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96 Chapter 3: Switched/Campus LAN Solutions
Foundation Summary
This section is a collection of tables that provide a convenient review of many key concepts in
this chapter. If you are already comfortable with the topics in this chapter, this summary might
help you recall a few details. If you have just read this chapter, this review should help solidify
some key facts. If you are doing your final preparation before the exam, Tables 3-3 through
3-6 are a convenient way to review the day before the exam.
Table 3-3
Comparing Store-and-Forward Features and Cut-Through Features
Switching Mode
Latency
Error
Checking
Catalyst
Models
Comments
Store-and-forward
Medium
Yes
1900, 2800,
2600, 2820,
2900, 3000,
3900, 3920,
5000, 5500
As network speeds continue to
increase, latency issues become
more manageable.
Required when using source and
destination segments with different
media.
Cut-through
Low
No
2600, 3000,
3900, 3920
Switch will allow bad frames to
pass, which can waste bandwidth.
Best bet for networks with low
error rates.
Table 3-4
Comparing Switching Technologies
Switching
Technology
Comments
Ethernet
Provides Layer 2 switching and broadcast domain segmentation.
Token Ring
Provides Layer 2 switching. Offers more bandwidth by reducing the size of
the Token Ring domain.
Fiber Distributed Data
Interface (FDDI)
Used largely as a campus backbone to consolidate Ethernet and Token
Ring networks that contain FDDI devices.
Copper Data Distributed
Interface (CDDI)
Operates on the same principles as FDDI while using copper. The use of
copper represents a tremendous cost savings.
ATM
Workgroup ATM switches typically are connected to an Ethernet switch
port and an ATM uplink to connect to a larger campus ATM switch.
Campus ATM switches are generally used for small-scale ATM backbones.
For example, campus ATM switches might link ATM routers or LAN
switches. Enterprise ATM switches are designed to form the core
backbones of large enterprise networks. Enterprise ATM switches are used
to interconnect campus ATM switches.
87200333.book Page 96 Wednesday, August 22, 2001 2:18 PM