3Com 5500-EI PWR, Справочное руководство

Страница: 258 / 1314

1-30
Link speed Duplex state
Path cost in
802.1d-1998
standard
Path cost in
IEEE 802.1t
standard
Path cost in
private
standard
10 Gbps
Full-duplex
Aggregated link 2 ports
Aggregated link 3 ports
Aggregated link 4 ports
2
1
1
1
200,000
1,000
666
500
2
1
1
1
Normally, when a port operates in full-duplex mode, the corresponding path cost is slightly less than that
when the port operates in half-duplex mode.
When the path cost of an aggregated link is calculated, the 802.1D-1998 standard does not take the
number of the ports on the aggregated link into account, whereas the 802.1T standard does. The
following formula is used to calculate the path cost of an aggregated link:
Path cost = 200,000,000 / link speed,
In this formula, the link speed is the sum of the speeds of the unblocked ports on the aggregated link,
which is measured in 100 Kbps.
You can use the stp cost command to manually configure the path cost of a port in a specified MSTI.
For details, see stp cost .
Examples
# Configure to use the IEEE 802.1D-1998 standard to calculate the default path costs of ports.
<Sysname> system-view
System View: return to User View with Ctrl+Z.
[Sysname] stp pathcost-standard dot1d-1998
# Configure to use the IEEE 802.1t standard to calculate the default path costs of ports.
<Sysname> system-view
System View: return to User View with Ctrl+Z.
[Sysname] stp pathcost-standard dot1t
stp point-to-point
Syntax
z
Ethernet port view:
stp point-to-point { force-true | force-false | auto }
undo stp point-to-point
z
System view:
stp interface interface-list point-to-point { force-true | force-false | auto }
undo stp interface interface-list point-to-point
View
System view, Ethernet port view
Parameters
force-true : Specifies that the link connected to the current Ethernet port is a point-to-point link.