Redundancy
RM Web L3E
Release
 
6.0
 
07/2010
7.5
 
Spanning Tree
185
Multiple  Spanning  Tree  Protocol  (MSTP)
MSTP is a further development of the Rapid Spanning Tree Protocol used to 
increase the benefits of VLANs. MSTP allows you to define multiple groups 
of VLANs, and to configure a separate Spanning Tree Instance for each 
group. This Spanning Tree Instance prevents loops within the related VLAN 
group and provides redundancy in the case of a failure.  
Additionally, MSTP enables existing connections to be used more efficiently 
in normal operation. For example, MSTP can set a connection between 
2 bridges to the “discarding” state for a certain VLAN group, while 
simultaneously operating the same connection for another VLAN group in the 
“forwarding” state. MSTP thus enables you to use your resources more 
efficiently.
Note: The following text uses the term Spanning Tree (STP) to describe 
settings or behavior that applies to STP, RSTP or MSTP.
7.5.1 Global
With this dialog you can:
X switch the Spanning Tree Protocol on/off and select the RSTP or MSTP 
protocol version
X display bridge-related information on the Spanning Tree Protocol
X configure bridge-related parameters of the Spanning Tree Protocol
X set bridge-related additional functions
X display the parameters of the root bridge and
X display bridge-related topology information.
Note:  Rapid Spanning Tree is activated on the device by default, and it 
automatically begins exploding the existing topology into a tree structure. If 
you have deactivated RSTP on individual devices, you avoid loops during the 
configuration phase.