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Chapter 3: Network Components
Core Idea
Networking is accomplished through a variety of different connection media and devices to
route information from one host to another.
Instructor Focus
This is a lengthy chapter with a large amount of material, predominantly terminology and
standards specifications. You will focus on the media connections between devices and the
Network+ Exam Objectives for this Chapter/Lesson
x 1.8 Explain the functions of network services
x 2.2 Given a scenario, determine the appropriate placement of networking devices on a network
and install/configure them
x 2.4 Explain the purposes of virtualization and network storage technologies
Terminology
Make an effort to define the following terms for the designated areas. After defining these,
calling on the students for repeat definitions as you progress through the slide deck will help
them retain the terminology.
Connection Media:
x Coaxial cable
x Twisted-pair cable
x Shielded twisted-pair cable
x Single-mode fiber (SMF)
Connection Devices:
x Hub
x Switch
x Router
x Multilayer switch
x Firewall
x Domain Name System (DNS) server
Connection-Specific Terminology:
x 66 block
x 110 block
x On-site
x Off-site
Focus Questions
x What are the characteristics of various media types?
x What is the role of a given network infrastructure component?
x What features are provided by specialized network devices?
x How are virtualization technologies impacting traditional corporate data center designs?
x What are some of the primary protocols and hardware components found in a Voice over IP
(VoIP) network?
Icebreaker Discussion
Choose one or both of the following:
1. Describe how one device can send a bit to another device.
The purpose of this is to get your students thinking about how devices connect and interact.
2. Why are standards important in networking devices?
The purpose of this is to get them thinking about how two disparate devices with no shared
purpose other than a cable (or in the case of wireless, the same air space) could
communicate in a meaningful way. Relate this back to networking in general and the topics
Icebreaker Activity
1. List as many connection media types as you can and add descriptors and terms to each
media type.
This is a good exercise to expand student’s background on different media connections. You
can start this as an individual activity, but it is worth sharing and building an overall map as a
group. (This is really a mind map construction for network media.) Ideally, different students
Main Activities
This chapter involves a lot of material and a lot of terminology. It is best to break this down into
manageable pieces for the students (and to keep you on track). There are three overall sections to
this chapter: media, devices, and specialized networking. Mention each category first and keep the
rest separate from the discussion until one section is completed.
1. Network Media
Keeping running diagrams and charts on the board is a good way to keep each area straight. One
of the main purposes of this is to decide which cable to use and when, so you should develop a
hierarchy as you go in terms of distance, price, and network capacity.
It is important to distinguish why a certain medium is used for communication. For instance,
copper wire is cheap but it is subject to a lot of issues like crosstalk and EMI. There are ways to
Using the triangle and other factors (such as up-front cost versus maintenance cost, scalability,
and so on), the final ranking you should establish is as follows:
a. Copper (or wireless where feasible) for short distances
b. MMF for longer distances
c. SMF where the others cannot be used
This should help your students identify the relative strengths and weaknesses of the media and
engage in debate and conversation to support the differences.
2. Network Routing
The next exercise should focus on the use of routers, switches, bridges, and hubs in a network.
Create a mock network on the board using at least two subnets and three nodes each. Connect
each node to a blank box in the subnet, such as the one shown here.
In turn, substitute the blank boxes with a hub, switch, and router, describing communication
between two of the devices on a subnet at a time. Compare the differences in the routing of
these devices and the communication efficiency it allows.
3. DHCP and DNS
If time permits, discuss how DNS and DHCP work. You can use the network from the second
4. VPN Concentrators
Think of a cruise ship as an Internet Provider and a VPN as a sub-marine following the cruise
ship. They are both going to the same destination. It is not hard to see where the cruise ship is
headed. However, the submarine is under the water and we would never know that it is going
Chapter 3: Network Simulator Activities
Matching Activity: Network Cabling
Create a Straight Cable and Test It
Quiz Questions
1. Rank the cabling that should be used from least to most expensive.
This is primarily a reiteration of the discussion above. The cheapest option may change between
2. How are physical signals sent over copper wire? How are physical signals sent over fiber-optic
cable?
This is, once again, a reiteration, but it is an essential item for understanding the chapter
contents. Electric voltage is used to send signals over copper wire, alternating between no
3. Briefly define a hub, a switch, and a router.
Hub: A small, simple device for joining multiple computers. A hub typically sends a message
4. What is the primary difference between routers and switches?
This is a concept you will want to reinforce. Both of these devices are capable of making
intelligent routing decisions (unlike a hub) and knowing the distinction will help in
5. How does virtualization change the size of the network’s square footage footprint and usage of
electrical resources?
Although it is not always true that a savings in electrical costs can be relied on, it is true that
6. What are the steps in a DHCP connection?
DHCP will appear again and again in the material, so it is important to revisit it regularly. When a
device attempts to register with a DHCP server, the following occurs:
1) Discovery: Client sends a UDP packet DHCPDISCOVER to 255.255.255.255 (or to a
specified subnet).
2) Offer: DHCP server receives the request, chooses an available IP address, leases it to the
3) Request: Client will choose one of the offers from a DHCP server (many may respond)
4) Acknowledgment: When the DHCP server receives the DHCPREQUEST packet from the
client, it sends a DHCPPACK packet with lease and configuration information. The client
must now use ARP to prevent any IP conflicts from overlapping pools of IP addresses
across different DHCP servers.
Chapter 3: Network Simulator Activity
DHCP Technology
