Advanced Traffic Management Guide K/KA/KB.15.15

Default: 15
Range: 4 - 30
Syntax:
spanning-tree vlan vid-list maximum age 6...40
Sets the maximum age in seconds of received STP information before it is discarded
for specified VLAN(s).
Default: 20
Range: 6 - 40
NOTE: Maximum age must be within the following bounds:
• greater than or equal to 2x (hello-time +1)
• less than or equal to 2x (forward-delay - 1)
Syntax:
spanning-tree vlan vid-list priority 0...15
Sets the switch (bridge) priority for the designated VLAN. The switch compares this
priority with the priorities of other switches on the same VLAN to determine the
RPVST+ root switch for the VLAN. The lower the priority value, the higher the priority.
The switch with the lowest Bridge Identifier on the VLAN is elected as the RPVST+
root switch for that VLAN.
The Bridge Identifier is composed of a configurable Priority (2 bytes) and the switch’s
MAC address (6 bytes). The ability to change the Priority provides flexibility for
determining which switch on the VLAN will be the root for RPVST+, regardless of
its MAC address.
The priority range for an RPVST+ 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:
(priority-multiplier) x 4096.
For example, if you configure “2” as the priority-multiplier on a given RPVST+ switch,
then the Switch Priority setting for the specified VLAN is 8,192.
NOTE: If multiple switches on the same VLAN have the same priority setting, then
the switch with the lowest MAC address becomes the root switch for that VLAN.
Syntax:
[no] spanning-tree vlan vid-list root { primary | secondary }
Specifies the switch as the primary or secondary root bridge for the specified
VLAN(s). Otherwise, by default, the root bridge for each VLAN will be determined
by the lowest MAC address in that topology.
The no form of the command returns the determination of root to the lowest MAC
address criterion.
Configuring per-port per-VLAN spanning tree
Syntax
[no]spanning-tree pathcostrapid-pvst | mstp[8021d | 8021t | proprietary]
Specify a standard to use when calculating the default pathcost.
Default: 8021t
Configuring RPVST+ 133