3Com Router User Manual

							Configuring DCC 727
Ta b l e 763   Implement ISDN Caller Identification Callback (Client Configuration) in 
Resource-Shared DCC
To configure the ISDN caller identification callback server in the resource-shared 
DCC implementation, perform the following configuration in dialer interface view.
Ta b l e 764   Implement ISDN Caller Identification Callback (Server Configuration) in 
Resource-Shared DCC 
By default, callback according to ISDN caller identification is not configured.
A dialer number should be configured on the dialer interface at server end 
through the dialer number command, but it is not required to be exactly the 
same as the dial-in dialer number.
Configuring Special DCC 
FunctionsConfiguring ISDN leased line
This function can only be used with circular DCC and must be implemented after 
circular DCC has been configured. ISDN leased line application is fulfilled through 
establishing semipermanent ISDN MP connections. Such application requires that 
a leased line has been established on the PBX of the telecommunication service 
provider and has been connected to the remote device.
Perform the following configuration in dial interface (ISDN BRI or PRI interface) 
view.
Ta b l e 765   Configure ISDN leased line for Circular DCC
By default, no B channel is configured for ISDN leased line connection.
Configuring auto-dial
This function can only be used with circular DCC. With a circular DCC, after the 
router is started, the DCC will automatically attempt to dial the remote end of the 
connection without requiring a triggering packet. If a normal connection cannot 
be established with the remote end, DCC will automatically retry at a certain 
interval. Compared with the auto-dial DCC triggered by packets, such connections 
OperationCommand
Configure the dial number for calling a 
remote enddialer number [ 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 dialer number for calling a 
remote enddialer number [ dial-number ]
OperationCommand
Configure a B channel for ISDN leased line 
connectiondialer isdn-leased channel-number
Delete the B channel for ISDN leased line 
connectionundo dialer isdn-leased 
channel-number 
						

							728CHAPTER 51: CONFIGURING DCC
do not automatically disconnect due to timeout. In other words, the dialer 
timer idle 
command does not take effect on auto-dial.
Perform the following configuration in dial interface (physical or dialer interface) 
view.
Ta b l e 766   Configure Auto-Dial
By default, auto-dial is not configured. If auto-dial function is enabled, the interval 
for auto-dial defaults to 300 seconds.
Configuring dialer number circular standby
This function can only be used with circular DCC. When setting the same 
destination addresses using circular DCC, multiple 
dialer route commands can 
be configured, these commands corresponding to different dialer numbers. These 
dialer route commands form a kind of circular standby, which means that if the 
calling dial number can not connect to peer end, then the number configured in 
next
 dialer route command will be selected automatically for recalling. 
Perform the following configuration in dial interface (physical or dialer interface) 
view.
Ta b l e 767   Configure Dialer Number Circular Standby
Configuring Attributes 
of DCC Dial Interfac
e
Circular DCC and resource-shared DCC also have some optional parameters to 
improve configuration flexibility improve DCC efficiency, and hence satisfies 
various requirements.
DCC dial interface attributes configuration includes:
■Configuring the Link Idle Time
■Configuring the link disconnection time before initiating the next call
■Configuring the link idle time when interface competion
■Configuring the timeout of call setting up
■Configuring the buffer queue length of the dialer
Configuring the Link Idle Time
In the case that a dial interface originates a call, DCC can be set to disconnect the 
line after the amount of time for which the line stays idle. In the duration of the 
OperationCommand
Configure one (or more) remote 
destination address(es) and dialer 
number(s) that the router will auto-dialdialer route protocol 
next-hop-address dialer-number 
autodial
Configure an auto-dial intervaldialer autodial-interval seconds
Restore the default auto-dial intervalundo dialer autodial-interval
OperationCommand
Configure one remote destination 
address(es) and dialer number(s)dialer route protocol 
next-hop-address dialer-number 
autodial 
						

