Networking Chapter 7 will introduce students to the OSI reference model layers and how they

Guide to Networking Essentials, Eighth Edition 7-1

Chapter 7

Network Reference Models and Standards

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, Eighth Edition 7-2

Lecture Notes

Overview

Chapter 7 will introduce students to the OSI reference model layers and how they relate

to hardware and software. They will also learn about IEEE 802 networking model and

the importance of standards in networking.

Objectives

• Describe the OSI and IEEE 802 networking models

• Summarize the IEEE 802 networking standards

Teaching Tips

Introducing the OSI and IEEE 802 Networking Models

1. Explain to students why the OSI model has become such a key part of networking.

Role of a Reference Model

2. Explain how the reference model also allows for additional flexibility when protocols

Structure of the OSI Model

1. Detail the 7 different layers of the OSI model:

a. Application

b. Presentation

2. Once you’ve shown students the OSI model, compare it to the TCP/IP model, and show

3. Explain what is meant by peer communication, and how layers interact between two

separate communicating devices.

5. Describe the process of encapsulation / deencapsulation

Application Layer

1. Discuss the services and functionality available at the application layer, such as file

sharing, HTTP, FTP, SMB/CIFS, and SMTP for mail.

Presentation Layer

1. Illustrate the functions at the presentation layer, where data is converted for the

2. Review possible problems at this layer including incompatible or missing translation

software, in which the Presentation layer on one system doesn’t have the necessary

Session Layer

1. Describe how the session layer handles communication setup and teardown, and handles

2. Point out that the synchronization process known as “checkpointing” occurs here. Point

Transport Layer

1. Show students how the transport layer creates segments out of large data chunks, so that

2. Describe the key elements of the transport layer header:

3. Discuss some of the issues that can occur at the transport layer, such as oversized

Network Layer

2. Students should know the PDU at this layer is a packet. Use Figure 7-7 in your

discussion.

4. List some of the hardware devices that function at the network level, such as routers,

firewalls, VPN servers, and even layer 3 switches.

5. The Network layer has the ability to perform access control; students should see an

Data Link Layer

2. Emphasize that the frame is the PDU for this layer

3. Explain how the Frame Check Sequence (FCS) makes use of the CRC error checking

4. Describe the process a frame goes through as it reaches each device. For example, what

happens when a frame, destined for another network, reaches a router?

5. List the devices that function primarily at the data link layer, such as switches.

Physical Layer

1. Break down the process of encoding bits into signals for passing over whatever media

might be in use.

3. Detail some problems that happen at the physical layer, such as EMI or failed NICs.

Summary of the OSI Model

1. Give a summary of what processes or primary functions occur at each level of the OSI

2. Show where networking devices function,

3. List common protocols that function on a given layer, such as DNS for Session, DHCP

for Application, and IP for Network.

Teaching

Tip

For a much more in depth look at the OSI model, download

http://standards.iso.org/ittf/PubliclyAvailableStandards/s020269_ISO_IEC_7498-

1_1994(E).zip , which contains the OSI document describing the OSI model.

Quick Quiz 1

1. Why has the OSI Reference Model become such a key part of networking?

2. What is meant by peer communication between layers?

3. Which layer permits two computers to hold ongoing communications across a network,

so applications on either end of the session can exchange data for as long as the session

lasts?

4. The segmenting of the data is important because every network technology has a

maximum frame size that called which of the following?

a. Maximum Frame Unit

b. Maximum Packet Unit

c. Maximum Transmission Unit

d. Maximum Segment Unit

5. What is the name of the PDU in use at the Transport layer of the OSI model?

a. Packet

b. Frame

c. Bit

d. Segment

IEEE 802 Networking Standards

IEEE 802 Specifications

1. Detail some of the most important and widely used standards, as well as some historical

standards that have helped to define newer ones. Use Table 7-3 in your discussion.

b. 802.11 for Wireless networks

Teaching

Tip

For a list of IEEE standards and links to packages describing each one, visit

http://ieee802.org/

IEEE 802 Extensions to the OSI Reference Model

1. Describe the extensions to the OSI reference model, and how they are used.

a. Students must learn that the Logical Link Control sublayer handles error

recovery and flow control

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Quick Quiz 2

1. Why did the IEEE feel the need to develop LAN standards?

2. In the IEEE 802 standards, each number after the dot represents which of the following?

a. The year the standard was drafted

b. The year the standard was revised

c. A different technology or subset of a technology

d. A subset of another standard

3. What are the names of the 2 sublayers of the Data Link Layer?

a. Logical Media Control and Media Link Control

b. Physical Media Control and Media Access Control

c. Logical Link Control and Media Transmission Control

d. Logical Link Control and Media Access Control

4. Which sublayer defines the use of logical interface points, called Service Access Points

(SAPs)?

5. Which 802 standard describes Wireless networks?

a. 802.2

b. 802.11

c. 802.16

d. 802.22

Class Discussion Topics

1. Have the class discuss what technologies or common problems would fall under a

2. Discuss the OSI model versus the TCP/IP model. If the OSI model is considered the

“official” model for network communication, why doesn’t the TCP/IP protocol suite

follow it completely?

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Additional Projects

1. Have students act out a transmission as if each student was a layer of the OSI model,

using some sort of prop. For example, if a student was sending a transmission, you

Additional Resources

1. The IEEE Get Program

2. Tutorial: The 7 Layers of the OSI model

3. Layers of the OSI model

4. The Network Layer

5. Devices Used at Each Layer of the OSI Model

Key Terms

For explanations of key terms, see the Glossary for this text.

➢ access control

➢ Application layer

➢ maximum transmission

➢ unit (MTU)

➢ Media Access Control (MAC)

➢ sublayer

Guide to Networking Essentials, Eighth Edition 7-9

➢ Network layer

➢ Open Systems

➢ Interconnection (OSI)

➢ reference model

Technical Notes for Hands-On Projects