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Table Of Contents
Supported Standards, MIBs, and RFCs
Shutting Down an Interface Configured for Dialer Persistence
Monitoring and Maintaining Dialer Persistence
Standard Dialer Persistent Configuration Example
Dialer Persistent Plus Failed Connection Delays Configuration Example
Dialer Persistent
Feature History
12.2(4)T
This feature was introduced.
12.2(11)T
This feature was implemented on Cisco access server platforms.
This document describes the Dialer Persistent feature. It includes the following sections.
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Supported Standards, MIBs, and RFCs
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Feature Overview
A new interface configuration command, dialer persistent, allows a dial-on-demand routing (DDR) dialer profile connection to be brought up without being triggered by interesting traffic. When configured, the dialer persistent command starts a timer when the dialer interface starts up and starts the connection when the timer expires. If interesting traffic arrives before the timer expires, the connection is still brought up and set as persistent. The command provides a default timer interval, or you can set a custom timer interval.
The connection is not brought down until the shutdown interface command is entered on the dialer interface. If the persistent connection is torn down for some other reason, such as the ISDN line goes down, the system immediately tries to bring the connection back up, and will use any other settings configured for dialing on the dialer interface.
Benefits
The Dialer Persistent feature allows the connection settings in the dialer profile to be configured as persistent, that is, the connection is not torn down until the shutdown interface command is entered on the dialer interface.
Until Cisco IOS Release 12.2(4)T, interesting traffic was used to bring up a DDR link. If there was no interesting traffic and the idle timeout interval was reached, the link was torn down. However, there are situations where a link needs to be up all the time. The Dialer Persistent feature provides the option to ignore idle timers and interesting traffic, thereby keeping the link up and maintaining DDR dialed calls indefinitely. The Dialer Persistent feature allows you to configure the intervals to be used for dial attempts, both initially on startup and when a persistent link is brought down due to external failures.
Restrictions
The Dialer Persistent feature is available only with dialer profiles and not with legacy dialers.
The dialer idle-timeout interface configuration command cannot be configured when the dialer persistent command is configured.
Related Documents
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Supported Platforms
See the next section for information about Feature Navigator and how to use this tool to determine the platforms and software images in which this feature is available.
Platform Support Through Feature Navigator
Cisco IOS software is packaged in feature sets that support specific platforms. To get updated information regarding platform support for this feature, access Feature Navigator. Feature Navigator dynamically updates the list of supported platforms as new platform support is added for the feature.
Feature Navigator is a web-based tool that enables you to quickly determine which Cisco IOS software images support a specific set of features and which features are supported in a specific Cisco IOS image.
To access Feature Navigator, you must have an account on Cisco.com. If you have forgotten or lost your account information, send a blank e-mail to cco-locksmith@cisco.com. An automatic check will verify that your e-mail address is registered with Cisco.com. If the check is successful, account details with a new random password will be e-mailed to you. Qualified users can establish an account on Cisco.com by following the directions at http://www.cisco.com/register.
Feature Navigator is updated when major Cisco IOS software releases and technology releases occur. As of May 2001, Feature Navigator supports M, T, E, S, and ST releases. You can access Feature Navigator at the following URL:
http://www.cisco.com/go/fn
Supported Standards, MIBs, and RFCs
Standards
None
MIBs
None
To obtain lists of supported MIBs by platform and Cisco IOS release, and to download MIB modules, go to the Cisco MIB website on Cisco.com at the following URL:
http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml
RFCs
None
Prerequisites
Before performing the configuration tasks in this document, review the overview of and steps to configure a dialer profile in the chapter "Configuring Peer-to-Peer DDR with Dialer Profiles" in the Cisco IOS Dial Technologies Configuration Guide, "Dial-on-Demand Routing Configuration" part, Release 12.2.
Configuration Tasks
See the following sections for configuration tasks for the Dialer Persistent feature. Each task in the list is identified as either required or optional:
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The section "Monitoring and Maintaining Dialer Persistence" describes how to monitor and maintain the Dialer Persistent feature. See the section"Configuration Examples" for an example of how to configure the Dialer Persistent feature.
