3Com Router User Manual

							Configuring DCC 717
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. In addition, when no dialer 
interface is created, the physical interface does not belong to any dialer circular 
group, and the default priority is assigned to physical interface 1, and this is added 
to a dialer circular group.
Configuring multiple interfaces to receive calls from multiple remote ends
Perform the following configuration steps after the basic DCC configuration is 
implemented. As shown in 
Figure 231, multiple local interfaces receive calls from 
multiple remote ends (the picture components of inverse color represent the 
routers irrelevant with the networking):
Figure 231   Multiple interfaces receiving calls from multiple remote ends
As shown in Figure 231, the local interfaces interface1 (if0), if1, and if2 receive 
DCC calls from the remote interfaces if1, if2 and if3. Since the local end is multiple 
interfaces, the dialer circular group must be used to configure DCC. The user can 
select to configure either PAP or CHAP authentication.
Use the local-user password command to configure the user name and 
password permitted to dial in system view, and perform other configurations in 
dial interface (physical or dialer interface) view.
Ta b l e 750   Configure Multiple Local Interfaces to Receive Calls From Multiple Remote Ends
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. If no dialer interface is 
created then by default, the physical interfaces do not belong to any dialer circular 
group.
OperationCommand
Enable Circular DCCdialer enable-circular
Create a dialer interface and enter the dialer 
interface viewinterface dialer number
Delete the existing configuration of the dialer 
interfaceundo interface dialer number
Add a physical interface to the specified dialer 
circular groupdialer circular-group number
Delete the physical interface from the specified 
dialer circular groupundo dialer circular-group
Local end
(Multiple interface)Remote end B
Single/Multiple interface(s)Remote end A
Single/Multiple interface(s)
Remote end C
Single/Multiple interface(s) if0
if1
if2if1
if2
if3
if4 Router
Router
Router
Router 
						

							718CHAPTER 51: CONFIGURING DCC
Configuring 
Resource-Shared DCCEach RS-attribute set consists of a dialer interface, the attributes of the interface, 
and a dialer bundle. Specifically, 
■Only one dialer number can be defined for a dialer interface. Since this dialer 
number has its own dial attributes set, all the calls originated by dialing this 
number can use the same DCC attribute parameters (such as dialing rate).
■Each dialer interface can use only one dialer bundle, which contains multiple 
physical interfaces of different priorities. However, each physical interface can 
be used by different dialer bundles. For an ISDN BRI or PRI interface, the user 
can set the number of B channels that will be used through setting dialer 
bundles.
■All the calls aimed to the same destination segment use the same RS-DCC set.
Due to the separation between logical and physical interface configurations, 
resource-shared DCC are applicable for more network topologies and DCC dialing 
requirements, especially for the situation in which multiple interface groups 
originate calls to multiple remote interfaces.
Figure 232   Multiple interfaces placing calls to multiple remote ends in the 
Resource-Shared DCC implementation
As shown in Figure 232, different dialer interfaces are used for placing calls to 
different remote ends. (That is, one dialer interface only corresponds to one 
remote end.) Through adding a physical interface to the bundle of some dialer 
interfaces, the interface can originate calls as needed.
When configure resource-shared DCC based on RS-attribute set, a physical 
interface only needs to be configured with the link layer protocol and the number 
of the dialer bundle to which the physical interface belongs.
When configuring resource-shared DCC based on RS-attribute set, a RS-attribute 
set is unable to apply its attributes to the physical interfaces in a dialer bundle. (For 
example, it is unable to apply PPP authentication to the physical interfaces). In 
other words, the physical interfaces do not inherit the authentication attribute of 
the RS-attribute set. Therefore, authentication of the related information must be 
configured on the physical interfaces at the receiving end.
Resource-Shared DCC configuration includes:
■Enabing Resource-Shared DCC
■Configuring the dialer interface and dialer number
■Creating dialer bundle and assigning physical interfaces to it
Router
Remote end C
Single/Multiple interface(s) Local end
(multiple interfaces)
Remote end B
Single/Multiple interface(s)Remote end A
Single/Multiple interface(s) if1
if2
if3
Physical interface
groups
Call
Remote end A
Call
Remote end B
Call
Remote end CDialer0
Dialer1
Dialer2
Router
Router
Router 
						

