Foundry NetIron M2404C and M2404F Metro Access Switches
Configuring MSTP (Rev. 03)
Overview
© 2008 Foundry Networks, Inc
Page 32 of 70
By default, the spanning tree port priority is 128.
Command Syntax
device-name
(config-if
UU/SS/PP
)#
mstp
<
instance-id
>
port-priority
<
priority
>
device-name
(config-if
UU/SS/PP
)#
no mstp
<
instance-id
>
port-priority
Argument Description
instance-id
The MST instance ID. The range is <0-15>.
port-priority
<
priority
>
The port priority value, range is 0 (highest priority) to 240 (lowest
priority). The default is 128.
Setting the Path Cost
The
mstp path-cost
command, in Interface Configuration mode, configures the cost for an MST
instance. The
no
form of this command returns the interface to its default settings.
A lower path cost represents higher-speed transmission
To prevent redundant paths, MSTP determines which interface to put in the forwarding state.
MSTP chooses the interface according to the path-cost parameter. You can assign lower-cost
values to preferred interfaces and higher-cost values to the other interfaces. Once you have
assigned the cost values, MSTP will prefer to utilize interfaces with lower path cost when building
the spanning tree. The default value is derived from the link speed of the interface.
Table 4
displays the default value calculated from the media speed of the interface.
Command Syntax
device-name
(config-if
UU/SS/PP
)#
mstp
<
instance-id
>
path-cost
<
cost
>
device-name
(config-if
UU/SS/PP
)#
no mstp
<
instance-id
>
path-cost
Argument Description
instance-id
The MST instance ID, the range is 0 to 15.
cost
The cost value, in the range <1-200000000>.
Setting the Edge Port
The
mstp edge-port
command, in Interface Configuration mode, changes the admin status. The
no
form of this command returns the interface to its default settings.
The
EdgePort
parameter is controlled by the MSTP state machine and the Command Line
Interface (CLI):
•
Admin EdgePort
The admin
EdgePort
parameter can be set by the CLI on a per-Port basis in order to indicate
that a given Port is permitted to transit directly to the Forwarding Port State when a Port
becomes
Designated
.
This functionality is provided in order to permit Bridge Ports that are (administratively) known
to be at the edge of the Bridged LAN to transition to Forwarding without delay.
However, as the presence of a Bridge on a Port that has been marked as an edge Port could
potentially cause a loop in the active topology, it is necessary to qualify the value of the