H3C Technologies H3C SecBlade NetStream Cards - Manual (Page 77)

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Task Remarks
Setting the MTU for an Ethernet interface or
subinterface
Optional
Applicable to Layer 3 Ethernet interfaces and
subinterfaces
Configuring an Ethernet interface to operate in
promiscuous mode Optional
Applicable to Layer 3 Ethernet interfaces
Setting the MTU for an Ethernet interface or subinterface
The value of Maximum Transmission Unit (MTU) affects the fragmentation and re-assembly of IP packets.
Follow these steps to set the MTU for an Ethernet interface or subinterface:
To do… Use the command… Remarks
Enter system view system-view —
Enter Ethernet interface or
subinterface view interface interface-type { interface-number |
interface-number.subnumber }
—
Set the MTU mtu size
Optional
1500 bytes by default.
NOTE:
Due to the QoS queue length limit (for example, the default length of an FIFO queue is 75), too small an
MTU will result in too many fragments, which will be discarded from the QoS queue. You can increase
MTU or QoS queue length properly.
Configuring an Ethernet interface to operate in promiscuous
mode
An Ethernet interface usually receives only packets with matched destination MAC addresses. After you
configure an Ethernet interface to operate in promiscuous mode, however, the interface no longer checks
the MAC addresses in received packets. Rather, it receives all Ethernet packets with correct format. You
may need to configure a network listening port to operate in promiscuous mode.
Follow these steps to configure an Ethernet interface to operate in promiscuous mode:
To do… Use the command… Remarks
Enter system view system-view —
Enter Ethernet interface view
interface interface-type
interface-number
—
Configure the Ethernet interface to
operate in promiscuous mode
promiscuous
Required
By default, an Ethernet interface does
not operate in promiscuous mode.