3Com Switch 7750 Series
Command Reference Guide – MSTP Chapter 1 MSTP Configuration Commands
1-34
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 calculating the path cost of an aggregated link, 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 / link transmission speed,
Where the link transmission speed is the sum of the speeds of the unblocked ports on
the aggregated link, which is measured in 100 Kbps.
Example
# Configure to use the IEEE 802.1D-1998 standard to calculate the default path costs
of ports.
<3Com> system-view
System View: return to User View with Ctrl+Z.
[3Com] stp pathcost-standard dot1d-1998
# Configure to use the IEEE 802.1t standard to calculate the default path costs of ports.
<3Com> system-view
System View: return to User View with Ctrl+Z.
[3Com] stp pathcost-standard dot1t
1.1.32 stp point-to-point Syntax
stp point-to-point { force-true | force-false | auto }
undo stp point-to-point
View
Ethernet port view
Parameter
force-true: Specifies that the link connected to the current Ethernet port is a
point-to-point link.
force-false: Specifies that the link connected to the current Ethernet port is not a
point-to-point link.
auto: Specifies to automatically determine whether or not the link connected to the
current Ethernet port is a point-to-point link.