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Chapter 4: Understanding LANs and LAN Switching
How to Best Use This Chapter
By taking the following steps, you can make better use of your study time:
•
•
Take the “Do I Know This Already?” quiz and write down your answers. Studies show
retention is significantly increased through writing facts and concepts down, even if you
never look at the information again!
•
Figure 4-1 helps guide you to the next step in preparation for this topic area on the CCNA
exam.
How to Use This Chapter
Do I know this already? Quiz
Application
Presentation
Medium score
Session
Transport
Data Link
Review Chapter
using charts and
Network
tables
Data Link
Physical
Physical
Read Chapter
Network
High score
Host B
Application
High
scorePresentation
want Session
more
review Transport
Skip
NetworkChapter
Data Link
NA2603q3
Low score
Host A
Physical
Router 1
End-of-chapter
exercises
Next Chapter
NA260401
Figure 4-1
Keep your notes and answers for all your work with this book in one place for easy
reference.
05.35700737 CH04 Page 123 Wednesday, February 17, 1999 3:15 PM
“Do I Know This Already?” Quiz
123
“Do I Know This Already?” Quiz
1. Name two benefits of LAN segmentation using transparent bridges.
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
2. What settings are examined by a bridge or switch to determine which bridge or switch
should be elected as root of the spanning tree?
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
3. Assume a building has 100 devices that are attached to the same Ethernet. These devices
are migrated to two different shared Ethernet segments, each with 50 devices. The two
segments are connected to a Cisco LAN switch to allow communication between the two
sets of users. List two benefits that would be derived for a typical user.
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
4. Name the two methods of internal switching on typical switches today. Which provides
less latency for an individual frame?
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
5. Describe how a transparent bridge decides whether it should forward a frame and how it
chooses the interface out of which to forward the frame.
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
6. Describe the benefits of the Spanning-Tree Protocol as used by transparent bridges and
switches.
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
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Chapter 4: Understanding LANs and LAN Switching
7. Does a bridge/switch examine just the incoming frame’s source MAC address, destination
MAC address, or both? Why?
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
8. When a bridge or switch using the Spanning-Tree Protocol first initializes, who does it
claim should be the root of the tree?
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
9. Define the difference between broadcast and multicast MAC addresses.
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
10. Define the term broadcast domain.
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
11. Explain the function of the loopback and collision detection features of an Ethernet NIC
in relation to half-duplex and full-duplex operation.
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
12. Name the three interface states that the Spanning-Tree Protocol uses, other than
forwarding. Which of these states is transitory?
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
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“Do I Know This Already?” Quiz
125
You can find the answers to the “Do I Know This Already?” quiz in Appendix B on page 555.
Review the answers, grade your quiz, and choose an appropriate next step in this chapter based
on the suggestions in the “How to Best Use this Chapter” topic earlier in this chapter. Your
choices for the next step are as follows:
•
•
5 or fewer correct—Read this chapter.
•
9 or more correct—If you want more review on these topics, skip to the exercises at the
end of this chapter. If you do not want more review on these topics, skip this chapter.
6, 7, or 8 correct—Review this chapter, looking at the charts and diagrams that
summarize most of the concepts and facts in this chapter.