R2511-HP MSR Router Series Interface Command Reference(V5)

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Default
Loopback testing is disabled on Ethernet interfaces.
Views
Ethernet interface view
Default command level
2: System level
Parameters
external: Enables external loopback testing for all on-chip functions related to Ethernet interfaces.
internal: Enables internal loopback testing for the hardware of Ethernet interfaces.
Usage guidelines
Enable loopback testing for troubleshooting purposes, such as identifying an Ethernet problem.
You cannot perform internal or external loopback testing on an administratively down (ADM DOWN)
port. On a physically down (DOWN) port, you can perform only internal loopback testing.
During loopback testing, the speed, duplex, mdi, and shutdown commands are not available. In
addition, the port is operating in full duplex mode, regardless of its duplex configuration. After loopback
testing is disabled, the duplex configuration of the port is restored.
Examples
# Enable internal loopback testing on Ethernet 1/1.
<Sysname> system-view
[Sysname] interface ethernet 1/1
[Sysname-Ethernet1/1] loopback internal
port link-mode
Use port link-mode to change the link mode of an Ethernet interface.
Use undo port link-mode to restore the default.
Syntax
port link-mode { bridge | route }
undo port link-mode
Views
Ethernet interface view
Default command level
2: System level
Parameters
bridge: Specifies the Layer 2 mode.
route: Specifies the Layer 3 mode.
Usage guidelines
Depending on the hardware structure of interface cards, some interfaces can operate only as Layer 2
Ethernet interfaces (in bridge mode), some can operate only as Layer 3 Ethernet interfaces (in route