
1. Describe how half-duplex communication compares to full-duplex.
a. How does half-duplex affect speeds? Access methods?
b. How does full-duplex affect speeds? Access methods?
Ethernet Standards
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Information Technology