HP 6120XG HP ProCurve Series 6120 Blade Switches Advanced Traffic Management G - Page 133

Priority, show spanning-tree, show running, root-guard, guard, Default: Disabled.

Page 133 highlights

Multiple Instance Spanning-Tree Operation Configuring MSTP Syntax: spanning-tree < port-list > priority < priority-multiplier > MSTP uses this parameter to determine the port(s) to use for forwarding. The port with the lowest priority number has the highest priority for use. The range is 0 to 240, and is configured by specifying a multiplier from 0 - 15. When you specify a priority multiplier of 0 - 15, the actual priority assigned to the switch is: (priority-multiplier) x 16 For example, if you configure "2" as the priority multiplier on a given port, then the actual Priority setting is 32. Thus, after you specify the port priority multiplier, the switch displays the actual port priority (and not the multiplier) in the show spanning-tree or show spanning-tree < port-list > displays. You can view the actual multiplier setting for ports by executing show running and looking for an entry in this format: spanning-tree < port-list > priority < priority-multiplier > For example, configuring port A2 with a priority multiplier of "3" results in this line in the show running output: spanning-tree A2 priority 3 Syntax: spanning-tree < port-list > root-guard MSTP only. When a port is enabled as root-guard, it cannot be selected as the root port even if it receives superior STP BPDUs. The port is assigned an "alternate" port role and enters a blocking state if it receives superior STP BPDUs. (A superior BPDU contains "better" information on the root bridge and/or path cost to the root bridge, which would normally replace the current root bridge selection.) The superior BPDUs received on a port enabled as rootguard are ignored. All other BPDUs are accepted and the external devices may belong to the spanning tree as long as they do not claim to be the Root device. Use this command on MSTP switch ports that are connected to devices located in other administrative network domains to: • Ensure the stability of the core MSTP network topology so that undesired or damaging influences external to the network do not enter. • Protect the configuration of the CIST root bridge that serves as the common root for the entire network. Default: Disabled. 4-29

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4-29
Multiple Instance Spanning-Tree Operation
Configuring MSTP
Syntax:
spanning-tree <
port-list
> priority < priority-multiplier >
MSTP uses this parameter to determine the port(s) to use
for forwarding. The port with the lowest priority number
has the highest priority for use. The range is 0 to 240, and
is configured by specifying a multiplier from 0 - 15. When
you specify a priority multiplier of 0 - 15, the actual
priority assigned to the switch is:
(
priority-multiplier
)
x
16
For example, if you configure “
2
” as the priority multiplier
on a given port, then the actual
Priority
setting is 32.
Thus,
after you specify the port priority multiplier, the switch
displays the actual port priority (and not the multiplier)
in the
show spanning-tree
or
show spanning-tree <
port-list
>
displays.
You can view the actual multiplier setting for ports by
executing
show running
and looking for an entry in this
format:
spanning-tree <
port-list
> priority <
priority-multiplier
>
For example, configuring port A2 with a priority
multiplier of “3” results in this line in the
show running
output:
spanning-tree A2 priority 3
Syntax:
spanning-tree <
port-list
> root-guard
MSTP only. When a port is enabled as
root-guard
, it cannot
be selected as the root port even if it receives superior STP
BPDUs. The port is assigned an “alternate” port role and
enters a blocking state if it receives superior STP BPDUs.
(A superior BPDU contains “better” information on the
root bridge and/or path cost to the root bridge, which would
normally replace the current root bridge selection.)
The superior BPDUs received on a port enabled as
root-
guard
are ignored. All other BPDUs are accepted and the
external devices may belong to the spanning tree as long
as they do not claim to be the Root device.
Use this command on MSTP switch ports that are
connected to devices located in other administrative
network domains to:
Ensure the stability of the core MSTP network topology
so that undesired or damaging influences external to the
network do not enter.
Protect the configuration of the CIST root bridge that
serves as the common root for the entire network.
Default: Disabled.