UTStarcom iSpirit 3026 Manual page 74

Spanning Tree: Enable
IGMP Snooping: Disable
So it's shown that STP is enabled. To disable STP:
Switch# no stp
More commands:
To set a switch as root, you need to set its bridge priority value smaller than that of the
two others (priority: smaller means higher priority; default: 32768, range: 0-65535):
Switch# stp bridge priority <priority>
To disable STP calculation of a port
Switch# disable stp ports <port>
To check possible errors:
(1) You may need to see which switch is the bridge root:
Switch# show stp bridge
— Designated Root Information — -
Priority : 32768
MAC Address : 00:09:ca:01:75:02
Hello Time : 2s
Forward Delay : 15s
Max Age : 20s
— Bridge STP Information — -
Bridge Priority : 32768
MAC Address : 00:09:ca:01:75:02
Root Path Cost : 0
Root Port : 0
Bridge Hello Time : 2s
Bridge Forward Delay : 15s
Bridge Max Age : 20s
(2) You may need to see STP ports information:
Switch# show stp port portnumber
Switch# show stp port 3
— Port Information -—
STP Port : Enable
***port: 1-26
***port number (1=<A<=26)