706 CHAPTER 51: CONFIGURING DCC
DCC Configuration
Methods 3Com routers provide two DCC configuration methods: circular DCC, and
resource-shared DCC. With distinguishing features, these two methods are
applicable to different applications. In applications, the participating parties of a
call can flexibly select either method as needed. In other words, one party can
adopt circular DCC while the other party adopt resource-shared DCC to originate
a call.
Circular DCC
Circular DCC has the following features:
■A logical dial (dialer) interface can use the services provided by multiple physical
interfaces (such as Serial0). However, a physical interface can only belong to
one dialer interface. That is, a physical interface can only provide one type of
dial service.
■The user can either bind a physical interface to a dialer interface for inheriting
the DCC parameters by assigning it to a dialer circular group, or directly
configure DCC parameters on the physical interface.
■All the physical interfaces served for the same dialer circular group inherit the
attributes of the same dialer interface.
■Through configuring the dialer route command, a dialer interface can be
associated with multiple dialing destination addresses. Through configuring the
dialer number command, however, a dialer can only be associated with one
dialing destination address.
In addition, all the B channels on an ISDN BRI interface inherit the configuration of
this physical interface, and the dial route will become more complicated as the
network grows and more protocols are supported. Therefore, the application of
circular DCC is restricted due to the static binding between the dialing destination
addresses and the physical interface configuration.
Association between the physical interfaces and dialer interfaces in
circular DCC
Figure 224 Association between the physical interfaces and dialer interfaces in Circular
DCC
As shown in Figure 224, in the case that dialer interfaces are used, a physical
interface can only belong to one dialer interface, but each dialer interface can
Dialer1
Dialer2
Destination A
Destination B
Destination C
Physical
interfaces Dialer
interfaces
Serial0
Bri1
Serial1
Bri0
Serial2
Async0
dialer route
dialer route
dialer number