							Configuring DCC 729
idle time, no the packet which complies with the “permit” statements are 
transmitted over the line.
Perform the following configuration in dial interface (physical or dialer interface) 
view.
Ta b l e 768   Configure the Link Idle Time
By default, the link idle time is 120 seconds.
Configuring the link disconnection time before initiating the next call
After a line for DCC calls enters the down status due to faults or disconnection, a 
specified period of time must be elapsed (the interval before it can originate the 
next call) before a new dialup connection can be established again. Thereby, the 
possibility of overloading the remote PBX can be prevented. 
Perform the following configuration in dial interface (physical or dialer interface) 
view.
Ta b l e 769   Configure the Link Disconnection Time Before Initiating the Next Call
By default, the link disconnection time is 20 seconds.
Configuring the link idle time when interface competion
If all the channels are unavailable when DCC originates a new call, a condition of 
contention occurs. Normally, after a line is set up, idle-timeout timer will take 
effect. However, if a call to a different destination address is originated at this 
time, competion will occur. In this case, DCC replaces the idle timeout timer with 
the compete-idle timer. In other words, the line will be automatically disconnected 
after the line-idle time exceeds the time specified by the compete-idle timer.
Perform the following configuration in dial interface (physical or dialer interface) 
view.
Ta b l e 770   Configure the Link Idle Time When Interface Competion
By default, the link idle time is 20 seconds when the interface competion occurs.
OperationCommand
Configure the link idle timedialer timer idle seconds
Restore the link idle time to the default 
valueundo dialer timer idle
OperationCommand
Configure the link disconnection time 
before initiating the next calldialer timer enable seconds
Restore the link disconnection time before 
initiating the next call to the default valueundo dialer timer enable
OperationCommand
Configure the link idle time when 
interface competiondialer timer compete seconds
Restore the link idle time when interface 
competion to the default valueundo dialer timer compete 
						

							730CHAPTER 51: CONFIGURING DCC
Configuring the timeout of call setting up
When placing DCC calls to some remote ends, the intervals between originating 
the calls and establishing the connections are not the same. To effectively control 
the time that should wait for the connection after a call is originated, the user can 
configure the wait-carrier timer to specify a duration, after which DCC will 
terminate the call if the connection cannot be established.
Perform the following configuration in dial interface (physical or dialer interface) 
view.
Ta b l e 771   Configure the Timeout of Call Setting Up
By default, the timeout of call setting up is 60 seconds.
Configuring the buffer queue length of the dialer
Before a dialer buffer queue is established, a packet received from the dial 
interface will be discarded if the connection is not established yet. However, if a 
buffer queue is established on the dial interface, the packet will be held until a 
connection is established rather than discarded.
Perform the following configuration in dial interface (physical or dialer interface) 
view.
Ta b l e 772   Configure the Buffer Queue Length of the Dial Interface
By default, no buffer queues are configured on dial interfaces.
Displaying and 
Debugging DCCAfter completing the above configuration steps, execute the display command in 
all views to display the running of the DCC configuration, and to verify the effect 
of the configuration.
Execute debugging command in all views for the debugging.
Ta b l e 773   Display and Debug DCC
OperationCommand
Configure the timeout of call setting updialer timer wait-carrier seconds
Restore the timeout of call setting up to 
the default valueundo dialer wait-carrier
OperationCommand
Configure the buffer queue length of the 
dial interfacedialer queue-length packets
Remove the buffer queue length of the 
dial interfaceundo dialer queue-length
OperationCommand
Display the dial interface informationdisplay dialer interface [ 
interface-type interface-number ]
Display the statically configured or 
dynamically formed dial number route.display dialer route [ detail ]
Enable DCC debuggingdebugging dialer { event | packet } 
						

							DCC Configuration Examples731
DCC Configuration 
Examples
DCC Applications in 
Common UseRouterA can call RouterB and RouterC via multiple interfaces. Likewise, RouterB 
and RouterC can respectively call RouterA. However, RouterB and RouterC cannot 
call each other.
As shown in Figure 233, when circular DCC is used, the addresses of RouterA, 
RouterB and RouterC are on the same segment. In this case, 100.1.1.1, 100.1.1.2, 
and 100.1.1.3 are the addresses respectively for RouterA, RouterB and RouterC. 
When resource-shared DCC are used, the addresses of RouterA and RouterB are 
on the same segment, so are the addresses of RouterA and RouterC. The 
addresses of the interfaces Dialer0 and Dialer1 on RouterA are respectively 
100.1.1.1 and 122.1.1.1. The address of the Dialer0 on RouterB is 100.1.1.2, and 
that of the Dialer0 on RouterC is 122.1.1.2.
Figure 233   Network of a DCC application in common use
Solution 1
Establish a connection via the serial interface by using Circular DCC, configure the 
DCC parameters on the dialer interface for RouterA with the help of a dialer 
circular group, and directly configure the DCC parameters on the physical 
interfaces on RouterB and RouterC.
1Configure RouterA:
[Router] dialer-rule 1 ip permit
[Router] interface dialer 0
[Router-Dialer0] ip address 100.1.1.1 255.255.255.0
[Router-Dialer0] dialer enable-circular
[Router-Dialer0] dialer-group 1
[Router-Dialer0] dialer route ip 100.1.1.2 8810052
[Router-Dialer0] dialer route ip 100.1.1.3 8810063
[Router-Dialer0] interface serial 0
[Router-Serial0] physical-mode async
[Router-Serial0] modem
Router A
Router C Modem
Modem
Modem
PSTNModem
ISDN 8810048
88100498810052
8810063
Connecting via serial interfaces across PSTN
88101488810152
8810163
Connecting via ISDN BRI or PRI interfaces across ISDN Router DRouter B
Router E
Router F Serial0
Serial1Serial0 Serial0
Bri0Bri0
Bri0
NT1
NT1
NT1 
						

