Layer 2 LAN Switching
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they cause more problems than they solve. In the following sections, we'll
discuss some of the most serious problems:
Broadcast storms
Multiple frame copies
Multiple loops
Broadcast Storms
If no loop avoidance schemes are put in place, the switches will flood broad-
casts endlessly throughout the internetwork. This is sometimes referred to as
a broadcast storm. Figure 4.2 shows how a broadcast may be propagated
throughout the network.
F I G U R E 4 . 2
Broadcast storms
Multiple Frame Copies
Another problem is that a device can receive multiple copies of the same
frame because the frame can arrive from different segments at the same time.
Figure 4.3 shows how multiple frames can arrive from multiple segments
simultaneously.
Segment 1
Segment 2
Broadcast
Switch A
Switch B
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