Example for Configuring the Rate and Duplex Mode of an Ethernet Interface
Overview
- 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.
- 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.
Networking Requirements
As shown in Figure 3-67, 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.
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