Example for Configuring the Rate and Duplex Mode of an Ethernet Interface

Overview

Interfaces can work in the following two duplex modes:

Half-duplex mode: An interface in this mode can send data only when it is not receiving data and, conversely, it can receive data only when it is not sending data. A limit on the transmission distance applies to this mode.
Full-duplex mode: An interface in this mode can send and receive data simultaneously. The maximum throughput in full-duplex mode is theoretically double that in half-duplex mode. There is no limit on the transmission distance in this mode.

You can configure the rate and duplex mode of an Ethernet interface working in either auto-negotiation or non-auto-negotiation mode.

In auto-negotiation mode, interfaces at both ends of a link negotiate the rate and duplex mode. If the negotiation succeeds, the two interfaces use the same duplex mode and rate. The auto-negotiation function takes effect only when both the connected devices support it. If the remote device does not support auto-negotiation or uses a different auto-negotiation mode, the connected interfaces may be Down.
You can configure the local interface to work in non-auto-negotiation mode and manually configure the interface rate and duplex mode in the following situations:

The remote device does not support auto-negotiation.

After auto-negotiation is configured, the local and remote devices cannot communicate.

After auto-negotiation is configured, the physical link between the local and remote devices is connected, but many error packets are generated or packet loss occurs.

Configuration Notes

Usage restrictions
- Ethernet interfaces at both ends of a link must work in the same auto-negotiation mode. Otherwise, the interfaces may be Down.
- When the working rate of a GE electrical interface is 1000 Mbit/s, the interface supports only the full-duplex mode and does not need to negotiate the duplex mode with the remote interface.
- Interfaces at both ends of a link must use the same rate and duplex mode.
- Rate and duplex mode of Ethernet interfaces lists the rate and duplex mode of Ethernet interfaces.

Networking Requirements

As shown in Figure 1, Server1, Server2, and Server3 form a server cluster and connect to GE1/0/1, GE1/0/2, and GE1/0/3 of the Switch respectively. The Switch connects to the Internet through GE1/0/4.

Due to limitations of network adapters on the servers, GE1/0/1, GE1/0/2, and GE1/0/3 can only work in half-duplex mode after negotiating with connected server interfaces. As a result, packet loss occurs when the service traffic volume is high. In addition, the rate is negotiated to 1000 Mbit/s for GE1/0/1, GE1/0/2, and GE1/0/3. When the three servers concurrently send data at the rate of 1000 Mbit/s, the outbound interface GE1/0/4 will be congested. Users require that packet loss and congestion do not occur.

Figure 1 Networking diagram for configuring the rate and duplex mode in non-auto-negotiation mode

Configuration Roadmap

The configuration roadmap is as follows:

Configure the switch interfaces to work in non-auto-negotiation mode to prevent the interface rate from being affected by the network adapter rate on the servers.
Set the duplex mode to full-duplex for the interfaces working in non-auto-negotiation mode to avoid packet loss.
Set the rate to 100 Mbit/s for the interfaces working in non-auto-negotiation mode to avoid congestion on the outbound interface.

Procedure

Create a port group and add GE1/0/1, GE1/0/2, and GE1/0/3 to the port group.

<HUAWEI> system-view
[HUAWEI] sysname Switch
[Switch] port-group portgroup1   //Create a permanent port group portgroup1.
[Switch-port-group-portgroup1] group-member  GE1/0/1 to  GE1/0/3   //Add GE1/0/1,GE1/0/2, and GE1/0/3 to portgroup1.

Configure GE1/0/1, GE1/0/2, and GE1/0/3to work in non-auto-negotiation mode, and set the duplex mode to full-duplex and rate to 100 Mbit/s for these interfaces in a batch.

[Switch-port-group-portgroup1] undo negotiation auto   //Configure interfaces to work in non-auto-negotiation mode in a batch.
[Switch-GigabitEthernet1/0/1] undo negotiation auto
[Switch-GigabitEthernet1/0/2] undo negotiation auto
[Switch-GigabitEthernet1/0/3] undo negotiation auto
[Switch-port-group-portgroup1] duplex full   //Set the duplex mode of the interfaces to full-duplex in a batch.
[Switch-GigabitEthernet1/0/1] duplex full
[Switch-GigabitEthernet1/0/2] duplex full
[Switch-GigabitEthernet1/0/3] duplex full
[Switch-port-group-portgroup1] speed 100   //Set the rate of the interfaces to 100 Mbit/s in a batch.
[Switch-GigabitEthernet1/0/1] speed 100
[Switch-GigabitEthernet1/0/2] speed 100
[Switch-GigabitEthernet1/0/3] speed 100
[Switch-port-group-portgroup1] quit

After a configuration command is executed in the port group view, the device will deliver the configuration to each port in the port group and display the configuration of each port.

