Configuring Loopback Testing On An Ethernet Interface - HP 5820X series Configuration Manual

Configuring loopback testing on an Ethernet interface

Perform loopback testing on an Ethernet interface to check whether the interface functions properly. The
Ethernet interface cannot forward data packets during the testing. Loopback testing falls into the following
categories:
Internal loopback testing, which tests all on-chip functions related to Ethernet interfaces. As shown in
•
Figure 2, internal loopback testing is performed on Port 1. During the internal loopback testing, the
interface sends out a certain number of test packets, which are looped back to the interface over the
self-loop created on the switching chip
Figure 2 Internal loopback testing
Test packets
Looped packets
External loopback testing, which tests the hardware of Ethernet interfaces. As shown in
•
external loopback testing is performed on Port 1. To perform external loopback testing on an
Ethernet interface, insert a loopback plug into the interface. During the external loopback testing,
the interface sends out a certain number of test packets, which are looped over the plug and back to
the interface. If the interface fails to receive any test packet, the hardware of the interface is faulty.
Figure 3 External loopback testing
To perform loopback testing on an Ethernet interface:
To do...
1. Enter system view
2. Enter Ethernet interface or
ONU interface view
3. Perform loopback testing
On an interface that is physically down, you can only perform internal loopback testing. On an interface
shut down administratively, you can perform neither internal nor external loopback testing.
The speed, duplex, mdi, and shutdown commands are unavailable during loopback testing.
During loopback testing, an Ethernet interface works in full duplex mode. When you disable loopback
testing, the original duplex setting of the interface restores.
Loopback testing is a one-time operation, and is not recorded in the configuration file.
Switch
Switching chip
Port 1 Port 2
Use the command...
system-view
interface interface-type interface-
number
loopback { external | internal }
Remarks
—
—
Required
8
Figure 3,