							732CHAPTER 51: CONFIGURING DCC
[Router-Serial0] dialer circular-group 0
[Router-Serial0] interface serial 1
[Router-Serial1] physical-mode async
[Router-Serial1] modem
[Router-Serial1] dialer circular-group 0
2Configure RouterB:
[Router] dialer-rule 1 ip permit
[Router] interface serial 0
[Router-Serial0] physical-mode async
[Router-Serial0] modem
[Router-Serial0] ip address 100.1.1.2 255.255.255.0
[Router-Serial0] dialer enable-circular
[Router-Serial0] dialer-group 1
[Router-Serial0] dialer route ip 100.1.1.1 8810048
[Router-Serial0] dialer route ip 100.1.1.1 8810049
3Configure RouterC:
[Router] dialer-rule 1 ip permit
[Router] interface serial 0
[Router-Serial0] physical-mode async
[Router-Serial0] modem
[Router-Serial0] ip address 100.1.1.3 255.255.255.0
[Router-Serial0] dialer enable-circular
[Router-Serial0] dialer-group 1
[Router-Serial0] dialer route ip 100.1.1.1 8810048
[Router-Serial0] dialer route ip 100.1.1.1 8810049
Solution 2 
Establish a connection via the serial interfaces by using Resource-Shared DCC, and 
configure the DCC parameters on the dialer interfaces.
aConfigure RouterA:
[Router] dialer-rule 1 ip permit
[Router] local-user userb password simple userb
[Router] local-user userc password simple userc
[Router] interface dialer 0
[Router-Dialer0] ip address 100.1.1.1 255.255.255.0
[Router-Dialer0] undo dialer enable-circular
[Router-Dialer0] dialer bundle 1
[Router-Dialer0] dialer user userb
[Router-Dialer0] dialer-group 1
[Router-Dialer0] ppp authentication-mode pap
[Router-Dialer0] ppp pap local-user usera password simple usera
[Router-Dialer0] dialer number 8810052
[Router-Dialer0] interface dialer 1
[Router-Dialer1] ip address 122.1.1.1 255.255.255.0
[Router-Dialer1] undo dialer enable-circular
[Router-Dialer1] dialer bundle 2
[Router-Dialer1] dialer user userc
[Router-Dialer1] dialer-group 1
[Router-Dialer1] ppp authentication-mode pap
[Router-Dialer1] ppp pap local-user usera password simple usera
[Router-Dialer1] dialer number 8810063
[Router-Dialer1] interface serial 0
[Router-Serial0] physical-mode async
[Router-Serial0] modem 
						

