202 C
HAPTER
 9: S
PANNING
 T
REE
 P
ROTOCOL
Connecting to STP 
Systems on Legacy 
Switch Units
If you are connecting your Switch to legacy units that support STP, note 
the following:
■
Your Switch supports one STP system; however legacy Switch units 
(for example, the SuperStack II Switch 1000) may support one STP 
system per VLAN. Consequently:
■
If the legacy Switch units use a single VLAN and you connect your 
Switch to them using an untagged link, the STP system of your 
Switch and the STP system of the legacy Switch units are 
combined. 
■
If the legacy Switch units use multiple VLANs and you connect your 
Switch to them using a VLT tagged link, the STP system of your 
Switch and the STP system of the legacy Switch units are 
completely separate. This means that if you connect your Switch to 
a legacy Switch unit using multiple VLT links, a loop may created.
■
Some legacy units cannot use VLAN 16 if they are using STP. If your 
Switch is connected to one of these units, VLAN 16 traffic is blocked 
on the port.
Enabling STP
To enable STP on your Switch via the command line interface, see 
“Enabling and Disabling Spanning Tree on a Bridge”
 on page 116.
To enable STP on your Switch via the web management interface:
1
From the web interface, click the 
Configuration
 icon on the side-bar. 
2
Click the 
Advanced Stack Setup
 hotlink. The Advanced Stack Setup page 
is displayed.
3
From the 
Spanning Tree
 listbox, select Enabled.
4
Click the 
Apply
 button.
You cannot enable STP if you have set up any resilient links on the Switch.