Allied Telesis AT-S63 - Manual (Page 529)

AT-S63 Management Software Menus Interface User’s Guide
Section V: Spanning Tree Protocols 529
3 - Bridge Forwarding
The waiting period in seconds 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, resulting in network loops. The range is 4 to 30 seconds.
The default is 15 seconds.
4 - 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
value 20, all bridges delete current configuration messages after 20
seconds. This parameter can be from 6 to 40 seconds.
When you select a value for maximum age, observe the following
rules:
MaxAge must be greater than (2 x (HelloTime + 1)).
MaxAge must be less than (2 x (ForwardingDelay - 1)).
Note
The aging time for BPDUs is different from the aging time used by
the MAC address table.
5 - Bridge Identifier
The bridge identifier of the switch. The identifier consists of the switch’s
bridge priority value and MAC address, separated by a slash (/). To
change the switch’s priority value, use option 1, Bridge Priority. The
MAC address of the switch cannot be changed.
6 - Root Bridge
The MAC address of the root bridge of the spanning tree domain. This
value cannot be changed and is only displayed when spanning tree is
activated on the switch.
7 - Root Priority
The priority value on the root bridge of the spanning tree domain. This
parameter is only displayed when spanning tree is enabled on the
switch. To change the priority value on the root bridge, you must start a
management session on the switch which is functioning as the root
bridge and change its bridge priority value.
8 - Root Path Cost
The cost of the path from the current switch to the root switch of the
spanning tree domain. If the current switch is the root switch, root path
cost will be “0”. This value cannot be changed and is only displayed
when RSTP is activated on the switch.