Command Reference Guide
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Rapid Spanning Tree Protocol / Multiple Spanning Tree 
Protocol configuration 
Command: /cfg/l2/mrst 
[Multiple Spanning Tree Menu] 
 cist - Common and Internal Spanning Tree menu 
 name - Set MST region name 
 rev - Set revision level of this MST region 
 maxhop - Set Maximum Hop Count for MST (4 - 60) 
 mode - Spanning Tree Mode 
 on - Globally turn Multiple Spanning Tree (MSTP/RSTP) ON 
 off - Globally turn Multiple Spanning Tree (MSTP/RSTP) OFF 
 cur - Display current MST parameters 
The switch supports the IEEE 802.1w Rapid Spanning Tree Protocol (RSTP) and IEEE 802.1s Multiple Spanning 
Tree Protocol (MSTP). MSTP allows you to map many VLANs to a small number of spanning tree groups, 
each with its own topology. 
You can configure up to 32 spanning tree groups on the switch. MRST is turned off by default.  
NOTE: When Multiple Spanning Tree is turned on, VLAN 1 is moved from Spanning Tree Group 1 to 
the Common Internal Spanning Tree (CIST). When Multiple Spanning Tree is turned off, VLAN 1 is 
moved back to Spanning Tree Group 1. 
The following table describes the Multiple Spanning Tree Configuration Menu options. 
Table 107  Multiple Spanning Tree Configuration Menu options 
Command 
Description 
cist 
Displays the Common Internal Spanning Tree (CIST) Menu. 
name <1-32 characters> 
Configures a name for the MSTP region. All devices within a MSTP region 
must have the same region name. 
rev <0-65535> 
Configures the revision level for the MSTP region. The revision level is used 
as a numerical identifier for the region. All devices within a MSTP region 
must have the same revision level number. The range is 0-65535. 
maxhop <4-60> 
Configures the maximum number of bridge hops a packet may to 
traverse before it is dropped. The range is from 4 to 60 hops. The default 
is 20. 
mode rstp|mstp 
Selects either Rapid Spanning Tree mode (RSTP) or Multiple Spanning 
Tree mode (MSTP). The default mode is RSTP. 
on 
Globally turn RSTP/MSTP ON. 
Note: When RSTP is turned on, the configuration parameters for STP 
group 1 apply to RSTP 
off 
Globally turn RSTP/MSTP OFF. This is the default. 
cur 
Displays the current RSTP/MSTP configuration. 
NOTE:   
  IEEE 802.1w standard-based RSTP implementation runs on one STG (i.e. same as one spanning 
tree instance) only. As a result, if ‗rstp‘ mode is selected under the /cfg/mrst/mode command, 
then only a single RSTP instance (default for STG 1) is supported for all VLANs, including the 
Default VLAN 1. 
  If multiple spanning tree instances are required, then select ‗mstp‘ mode so that multiple VLANs 
are handled by multiple spanning tree instances, as specified by IEEE 802.1s standard-based 
MSTP implementation. 
  IEEE 802.1s MSTP supports rapid convergence using IEEE 802.1w RSTP. 
  PVST+ does not support rapid convergence in current versions. 










