H3C Technologies H3C WX5500E Series Access Controllers - Manual (Page 59)

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Item Description
MDI
Set the MDI mode of the port.
You can use two types of Ethernet cables to connect Ethernet devices: crossover cable and
straight-through cable. To accommodate these two types of cables, an Ethernet port can
operate in one of the following three MDI modes: across, normal, and auto.
An Ethernet port is composed of eight pins. By default, each pin has its particular role. For
example, pin 1 and pin 2 are used for transmitting signals, and pin 3 and pin 6 are used
for receiving signals. You can change the pin roles by setting the MDI mode.
• For an Ethernet port in across mode, pin 1 and pin 2 are used for transmitting signals.
and pin 3 and pin 6 are used for receiving signals. The pin roles are not changed.
• For an Ethernet port in auto mode, the pin roles are decided through auto negotiation.
• For an Ethernet port in normal mode, the pin roles are changed. Pin 1 and pin 2 are
used for receiving signals. Pin 3 and pin 6 are used for transmitting signals.
To enable normal communication, you must connect the local transmit pins to the remote
receive pins. Configure the MDI mode depending on the cable types.
• Normally, the auto mode is recommended. The other two modes are used only when
the device cannot determine the cable type.
• When straight-through cables are used, the local MDI mode must be different from the
remote MDI mode.
• When crossover cables are used, the local MDI mode must be the same as the remote
MDI mode, or the MDI mode of at least one end must be set to auto.
Flow Control
Enable or disable flow control on the port.
With flow control enabled at both sides, when traffic congestion occurs on the ingress
port, the ingress port sends a Pause frame notifying the egress port to temporarily suspend
the sending of packets. The egress port is expected to stop sending any new packet when
it receives the Pause frame. In this way, flow control helps to avoid dropping of packets.
Flow control works only after it is enabled on both the ingress and egress ports.
Jumbo Frame
Forwarding
Enable or disable the forwarding of jumbo frames.
Power Save
Enable or disable auto power down on the port.
With auto power down enabled, when an Ethernet port does not receive any packet for
a certain period, it automatically enters the power save mode and resumes its normal state
upon the arrival of a packet.
Max MAC Count
Set the MAC learning limit on the port. Available options include:
• User Defined—Select this option to set the limit manually.
• No Limited—Select this option to set no limit.