Stp Cost - 3Com 5500-EI PWR Reference Manual

# Enable the digest snooping feature on Ethernet 1/0/2 to Ethernet 1/0/4.
<Sysname> system-view
[Sysname] stp interface Ethernet 1/0/2 to Ethernet1/0/4 config-digest-snooping
[Sysname] stp config-digest-snooping

stp cost

Syntax
Ethernet port view:
stp [ instance instance-id ] cost cost
undo stp [ instance instance-id ] cost
System view:
stp interface interface-list [ instance instance-id ] cost cost
undo stp interface interface-list [ instance instance-id ] cost
View
System view, Ethernet port view
Parameters
instance-id: ID of an MSTI ranging from 0 to 16. The value of 0 refers to the CIST.
cost: Path cost to be set for the port. STP uses path costs to indicate the quality of links. A smaller path
cost indicates a higher link quality. The range of the cost argument varies with the standard used for
calculating the default path cost of a port as follows:
With the IEEE 802.1D-1998 standard selected, the path cost of an Ethernet port ranges from 1 to
65535.
With the IEEE 802.1t standard selected, the path cost of an Ethernet port ranges from 1 to
200000000.
With the proprietary standard selected, the path cost of an Ethernet port ranges from 1 to 200000.
interface-list: Ethernet port list. You can specify multiple Ethernet ports by providing this argument in the
form of interface-list = { interface-type interface-number [ to interface-type interface-number ] } &<1-10>,
where &<1-10> means that you can provide up to 10 port indexes/port index ranges for this argument.
Description
Use the stp cost command to set the path cost of the current port in a specified MSTI in ethernet
port view. Use the undo stp cost command to restore the default path cost of the current port in
the specified MSTI in ethernet port view.
Use the stp interface cost command to set the path cost(s) of the specified port(s) in a specified
MSTI in system view. Use the undo stp interface cost command to restore the default value of
the path cost(s) of the specified port(s) in the specified MSTI in system view.
By default, a switch automatically calculates the path costs of a port in different MSTIs based on a
specified standard.
Path cost is an important factor in spanning tree calculation. Setting different path costs for a port in
MSTIs allows VLAN traffic flows to be forwarded along different physical links, thus achieving
VLAN-based load balancing.
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