3com 3031 Instruccion De Instalación

As a Null interface drops all the packets reaching it, it provides you with a means 
of packet filtering. You can simply make the configuration to send all the 
undesired network traffic to the interface Null0 rather than bothering yourself 
with the complex work of configuring ACL (Access Control List).

 For example, you can drop all the packets destined to the segment 192.101.0.0 
by configuring the static routing command 

.

This section describes the configuration of a subinterface.

Introducing the concept of subinterface into the software allows the users of 
3Com Series Routers of high flexibility as the users can configure multiple 
subinterfaces on a single physical interface in this case.

Subinterfaces are the logical virtual interfaces configured on a physical interface. 
They share the physical layer parameters of the physical interface and can be 
separately configured with the link layer and network layer parameters. As they 
can be associated with a physical interface, they are often called “subinterfaces”.

On 3Com Series Routers, the subinterface-supported physical interfaces include:

■

Ethernet interface. Without VLAN ID, an Ethernet subinterface can only 
support IPX. Assigned with a VLAN ID, the subinterface can support both IPX 
and IP.

■

WAN interface encapsulated with FR. The subinterfaces of such a WAN 
interface can support both IP and IPX.

■

WAN interface encapsulated with X.25. The subinterfaces of such a WAN 
interface can support both IP and IPX.

Perform the following tasks to configure a subinterface:

■

Configure Ethernet subinterface

■

Configure a subinterface on a WAN interface encapsulated with FR

■

Configure a subinterface on a WAN interface encapsulated with X.25

1 Create/Delete an Ethernet subinterface

Perform the following in the System View.

If the Ethernet subinterface (the same as sub-number) that you intend to create 
has existed, the system will directly enter the view of the subinterface. Otherwise, 

Table 249   Creating/Deleting an Ethernet subinterface

Create an Ethernet subinterface and 
enter the Ethernet subinterface view

Delete the specified Ethernet 
subinterface