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Table Of Contents
Multilink PPP Minimum Links Mandatory
Supported Standards, MIBs, and RFCs
Configuring Multilink PPP Minimum Links Mandatory
Verifying Multilink PPP Down Support
Monitoring and Maintaining Multilink PPP Minimum Links Mandatory
Configuring Multilink PPP Example
Configuring Multilink PPP Minimum Links Mandatory Example
Multilink PPP Minimum Links Mandatory
Feature History
This document describes the Multilink PPP Minimum Links Mandatory feature in Cisco IOS Release 12.1(11b)E and contains the following sections:
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Supported Standards, MIBs, and RFCs
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Feature Overview
Multilink PPP allows establishing multiple PPP links in parallel to the same destination. This is often used with dialup lines or ISDN connections to easily increase the amount of bandwidth between points.
With the introduction of the Multilink PPP Minimum Links Mandatory feature, you can configure the minimum number of links in a Multilink PPP (MLP) bundle required to keep that bundle active by entering the multilink min-links links mandatory command. When you configure this command, all Network Control Protocols (NCPs) for a MLP bundle are disabled until the MLP bundle has the required minimum number of links. When a new link is added to the MLP bundle that brings the number of links up to the required minimum number of links, the NCPs are activated for the MLP bundle. When a link is removed from an MLP bundle, and the number of links falls below the required minimum number of links for that MLP bundle, the NCPs are disabled for that MLP bundle.
Benefits
Using this feature you can configure the required number of physical links in an MLP bundle.
Related Documents
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Supported Platforms
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Determining Platform Support Through Cisco 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 Cisco Feature Navigator. Cisco Feature Navigator dynamically updates the list of supported platforms as new platform support is added for the feature.
Cisco Feature Navigator is a web-based tool that enables you to determine which Cisco IOS software images support a specific set of features and which features are supported in a specific Cisco IOS image. You can search by feature or release. Under the release section, you can compare releases side by side to display both the features unique to each software release and the features in common.
Cisco Feature Navigator is updated regularly when major Cisco IOS software releases and technology releases occur. For the most current information, go to the Cisco Feature Navigator home page at the following URL:
Availability of Cisco IOS Software Images
Platform support for particular Cisco IOS software releases is dependent on the availability of the software images for those platforms. Software images for some platforms may be deferred, delayed, or changed without prior notice. For updated information about platform support and availability of software images for each Cisco IOS software release, refer to the online release notes or Cisco Feature Navigator.
Supported Standards, MIBs, and RFCs
Standards
No new or modified standards are supported by this feature.
MIBs
No new or modified MIBs are supported by this feature.
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
RFC 1990, The PPP Multilink Protocol (MP)
Configuration Tasks
See the following sections for configuration tasks for the Multilink PPP Minimum Links Mandatory feature. Each task in the list is identified as either required or optional.
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Configuring PPP
To configure PPP, use the following commands beginning in global configuration mode:
Configuring Multilink PPP
To configure Multilink PPP, use the following commands beginning in global configuration mode:
Configuring Multilink PPP Minimum Links Mandatory
To configure the Multilink PPP Minimum Links Mandatory feature, use the following commands in interface configuration mode:
Verifying Multilink PPP Down Support
Use the show running-configuration command to verify configuration of the Multilink PPP Minimum Links Mandatory feature:
Router# show running-configuration...interface multilink1ip address 10.1.1.1 255.255.255.0ppp encapsulationppp authentication chapppp multilinkmultilink max-links 100multilink min-links 10 mandatoryinterface BRI2/1no ip addressencapsulation pppdialer pool-member 2no fair-queueno cdp enableppp authentication chapppp multilinkinterface bri 0description connected to abc 81012345678902ip address 171.1.1.7 255.255.255.0encapsulation pppdialer idle-timeout 30dialer map ip 172.16.0.0 name cisco 81012345678901dialer-group 1ppp authentication papppp multilinkmultilink min-links 2 mandatoryMonitoring and Maintaining Multilink PPP Minimum Links Mandatory
To monitor and maintain Multilink PPP Minimum Links Mandatory, use the following EXEC commands:
Configuration Examples
This section provides the following configuration examples:
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Configuring PPP Example
The following example shows how to configure PPP on a serial interface with CHAP authentication:
interface serial 1/0encapsulation pppauthentication chapexitusername abc password password1Configuring Multilink PPP Example
The following example shows how to configure Multilink PPP. In this example, the MLP bundle is configured with CHAP authentication. The minimum number of links for this MLP bundle is 5 and the maximum number of links is 100.
interface multilink 3ip address 172.16.0.0encapsulation pppppp multilinkppp authentication chapppp chap hostname namemultilink min-links 5multilink max-links 100bridge-group 2no shutdownConfiguring Multilink PPP Minimum Links Mandatory Example
The following example shows how to configure a MLP bundle to be required to have at least five active sessions:
ppp multilinkmultilink min-links 5 mandatoryCommand Reference
This section documents the following modified command. All other commands used with this feature are documented in the Cisco IOS Release 12.1 command reference publications.
multilink min-links
To specify the preferred minimum number of links in a Multilink PPP (MLP) bundle, use the multilink min-links command in interface configuration mode. To reset the default value, use the no form of this command.
multilink min-links links [mandatory]
no multilink min-links links [mandatory]
Syntax Description
links
Minimum number of links, in the range 0 to 255.
mandatory
(Optional) If the minimum number of links is not present, the MLP bundle is deactivated.
Defaults
The minimum number of links is 0.
Command Modes
Interface configuration
Command History
11.3
This command was introduced.
12.1(11b)E
The optional mandatory keyword was introduced.
Usage Guidelines
If a bundle contains fewer links and there is a means to establish additional channels (for example, available dialer channels), then MLP attempts to increase the number of links up to this limit.
If the dialer max-links command is configured, MLP will not exceed its value even if the ppp multilink max-link command is a higher value. This restriction does not affect the number of links you can configure, but rather what happens at run time.
The value set in the multilink min-links command specifies the minimum number of links that MLP will try to keep in a bundle. MLP attempts to dial up additional links to obtain the number specified by the links argument, even if the load does not exceed the load threshold.
If you configure the optional mandatory keyword, the MLP bundle is disabled if the specified minimum number of links is not available.
Examples
The following example shows how to set the minimum number of links to 12:
multilink min-links 12The following example shows how to set a mandatory minimum number of links to 5:
multilink min-links 5 mandatoryRelated Commands
multilink max-links
Limits the maximum number of links that MLP can dial for dynamic allocation.