Influence Mstp Root Selection; Interoperate With Non-Ftos Bridges - Dell Force10 S4810P Configuration Manual

Influence MSTP Root Selection

MSTP determines the root bridge, but you can assign one bridge a lower priority to increase the probability
that it will become the root bridge.
To change the bridge priority:
Task
Assign a number as the bridge priority. A lower number
increases the probability that the bridge becomes the root
bridge.
Range: 0 to 61440, in increments of 4096
Default: 32768
The simple configuration
Figure 32-5, shows how R3 is assigned bridge priority 0 for MSTI 2, which elects a different root bridge
than MSTI 2. View the bridge priority using the command
also shown in Figure
Figure 32-5. Changing the Bridge Priority
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
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-FTOS Bridges

FTOS 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 FTOS is null.
• Revision is a two-byte number. The default revision number on FTOS is 0.
• VLAN-to-instance mapping is the placement of a VLAN in an MSTI.
Figure 32-1 by default yields the same forwarding path for both MSTIs.
32-5.
Command Syntax
msti instance bridge-priority priority
from PROTOCOL MSTP mode,
show config
New Root: 0:0001.e809.c24a
Multiple Spanning Tree Protocol (MSTP) | 697
Command Mode
PROTOCOL MSTP