PLANET XGS3-24042 - Manual (Page 163)

17-11
Figure 17-5 The Topology Of the Instance 4 after the MSTP Calculation
17.4 MSTP Troubleshooting
 In order to run the MSTP on the switch port, the MSTP has to be enabled globally. If the MSTP is not
enabled globally, it can’t be enabled on the port.
 The MSTP parameters co work with each other, so the parameters should meet the following
conditions. Otherwise, the MSTP may work incorrectly.
2×(Bridge_Forward_Delay -1.0 seconds) >= Bridge_Max_Age
Bridge_Max_Age >= 2 ×(Bridge_Hello_Time + 1.0 seconds)
 When users modify the MSTP parameters, they have to be sure about the changes of the topologies.
The global configuration is based on the bridge. Other configurations are based on the individual
instances.
Switch2
Switch3
Switch4
2 2X
3X 3
4
4
5X
5
6
7X
6
7