							Configuring DCC 719
■Configuring dialing authentication for resource-shared DCC
Enabing Resource-Shared DCC
Before enabling the resource-shared DCC, please use the command undo dialer 
enable-circular 
to disable circular DCC first, then enable the resource-shared 
DCC by using 
dialer bundle command.
Perform the following configuration in dialer interface view.
Ta b l e 751   Enable Resource-Shared DCC
By default, circular DCC has been enabled on ISDN BRI and PRI interfaces, so you 
need to configure the 
undo dialer enable-circular command when enable 
resource-shared DCC. Circular DCC has been disabled on other interfaces (serial, 
asynchronous, AUX, etc). Resource-shared DCC are disabled by default, and no 
dialer bundle is created.
Configuring the dialer interface and dialer number
Since the attributes of the physical interface may be changed by the dialer 
number, the DCC parameters should be configured on the dialer interface. 
Furthermore, only the 
dialer number command can be used to configure the 
dialer numbers for calling the remote ends.
Use the interface dialer command to create a dialer interface in system view, 
then perform other configurations in dialer interface view.
Ta b l e 752   Configure a Dialer Interface and Dialer Number
By default, no dialer interface is created.
Creating dialer bundle and assigning physical interfaces to it
To implement the resource-shared DCC, the system selects a physical interface 
based on the dialing priority from a dialer bundle. The command
 dialer bundle 
is used for creating the dialer bundle for a dialer interface and to enable the 
resource-shared DCC function simultaneously, which is mentioned above.
Perform the following configuration steps in physical interface view.
OperationCommand
Disable Circular DCCundo dialer enable-circular
Enable Resource-Shared DCC and 
configure the dialer bundle used by Dialer 
interfacedialer bundle number
Disable Resource-Shared DCC and delete 
the dialer bundle.undo dialer bundle
OperationCommand
Create a dialer interface, and enter the 
dialer interface viewinterface dialer number
Delete the existing configuration of the 
dialer interfaceundo interface dialer number
Configure a dialer number for calling a 
remote enddialer number dial-number
Delete the dialer number for calling a 
remote endundo dialer number 
						

							720CHAPTER 51: CONFIGURING DCC
Ta b l e 753   Create a Dialer Bundle and Assigning the Physical Interfaces to it
By default, no dialer bundle is created, and the physical interfaces do not belong 
to any dialer bundle. If a physical interface is assigned to a dialer bundle, a default 
priority of 1 is assigned. 
Configuring dialing authentication for resource-shared DCC
To implement the resource-shared DCC, the called party must identify the calling 
parties through authentication through the communications between the physical 
interfaces and the dialer interfaces. Therefore, PAP or CHAP authentication must 
be configured.
Use the dialer user command in dialer interface view then use the local-user 
password
 command in the system view to perform other configuration steps in 
dial interface (physical or dialer interface) view.
Ta b l e 754   Configure Multiple Interfaces to Receive Calls From Multiple Remote Ends
The users are recommended to configure either PAP or CHAP authentication on 
both the physical and dialer interfaces of both sender and receiver.
When PPP is encapsulated on a Dialer interface, the remote user name gained 
through PPP authentication procedure will determine the Dialer interface for 
receiving calls, then the command
 dialer user is a must and the command 
dialer number is optional. While Frame Relay is encapsulated on a Dialer 
interface, because of no username negotiation procedure, the called end will 
distinguish Dialer interfaces according to the received number dialed by calling 
end, hence the command 
dialer user is optional and the command dialer 
number
 is a must.
OperationCommand
Add a physical interface to the specified 
dialer bundledialer bundle-member number [ 
priority priority ]
Delete the physical interface from the 
dialer bundleundo dialer bundle-member number
OperationCommand
Configure the remote user namedialer user username
Delete the remote user nameundo dialer user
Configure the link layer protocol to PPP link-protocol ppp
Configure an authentication modeppp authentication-mode { pap | chap 
}
Configure the interface to send the local 
user name and password for PAP 
authenticationppp pap local-user username password 
{ cipher | simple } password
Configure the user name that the local 
end will send to the remote end for CHAP 
authenticationppp chap user username
Configure the password that the local end 
will send to the remote end for CHAP 
authenticationppp chap password { cipher | simple } 
password
Configure the user name and password 
that the remote end is allowed to dial inlocal-user username password { cipher 
| simple } password 
						

