107
 GS748T Smart Switch
6. Click Cancel to cancel the configuration on the screen and reset the data on the screen to 
the latest value of the switch
7. If you
 make any configuration changes, click Apply to send the updated configuration to the 
switch. Configuration changes take place immediately.
The following table describes the read-only MST port configuration information displayed on 
t
he Spanning Tree CST Configuration page
Field Description
Auto-calculated Port Path 
Cost
Displays whether the path cost is automatically calculated (Enabled) or not 
(Di
sabled). Path cost is calculated based on the link speed of the port if the 
configured value for Port Path Cost is zero.
Port ID The port identifier for the specified port 
within the selected MST instance. It 
is made up from the port priority and the interface number of the port.
Port Up Time Since Counters 
Last Cl
eared
Time since the counters were last cleared, displayed in Days, Hours, 
Minutes, and Seconds.
Port Mode Spanning Tree Protocol Administrative Mode associated with the port or port 
channel. Possible values are Enable or Disable.
Port Forwarding State Indicates the current STP state of a port. If enabled, the port state 
d
etermines what forwarding action is taken on traffic. Possible port states 
are:
• D
isabled: STP is currently disabled on the port. The port forwards traffic 
while learning MAC addresses.
• B
locking: The port is currently blocked and cannot be used to forward 
traffic or learn MAC addresses.
• L
istening: The port is currently in the listening mode. The port cannot 
forward traffic nor can it learn MAC addresses.
• L
earning: The port is currently in the learning mode. The port cannot 
forward traffic, however, it can learn new MAC addresses.
• F
orwarding: The port is currently in the forwarding mode. The port can 
forward traffic and learn new MAC addresses
Port Role Each MST Bridge Port that is enabled is assig
ned a Port Role for each 
spanning tree. The port role will be one of the following values: Root Port, 
Designated Port, Alternate Port, Backup Port, Master Port, or Disabled 
Port.
Designated Root Root Bridge for the selected MST instance. It is made up using the bridge 
p
riority and the base MAC address of the bridge.
Designated Cost Displays cost of the port p
articipating in the STP topology. Ports with a lower 
cost are less likely to be blocked if STP detects loops.
Designated Bridge Bridge Identifier of the bridge with the
 Designated Port. It is made up using 
the bridge priority and the base MAC address of the bridge.
Designated Port Port Identifier on the Designated
 Bridge that offers the lowest cost to the 
LAN. It is made up from the port priority and the interface number of the port.
Click Refresh to update the screen with the latest MST information.