3com 3031 Instruccion De Instalación

Logical interface refers to such an interface that can implement data exchange but 
does not physically exist and needs to be set up through configuration. It can be a 
dialer interface, subinterface, LoopBack interface, NULL interface, backup center 
logic-channel or a virtual-template

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This chapter covers the following topics:

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This section introduces the Dialer interface.

As the name implies, a Dialer interface is used for the dialing purpose. The 
dial-supported interfaces available for 3Com Series Routers include synchronous 
serial interface, asynchronous serial interface, and ISDN PRI interface. The software 
has implemented the DCC (Dialup Control Center) function. In addition, the 
software provides the users with two DCC configuration approaches, specifically, 
Circular DCC (C-DCC) and Resource-Shared DCC (RS-DCC), so that the users can 
make full use of the DCC function and various Dialer interfaces. 

See Dialup Configuration module of this manual for details about configuring 
polling DCC and shared DCC, displaying and debugging, configuration example, 
troubleshooting.

This section introduces the Loopback interface.

The TCP/IP suite provisions that the addresses in the 127.0.0.0 segment are 
loopback addresses. The interfaces at such addresses are called loopback 
interfaces. So far as a 3Com Series Router is concerned, the interface Loopback0 is 
the loopback interface for receiving all the packets sent to the local routers. 

In some applications (such as configuring localpeers in an SNA), there is often the 
need to assign a fixed IP address to a local interface without affecting the physical 
interface configuration. To save the scarce IP address resources, this IP address