HP procurve 8100fl series Management And Configuration Manual page 139

Syntax: spanning-tree priority < priority-multiplier >
Every switch running an instance of MSTP has a Bridge Identifier,
which is a unique identifier that helps distinguish this switch from
all others. The switch with the lowest Bridge Identifier is elected as
the root for the tree.
The Bridge Identifier is composed of a configurable Priority
component (2 bytes) and the bridge's MAC address (6 bytes). The
ability to change the Priority component provides flexibility in
determining which switch will be the root for the tree, regardless of
its MAC address.
This command sets the switch (bridge) priority for the designated
region in which the switch resides. The switch compares this priority
with the priorities of other switches in the same region to determine
the root switch for the region. The lowest priority value determines
the root. (If there is only one switch in the region, then that switch is
the root switch for the region.) The root bridge in a region provides
the path to connected regions for the traffic in VLANs assigned to the
region's IST instance. (Traffic in VLANs assigned to a numbered STP
instance in a given region moves to other regions through the root
switch for that instance.)
The priority range for an MSTP switch is 0-61440. However, this
command specifies the priority as a multiplier (0 - 15) of 4096. That
is, when you specify a priority multiplier value of 0 - 15, the actual
priority assigned to the switch is:
For example, if you configure "2" as the priority-multiplier on a given
MSTP switch, then the Switch Priority setting is 8,192.
Note: If multiple switches in the same MST region have the same
priority setting, then the switch with the lowest MAC address becomes
the root switch for that region.
Syntax: [no] member-vlan <vid>
This command is used within the spanning-tree instance
configuration context and moves the VLANs you specify from the IST
to the MSTI. You can create up to 16 MSTIs in a region. The no form
of the command deletes the specified VLAN or if no VLANs are
specified, the no form of the command deletes the specified MSTI.
(Removing a VLAN from an MSTI returns the VLAN to the IST
instance, where it can either remain or be re-assigned to another
MSTI configured in the region.)
The no form of the command deletes the specified VLAN, or if no
VLANs are specified, the no form of the command deletes the specified
MSTI.
Note: At least one VLAN must be mapped to a MSTI when you create
it. (A VLAN cannot be mapped to more than one instance at a time.)
When a VLAN is unmapped from an MSTI, it is associated with the
Internal Spanning Tree (IST) instance. VLAN 1 is always associated
with the IST instance and cannot be mapped to a new MSTI.
(priority-multiplier) x 4096
Spanning-Tree Operation
Configuring MSTP
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