We always find the similar description from the Huawei switch datasheet, such as: S5720-36C-EI-28S-AC, 28×10/1000Base-X SFP ports, 4x combo 10/100/1000Base-T Ethernet ports, and 4x10G SFP+ ports. Some friends may ask what is combo mean.
Therefore, we will explain to you in this article.
A combo interface consists of a GE electrical interface and a GE optical interface on the panel. The multiplexed electrical and optical interfaces cannot work at the same time. When one interface works, the other interface is disabled. You can use the electrical or optical interface according to networking requirements.
The electrical and optical interfaces share one interface view. When you enable the electrical or optical interface, configure the interface attributes (such as the rate and duplex mode) in the same interface view.
For example, part 3 on the panel shown in the below picture consists of eight combo interfaces, each of which contains a GE electrical interface and a GE optical interface on the panel. The electrical and optical interfaces share one interface view and cannot work concurrently.
There are some usage restrictions of combo ports:
The electrical and optical interfaces of a combo interface are multiplexed. The optical interface cannot have a copper module installed.
When a combo interface works in auto mode and the combo optical interface has an optical module installed, the combo interface works as an optical interface after the device restarts.
You can configure the working mode of the combo interface based on the remote interface type. If the local combo electrical interface is connected to a remote electrical interface, configure the combo interface to work in copper mode. If the local combo optical interface is connected to a remote optical interface, configure the combo interface to work in fiber mode. If the local combo interface is configured to work in a different mode from the remote interface, the two interfaces cannot communicate.
Then, how to configure the Working Mode of a Combo Interface?
As shown in the below picture, PC1, PC2, and PC3 connect to GE0/0/1, GE0/0/2, and GE0/0/3 of the switch respectively. Due to limitations of network adapters on the PCs, the maximum transmission rate of is 100 Mbit/s. The Switch connects to the Internet through the combo interface GE0/0/4. You can configure the working mode of the combo interface based on the remote interface type. In this example, the remote interface at the Internet side is an electrical interface.
- Configure the combo interface GE0/0/4 to work as an electrical interface.
[HUAWEI] sysname Switch
[Switch] interface gigabitethernet 0/0/4
[Switch-GigabitEthernet0/0/4] combo-port copper
- Verify the configuration.
Run the display interface GigabitEthernet 0/0/4 command in any view to check the working mode of the combo interface.
[Switch] display interface gigabitethernet 0/0/4…
Port Mode: FORCE COPPER
Speed : 1000, Loopback: NONE
Duplex: FULL, Negotiation: ENABLE
Mdi : AUTO, Flow-control: DISABLE …
The command output shows that the combo interface works as an electrical interface.
Configure the combo interface to work as an electrical interface. This configuration ensures that the combo interface’s working mode does not change when the transmission medium changes, for example, a GE copper module is installed.