Configuring The Priority Of A Port - 3Com 5500-SI Configuration Manual

Configuring the Priority
of a Port
Configuration example (A)
Configure the path cost of port Ethernet1/0/1 in spanning tree instance 1 to be
2,000.
1 Configure in system view.
<S5500> system-view
System View: return to User View with Ctrl+Z.
[S5500] stp interface ethernet1/0/1 instance 1 cost 2000
2 Configure in Ethernet port view.
<S5500> system-view
System View: return to User View with Ctrl+Z.
[S5500] interface ethernet1/0/1
[S5500-Ethernet1/0/1] stp instance 1 cost 2000
Configuration example (B)
Configure to make MSTP automatically calculate the path cost of port Ethernet1/0/1
in spanning tree instance 1 by using the IEEE 802.1D-1998 standard.
1 Configure in system view.
<S5500> system-view
System View: return to User View with Ctrl+Z.
[S5500] undo stp interface ethernet1/0/1 instance 1 cost
[S5500] stp pathcost-standard dot1d-1998
2 Configure in Ethernet port view.
<S5500> system-view
System View: return to User View with Ctrl+Z.
[S5500] interface ethernet1/0/1
[S5500-Ethernet1/0/1] undo stp instance 1 cost
[S5500-Ethernet1/0/1] quit
[S5500] stp pathcost-standard dot1d-1998
Port priority is an important criterion for determining the root port. With other
parameters being the same, the port with the highest priority becomes the root port.
A port on an MSTP-enabled switch can have different port priorities and play different
roles in different spanning tree instances. This enables packets of different VLANs to
be forwarded along different physical paths, implementing VLAN-based load
balancing.
You can configure port priorities in the following two ways.
Configuring the priorities of ports in system view
Table 164 Configure the priorities of specified ports in system view
Operation
Enter system view
Configure the port priorities
of specified ports
Command
system-view
stp interface interface-list
instance instance-id port
priority priority
Leaf Node Configuration 183
Description
-
Required
By default, all Ethernet ports of a
switch have the same priority,
namely 128.