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loopback
Syntax loopback
undo loopback
View Serial interface view, AUX interface view, AM interface view
Parameter None
Description Use the
loopback command to enable internal loopback on the serial interface.
Use the undo loopback command to restore the default.
By default, loopback is disabled.
Loopback is intended for test use. Disable it otherwise.
Example # Enable internal loopback on interface Serial 2/0.
<Sysname> system-view
[Sysname] interface serial 2/0
[Sysname-Serial1/0] loopback
mtu (on serial interfaces)
Syntax mtu size
undo mtu
View Serial interface view, AUX interface view, AM interface view, USB interface view
Parameter size: Maximum transmission unit (MTU) to be set for a serial interface, in the range
128 to 1,500 (in bytes).
Description Use the
mtu command to set the MTU for a serial interface.
Use the undo mtu command to restore the default.
By default, the MTU of a serial interface is 1,500 bytes.
Due to the length of Qos queue, a packet may be discarded if the MTU is relatively
small and the packet is segmented into too many fragments. You can increase the
Qos queue length to avoid this situation. To do so, use the qos fifo queue-length
command in interface view. For details, refer to the “FIFO Queuing Configuration
Commands” on page 1809.
The MTU setting can affect IP packets assembly and fragmentation on the
interface.
