3Com Router User Manual

DCC Overview707
associate with multiple destination addresses. Each dialer interface can contain 
multiple physical interfaces. In addition, a physical interface does not necessarily 
belong to any dialer interface, and can directly route to one or multiple destination 
addresses.
As shown in Figure 224, physical interfaces Serial1, Bri0 and Serial2 belong to 
Dialer2, and on Dialer2 there are the maps of the string dialed and destination 
addresses.
Resource-Shared DCC
Compared to circular DCC,...

708CHAPTER 51: CONFIGURING DCC
As shown in Figure 225, a physical interface can belong to multiple dialer bundles 
and hence serve multiple dialer interfaces, but each dialer interface associates with 
only one destination address. Each dialer interface can use only one dialer bundle 
that contains multiple physical interfaces having different priorities.
In Figure 225, Dialer2 uses Dialer bundle2, and physical interfaces Bri0, Bri1 and 
Bri2 are members of Dialer bundle2. These physical interfaces have...

Configuring DCC 709
Preparing to Configure 
DCCDetermine the topology of DCC application
■Determine which routers will provide DCC and the relevant communication 
parameters between the routers.
■Determine the interfaces on the routers that provide DCC the functions carried 
out by each router.
■Determine the transmission medium, PSTN or ISDN. 
Prepare the data for DCC configuration
■Identify the interface type (synchronous/asynchronous serial interface, ISDN BRI 
or PRI interface, AM interface, AUX...

710CHAPTER 51: CONFIGURING DCC
Configuring the mode of the physical interface
For a synchronous/asynchronous serial interface, configure the physical interface 
to operate in asynchronous and dial mode if it is connected to an asynchronous 
modem. If the physical interface is connected to a synchronous modem, configure 
the physical interface to operate in synchronous and dial mode. For an ISDN BRI or 
PRI interface, this step can be ignored.
Perform the following configuration in dial interface...

Configuring DCC 711
becomes the same as that on the Dialer interface, which allows the same B 
channel to be used by different link layer protocols, improving flexibility. When the 
B channel is disconnected, the encapsulation protocol on the ISDN interface will 
be automatically restored to PPP.
Associating a DCC dialer ACL with the interface
A properly configured dialer ACL can filter various packets that traverse the dial 
interface. The packets fall into two categories, depending on whether the...

712CHAPTER 51: CONFIGURING DCC
Assure that the commands dialer rule dialer-group and dialer-group 
dialer-group adopt the same dialer-group.
Do not concurrently configure the functional arguments of the protocol-name and 
acl-number for the same 
dialer rule command when configuring a dialer ACL. 
Configuring Circular DCCIf Circular DCC is used, each physical interface can either be directly configured 
with the DCC parameters, or bound to a dialer interface to inherit the DCC 
parameters through a...

Configuring DCC 713
Figure 226   An interface placing a call to a remote end
As shown in this figure, the single local interface interface0 (if0) originates a DCC 
call to the single remote interface if1. Since the call originates at a single remote 
end the dialer string can be configured using the dialer number or dialer route 
command. When the call originates from the single interface at the local end, the 
dialer circular group can be used to configure the DCC. The user can choose to 
configure...

714CHAPTER 51: CONFIGURING DCC
As shown in this figure, the single local interface interface0 (if0) receives a DCC 
call from a single remote interface if1. Since the call is received by a single local 
interface, the dialer circular group can be used to configure DCC. You can choose 
to configure either PAP or CHAP authentication.
Perform the following configuration in dial interface (physical or dialer interface) 
view.
Ta b l e 746   Configure a local interface to receive calls from a remote...

Configuring DCC 715
By default, Circular DCC is enabled on ISDN BRI and PRI interfaces, but disabled on 
other interfaces (serial, asynchronous, AUX, etc.) and the user should manually 
configure the 
dialer enable-circular command. No dialer numbers for calling 
the remote ends are configured by default.
Configuring an interface to receive calls from multiple remote ends
Perform the following configuration steps after the basic DCC configuration is 
implemented. As shown in 
Figure 229, a local...

716CHAPTER 51: CONFIGURING DCC
Figure 230   Multiple interfaces placing calls to multiple remote ends
As shown in Figure 230, the local interfaces interface0 (if0), if1, and if2 originate 
DCC calls to the remote interfaces if1, if2 and if3. For allowing calls to originate 
from multiple remote ends, the user must use the 
dialer route command to 
configure the dialer strings and destination addresses. For the calls to originate 
from multiple interfaces, the dialer circular group must be used to...