Signamax Managed Hardened PoE Industrial DIN-rail Mount Switch - Manual (Page 59)

11 Spanning Tree
54
the other links to prune the network into a tree.
11.1 STP

Note: Enable STP in 3 Advanced Configuration .
11.1.1 Basic STP
The following factors should be considered when setting STP configuration:
Priority：The priority of switch, it ranges from 0 to 65535, and the default value is 32768. The
smaller the value is, the higher the priority is.
Hello Time：The interval for sending hello packets. Hello packets are used to check link state.
A switch sends hello packets to its neighboring devices at a regular interval (the hello time) to
check whether the links are faulty. It ranges from 1 to 10 seconds, and the default value is 2
seconds.
Max Age：Lifetime for the configuration BPDUs to be kept in a switch. Switches use max age
parameter to determine whether a received configuration BPDU times out. Spanning trees
will be recalculated if a configuration BPDU received by a port times out. This value is in the
range of 6 to 40 seconds, and is 20 seconds by default.
Forward Delay Time：This value is in the range of 4 to 30 seconds, and is 15 seconds by
default. To prevent the occurrence of a temporary loop, when a port changes its state from
discarding to forwarding, it undergoes an intermediate state and waits for a specific period of
time to synchronize with the state transition of the remote switches. This state transition
period is determined by Forward Delay Time configured on the root bridge, and applies to all
non-root bridges.
Fast Detection：Enable or disable Fast Detection, it is disabled by default.
To prevent temporary loopback, when a port status changes from discarding to forwarding, it
will experience an intermediate state and wait for a specified time to synchronize with remote
switched. Forward Delay Time configured in the root bridge determines the intermediate state
time.
As for the configuration of the three time-related parameters (that is, the hello time, forward
delay, and max age parameters), the following formulas must be met to prevent frequent
network jitter.
2 x (forward delay – 1 second) >= max age
Max age >= 2 x (hello time + 1 second)