Specifications

Waters Network Systems User’s Manual Page 75
GSM-2108/GSM-1008SFP
5.19.2 STP Configuration
STP includes Rapid Spanning Tree Protocol (RSTP). STP has six parameters to be configured.
These parameters are described below.
Function name:
STP Configuration
Function description:
Set the following Spanning Tree parameters to control STP function (enable/disable). Select mode
RSTP/STP and affect STP state machine behavior to send BPDU in the switch. The default setting
of STP is Disable.
Parameter description:
Spanning Tree Protocol:
Set 802.1W Rapid STP function Enable / Disable. Default is “Disable”
Bridge Priority:
The lower the number for bridge priority, the higher the priority it will have. Usually, the bridge
with the highest bridge priority is the root. If you want this switch to be the root bridge, set the
value lower than that of the bridge in the LAN. The valid value is 0 ~ 61440. The default is
32768.
Hello Time:
Hello Time is used to determine the periodic time to send normal BPDU from designated ports
among bridges. It decides how long a bridge should notify other bridges to say that it is up and
connected. If the GSM switch is the root bridge of the LAN, for example, all other bridges will
use the hello time assigned by this switch to communicate with each other. The valid value is 1
~ 10 in unit of second. The default is 2 seconds.
Max. Age:
When the GSM switch is the root bridge, the whole LAN will apply the number set by the switch
as their maximum age time. When a bridge received a BPDU originating from the root bridge
and if the message age conveyed in the BPDU exceeds the Max. Age of the root bridge, the
bridge will treat the root bridge as malfunctioning and issue a Topology Change Notification
(TCN) BPDU to all other bridges. All bridges in the LAN will re-calculate to determine who the
root bridge is. The valid value of Max. Age is 6 ~ 40 seconds. Default is 20 seconds.
Forward Delay:
You can set the root bridge forward delay time. This figure is set by the root bridge only. The
forward delay time is defined as the time spent from Listening state moved to Learning state
and also from Learning state moved to Forwarding state of a port in bridge. The forward delay
time contains two states, Listening state to Learning state and Learning state to Forwarding
state. It assumes that forward delay time is 15 seconds, then total forward delay time will be 30
seconds.
The valid value is 4 ~ 30 seconds, default is 15 seconds.
Force Version:
Two options are offered for the STP algorithm. One is RSTP and the other is STP. If STP is
chosen, RSTP will run as a legacy STP. The switch supports RSTP (802.1w) which is backward
compatible with STP (802.1d).