Module A
Networking Concepts
Instructor’s Manual
Overview
The broad goal of this module is to review networking concepts. Because the review is
designed done to prepare the student to deal with networking concepts in the security
context, there are many notes about the security implications of networking individual
concepts. It is suggested that this review be done before Chapter 3, which is the first chapter
to deal with networking concepts.
Teaching Suggestions
Special Issues
If you do not have networking as a prerequisite or co-requisite, this material will be
challenging for your students. However, without a decent knowledge of networking, it is
impossible to master security today.
Students who have had networking probably will find that they forgot a lot of what
they learned, so even they will be challenged. Even if they took a networking course, they
may not have seen some topics, such as TCP sequence numbers and acknowledgement
numbers, which are important in networking.
Teaching the Material
Flow of Material
Module A covers the following network topics:
, A sampling of networks to show the main elements of networks
Network protocols and vulnerabilities. This is a pure security topic.
Core layers in layered standards architecture. This section divides network
protocols into single-network protocols, internet protocols, and application
protocols.
Standards architectures. This section introduces the OSI and TCP/IP standards
architectures. It then discusses the hybrid TCP/IP-OSI standards architecture that
most real organizations use.
Single-network standards. This section looks at physical and data link layer
standards, including switch operation, transmission media, and switch supervisory
standards.
Internetwork standards. This section introduces the standards used in
Internetworking. This is followed by sections on the Internet Protocol (IP), TCP,
UDP, and TCP/IP supervisory standards. Although these are being listed in a single
bullet point, they collectively make up the majority of the chapter.
Application standards. This section covers application standards in general and
looks specifically at HTTP, HTML, e-mail, Telnet, FTP, and SSH. It notes the security
issues regarding this standard.
Covering the Material
This is pretty much a lecture module.
Assigning Homework
To focus students, you can specify specific test your understanding questions and end-of-
chapter questions or parts of questions they should master or even hand in as homework.
You can also specify questions or parts of questions they do not have to master. Multiple
choice and true/false questions are tied to specific parts of specific questions, so creating
multiple guess questions on exams is relatively straightforward.
, Answer Key
Module A
Networking Concepts
Introduction
1. a) What is an octet? [437]
A collection of 8 bits.
b) What is a host? [437]
Any device with an IP address.
c) Is a home PC connected to the Internet a host? [437]
Yes.
d) Distinguish between the terms internet and Internet. [437]
When the term is spelled with a lower-case i, it refers to any internet or the
internet layer. When it is spelled with an upper-case I, it refers to the global
Internet.
A Sampling of Networks
A Simple Home Network
2. a) What are the functions of an access router? Explain each function in one sentence.
[438-439]
It is a switch, a wireless access point (sometimes), a router to connect the
firm to the Internet, a DHCP server, and a NAT provider.
b) Describe the technology of 4-pair UTP wiring. [440]
A UTP cord contains eight copper wires organized as four pairs. The two
wires of each pair are twisted around each other several times an inch to
reduce interference.
c) What is an Internet access line? [440]
, A transmission line that connects a home or business to its Internet service
provider.
d) What is a broadband modem? [440]
A broadband modem transmits signals over a broadband access line.
e) Why is wireless transmission dangerous? [439]
Eavesdroppers can intercept wireless transmissions.
A Building LAN
3. a) What is a local area network? [440]
A LAN is a network that operates on the customer premises.
b) What is the customer premises?
The land and buildings owned by the corporations.
c) Distinguish between workgroup switches and core switches. [440]
Workgroup switches connect users to the network. Core switches connect
switches to other switches.
d) Why is UTP dangerous? [440-441]
It is easy to tap and generates signals that can be picked up even without
tapping the UTP cord.
e) Why is 802.1X needed? [441]
Most switches today have 802.1X capability that requires any device
connecting to a wall jack to authenticate itself before being allowed to
transmit beyond the switch.
A Firm’s Wide Area Networks (WANs)
4. a) Distinguish between LANs and WANs. [442]
LANs operate within a company’s premises. WANs connect different
premises.
b) Why do companies use carriers for WAN transmission? [442]
They lack the right of way to lay communication facilities between sites.
c) What two WAN technologies are illustrated in the figure Figure A-4? [442]
Point-to-point networks and public switched data networks (Frame Relay)
d) Why is carrier WAN traffic generally considered safe? [443]
Access to the network is limited, and internal routing is hidden.
The Internet
5. a) Which organization created the Internet? [443]
The Defense Advanced Research Projects Agency.
