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

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Examples
# Enable Layer 3 VE interface Virtual-Ethernet 1 to check the destination MAC addresses of incoming IP
packets.
<Sysname> system-view
[Sysname] interface Virtual-Ethernet 1
[Sysname-Virtual-Ethernet1] mac-address valid-check enable
mtu
Use mtu to set the MTU for an Ethernet interface or subinterface.
Use undo mtu to restore the default.
Syntax
mtu size
undo mtu
Default
The MTU of an Ethernet interface or subinterface is 1500 bytes.
Views
Layer 3 Ethernet interface view, Layer 3 Ethernet subinterface view
Default command level
2: System level
Parameters
size: Sets the maximum transmission unit (MTU) in bytes. The value range for this argument varies by
router model.
The following matrix shows the command and router compatibility:
Argument MSR900 MSR93X MSR20-1X MSR20 MSR30 MSR50
MSR100
0
size 46 to 1650 46 to 1650 46 to 1500
46 to
1500
46 to
1650
46 to 1650
46 to
1650
Usage guidelines
As the size of MTU decreases, the number of fragments grows. When setting MTU for an interface, you
should consider QoS queue lengths (for example, the default FIFO queue length is 75) to avoid a too
small MTU causing packet drop in QoS queuing. To achieve the best result, you can tune MTU with the
mtu command or QoS queue lengths with the qos fifo queue-length command. For more information,
see ACL and QoS Command Reference.
Examples
# Set the MTU to 1430 bytes for the Layer 3 Ethernet interface Ethernet 2/0.
<Sysname> system-view
[Sysname] interface ethernet 2/0
[Sysname-Ethernet2/0] mtu 1430
# Set the MTU to 1400 bytes for the Layer 3 Ethernet subinterface Ethernet 2/0.1.
<Sysname> system-view