3Com 2928 User Guide - Page 107

1 Loopback Test Configuration Overview You can check whether an Ethernet port works normally by performing the Ethernet port loopback test, during which the port cannot forward data packets normally. Ethernet port loopback test can be an internal loopback test or an external loopback test. z In an internal loopback test, self loop is established in the switching chip to check whether there is a chip failure related to the functions of the port. z In an external loopback test, a loopback plug is used on the port. Packets forwarded by the port will be received by itself through the loopback plug. The external loopback test can be used to check whether there is a hardware failure on the port. Loopback Operation Select Device > Loopback from the navigation tree to enter the loopback test configuration page, as shown in Figure 1-1. Figure 1-1 Loopback test configuration page Table 1-1 describes the loopback test configuration items. Table 1-1 Loopback test configuration items Item Description Testing type External Internal Sets the loopback test type, which can be External or Internal. 1-1