16-8
Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide
78-11380-10
Chapter 16 Configuring Optional Spanning-Tree Features
Understanding Optional Spanning-Tree Features
Connecting the Stack Ports
A fast transition occurs across the stack of switches if the multidrop backbone connections are a
continuous link from one GigaStack GBIC module to another as shown in the top half of Figure 16-6.
The bottom half of Figure 16-6 shows how to connect the GigaStack GBIC module to achieve a normal
convergence time.
You should follow these guidelines:
• A switch supports only one stack port.
• Do not connect alternate stack-root ports to stack ports.
• Connect all stack ports on the switch stack to the multidrop backbone.
• You can connect the open ports on the top and bottom GigaStack GBIC modules within the same
stack to form a redundant link.
Figure 16-6 GigaStack GBIC Module Connections and Spanning-Tree Convergence
Catalyst 2950G-24
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Catalyst 3508G XL
GigaStack GBIC connection for fast convergence
GigaStack GBIC connection for normal convergence
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Catalyst 2950G-48
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