This article explains how Multiple Spanning Tree Protocol (MSTP) is implemented on Dell Networking Force10 Switches.
Objective
Table of Contents
Overview
Enable MSTP
MSTP is not enabled by default. To enable MSTP globally, use the following commands.
When you enable MSTP, all physical, VLAN, and port-channel interfaces that are enabled and in Layer 2 mode are automatically part of the MSTI 0.
You can configure 64 MSTIs including the default instance 0 (CIST).
Enter PROTOCOL MSTP mode. CONFIGURATION mode
console(conf) # protocol spanning-tree mstp
Enable MSTP. PROTOCOL MSTP mode
console(config-mstp) # no disable
Creating Multiple Spanning Tree Instances
To create multiple spanning tree instances, use the following command.
A single MSTI provides no more benefit than RSTP. To take full advantage of MSTP, create multiple MSTIs and map VLANs to them.
console(conf) # protocol spanning-tree mstp
console(conf-mstp) # msti 1 vlan 100
console(conf-mstp) # msti 2 vlan 200-300
console(conf-mstp) # show config
!
protocol spanning-tree mstp
no disable
MSTI 1 VLAN 100
MSTI 2 VLAN 200-300
Set Root Priorities
MSTP determines the root bridge, but you can assign one bridge a lower priority to increase the probability that it becomes the root bridge.
To change the bridge priority, use the following command.
PROTOCOL MSTP mode
console(conf-mstp) # msti 1 bridge-priority 4096
A lower number sets the higher priority so that the bridge becomes the root bridge. The range is from 0 to 61440, in increments of 4096. The default is 32768.
Enable Edgeport
The EdgePort feature enables interfaces to begin forwarding traffic approximately 30 seconds sooner.
In this mode an interface forwards frames by default until it receives a BPDU that indicates that it should behave otherwise; it does not go through the Learning and Listening states.
console(conf) # interface te 0/1
console(conf-if-te 0/1) # spanning-tree mstp edge-port
Verify Configuration
console # show spanning-tree mst config
MST region name: Dell
Revision: 0
MSTI VID
1 100
2 200-300