Planet Technology FGSW-2620PVM User Manual

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A value used by STP to evaluate paths – 

STP calculates path costs and selects the 

path with the minimum cost as the active 

path. 

200,000-100Mbps Fast Ethernet ports

20,000-1000Mbps Gigabit Ethernet 

ports 

0 - Auto 

Enable state   

STP disabled for all ports 

Port priority 

128 

Port cost 

0 

Bridge Priority 

32,768 

 

 

The Hello Time cannot be longer than the Max. Age. Otherwise, a configuration error will 

occur. 

 

 

Observe the following formulas when setting the above parameters: 

 

 

 

A simple illustration of three switches connected in a loop is depicted in the below diagram. In this example, you can 

anticipate some major network problems if the STP assistance is not applied.   

If switch A broadcasts a packet to switch B, switch B will broadcast it to switch C, and switch C will broadcast it to back to 

switch A and so on. The broadcast packet will be passed indefinitely in a loop, potentially causing a network failure. In this 

example, STP breaks the loop by blocking the connection between switch B and C. The decision to block a particular 

connection is based on the STP calculation of the most current Bridge and Port settings.   

Now, if switch A broadcasts a packet to switch C, then switch C will drop the packet at port 2 and the broadcast will end 

there. Setting-up STP using values other than the defaults, can be complex. Therefore, you are advised to keep the default 

factory settings and STP will automatically assign root bridges/ports and block loop connections. Influencing STP to choose 

a particular switch as the root bridge using the Priority setting, or influencing STP to choose a particular port to block using 

the Port Priority and Port Cost settings is, however, relatively straight forward.