Allied Telesis AT-S39 - Manual (Page 292)

Section III: Web Browser Management
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2. Adjust the parameters are needed. The parameters are defined
below.
Force Version
This selection determines whether the bridge will operate with
RSTP or in an STP-compatible mode. If you select RSPT, the bridge
will operate all ports in RSTP, except for those ports that receive
STP BPDU packets. If you select Force STP Compatible, the bridge
will operate all ports in STP. The default is RSTP.
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 lowest priority
number automatically takes over as the root bridge. This
parameter can be from 0 (zero) to 61,440 in increments of 4096,
with 0 being the highest priority. For a list of the increments, refer
to Table 4, RSTP Bridge Priority Value Increments on page 98
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.
Bridge Forwarding
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 range is 4 to 30 seconds. 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.
In selecting a value for maximum age, the following must be
observed:
MaxAge must be greater than (2 x (HelloTime + 1)).
MaxAge must be less than (2 x (ForwardingDelay - 1)).