Allied Telesis AT-S39 - Manual (Page 206)

Section III: Web Browser Management
206
4. To enable or disable STP on the switch, click the Enable STP check box.
A check in the box indicates that STP is enabled on the switch.
5. Adjust the bridge STP settings as needed. The parameters are
described below.
Bridge Identifier
The MAC address of the bridge. The bridge identifier is used as a
tie breaker in the selection of the root bridge when two or more
bridges have the same bridge priority value. This value cannot be
changed.
Bridge Priority
The priority number for the bridge. This number is used in
determining the root bridge for STP. The bridge with the lowest
priority number is selected as the root bridge. If two or more
bridges have the same priority value, the bridge with the
numerically lowest MAC address becomes the root bridge. When
a root bridge goes off-line, the bridge with the next priority
number automatically takes over as the root bridge. This
parameter can be from 0 (zero) to 65,535, with 0 being the highest
priority.
Bridge Hello Time
The time interval between generating and sending configuration
messages by the bridge. This parameter can be from 1 to 10
seconds. The default is 2 seconds.
Enable STP
Enables and disables STP on the switch. The default setting is
disabled.
Bridge Forwarding Delay
The waiting period before a bridge changes to a new state, for
example, becomes the new root bridge after the topology
changes. If the bridge transitions too soon, not all links may have
yet adapted to the change, possibly resulting in a network loop.
The default is 15 seconds.
Bridge Max Age
The length of time after which stored bridge protocol data units
(BPDUs) are deleted by the bridge. All bridges in a bridged LAN
use this aging time to test the age of stored configuration
messages called bridge protocol data units (BPDUs). For example,
if you use the default 20, all bridges delete current configuration
messages after 20 seconds. This parameter can be from 6 to 40
seconds. The default is 20 seconds.