HP ProCurve Series 3400cl Release Notes page 147

All switches in a region must be configured with the same VLAN ID-to-MSTI mappings and the
same MSTP configuration identifiers (region name and revision number).
■ Flexibility: By preconfiguring identical VLAN ID-to-MSTI mappings on all switches in an MST
region, you can combine switches that support different maximum numbers of VLANs.
■ Network stability: You can reduce the interruptions in network connectivity caused by the
regeneration of spanning trees in the entire network each time a configuration change in VLAN-
to-MSTI mapping is detected on a switch. The negative impact on network performance is
reduced if all newly created VLANs are pre-mapped to the correct MST instances. Later, VLAN
creation and deletion are ignored by MSTP and no interruption in spanning-tree traffic occurs.
Usability: Dynamically learned GVRP VLANs can be mapped to MSTIs and support MSTP load
■
balancing.
Enabling MSTP on the Switch
If you have not enabled MSTP on the switch, you must enable it to use this feature. To enable MSTP,
perform these steps.
1. Enter the command to enable MSTP:
ProCurve(config)# spanning-tree protocol-version mstp
You will see this message:
STP version was changed. To activate the change you must save the
configuration to flash and reboot the device.
2. Save the configuration change to flash.
ProCurve(config)# write mem
3. Reboot the switch.
ProCurve(config)# reload
Device will be rebooted, do you want to continue [y/n]? y
PreConfiguring VLANs in an MST Instance
When you configure an MSTP regional topology, you create multiple spanning-tree instances. Each
MST instance provides a fully connected active topology for a particular set of VLANs.
Each switch in an MSTP region is configured with the following set of common parameters:
Region name (spanning-tree config-name)
■
Region revision number (spanning-tree config-revision)
■
Identical VLAN ID-to-MSTI mapping (spanning-tree instance vlan)
■
Enhancements
Release M.10.65 Enhancements
137