HP V1910 Switch Series User Manual page 81

Item
MDI
Flow Control
Power Save
Max MAC Count
Description
Set the Medium Dependent Interface (MDI) mode of the port. Two types of
Ethernet cables can be used 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;
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; 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. Therefore, you should configure the MDI mode
depending on the cable types.

HP does not recommend you to use the auto mode. 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.
IMPORTANT:
SFP optical ports do not support this feature.
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 will send 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.
IMPORTANT:
Flow control works only after it is enabled on both the ingress and egress ports.
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 of time, it automatically enters the power save
mode and resumes its normal state upon the arrival of a packet.
By default, auto power down is disabled.
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.
67