Verify the configuration.

Run the display interface gigabitethernet 1/0/1 command in any view to check the interface rate and duplex mode.

[Switch] display interface gigabitethernet 1/0/1
...
Port Mode: COMMON COPPER                                                        
Speed : 100,    Loopback: NONE                                                  
Duplex: FULL,   Negotiation: DISABLE                                            
Mdi   : AUTO,   Flow-control: DISABLE  
...

The command output shows that the interface works in non-negotiation mode, the rate is 100 Mbit/s, and the duplex mode is full-duplex.

Similarly, run the display interface gigabitethernet 1/0/2 and display interface gigabitethernet 1/0/3 commands on GE1/0/2 and GE1/0/3 respectively to check interface working information.

Configuration File

Switch configuration file

#
 sysname Switch
#
interface GigabitEthernet1/0/1
 undo negotiation auto
 speed 100
#
interface GigabitEthernet1/0/2
 undo negotiation auto
 speed 100
#
interface GigabitEthernet1/0/3
 undo negotiation auto
 speed 100
#
port-group portgroup1         
 group-member GigabitEthernet1/0/1       
 group-member GigabitEthernet1/0/2        
 group-member GigabitEthernet1/0/3       
#
return

Rate and duplex mode of Ethernet interfaces

Interface Type	Rate and Duplex mode
MultiGE interfaces	Transmission medium: network cable Rate: 100 Mbit/s, 1000 Mbit/s, 2500 Mbit/s, 5000 Mbit/s, and 10 Gbit/s Duplex mode: When the rate is 100 Mbit/s, full-duplex and half-duplex are supported. When the rate is 1000 Mbit/s, 2500 Mbit/s, 5000 Mbit/s, and 10 Gbit/s, only full-duplex is supported. Auto-negotiation: supported NOTE: Only the S5720-14X-PWH-SI-AC, S5720-28X-PWH-LI-AC, S5720-28X-PWH-LI-ACF, S5732-H24UM2CC, S5732-H48UM2CC, S6720-32C-SI-AC, S6720-32C-SI-DC, S6720-32C-PWH-SI-AC, S6720-52X-PWH-SI, S6720-56C-PWH-SI-AC, S6720-56C-PWH-SI, and S6720-32C-PWH-SI support MultiGE interfaces. You can set the rate of a MultiGE interface to 100 Mbit/s and duplex mode to half-duplex only when the interface works in auto-negotiation mode on the S5720-14X-PWH-SI-AC. This limitation does not apply to MultiGE interfaces on other switches.
FE electrical interfaces	Transmission medium: network cable Rate: 10 Mbit/s and 100 Mbit/s Duplex mode: full-duplex/half-duplex Auto-negotiation: supported
GE electrical interfaces	Transmission medium: network cable Rate: 10 Mbit/s and 100 Mbit/s and 1000 Mbit/s Duplex mode: full-duplex/half-duplex. When the rate is 1000 Mbit/s, only full-duplex is supported. Auto-negotiation: supported NOTE: Physical interfaces of the S5732-H, S6720-EI, S6720-HI, S6720S-EI, S6730-H, S6730S-H, S6730-S, and S6730S-S do not support the half duplex mode. Physical interfaces of the X series cards on a modular switch do not support the half duplex mode.
XGE (10GE) electrical interfaces	Transmission medium: network cable Rate: 10000 Mbit/s Duplex mode: full-duplex Auto-negotiation: supported NOTE: Only the ES5D21X02T01 card of the S5720-EI, the ES5D21X08T00 card of the S5730-HI, S5731-H, and S5731S-H support XGE electrical interfaces.
FE optical interfaces	Transmission medium: FE optical module Rate: 100 Mbit/s Duplex mode: full-duplex Auto-negotiation: not supported
GE optical interfaces	When the transmission medium is an FE optical module: Rate: 100 Mbit/s Duplex mode: full-duplex Auto-negotiation: not supported When the transmission medium is a GE optical module: Rate: 100 Mbit/s and 1000 Mbit/s Duplex mode: full-duplex Auto-negotiation: supported When the transmission medium is a GE copper module: Rate: 10 Mbit/s, 100 Mbit/s, and 1000 Mbit/s Duplex mode: full-duplex/half-duplex. When the rate is 1000 Mbit/s, only full-duplex is supported. Auto-negotiation: supported NOTE: By default, auto-negotiation is enabled on GE optical interfaces and rate auto-negotiation is disabled. You can run the speed auto-negotiation command to enable rate auto-negotiation. After a GE interface on the S5700-SI, S5700-EI, or S5700-HI has a GE copper module installed, the interface can go Up. However, you cannot configure the rate, duplex mode, and auto-negotiation mode on the interface.