							Configuring DCC 721
Configuring MP Binding 
for DCCIn DCC applications, the user can configure a traffic threshold for links. Setting the 
traffic threshold to 0 means that the max bandwidth of all the channels is enabled 
and there is no flow control. If the traffic threshold is in the range 1 to 100, MP 
binding will adjust the allocated bandwidth by the actual traffic percentage. 
Specifically, if the percentage of the actual traffic on a link to the bandwidth 
exceeds the defined traffic threshold, the system will automatically enable the 
second link, and implement MP binding on these two links. If the percentage of 
the actual traffic on these two links to the bandwidth exceeds the defined traffic 
threshold, the system will enable the third link, and implement MP binding, so on 
and so forth. Thereby, an appropriate traffic can be ensured for the DCC links. On 
the contrary, if the percentage of the traffic of N (which is an integer greater than 
2) links to the bandwidth of N-1 links is smaller than the defined traffic threshold, 
the system will automatically shutdown a link, so on and so forth. Thereby, the 
utility rate of the DCC links can be kept within an appropriate range.
Configuring MP binding in circular DCC
In a circular DCC, if a physical interface is a serial, asynchronous interface or an 
AUX interface, then a dialer circular group must be used to implement MP 
binding. (That is, it is required to configure the 
dialer threshold command on 
dialer interfaces.) If a physical interface is an ISDN BRI or PRI interface, the user can 
either use a dialer circular group or directly configure MP binding on the physical 
interface.
After the dialer threshold command is configured on a dialer interface, if the 
percentage of the traffic on a physical interface (or B channels) to the bandwidth 
exceeds the traffic threshold, the circular DCC will enable another physical 
interface in the dialer circular group and implement MP binding on these links. If 
the command is configured on an ISDN BRI or PRI physical interface, circular DCC 
will select available B channels on the physical interface to implement MP binding. 
But if all channels are busy, MP binding will be failed.
Use the dialer threshold command to configure traffic-percentage threshold in 
dial interface (ISDN BRI, PRI or dialer interface) view, and then perform other 
configurations in physical interface view.
Ta b l e 755   Configure MP Binding in Circular DCC
By default, neither MP binding nor traffic-percentage threshold is configured. That 
is, MP binding is not supported.
OperationCommand
Bundle a physical interface with the 
specified dialer circular group.dialer circular-group number
Set the traffic-percentage threshold for 
MP bindingdialer threshold traffic-percentage 
[ in-out | in | out ]
Restore the default traffic-percentage 
threshold of MP binding (that is, no flow 
control will be implemented).undo dialer threshold
Enable PPP encapsulation.link-protocol ppp
Configure MP binding on the physical 
interface.ppp mp [ interface virtual-template 
number ] 
						

							722CHAPTER 51: CONFIGURING DCC
Configuring MP binding in resource-shared DCC
If an interface is a serial, asynchronous interface or an AUX interface, then the 
resource-shared DCC will enable another physical interface in the dialer bundle of 
the dialer interface whenever the percentage of traffic on the physical interface to 
the bandwidth exceeds the traffic threshold. At the same time, it implements MP 
binding on these links. If the physical interface is an ISDN BRI or PRI interface, the 
resource-shared DCC will first select the available B channels on the interface, and 
then the B channels on other ISDN interfaces to implement MP binding.
Use the link-protocol ppp or ppp mp command to configure PPP encapsulation 
and MP binding in dial interface (physical or dialer interface) view, and use the 
dialer threshold command to configure a traffic-percentage threshold for MP 
binding in dialer interface view.
Ta b l e 756   Configure MP Binding in Resource-Shared DCC
By default, neither MP binding, nor traffic-percentage threshold is configured. 
That is, MP binding is not supported.
Configuring PPP 
CallbackWhen configuring PPP callback, one endpoint of a connection should be 
configured as client, and the other endpoint as server. The calling party is the 
callback client and the called party is the callback server. The client first originates 
a call, and the server determines whether to originate a return call. If it determines 
to do that, the callback server disconnects and then originates a return call 
according to the information such as user name or callback number.
Configure PPP callback after completing the basic configuration of Circular DCC or 
Resource-Shared DCC.
PPP callback implementation requires authentication. The users are recommended 
to configure PAP or CHAP authentication on both the physical and dialer interfaces 
on both the callback client and server.
Configuring PPP callback in the circular DCC implementation
1Configure PPP callback client in the circular DCC implementation
As a callback client, a router can originate calls to the remote end (which can be a 
router or Windows NT server having the PPP callback server function), and receive 
the return calls from the remote end.
Use the local-user password command to configure the user name in system 
view, and perform the other configurations in dial interface (physical or dialer 
interface) view.
OperationCommand
Set a traffic-percentage threshold for MP 
bindingdialer threshold traffic-percentage 
[ in-out | in | out ]
Restore the default traffic-percentage 
threshold of MP binding (that is, no flow 
control will be implemented).undo dialer threshold
Enable PPP encapsulationlink-protocol ppp
Configure MP binding on interfacesppp mp [ interface virtual-template 
number ] 
						

