3Com 5500 SI - Switch - Stackable, Configuration Manual

Page: 553 / 686

RSTP Configuration 553
Specify the standard to be followed in Path Cost calculation
The following two standards are currently available on the Switch:
■
dot1d-1998 : The Switch calculates the default Path Cost of a port by the IEEE
802.1D-1998 standard.
■
dot1t : The Switch calculates the default Path Cost of a port by the IEEE 802.1t
standard.
You can specify the intended standard by using the following commands.
Perform the following configuration in System View.
Table 609 Specifying the Standard to be Followed in Path Cost Calculation
By default, the Switch calculates the default Path Cost of a port by the IEEE 802.1t
standard.
Set the Priority of a
Specified Port
The port priority is an important basis to decide if the port can be a root port. In the
calculation of the spanning tree, the port with the highest priority will be selected as
the root assuming all other conditions are the same.
You can use the following command to set the priority of a specified port.
Perform the following configurations in the Ethernet Port View.
Table 610 Set the Priority of a Specified Port
By setting the priority of an Ethernet port, you can put a specified Ethernet port into
the final spanning tree. Generally, the lower the value is set, the higher priority the
port has and the more likely it is for this Ethernet port to be included in the spanning
tree. If all the Ethernet ports of the bridge adopt the same priority parameter value,
then the priority of these ports depends on the Ethernet port index number. Note that
changing the priority of Ethernet port will cause recalculation of the spanning tree.
You can set the port priority at the time when setting up the networking
requirements.
By default, priorities of all the Ethernet ports are 128.
Configure a Specified
Port to be Connected to
Point-to-Point Link
Generally, a point-to-point link connects the Switches.
You can use the following command to configure a specified port to be connected to
a point-to-point link.
Perform the following configurations in the Ethernet Port View.
Operation Command
Specify the standard to be adopted when the
Switch calculates the default Path Cost for the
connected link
stp pathcost-standard {
dot1d-1998 | dot1t }
Restore the default standard to be used
undo stp pathcost-standard
Operation Command
Set the priority of a specified port
stp port priority port_priority
Restore the default priority of the specified port
undo stp port priority