3Com MSR 30 manual Mtu, That the state of the link layer protocol is reported up, Syntax mtu size

158CHAPTER 7: POS INTERFACE CONFIGURATION COMMANDS

n	■	If you enable loopback on a POS interface encapsulated with PPP, it is normal
		that the state of the link layer protocol is reported up.
	■	Loopback and clock slave cannot be set at the same time; otherwise, POS
		interfaces cannot be connected successfully.

Example # Enable internal loopback on interface POS 1/0.

<Sysname> system-view [Sysname] interface pos 1/0 [Sysname-Pos1/0] loopback local

mtu

Syntax mtu size

undo mtu

View POS interface view

Parameter size: Size (in bytes) of the maximum transmission unit (MTU). MTU range and the default value vary with device.

Description Use the mtu command to set the MTU size of the POS interface.

Use the undo mtu command to restore the default.

The MTU setting of the POS interface can affect the assembly and fragmentation of IP packets on it.

In QoS, the length of queues is limited. If MTU on the interface is too small, there is likelihood for a large packet to be fragmented into so many fragments that the queue cannot hold them and as such discard them. To avoid this situation, you can extend the queue length by using the qos fifo queue-lengthcommand in interface view. The default queuing mechanism on the interface is FIFO. For more information on how to configure queuing, refer to “FIFO Queuing Configuration Commands” on page 1809.

Related command: display interface pos.

Example # Set MTU of POS interface 0/0/0 to 1492.

<Sysname> system-view

[Sysname] interface pos 1/0

[Sysname-Pos1/0] mtu 1492

scramble

Syntax scramble

undo scramble