Configuring MSTP at a glance

The general steps for configuring MSTP via the CLI are:

Configure MSTP global parameters. This involves:

Selecting MSTP as the spanning tree mode:spanning-tree mode mstp
Clearing spanning tree debug counters:

spanning-tree clear-debug-counters
Specifying required parameters for MST region identity:

Region Name:spanning-tree config-name

Region Revision Number:spanning-tree config-revision
Optionally, specifying MSTP parameter changes for region settings:

HP recommends that you leave these parameters at their default settings for most networks. See the Caution below.
- The maximum number of hops before the MSTP BPDU (Bridge Protocol Data Unit) is discarded: spanning-tree max-hops (default: 20)
- Force-Version operation: spanning-tree force-version
- Forward Delay: spanning-tree forward-delay
- Hello Time (if it is the root device): spanning-tree hello-time
- Maximum age to allow for STP packets before discarding: spanning-tree maximum-age
- Device spanning tree priority. Specifies the priority value used along with the switch MAC address to determine which device is root. The lower a priority value, the higher the priority: spanning-tree priority
Enabling SNMP traps:

[no] spanning-tree trap { errant-bpdu | loop-guard | new-root | root-guard }


	CAUTION: When you enable MSTP on the switch, the default MSTP spanning tree configuration settings comply with the values recommended in the IEEE 802.1s Multiple Spanning Tree Protocol (MSTP) standard. Inappropriate changes to these settings can cause severely degraded network performance. Thus HP strongly recommends that changing these default settings be reserved only for experienced network administrators with a full understanding of IEEE 802.1D/w/s standards and operation.

Configure per port parameters. HP recommends that you use the default settings for these parameters and apply changes on a per-port basis only where a non-default setting is clearly indicated by the circumstances of individual links. Other features you might consider include BPDU Filtering or BPDU Protection—these provide additional per-port control over spanning tree operations and security on the switch.
Configure MST instances. Configure one instance for each VLAN group that you want to operate as an active topology within the region to which the switch belongs. When you create the instance, you must include a minimum of one VID. You can add more VIDs later if desired. Use the following command:

spanning-tree instance <n> vlan <vid>

To move a VLAN from one instance to another, first use no spanning-tree instance <n> vlan <vid> to unmap the VLAN from the current instance, then add the VLAN to the other instance. (While the VLAN is unmapped from an MSTI, it is associated with the region's IST instance.)
Configure the priority for each instance with the following command: spanning-tree instance <n> priority <n>
Configure MST instance port parameters. HP recommends that you apply changes on a per-port basis only where a non-default setting is clearly indicated by the circumstances of individual links. For example, you might want to set the path cost value for the ist or for the ports used by a specific MST instance. Use the following command:

spanning-tree instance <ist | 1..4 port-list> path-cost [<auto> | <1..200000000>]

Alternatively, leaving this setting at the default (auto) allows the switch to calculate the path-cost from the link speed.
Enable spanning tree operation on the switch with the spanning-tree command.

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