3Com Router User Manual

8
INTERFACE CONFIGURATION 
O
VERVIEW
This chapter contains information on the following topics:
■Interface Configuration Overview
■Configure Interface
■Display and Debug Interface
Interface 
Configuration 
OverviewThe router interface refers to the part through which the router exchanges data 
and interacts with other devices in the network. It functions to implement data 
exchange between the router and other network devices. 
The 3Com Router supports physical interface and logical interface on the...

108CHAPTER 8: INTERFACE CONFIGURATION OVERVIEW
In the 3Com Router, the command to enter E1/T1 interface view is controller { 
e1 | t1 }, which is different from the command of other interfaces.
Exit the Interface View.
In the interface view, input quit to return to the system view.
Set Interface DescriptionThe 3Com Router has a configuration item of interface description for router’s 
physical interface. Interface description is mainly used to help identifying the 
usage of interface. Please use this...

Display and Debug Interface109
■If a firewall is to be established on this interface, please configure parameters 
about related message filtering or address conversion.
There are lots of parameters to be configured in the interface view. So, this part 
will mainly introduce configurations of some parameters specific to the physical 
interface, and briefly introduce the logical interface definition. Configurations 
about the link layer protocol, network layer protocol, parameter and some special...

110CHAPTER 8: INTERFACE CONFIGURATION OVERVIEW 

9
CONFIGURING LAN INTERFACE
This chapter contains information on the following topics:
■Ethernet Interface Overview
■Configure Ethernet Interface
■Display and Debug Ethernet Interface
■Typical Ethernet Interface Configuration Example
■Troubleshooting
Ethernet Interface 
OverviewEthernet interface of the 3Com Router series comprises fast Ethernet interface.
The conventional Ethernet interface complies with 10BASE-T physical layer 
specifications, working at 10 Mbps and in two modes: full duplex and half...

112CHAPTER 9: CONFIGURING LAN INTERFACE
Ta b l e 85   Enter view of specified Ethernet interface
2Set network protocol address
The 3Com Router supports IP and IPX at Ethernet interface. Therefore, it is 
necessary to configure IP or IPX network address. 
Please use the following commands in Ethernet interface view. 
Ta b l e 86   Set IP address
When an Ethernet interface is configured with two or more IP addresses, use 
keyword sub to identify them.
Please use the ipx enable command in system view, and...

Display and Debug Ethernet Interface113
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....

114CHAPTER 9: CONFIGURING LAN INTERFACE
Typical Ethernet 
Interface 
Configuration 
ExampleI. Networking Requirement
As shown below, the Ethernet interfaces of Routers A is connected to IP networks 
192.168.0.0. The computer in LAN connects to the Internet through Router A. Set 
the MTU of Ethernet interface to 1492 bytes, and set the frame format to 
Ethernet_II.
II. Network Diagram
Figure 45   Networking diagram of Ethernet configuration example
III. Configuration Procedure
1Specify the IP address as...

Troubleshooting115
the party with 100 Mbps configuration shows no connection, while the party with 
10 Mbps connection shows the connection has been established. Furthermore, 
the activity indicator of the physical layer blink quickly and messages can not be 
received or transmitted normally.
On checking the connection of fast Ethernet interface of the 3Com Router series, 
the following prompt information is very helpful. Both these two pieces of 
information are output on the control console when the...

116CHAPTER 9: CONFIGURING LAN INTERFACE
HUB is connected, all the other devices on the whole network segment will show 
serious network collisions), while the party working in full duplex mode shows 
large amount of error messages received, accompanied with serious message 
losses at both parties. In this case, use 
display interfaces ethernet command 
to view the error ratio of transceiving messages of the Ethernet interface. Usually, 
the collision can be observed through the status indicator of the...