Advanced Management
Maximum Age
Each bridge should receive regular configuration BPDUs from the direction of the root bridge. If the maximum age timer expires before the bridge receives another BPDU, it assumes that a change in the topology has occurred, and it begins recalculating the spanning tree.
Forward Delay
After a recalculation of the spanning tree, the Forward Delay parameter regulates the delay before each port begins transmitting traffic. If a port begins forwarding traffic too soon, the network can be adversely affected. The permitted range of the Forward Delay is 4 to 30 seconds.
KNote: The Hello Time, Maximum Age, and Forward Delay are constrained by the following formula:
(Hello Time + 1) <= Maximum Age <= 2 x (Forward Delay
In general, reducing the values of these timers will make the spanning tree react faster when the topology changes, but may cause temporary loops as the tree stabilizes in a new configuration. Lengthening the timers will make the tree react more slowly to changes in configuration but will make an unintended reconfiguration less likely. All of the bridges in the tree must agree on the values of these timers, so each bridge uses the ones advertised by the root.
Port Priority
If two ports are connected to the same segment, changing the Port Priority increases or decreases the probability that either port will be chosen for inclusion in the tree.
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