R3303-HP HSR6800 Routers Interface Command Reference

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Usage guidelines
Loopback is intended for test use. Disable loopback in other cases.
Examples
# Enable loopback on interface Serial 1/0/0.
<Sysname> system-view
[Sysname] interface serial 1/0/0
[Sysname-Serial1/0/0] loopback
mtu
Use mtu to set the MTU of an interface.
Use undo mtu to restore the default.
Syntax
mtu size
undo mtu
Default
The MTU of an interface is 1500 bytes.
Views
Serial interface view
Default command level
2: System level
Parameters
size: Specifies an MTU value. The value range is 128 to 9600 bytes. The maximum MTU configurable on
an interface might be lower than 9600 bytes depending on the device model, interface module model,
and interface type.
Usage guidelines
For the MTU setting to take effect, execute the shutdown command, and then the undo shutdown
command.
The MTU setting affects IP packets assembly and fragmentation on an interface. The lower the MTU, the
more segments a large packet has. The risk of packet losses increases in a congestion condition, because
the risk of QoS queue length being exceeded increases.
To avoid the situation, you can increase the QoS queue length. The default queuing mechanism is FIFO
on an interface. You can use the qos fifo queue-length command to increase the queue length for the
interface. For more information, see ACL and QoS Configuration Guide.
Examples
# Set the MTU of interface Serial 1/0/0 to 1200 bytes.
<Sysname> system-view
[Sysname] interface serial 1/0/0
[Sysname-Serial1/0/0] mtu 1200