Cisco Systems 2950, 2955 Limitations, Connecting the Stack Ports

15-8
Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide
OL-10101-02
Chapter 15 Configuring Optional Spanning-Tree Features
Understanding Optional Spanning-Tree Features
Limitations
These limitations apply to CSUF:
• CSUF uses the GigaStack GBIC module and runs on all Catalyst 3550 switches, all Catalyst 3500
XL switches, Catalyst 2950 switches with GBIC module slots, and only on modular Catalyst 2900
XL switches that have the 1000BASE-X module installed.
• Up to nine stack switches can be connected through their stack ports to the multidrop backbone.
Only one stack port per switch is supported.
• Each stack switch can be connected to the spanning-tree backbone through one uplink.
• If the stack consists of a mixture of Catalyst 3550, Catalyst 3500 XL, Catalyst 2950, and
Catalyst 2900 XL switches, up to 64 VLANs with spanning tree enabled are supported. If the stack
consists of only Catalyst 3550 switches, up to 128 VLANs with spanning tree enabled are
supported.
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 15-6.
The bottom half of Figure 15-6 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.