Service Manual

The range is from 0 to 61440, in increments of 4096.
The default is 32768.
Example of Assigning and Verifying the Root Bridge Priority
By default, the simple conguration shown previously yields the same forwarding path for both MSTIs. The following example shows
how R3 is assigned bridge priority 0 for MSTI 2, which elects a dierent root bridge than MSTI 2.
To view the bridge priority, use the show config command from PROTOCOL MSTP mode.
R3(conf-mstp)#msti 2 bridge-priority 0
1d2h51m: %RPM0-P:RP2 %SPANMGR-5-STP_ROOT_CHANGE: MSTP root changed for instance 2. My
Bridge ID: 0:0001.e809.c24a Old Root: 32768:0001.e806.953e New Root: 0:0001.e809.c24a
R3(conf-mstp)#show config
!
protocol spanning-tree mstp
no disable
MSTI 1 VLAN 100
MSTI 2 VLAN 200,300
MSTI 2 bridge-priority 0
Interoperate with Non-Dell Networking OS Bridges
Dell Networking OS supports only one MSTP region.
A region is a combination of three unique qualities:
• Name is a mnemonic string you assign to the region. The default region name on Dell Networking OS is null.
• Revision is a 2-byte number. The default revision number on Dell Networking OS is 0.
• VLAN-to-instance mapping is the placement of a VLAN in an MSTI.
For a bridge to be in the same MSTP region as another, all three of these qualities must match exactly. The default values for name
and revision match on all Dell Networking OS equipment. If you have non-Dell Networking OS equipment that participates in MSTP,
ensure these values match on all the equipment.
NOTE: Some non-Dell Networking OS equipment may implement a non-null default region name. SFTOS, for example,
uses the Bridge ID, while others may use a MAC address.
Changing the Region Name or Revision
To change the region name or revision, use the following commands.
• Change the region name.
PROTOCOL MSTP mode
name name
• Change the region revision number.
PROTOCOL MSTP mode
revision number
Example of the name Command
To view the current region name and revision, use the show spanning-tree mst configuration command from EXEC
Privilege mode.
Dell(conf-mstp)#name my-mstp-region
Dell(conf-mstp)#exit
Dell(conf)#do show spanning-tree mst config
Multiple Spanning Tree Protocol (MSTP)
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