Allied Telesis AT-S63 - Manual (Page 570)

Chapter 24: Multiple Spanning Tree Protocol
570 Section V: Spanning Tree Protocols
seconds. The default is 2 seconds. This value is active only if the
bridge is selected as the root bridge of the network.
3 - 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 range is 4 to 30
seconds. The default is 15 seconds. This setting applies only to ports
running in the STP-compatible mode.
4 - 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 6 to 40 seconds. The default is 20 seconds.
When you select a value for maximum age, observer the following
rules:
MaxAge must be greater than (2 x (HelloTime + 1)).
MaxAge must be less than (2 x (ForwardingDelay - 1))
5 - Max Hops
MSTP regions use this parameter to discard BPDUs. The Max Hop
counter in a BPDU is decremented every time the BPDU crosses an
MSTP region boundary. After the counter reaches zero, the BPDU is
deleted.
6 - 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 include Sales
Region and Production Region.
7 - Revision Level
The revision level of an MSTP region. The range is 0 (zero) to 255.
This is an arbitrary number that you assign to a region. The revision
level must be the same on all bridges in a region. Different regions can
have the same revision level without conflict.
8 - Bridge Identifier
The MAC address of the bridge. The bridge identifier is used as a tie
breaker in the selection of a root bridge when two or more bridges
have the same bridge priority value. This value cannot be changed.