3Com 10014299 manual Display and Debug, Select work mode of Ethernet interface

Display and Debug Ethernet Interface 113

Recover MTU default value

undo mtu

Value ranges and default values of MTUs with different link layer protocol are different. When Ethernet_II frame format is adopted, MTU value range will be 46-1500 bytes with the default value as 1500 bytes, and when Ethernet_SNAP frame format is adopted, MTU value range will be 46-1492 bytes with default value 1492 bytes.

5Select work rate of fast Ethernet interface

As described before, the fast Ethernet interface can work at rates of 10Mbps and 100Mbps. Therefore, it is possible to select interface working rate with following command in Ethernet interface view.

Table 90 Select working rate of fast Ethernet interface

Operation	Command
Select working rate of fast Ethernet interface	speed { 100 10 negotiation }

The default is “negotiation”, i.e. the system automatically chooses an optimum working rate. The user can also specify the interface working rate. But the rate specified must be the same as that of the actually connected network.

6 Select work mode of Ethernet interface

’s Ethernet interface should work in half duplex mode when connected with HUB and in full duplex mode when connected with LAN Switch. Therefore, it is possible to select working mode with the following command in Ethernet interface view.

Table 91 Select working mode of Ethernet interface

Operation	Command
Select working mode of Ethernet interface	duplex	{ negotiation full
	half }

The default is “negotiation”, i.e. the system automatically chooses an optimum working mode.

7 Enable or disable internal loopback and external loopback

When performing special functionality test on Ethernet interface, it needs to be set as internal loopback and external loopback sometimes. Therefore, it is possible to enable internal loopback and external loopback with the following commands in Ethernet interface view.

Table 92 Enable or disable internal loopback and external loopback

Operation	Command
Enable internal loopback and external loopback	loopback
Disable internal loopback and external loopback	undo loopback

The default is to disable both internal loopback and external loopback.

Display and Debug	The following command can be used to view the state of Ethernet interface in all
Ethernet Interface	views, so that the specified Ethernet interface can be displayed and debugged.
	Table 93 Display the state of specified Ethernet interface
		Operation	Command
		Display the state of specified Ethernet	display interfaces ethernet
		interface	number