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Catalyst 3750 Switch Hardware Installation Guide
OL-6336-07
Chapter 2 Switch Installation
Planning the Stack
Planning Considerations
Before connecting the Catalyst 3750 switches in a stack, observe these planning considerations:
• Size of the switch. For switch dimensions, see Appendix A, “Technical Specifications.” Some
switches are deeper than the other switches. Stacking switches of the same size together makes it
easier to cable the switches.
• Length of cable. Depending on the configurations that you have, you might need cables of different
sizes. If you do not specify the length of the StackWise cable, the 0.5-meter cable is supplied. If you
require the 1-meter cable or the 3-meter cable, you can order it from your Cisco supplier. For cable
numbers, see the “StackWise Ports” section on page 1-25. The “Recommended Cabling
Configurations” section on page 2-10 provides examples of recommended configurations.
• Access to the rear ports for unrestricted cabling.
Make sure that you have access to the rear of the rack if you plan to stack the switches. If you do
not have access to the rear panel, make sure that you cable the switches before you rack-mount them.
• For concepts and procedures to manage switch stacks, see the switch software configuration guide.
Powering Considerations
Consider the following guidelines before you power on the switches in a stack:
• The sequence in which you initially power on the switches might affect the switch that becomes the
stack master.
• If you want a particular switch to become the stack master, power on that switch first. This switch
becomes the stack master and remains the stack master until a master re-election is required. After
approximately 10 seconds, power on the remaining switches in the stack.
• If you have no preference as to which switch becomes the stack master, power on all the switches in
the stack within a 10-second timeframe. These switches participate in the stack master election.
Switches powered up after the 10-second timeframe do not participate in the election.
• Power off a switch before you add it to or remove it from an existing switch stack.
Note For conditions that can cause a stack master re-election or to manually elect the stack master, see the
“Managing Switch Stacks” chapter in the switch software configuration guide.
Cabling Considerations
The illustrations in this section display cabling configuration examples that show the stack bandwidth
and possible stack partitioning.
Figure 2-1 shows an example of a stack of Catalyst 3750 switches that provides full bandwidth and
redundant StackWise cable connections.
