auto duplex

Function

The auto duplex command configures the duplex mode on an Ethernet electrical interface in auto-negotiation mode.

The undo auto duplex command restores the default duplex mode on an Ethernet electrical interface in auto-negotiation mode.

By default, the duplex mode on an Ethernet electrical interface is negotiated with the peer interface.

Format

auto duplex { half | full }^*

undo auto duplex

Parameters

Parameter	Description	Value
half	Sets the duplex mode on an Ethernet electrical interface in auto-negotiation mode to half-duplex.	-
full	Sets the duplex mode on an Ethernet electrical interface in auto-negotiation mode to full-duplex.	-

Views

Ethernet interface view, MultiGE interface view, GE interface view, port group view

Default Level

2: Configuration level

Usage Guidelines

Usage Scenario

In auto-negotiation mode, interfaces on both ends of a link negotiate their duplex mode. If the negotiated duplex mode is not the required one, you can run the auto duplex command to set the required duplex mode in auto-negotiation mode.

If service traffic volume of enterprise users is high, interfaces at both ends of a link must work in full-duplex mode. Otherwise, packet loss occurs. You can run the auto duplex full command to set the duplex mode to full-duplex. After the auto-negotiation succeeds, the interfaces work in full-duplex mode.
If service traffic volume of enterprise users is low, interfaces at both ends of a link can meet data transmission requirements when they work in half-duplex mode. You can run the auto duplex half command to set the duplex mode to half-duplex. After the auto-negotiation succeeds, the interfaces work in half-duplex mode.

Prerequisites

Run the negotiation auto command to configure Ethernet interface to work in auto-negotiation mode.

Precautions

In auto-negotiation mode, an FE electrical interface negotiates the duplex mode with the peer device on the link.
In auto-negotiation mode, a GE electrical interface that works at a rate of 1000 Mbit/s only supports the full-duplex mode. If the duplex mode is changed to half-duplex, the GE electrical interface works at a maximum rate of 100 Mbit/s.
The GE optical interfaces support the duplex mode configuration when they are equipped with GE copper modules.
The interfaces on both ends of a link must have the same duplex mode.

Example

# Configure Ethernet electrical interface GE0/0/1 in auto-negotiation mode to work in half-duplex mode.

<HUAWEI> system-view
[HUAWEI] interface gigabitethernet 0/0/1
[HUAWEI-GigabitEthernet0/0/1] negotiation auto
[HUAWEI-GigabitEthernet0/0/1] auto duplex half