							DCC Configuration Examples733
[Router-Serial0] dialer bundle-member 1
[Router-Serial0] dialer bundle-member 2
[Router-Serial0] link-protocol ppp
[Router-Serial0] ppp authentication-mode pap
[Router-Serial0] ppp pap local-user usera password simple usera
[Router-Serial0] interface serial 1
[Router-Serial1] physical-mode async
[Router-Serial1] modem
[Router-Serial1] dialer bundle-member 1
[Router-Serial1] dialer bundle-member 2
[Router-Serial1] link-protocol ppp
[Router-Serial1] ppp authentication-mode pap
[Router-Serial1] ppp pap local-user usera password simple usera
4Configure RouterB:
[Router] dialer-rule 2 ip permit
[Router] local-user usera password simple usera
[Router] interface dialer 0
[Router-Dialer0] ip address 100.1.1.2 255.255.255.0
[Router-Dialer0] undo dialer enable-circular
[Router-Dialer0] dialer bundle 1
[Router-Dialer0] dialer number 8810052
[Router-Dialer0] dialer user usera
[Router-Dialer0] dialer-group 2
[Router-Dialer0] ppp authentication-mode pap
[Router-Dialer0] ppp pap local-user userb password simple userb
[Router-Dialer0] interface serial 0
[Router-Serial0] physical-mode async
[Router-Serial0] modem
[Router-Serial0] dialer bundle-member 1
[Router-Serial0] link-protocol ppp
[Router-Serial0] ppp authentication-mode pap
[Router-Serial0] ppp pap local-user userb password simple usera
5Configure RouterC:
[Router] dialer-rule 1 ip permit
[Router] local-user usera password simple usera
[Router] interface dialer 0
[Router-Dialer0] ip address 122.1.1.2 255.255.255.0
[Router-Dialer0] undo dialer enable-circular
[Router-Dialer0] dialer bundle 1
[Router-Dialer1] dialer number 8810049
[Router-Dialer0] dialer user usera
[Router-Dialer0] dialer-group 1
[Router-Dialer0] ppp authentication-mode pap
[Router-Dialer0] ppp pap local-user userc password simple userc
[Router-Dialer0] interface serial 0
[Router-Serial0] physical-mode async
[Router-Serial0] modem
[Router-Serial0] dialer bundle-member 1
[Router-Serial0] link-protocol ppp
[Router-Serial0] ppp authentication-mode pap
[Router-Serial0] ppp pap local-user userc password simple userc 
						

							734CHAPTER 51: CONFIGURING DCC
 Solution 3: 
Establish a connection via ISDN BRI or PRI interfaces by using Circular DCC, and 
configure the DCC parameters on the physical interfaces.
1Configure RouterA:
[Router] dialer-rule 1 ip permit
[Router] interface bri 0
[Router-Bri0] ip address 100.1.1.1 255.255.255.0
[Router-Bri0] dialer enable-circular
[Router-Bri0] dialer-group 1
[Router-Bri0] dialer route ip 100.1.1.2 8810052
[Router-Bri0] dialer route ip 100.1.1.3 8810063
2Configure RouterB:
[Router] dialer-rule 2 ip permit
[Router] interface bri 0
[Router-Bri0] ip address 100.1.1.2 255.255.255.0
[Router-Bri0] dialer enable-circular
[Router-Bri0] dialer-group 2
[Router-Bri0] dialer route ip 100.1.1.1 8810048
3Configure RouterC:
[Router] dialer-rule 1 ip permit
[Router] interface bri 0
[Router-Bri0] ip address 100.1.1.3 255.255.255.0
[Router-Bri0] dialer enable-circular
[Router-Bri0] dialer-group 1
[Router-Bri0] dialer route ip 100.1.1.1 8810048
Solution 4: 
Establish a connection via the ISDN BRI or PRI interfaces by using Resource-Shared 
DCC, and configure the DCC parameters on the dialer interfaces.
1Configure RouterA:
[Router] dialer-rule 1 ip permit
[Router] local-user userb password simple userb
[Router] local-user userc password simple userc
[Router] interface dialer 0
[Router-Dialer0] ip address 100.1.1.1 255.255.255.0
[Router-Dialer0] undo dialer enable-circular
[Router-Dialer0] dialer bundle 1
[Router-Dialer0] dialer user userb
[Router-Dialer0] dialer-group 1
[Router-Dialer0] ppp authentication-mode pap
[Router-Dialer0] ppp pap local-user usera password simple usera
[Router-Dialer0] dialer number 8810152
[Router-Dialer0] interface dialer 1
[Router-Dialer1] ip address 122.1.1.1 255.255.255.0
[Router-Dialer1] undo dialer enable-circular
[Router-Dialer1] dialer bundle 2
[Router-Dialer1] dialer user userc
[Router-Dialer1] dialer-group 1
[Router-Dialer1] ppp authentication-mode pap
[Router-Dialer1] ppp pap local-user usera password simple usera
[Router-Dialer1] dialer number 8810163
[Router-Dialer1] interface bri 0
[Router-Bri0] undo dialer enable-circular 
						