							Configuring DCC 723
Ta b l e 757   Implement PPP Callback (Client Configuration) in Circular DCC 
By default, the system does not enable callback function and is not configured 
with any Windows NT server callback dial number.
2Configure the PPP callback server in the circular DCC implementation
The callback server can originate a return call according to either the network 
address configured in the
 dialer route command (PPP authentication must be 
configured in this case), or the dial number configured in the 
local-user 
callback-number
 command. Therefore, the user must configure either method in 
the 
dialer callback-center command for placing the return call.
The user should configure the callback client user name in the dialer route 
command, so that the callback server can authenticate whether a calling party is a 
legal callback user when receiving its call requesting callback.
Use the local-user callback-number command to configure the callback user 
and callback dial number in system view, and perform other configurations in dial 
interface (physical or dialer interface) view.
Ta b l e 758   Implement PPP Callback (Server Configuration) in Circular DCC
OperationCommand
Configure PPP encapsulationlink-protocol ppp
Configure the local end to send the user 
name and password for PAP 
authenticationppp pap local-user username password 
{ cipher | simple } password
Configure the local user name sent to the 
remote end for CHAP authenticationppp chap user username
Configure the password that the local end 
will send to the remote end for CHAP 
authenticationppp chap password { cipher | simple } 
password
Configure the user name and password 
that the remote end is allowed to dial inlocal-user username password { cipher 
| simple } password
Configure the local end to be the PPP 
callback clientppp callback client
Disable the local end to be the PPP 
callback clientundo ppp callback client
Configure the destination addresses and 
dial number(s) for calling one (or more) 
remote endsdialer route protocol 
next-hop-address dial-number 
Configure the dial number for a Windows 
NT server to originate return calls to the 
routerppp callback ntstring dial-number
Delete the dial number that a Windows 
NT server needs for placing return calls to 
the routerundo ppp callback ntstring
OperationCommand
Configure PPP encapsulationlink-protocol ppp
Configure an authentication modeppp authentication-mode { pap | chap 
}
Configure the user name that the local 
end will send to the remote end for CHAP 
authenticationppp chap user username
Configure the password that the local end 
will send to the remote end for CHAP 
authenticationppp chap password { cipher | simple } 
password 
						

							724CHAPTER 51: CONFIGURING DCC
By default, the system does not enable the callback function. Once it is enabled, 
the server will originate return calls according to the user name configured in the 
dialer route command.
If the callback client adopts the dynamically assigned network address, the server 
will be unable to use the dialer route command to configure a callback dial 
number to associate with the network address. In this case, the callback client can 
only use the 
local-user callback-number command to configure a callback dial 
number to associate with the callback user name, and hence determine the 
callback reference.
Configuring PPP callback in the resource-shared DCC implementation
1Configure the PPP callback client in the resource-shared DCC implementation
As a callback client, a router can originate calls to the remote end (which can be a 
router or Windows NT server having the PPP callback server function), and receive 
the return calls from the remote end.
When resource-shared DCC are used to implement PPP callback, the PPP 
authentication configuration at client end is the same as that of circular DCC, 
except that the client in resource-shared DCC implementation must use the 
dialer number command to configure a dial number. See “Configure PPP 
callback client in the circular DCC implementation” in Dial-up. 
Perform the following configuration in dialer interface view.
Ta b l e 759   Implement PPP Callback (Client Configuration) in Resource-Shared DCC
Configure the callback user and callback 
numberlocal-user username callback-number 
telephone-number
Configure the local end to be the PPP 
callback serverppp callback server
Disable the local end to be the PPP 
callback serverundo ppp callback server
Configure the PPP callback referencedialer callback-center [ user ] [ 
dial-number ]
Disable the callback server function of the 
routerundo dialer callback-center
Configure the destination address(es) and 
dial number(s) for calling one (or more) 
remote endsdialer route protocol 
next-hop-address user username 
dial-number 
Operation Command
OperationCommand
Configure the local end to be the PPP 
callback clientppp callback client
Disable the local end to be the PPP 
callback clientundo ppp callback client
Configure the dialer number for calling a 
remote enddialer number dial-number
Configure the dial number for a Windows 
NT server to originate return calls to the 
routerppp callback ntstring dial-number
Delete the dial number that a Windows 
NT server needs for placing return calls to 
the routerundo ppp callback ntstring 
						

