3com WX3000 Manuel D’Utilisation

 

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You can configure a device as the root bridges of multiple spanning tree instances. But you cannot 
configure two or more root bridges for one spanning tree instance. So, do not configure root 
bridges for the same spanning tree instance on two or more devices using the stp root primary 
command. 

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You can configure multiple secondary root bridges for one spanning tree instance. That is, you can 
configure secondary root bridges for the same spanning tree instance on two or more devices 
using the stp root secondary command. 

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You can also configure the current device as the root bridge by setting the priority of the device to 0. 
Note that once a device is configured as the root bridge or a secondary root bridge, its priority 
cannot be modified. 

 

# Configure the current device as the root bridge of spanning tree instance 1 and a secondary root 
bridge of spanning tree instance 2. 

<device> system-view 

[device] stp instance 1 root primary 

[device] stp instance 2 root secondary 

Root bridges are selected according to the bridge priorities of the devices. You can make a specific 
device be selected as a root bridge by setting a lower bridge priority for it. An MSTP-enabled device can 
have different bridge priorities in different spanning tree instances. 

Follow these steps to configure the bridge priority of the current device: 

Enter system view 

— 

Set the bridge priority for the 
current device 

[ instance instance-id ] 

priority priority

 

Required 
The default bridge priority of a 
device is 32,768. 

 

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Once you specify a device as the root bridge or a secondary root bridge by using the stp root 

 or stp root secondary command, the bridge priority of the device cannot be configured 

any more. 

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During the selection of the root bridge, if multiple devices have the same bridge priority, the one 
with the smallest MAC address becomes the root bridge.