Configuring Dialer Persistent
To configure a dialer interface as persistent, use the following commands beginning in global configuration mode:
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:
Verifying Dialer Persistent
To verify that dialer persistent is configured correctly, perform the following verification steps:
Step 1
Router# show dialer interface dialer 1Di1 - dialer type = DIALER PROFILEIdle timer (never), Fast idle timer (20 secs)Wait for carrier (30 secs), Re-enable (15 secs)Dialer state is data link layer upNumber of active calls = 1Dial String Successes Failures Last DNIS Last status7135551234 4 0 00:00:06 successful DefaultBRI1/0 - dialer type = ISDNDial String Successes Failures Last DNIS Last status0 incoming call(s) have been screened.0 incoming call(s) rejected for callback.BRI1/0:2 - dialer type = ISDNIdle timer (never), Fast idle timer (20 secs)Wait for carrier (30 secs), Re-enable (15 secs)Dialer state is data link layer upDial reason: Dialing on persistent Dialer ProfileInterface bound to profile Di1Time until disconnect neverCurrent call connected 00:00:06Connected to 7135550134 (7135550134)Step 2
Di1 DDR: Persistent Dialer Profile nailed up successfully
Monitoring and Maintaining Dialer Persistence
To monitor and maintain a dialer interface configured for dialer persistent, use the following commands in EXEC mode, as needed:
Configuration Examples
This section provides the following Dialer Persistent configuration examples:
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Standard Dialer Persistent Configuration Example
The following example shows how to configure a 5-second initial delay before the persistent connection is established:
!interface dialer 1ip address negotiatedencapsulation pppdialer pool 1dialer remote-name remote1dialer idle-timeout 0 eitherdialer string 7135550199dialer persistent delay initial 5ppp authentication chapppp chap hostname DDRppp chap password secret!ip classlessip route 0.0.0.0 0.0.0.0 dialer 1ip route 172.30.21.0 255.255.255.0 1.1.1.5ip route 172.30.114.0 255.255.255.0 172.30.21.1no ip http server!!map-class dialer testdialer isdn speed 56access-list 183 permit ip host 10.239.28.2 host 10.239.28.128access-list 183 permit ip host 10.239.28.128 host 10.239.28.2!Dialer Persistent Plus Failed Connection Delays Configuration Example
The following example shows how to configure a 1-minute delay at boot-up, and a 10-second delay for redialing after a failed connection with a maximum of five tries before stopping:
!interface dialer 1ip address negotiatedencapsulation pppdialer pool 1dialer remote-name remote1dialer idle-timeout 0 eitherdialer string 7135550199dialer persistent delay initial 60dialer persistent delay 10dialer persistent max-attempts 5ppp authentication chapppp chap hostname DDRppp chap password mysecret!ip classlessip route 0.0.0.0 0.0.0.0 dialer 1ip route 172.30.21.0 255.255.255.0 1.1.1.5ip route 172.30.114.0 255.255.255.0 172.30.21.1no ip http server!!map-class dialer testdialer isdn speed 56access-list 183 permit ip host 10.239.28.2 host 10.239.28.128access-list 183 permit ip host 10.239.28.128 host 10.239.28.2!Command Reference
This section documents the new dialer persistent command that configures the Dialer Persistent feature. All other commands used with this feature are documented in the Cisco IOS Release 12.2 command reference publications.
dialer persistent
To force a dialer interface to be connected at all times, even in the absence of interesting traffic, use the dialer persistent command in interface configuration mode. To disable this option, use the no form of this command.
dialer persistent [delay [initial] seconds | max-attempts number]
no dialer persistent
Syntax Description
Defaults
No persistent connections are established. The default delay and initial delay interval is 1 second. There is no default or limit to the number of reconnection attempts.
Command Modes
Interface configuration
Command History
12.2(4)T
This command was introduced.
12.2(11)T
This feature was implemented on Cisco access server platforms.
Usage Guidelines
Do not use the dialer redial command when a dialer profile has been configured with the dialer persistent command. Both these configuration commands prompt the router to dial out, so it is desirable to configure only one of them.
Do not use the dialer idle-timeout interface configuration command when a dialer profile has been configured with the dialer persistent command. Doing so has no effect on the idle timer, which is overridden by the dialer idle-timeout command as dialer idle-timeout 0.
You can use the clear interface EXEC command on the dialer interface to clear unsuccessful dial attempts on a line without interesting traffic; the dialer software continues attempting to bring up the connection as persistent. To disconnect a persistent connection and prevent the software from attempting more dialing, use the shutdown interface configuration command.
Once a connection has been brought up as persistent, it cannot be torn down due to a fast-idle timeout.
Examples
The following example shows how to configure a dialer interface for dialer persistent:
!interface dialer 0ip address 10.1.1.2 255.255.255.0encapsulation pppdialer string 5550189dialer pool 1dialer-group 1dialer persistent delay initial 20!access-list 101 permit icmp any anyaccess-list 101 deny ip any anydialer-list 1 protocol ip list 101Related Commands
Glossary
interesting packets—Dialer access lists are central to the operation of DDR. In general, access lists are used as the screening criteria for determining when to initiate DDR calls. All packets are tested against the dialer access list. Packets that match a permit entry are deemed interesting.
persistent connection—A connection that is brought up even without interesting traffic, and is not torn down until the shutdown interface configuration command is entered on the interface.