							Configuring DCC 725
By default, the system does not enable callback function and is not configured 
with any Windows NT server callback dial number.
2Configure the PPP callback server in the resource-shared DCC implementation
When resource-shared DCC are adopted to implement PPP callback, the PPP 
authentication configuration at server end is the same as that of circular DCC, 
except that the server in the resource-shared DCC implementation can only 
originate a return call according to the dial number configured in the 
local-user 
callback-number
 command. See “Configure the PPP callback server in the 
circular DCC implementation” in Dial-up.
Use the local-user callback-number command to configure the callback user 
and callback dial number in system view, and perform other configurations in 
dialer interface view.
Ta b l e 760   Implement PPP Callback (Server Configuration) in Resource-Shared DCC
By default, the system does not enable the callback function.
Configuring ISDN Caller 
Identification CallbackIn an ISDN environment, implementing DCC callback through the ISDN caller 
identification function requires no authentication, nor are there other 
configurations requirements.
Features of ISDN caller identification callback
In the applications of ISDN caller identification callback, the callback server can process 
a incoming call in three ways, depending on the matching result of the calling number 
and the dialer call-in command at the local end:
■Denies the incoming call: The dialer call-in command has been configured, 
but no match is found for the dial-in number and the configured dialer callers.
■Accepts the incoming call: The dialer call-in command is not configured, 
or a match is found for the dial-in number and a
 dialer call-in command 
configured without the keyword “callback”.
■Calls back: The dialer call-in command has been configured, and a match 
is found for the dial-in number and a 
dialer call-in command configured 
with the keyword callback.
The best match for the incoming number and the dialer call-in commands is 
determined on the basis of right-most matching. The character “*” in the number 
represents any characters. If multiple 
dialer call-in commands match the 
incoming number, the following rules will apply for determining the best match:
■Primary rule: The best match is the number with the fewest “*”.
OperationCommand
Configure the callback user and callback 
numberlocal-user username callback-number 
telephone-number
Configure the local end to be the PPP 
callback serverppp callback server
Disable the local end to be the PPP 
callback serverundo ppp callback server
Configure the PPP callback referencedialer callback-center dial-number
Disable the callback server function of the 
routerundo dialer callback-center 
						

							726CHAPTER 51: CONFIGURING DCC
■Secondary rule: The best match is the one that is found first.
Confirm which dialer call-in at server end is associated with the incoming call
■In circular DCC, upon receiving an incoming call, the server searches for the 
dialer call-in matching the incoming number in the 
dialer call-in 
commands configured on the physical interface or the dialer interface to which 
the physical interfaces belongs.
■In resource-shared DCC, upon receiving an incoming call, the server searches 
for the dialer call-in matching the incoming number in the 
dialer call-in 
commands configured for the dialer interfaces on it.
Configuring ISDN caller identification callback in the circular DCC 
implementation
To  configure ISDN caller identification callback client in the circular DCC 
implementation, p
erform the following configuration in dial interface (physical or 
dialer interface) view.
Ta b l e 761   Implement ISDN Caller Identification Callback (Client Configuration) in Circular 
DCC
To configure the ISDN caller identification callback server in the circular DCC 
implementation perform the following configuration in dial interface (physical or 
dialer interface) view.
Ta b l e 762   Implement ISDN Caller Identification Callback (Server Configuration) in Circular 
DCC
By default, callback according to ISDN caller identification is not configured.
The dialer route command configured on the dial interface (physical or dialer) 
at the server should be exactly the same dialer route in the dial-in dialer number.
Configuring ISDN caller identification callback in the resource-shared DCC 
implementation
To  configure ISDN caller identification callback client in the resource-shared DCC 
implementation,
 perform the following configuration in dialer interface view.
OperationCommand
Configure the destination addresses and 
dial number(s) for calling one (or more) 
remote endsdialer route protocol 
next-hop-address dial-number 
OperationCommand
Configure the local end to implement 
ISDN callback according to the ISDN caller 
identificationdialer call-in remote-number [ 
callback ]
Disable the local end to implement ISDN 
callback according to the ISDN caller 
identificationundo dialer call-in remote-number [ 
callback ]
Configure the destination address(es) and 
dial number(s) for calling one (or more) 
remote endsdialer route protocol 
next-hop-address dial-number