Networking Concepts
Instructor’s Manual
Overview
The broad goal of this module is to review networking concepts. Because the review is
designed done to prepare the student to deal with networking concepts in the security
context, there are many notes about the security implications of networking individual
concepts. It is suggested that this review be done before Chapter 3, which is the first chapter
to deal with networking concepts.
Teaching Suggestions
Special Issues
If you do not have networking as a prerequisite or co-requisite, this material will be
challenging for your students. However, without a decent knowledge of networking, it is
impossible to master security today.
Students who have had networking probably will find that they forgot a lot of what
they learned, so even they will be challenged. Even if they took a networking course, they
may not have seen some topics, such as TCP sequence numbers and acknowledgement
numbers, which are important in networking.
Teaching the Material
Flow of Material
Module A covers the following network topics:
, A sampling of networks to show the main elements of networks
Network protocols and vulnerabilities. This is a pure security topic.
Core layers in layered standards architecture. This section divides network
protocols into single-network protocols, internet protocols, and application
protocols.
Standards architectures. This section introduces the OSI and TCP/IP standards
architectures. It then discusses the hybrid TCP/IP-OSI standards architecture that
most real organizations use.
Single-network standards. This section looks at physical and data link layer
standards, including switch operation, transmission media, and switch supervisory
standards.
Internetwork standards. This section introduces the standards used in
Internetworking. This is followed by sections on the Internet Protocol (IP), TCP,
UDP, and TCP/IP supervisory standards. Although these are being listed in a single
bullet point, they collectively make up the majority of the chapter.
Application standards. This section covers application standards in general and
looks specifically at HTTP, HTML, e-mail, Telnet, FTP, and SSH. It notes the security
issues regarding this standard.
Covering the Material
This is pretty much a lecture module.
Assigning Homework
To focus students, you can specify specific test your understanding questions and end-of-
chapter questions or parts of questions they should master or even hand in as homework.
You can also specify questions or parts of questions they do not have to master. Multiple
choice and true/false questions are tied to specific parts of specific questions, so creating
multiple guess questions on exams is relatively straightforward.
, Answer Key
Module A
Networking Concepts
Introduction
1. a) What is an octet? [437]
A collection of 8 bits.
b) What is a host? [437]
Any device with an IP address.
c) Is a home PC connected to the Internet a host? [437]
Yes.
d) Distinguish between the terms internet and Internet. [437]
When the term is spelled with a lower-case i, it refers to any internet or the
internet layer. When it is spelled with an upper-case I, it refers to the global
Internet.
A Sampling of Networks
A Simple Home Network
2. a) What are the functions of an access router? Explain each function in one sentence.
[438-439]
It is a switch, a wireless access point (sometimes), a router to connect the
firm to the Internet, a DHCP server, and a NAT provider.
b) Describe the technology of 4-pair UTP wiring. [440]
A UTP cord contains eight copper wires organized as four pairs. The two
wires of each pair are twisted around each other several times an inch to
reduce interference.
c) What is an Internet access line? [440]
, A transmission line that connects a home or business to its Internet service
provider.
d) What is a broadband modem? [440]
A broadband modem transmits signals over a broadband access line.
e) Why is wireless transmission dangerous? [439]
Eavesdroppers can intercept wireless transmissions.
A Building LAN
3. a) What is a local area network? [440]
A LAN is a network that operates on the customer premises.
b) What is the customer premises?
The land and buildings owned by the corporations.
c) Distinguish between workgroup switches and core switches. [440]
Workgroup switches connect users to the network. Core switches connect
switches to other switches.
d) Why is UTP dangerous? [440-441]
It is easy to tap and generates signals that can be picked up even without
tapping the UTP cord.
e) Why is 802.1X needed? [441]
Most switches today have 802.1X capability that requires any device
connecting to a wall jack to authenticate itself before being allowed to
transmit beyond the switch.
A Firm’s Wide Area Networks (WANs)
4. a) Distinguish between LANs and WANs. [442]
LANs operate within a company’s premises. WANs connect different
premises.
b) Why do companies use carriers for WAN transmission? [442]
They lack the right of way to lay communication facilities between sites.
c) What two WAN technologies are illustrated in the figure Figure A-4? [442]
Point-to-point networks and public switched data networks (Frame Relay)
d) Why is carrier WAN traffic generally considered safe? [443]
Access to the network is limited, and internal routing is hidden.
The Internet
5. a) Which organization created the Internet? [443]
The Defense Advanced Research Projects Agency.