							DCC Configuration Examples735
[Router-Bri0] dialer bundle-member 1
[Router-Bri0] dialer bundle-member 2
[Router-Bri0] link-protocol ppp
[Router-Bri0] ppp authentication-mode pap
2Configure RouterB:
[Router] dialer-rule 2 ip permit
[Router] local-user usera password simple usera
[Router] interface dialer 0
[Router-Dialer0] ip address 100.1.1.2 255.255.255.0
[Router-Dialer0] undo dialer enable-circular
[Router-Dialer0] dialer bundle 1
[Router-Dialer0] dialer number 8810148
[Router-Dialer0] dialer user usera
[Router-Dialer0] dialer-group 2
[Router-Dialer0] ppp authentication-mode pap
[Router-Dialer0] ppp pap local-user userb password simple userb
[Router-Dialer0] interface bri 0
[Router-Bri0] undo dialer enable-circular
[Router-Bri0] dialer bundle-member 1
[Router-Bri0] link-protocol ppp
[Router-Bri0] ppp authentication-mode pap
3Configure RouterC:
[Router] dialer-rule 1 ip permit
[Router] local-user usera password simple usera
[Router] interface dialer 0
[Router-Dialer0] ip address 122.1.1.2 255.255.255.0
[Router-Dialer0] undo dialer enable-circular
[Router-Dialer0] dialer bundle 1
[Router-Dialer0] dialer number 8810148
[Router-Dialer0] dialer user usera
[Router-Dialer0] dialer-group 1
[Router-Dialer0] ppp authentication-mode pap
[Router-Dialer0] ppp pap local-user userc password simple userc
[Router-Dialer0] interface bri 0
[Router-Bri0] undo dialer enable-circular
[Router-Bri0] dialer bundle-member 1
[Router-Bri0] link-protocol ppp
[Router-Bri0] ppp authentication-mode pap
DCC Application 
Providing MP Binding
 
The local router is connected to the remote end via two ISDN BRI interfaces.The 
traffic threshold must be set to distribute the traffic. Thus, the bandwidth 
resources can be allocated according to the actual traffic. The maximum available 
bandwidth is specified.
As shown in Figure 234, the ISDN BRI interfaces on RouterA and the ISDN PRI 
interface on RouterB are connected through an ISDN network. RouterA must 
adopt resource-shared DCC to call RouterB, and RouterB adopts circular DCC to 
call RouterA. The addresses of RouterA and RouterB are 100.1.1.1 and 100.1.1.2, 
respectively. 
						

							736CHAPTER 51: CONFIGURING DCC
Figure 234   Network for the DCC application providing MP binding
1Configure RouterA:
[Router] dialer-rule 1 ip permit
[Router] local-user userb password simple userb
[Router] flow-interval 3
[Router] interface dialer 0
[Router-Dialer0] ip address 100.1.1.1 255.255.255.0
[Router-Dialer0] undo dialer enable-circular
[Router-Dialer0] dialer bundle 1
[Router-Dialer0] ppp mp
[Router-Dialer0] dialer threshold 50
[Router-Dialer0] dialer user userb
[Router-Dialer0] dialer-group 1
[Router-Dialer0] ppp authentication-mode pap
[Router-Dialer0] ppp pap local-user usera password simple usera
[Router-Dialer0] dialer number 8810152
[Router-Dialer0] interface bri 0
[Router-Bri0] undo dialer enable-circular
[Router-Bri0] dialer bundle-member 1
[Router-Bri0] ppp mp
[Router-Bri0] link-protocol ppp
[Router-Bri0] ppp authentication-mode pap
[Router-Bri0] ppp pap local-user usera password simple usera
[Router-Bri0] interface bri 1
[Router-Bri1] undo dialer enable-circular
[Router-Bri1] dialer bundle-member 1
[Router-Bri1] ppp mp
[Router-Bri1] link-protocol ppp
[Router-Bri1] ppp authentication-mode pap
[Router-Bri1] ppp pap local-user usera password simple usera
2Configure RouterB:
[Router] dialer-rule 2 ip permit
[Router] local-user usera password simple usera
[Router] flow-interval 3
[Router] controller e1 0
[Router-E1-0] pri-set
[Router-E1-0] interface serial 0:15
[Router-Serial0:15] link-protocol ppp
[Router-Serial0:15] ppp mp
[Router-Serial0:15] ip address 100.1.1.2 255.255.255.0
[Router-Serial0:15] ppp authentication-mode pap
[Router-Serial0:15] ppp pap local-user userb password simple userb
[Router-Serial0:15] dialer enable-circular
[Router-Serial0:15] dialer-group 2
[Router-Serial0:15] dialer route ip 100.1.1.1 8810148
[Router-Serial0:15] dialer route ip 100.1.1.1 8810149
ISDN8810152 8810148
Pri0 Bri0
Bri18810149
Router ARouter B
NT
1
NT
1