Cisco Catalyst 3750-X User Manual

20-21
Catalyst 3750-X and 3560-X Switch Software Configuration Guide
OL-21521-01
Chapter 20 Configuring STP
Configuring Spanning-Tree Features
To return to the default setting, use the no spanning-tree [vlan vlan-id] cost interface configuration
command. For information on how to configure load sharing on trunk ports by using spanning-tree path
costs, see the “Configuring Trunk Ports for Load Sharing” section on page 15-22.
Configuring the Switch Priority of a VLAN
You can configure the switch priority and make it more likely that a standalone switch or a switch in the
stack will be chosen as the root switch.
Note Exercise care when using this command. For most situations, we recommend that you use the
spanning-tree vlan vlan-id root primary and the spanning-tree vlan vlan-id root secondary global
configuration commands to modify the switch priority.
Beginning in privileged EXEC mode, follow these steps to configure the switch priority of a VLAN. This
procedure is optional.
To return to the default setting, use the no spanning-tr
ee vlan vlan-id priority global configuration
command.
Command Purpose
Step 1
configure terminal Enter global configuration mode.
Step 2
spanning-tree vlan vlan-id priority priority Configure the switch priority of a VLAN.
• For vlan-id, you can specify a single VLAN identified by
VLAN ID number, a range of VLANs separated by a
hyphen, or a series of VLANs separated by a comma. The
range is 1 to 4094.
• For priority, the range is 0 to 61440 in increments of
4096; the default is 32768. The lower the number, the
more likely the switch will be chosen as the root switch.
Valid priority values are 4096, 8192, 12288, 16384,
204
80, 24576, 28672, 32768, 36864, 40960, 45056,
49152, 53248, 57344, and 61440. All other values are
rejected.
Step 3
end Return to privileged EXEC mode.
Step 4
show spanning-tree vlan vlan-id Verify your entries.
Step 5
copy running-config startup-config (Optional) Save your entries in the configuration file.

Cisco Catalyst 3750-X Specifications

General

Switching Capacity	160 Gbps
Stacking Bandwidth	64 Gbps
Max Stacking Units	9
Layer Support	Layer 2 and Layer 3
Form Factor	Rack-mountable
DRAM	256 MB
Flash Memory	64 MB
Model	Cisco Catalyst 3750-X Series
Ports	24 or 48 10/100/1000 Ethernet ports
Uplink Interfaces	4 SFP or 2 SFP+
Features	StackWise Plus, EnergyWise
Image	IP Base or IP Services
Operating Temperature	0 to 40°C
Operating Humidity	10 to 85% noncondensing