Dell S4048-ON, Configuration Manual

Page: 550 / 1039

Example of the
forward-delay
Parameter
To view the current values for MSTP parameters, use the
show running-config spanning-tree mstp
command from
EXEC privilege mode.
Dell(conf-mstp)#forward-delay 16
Dell(conf-mstp)#exit
Dell(conf)#do show running-config spanning-tree mstp
!
protocol spanning-tree mstp
no disable
name my-mstp-region
MSTI 1 VLAN 100
MSTI 2 VLAN 200-300
forward-delay 16
MSTI 2 bridge-priority 4096
Dell(conf)#
Modifying the Interface Parameters
You can adjust two interface parameters to increase or decrease the probability that a port becomes a forwarding port.
• Port cost is a value that is based on the interface type. The greater the port cost, the less likely the port is selected to be a
forwarding port.
• Port priority influences the likelihood that a port is selected to be a forwarding port in case that several ports have the same
port cost.
The following lists the default values for port cost by interface.
Table 62. Default Values for Port Costs by Interface
Port Cost Default Value
100-Mb/s Ethernet interfaces 200000
1-Gigabit Ethernet interfaces 20000
10-Gigabit Ethernet interfaces 2000
Port Channel with 100 Mb/s Ethernet interfaces 180000
Port Channel with 1-Gigabit Ethernet interfaces 18000
Port Channel with 10-Gigabit Ethernet interfaces 1800
To change the port cost or priority of an interface, use the following commands.
1. Change the port cost of an interface.
INTERFACE mode
spanning-tree msti number cost cost
The range is from 0 to 200000.
For the default, refer to the default values shown in the table..
2. Change the port priority of an interface.
INTERFACE mode
spanning-tree msti number priority priority
The range is from 0 to 240, in increments of 16.
The default is 128 .
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Multiple Spanning Tree Protocol (MSTP)