If you have ever tried to setup remote access or perform remote testing on a network with a cellular internet connection, you are probablly aware of the difficulties associated with the defualt dialer configuration.
The problem is that after a short time-out period, the 3G interface goes into a spoofing mode where it show as UP/UP but the connection to the cell phone tower is shut down to save on your bandwitdth or minutes usage.
The alternative to this, assuming that you have an unlimited data plan, is to configure the ‘Dialer Persitent’ setting.
Configuring Dialer Persistent
To configure a dialer interface as persistent, use the following commands beginning in global configuration mode:
Step 1
Router(config)# interface dialer number
Creates a dialer interface and enters interface configuration mode.
Step 2
Router(config-if)# ip address address mask
Specifies the IP address and mask of the dialer interface as a node in the destination network to be called.
Step 3
Router(config-if)# encapsulation type
Specifies the encapsulation type.
Step 4
Router(config-if)# dialer string dial-string class class-name
Specifies the remote destination to call and the map class that defines characteristics for calls to this destination.
Step 5
Router(config-if)# dialer poolnumber
Specifies the dialing pool to use for calls to this destination.
Step 6
Router(config-if)# dialer-group group-number
Assigns the dialer interface to a dialer group.
Step 7
Router(config-if)# dialer-list dialer-group protocol protocol-name{permit|deny|listaccess-list-number}
Specifies an access list by list number or by protocol and list number to define the interesting packets that can trigger a call.
Step 8
Router(config-if)# dialer remote-name user-name
(Optional) Specifies the authentication name of the remote router on the destination subnetwork for a dialer interface.
Step 9
Router(config-if)# dialer persistent [delay [initial] seconds | max-attempts number]
Forces a dialer interface to be connected at all times, even in the absence of interesting traffic.
See the configuration example in the section “Configuration Examples” and the “Examples” section in the dialer persistent command reference page for additional commands that might be entered for this configuration.
Shutting Down an Interface Configured for Dialer Persistence
To fully tear down (shut down) a dialer interface configured for dialer persistent, use the following commands beginning in global configuration mode:
Step 1
Router(config)# interface dialer number
Enters interface configuration mode on the specified dialer interface.
Step 2
Router(config-if)# shutdown
Fully tears down a persistent connection and prevents the software from attempting more dialing.
Verifying Dialer Persistent
To verify that dialer persistent is configured correctly, perform the following verification steps:
Step 1 
Enter the show dialer interface EXEC command with the interface type and number to display statistics on the physical interface bound to the dialer interface. Output includes the configured timers. The “Idle timer (never)” and “Dial reason:” lines indicate that persistent dialing is configured.
Router# show dialer interface dialer 1
Di1 - dialer type = DIALER PROFILE
Idle timer (never), Fast idle timer (20 secs)
Wait for carrier (30 secs), Re-enable (15 secs)
Dialer state is data link layer up
Number of active calls = 1
Dial String Successes Failures Last DNIS Last status
7135551234 4 0 00:00:06 successful Default
BRI1/0 - dialer type = ISDN
Dial String Successes Failures Last DNIS Last status
0 incoming call(s) have been screened.
0 incoming call(s) rejected for callback.
BRI1/0:2 - dialer type = ISDN
Idle timer (never), Fast idle timer (20 secs)
Wait for carrier (30 secs), Re-enable (15 secs)
Dialer state is data link layer up
Dial reason: Dialing on persistent Dialer Profile
Interface bound to profile Di1
Time until disconnect never
Current call connected 00:00:06
Connected to 7135550134 (7135550134)
Step 2 Enter the debug dialer EXEC command and verify that the following message appears:
Di1 DDR: Persistent Dialer Profile nailed up successfully