XGE (10GE) optical interfaces	When the transmission medium is an XGE optical module: Rate: 10000 Mbit/s Duplex mode: full-duplex Auto-negotiation: not supported When the transmission medium is a GE optical module: Rate: 1000 Mbit/s Duplex mode: full-duplex Auto-negotiation: supported When the transmission medium is a GE copper module: Rate: 100 Mbit/s and 1000 Mbit/s Duplex mode: full-duplex Auto-negotiation: supported When the transmission medium is an XGE/GE optical module: Rate: 1000 Mbit/s and 10000 Mbit/s Duplex mode: full-duplex Auto-negotiation: not supported NOTE: Assume that an XGE optical interface has an XGE/GE optical module installed and the interface rate is set to 1000 Mbit/s by running the speed auto 1000 command. When you run the display interface command on the interface, the command output shows that auto-negotiation is enabled. However, you cannot run the negotiation auto command to configure the auto-negotiation mode. Only modular switches running V200R007 and later versions support XGE/GE optical modules. Only the ES5D21X02T01 card of the S5720-EI and the ES5D21X08S00 card of the S6720-EI and S5730-HI support XGE electrical interfaces. Only XGE optical interfaces on the S6720-EI and S6720S-EI running V200R009 and later versions can automatically negotiate the rate to 100 Mbit/s after having GE copper modules installed.
25GE optical interfaces	When the transmission medium is a 25GE optical module: Rate: 25000 Mbit/s Duplex mode: full-duplex Auto-negotiation mode: not supported When the transmission medium is a high-speed cable: Rate: 25000 Mbit/s Duplex mode: full-duplex Auto-negotiation mode: not supported When the transmission medium is a 25G AOC cable: Rate: 25000 Mbit/s Duplex mode: full-duplex Auto-negotiation mode: supported When the transmission medium is an XGE optical module: Rate: 10000 Mbit/s Duplex mode: full-duplex Auto-negotiation mode: not supported When the transmission medium is a GE optical module: Rate: 1000 Mbit/s Duplex mode: full-duplex Auto-negotiation mode: supported When the transmission medium is a GE copper module: Rate: 100 Mbit/s and 1000 Mbit/s Duplex mode: full-duplex Auto-negotiation mode: supported NOTE: Before installing a GE medium on a 25GE interface, you need to run the port mode ge command to configure the 25GE interface to work at the rate of 1 Gbit/s. When a 25GE interface has an XGE medium installed, the interface can work at the rate of 10 Gbit/s.
40GE optical interfaces	When the transmission medium is a 40GE optical module Rate: 40000 Mbit/s Duplex mode: full-duplex Auto-negotiation: not supported When the transmission medium is a high-speed cable: Rate: 40000 Mbit/s Duplex mode: full-duplex Auto-negotiation: supported NOTE: When you run the display interface command on a 40GE optical interface that has a high-speed cable installed, the command output shows that auto-negotiation is enabled. However, you cannot run the negotiation auto command to configure the auto-negotiation mode.
100GE optical interfaces	When the transmission medium is a 100GE optical module: Rate: 100000 Mbit/s Duplex mode: full-duplex Auto-negotiation: not supported When the transmission medium is a 40GE optical module: Rate: 40000 Mbit/s Duplex mode: full-duplex Auto-negotiation: not supported When the transmission medium is a high-speed cable: Rate: 40000 Mbit/s and 100000 Mbit/s Duplex mode: full-duplex Auto-negotiation: not supported NOTE: Only the S6720-HI, S6730S-H, and S6730-H support 100GE optical interfaces.