3Com 3C13636 Configuration Manual page 1403

3Com Router 3000 Ethernet Family
Configuration Guide
flexibly select either method as needed. In other words, one end can adopt C-DCC
while the other end adopts RS-DCC to originate a call.
I. C-DCC
1) C-DCC is powerful and popular while relatively lacks flexibility and
features of C-DCC are:
A logical dial (dialer) interface can use the services provided by multiple physical
interfaces (such as Serial0/0/0). 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 through 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 interface can only be associated with
one dialing destination address.
In addition, all the B channels on an ISDN BRI interface will 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 C-DCC is
restricted due to the static binding between the dialing destination addresses and the
physical interface configuration.
2) Association between the physical interfaces and dialer interfaces in C-DCC
Physical
interface
Serial 0/0/0
Bri 1/0/0
Serial 1/0/0
Bri 0/0/0
Serial 2/0/0
Async 0/0/0
Figure 1-1 Association between the physical interfaces and dialer interfaces in C-DCC
As shown in Figure 1-1, in the case that dialer interfaces are used, a physical interface
can only belong to one dialer interface, but each dialer interface can associate with
multiple destination addresses. Each dialer interface can contain multiple physical
Dialer
interface
Dialer number
Dialer 1
Dialer route
Dialer 2
Dialer route
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1-2
Chapter 1 DCC Configuration
scalability
Destination A
Destination B
Destination C
. The