NOTE:
•
Among the auto-negotiation-capable Layer 2 ports, the FE copper ports support only the
10
and
100
keywords, the GE copper ports support all keywords, and the GE fiber ports support only the
100
and
1000
keywords.
•
The
speed
and
speed auto
commands supersede each other, and whichever is configured last takes
effect.
Configuring flow control on an Ethernet interface
You can avoid packet drops on a link by enabling flow control at both ends of the link. The flow control
function enables the receiving end to require the sending end to suspend sending packets when
congestion occurs. An interface implements flow control by sending and receiving common pause
frames.
Follow these steps to enable flow control on an interface:
To do…
Use the command…
Remarks
Enter system view
system-view
—
Enter Ethernet interface view
interface
interface-type
interface-number
—
Enable flow control
flow-control
Required
By default, flow control is disabled
on an interface.
Configuring link change suppression on an Ethernet interface
An Ethernet interface has two physical link states: up and down. Each time the physical link of an
interface goes up or comes down, the physical layer reports the change to the upper layers, and the
upper layers handle the change, resulting in increased overhead.
To prevent physical link flapping from affecting system performance, configure link change suppression
to delay the reporting of physical link state changes. When the delay expires, the interface reports any
detected change.
Link change suppression does not suppress administrative up or down events. When you shut down or
bring up an interface by using the
shutdown
or
undo shutdown
command, the interface reports the event
to the upper layers immediately.
On an A3100 v2 switch, you can configure link-down event suppression or link-up event suppression, but
not both.
Link-down event suppression enables an interface to suppress link-down events and start a delay timer
each time the physical link goes down. During this delay, the interface does not report the link-down
event, and the
display interface brief
or
display interface
command displays the interface state as UP. If
the physical link is still down when the timer expires, the interface reports the link-down event to the upper
layers.
Link-up event suppression enables an interface to suppress link-up events and start a delay timer each
time the physical link goes up. During this delay, the interface does not report the link-up event, and the
display interface brief
or
display interface
command displays the interface state as DOWN. If the
physical link is still up when the timer expires, the interface reports the link-up event to the upper layers.
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