Allied Telesis AT-S63 - Manual (Page 186)

Chapter 15: MSTP
186 Section II: Advanced Features
Force Version
This selection determines whether the bridge operates with MSTP
or in an STP-compatible mode. If you select MSTP, the bridge
operates all ports in MSTP, except those ports that receive STP or
RSTP BPDU packets. If you select Force STP Compatible, the bridge
uses its MSTP parameter settings, but sends only STP BPDU
packets from the ports. The default is MSTP.
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. This value is active only if the
bridge is selected as the root bridge of the network.
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 of the links may
have adapted to the change, possibly resulting in a network loop.
The range is from 4 to 30 seconds. The default is 15 seconds. This
setting applies only to ports running in the STP-compatible mode.
Configuration Name
The name of the MSTP region. The range is 0 (zero) to 32
alphanumeric characters in length. The name, which is case
sensitive, must be the same on all bridges in a region. Examples of
a configuration name include Sales Region and Production
Region.
Bridge Max Age
The length of time after which stored bridge protocol data units
(BPDUs) are deleted by the bridge. This parameter applies only if
the bridged network contains an STP or RSTP single-instance
spanning tree. Otherwise, the bridges use the Max Hop counter to
delete BPDUs.
All bridges in a single-instance 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 of
20, all bridges delete current configuration messages after 20
seconds. The range of this parameter is 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))