H3C S7500E Series Command Reference Manual

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H3C S7500E Series Command Reference Manual Manual pdf 41 page image

1-26loopbackSyntaxloopback { external | internal }undo loopbackViewEthernet interface viewDefault Level2: System levelParametersexternal: Enables external loopback testing on the Ethernet port. External loopback testing is alsocalled remote loopback testing.internal: Enables internal loopback testing on the Ethernet port.DescriptionUse the loopback command to enable loopback testing on an Ethernet interface.Use the undo loopback command to disable loopback testing on an Ethernet interface.By default, loopback testing is disabled on Ethernet interfaces.z You enable loopback testing for troubleshooting purposes, such as identifying an Ethernetproblem.z You can perform neither internal nor external loopback testing on an administratively down (ADMDOWN) port. On a physically down (DOWN) port, you can perform only internal loopback testing.z During loopback testing, the speed, duplex, mdi, and shutdown commands are not available. Inaddition, the port is operating in full duplex mode, regardless of its duplex configuration. Afterloopback testing is disabled, the duplex configuration of the port restores.Examples# Enable internal loopback testing on port GigabitEthernet 2/0/1. system-view[Sysname] interface gigabitethernet 2/0/1[Sysname-GigabitEthernet2/0/1] loopback internalloopback-detection actionSyntaxloopback-detection action { no-learning | semi-block | shutdown }undo loopback-detection actionViewEthernet interface view, port group viewDefault Level2: System level