Port Loopback Test

A port loopback test is used to check whether the internal forwarding chip controls forwarding on the interface properly.

Figure 1 shows the interface status and symbols of optical and electrical interfaces.

Figure 1 Interface status and symbols of optical and electrical ports

If the switch does not support the MEth port, click Configuration > Basic Services > Interface Settings to access the configuration page.

Choose Configuration > Basic Services > Interface Settings > Service Interface Setting. Select Port Loopback Test, as shown in Figure 2.
Figure 2 Port Loopback Test
Select the interface that you want to configure. Perform either of the following operations as required.
- Click an interface icon to select an interface.
- Drag the mouse to select multiple consecutive interfaces in a batch.
- Click multiple port icons to select these ports, and click a port icon again to deselect the port.
- Click the check box before a front panel name to select all the interfaces on the front panel.
Click Apply. In the dialog box that is displayed, click OK.

The returned information is displayed in Configure Interface, as shown in Figure 3.

Figure 3 Configure Interface

Table 1 describes parameters on the displayed page.

**Table 1** Interface parameter list
Parameter	Description
Interface	Indicates the type and number of the interface where a loopback test is performed.
Management Status	Indicates the management status. Down: indicates that the interface is disabled. Up: indicates that the interface is enabled. Shutdown: indicates that the shutdown command has been run on the interface.
Detection Result	Indicates the loopback test result.