Cisco 3750G - Catalyst Integrated Wireless LAN Controller User Manual

20-18
Catalyst 3750 Switch Software Configuration Guide
OL-8550-02
Chapter 20 Configuring Optional Spanning-Tree Features
Configuring Optional Spanning-Tree Features
Beginning in privileged EXEC mode, follow these steps to enable root guard on an interface. This
procedure is optional.
To disable root guard, use the no spanning-tree guard interface configuration command.
Enabling Loop Guard
You can use loop guard to prevent alternate or root ports from becoming designated ports because of a
failure that leads to a unidirectional link. This feature is most effective when it is configured on the entire
switched network. Loop guard operates only on interfaces that are considered point-to-point by the
spanning tree.
Note You cannot enable both loop guard and root guard at the same time.
You can enable this feature if your switch is running PVST+, rapid PVST+, or MSTP.
Beginning in privileged EXEC mode, follow these steps to enable loop guard. This procedure is optional.
To globally disable loop guard, use the no spanning-tree loopguard default global configuration
command. You can override the setting of the no spanning-tree loopguard default global configuration
command by using the spanning-tree guard loop interface configuration command.
Command Purpose
Step 1
configure terminal Enter global configuration mode.
Step 2
interface interface-id Specify an interface to configure, and enter interface configuration mode.
Step 3
spanning-tree guard root Enable root guard on the interface.
By default, root guard is disabled on all interfaces.
Step 4
end Return to privileged EXEC mode.
Step 5
show running-config Verify your entries.
Step 6
copy running-config startup-config (Optional) Save your entries in the configuration file.
Command Purpose
Step 1
show spanning-tree active
or
show spanning-tree mst
Verify which interfaces are alternate or root ports.
Step 2
configure terminal Enter global configuration mode.
Step 3
spanning-tree loopguard default Enable loop guard.
By default, loop guard is disabled.
Step 4
end Return to privileged EXEC mode.
Step 5
show running-config Verify your entries.
Step 6
copy running-config startup-config (Optional) Save your entries in the configuration file.

Cisco 3750G - Catalyst Integrated Wireless LAN Controller Specifications

General

Switching Capacity	32 Gbps
RAM	128 MB
Flash Memory	32 MB
Power Device	Internal power supply
Ports	48 x 10/100/1000 + 4 x SFP
Performance	38.7 Mpps
Wireless LAN Controller Capacity	50
Stacking	Yes
Features	VLAN support, QoS
Compliant Standards	IEEE 802.3, IEEE 802.3u, IEEE 802.3ab, IEEE 802.3z
Operating Humidity	10% to 85% non-condensing
Power over Ethernet (PoE)	Yes (optional)