Waters Network Systems GSM2108 Operating Manual page 74

Displays port number connected to root bridge with the lowest path cost.
Root Path Cost:
Displays the path cost between the root port and the designated port of the root bridge.
Current Max. Age:
Displays the current root bridge maximum age time. Maximum age time is used to monitor STP
topology. When a bridge does not receive a hello message from root bridge until the maximum
age time is counted down to 0, the bridge will treat the root bridge as malfunctioned and issue a
Topology Change Notification (TCN) BPDU to all other bridges.
All bridges in the LAN will re-learn and determine the root bridge. Maximum Age time is
assigned by root bridge in unit of seconds. Default is 20 seconds.
Current Forward Delay:
Displays the current root bridge forward delay time. The value of Forward Delay time is set by
root. The Forward Delay time is defined as the time spent from Listening state moved to
Learning state or from Learning state moved to Forwarding state of a port in bridge.
Hello Time:
Displays the current hello time of the root bridge. Hello time is a time interval specified by root
bridge. It is used to request all other bridges periodically sending hello message to the bridge
attached to its designated port.
STP Topology Change Count:
STP Topology Change Count expresses the time spent in a unit of seconds since the beginning
of the Spanning Tree Topology Change to the end of the STP convergence. Once the STP
change is converged, the Topology Change count will be reset to 0. The figures showing in the
screen may not be the exact time it spent but very close to, because the time is eclipsing.
Time Since Last Topology Change:
Time Since Last Topology Change is the accumulated time in unit of seconds the STP has been
since the last STP Topology Change was made. When Topology Change is initiated again, the
counter will be reset to 0 and resume counting once the STP topology change is completed.
Waters Network Systems
Figure 5.45 – STP Status
User's Manual
GSM-2108/GSM-1008SFP
Page 74