Table Of Contents
Multilink PPP Minimum Links Mandatory
Information About Multilink PPP Minimum Links Mandatory
How to Configure Multilink PPP Minimum Links Mandatory
Configuring Multilink PPP Minimum Links Mandatory
Verifying the Multilink PPP Minimum Links Mandatory Configuration
Configuration Examples for Multilink PPP Minimum Links Mandatory
Configuring Multilink PPP: Example
Configuring Multilink PPP Minimum Links Mandatory: Example
Multilink PPP Minimum Links Mandatory
Multilink PPP allows multiple PPP links to be established in parallel to the same destination. Multilink PPP 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 ppp multilink links minimum links mandatory command. When you configure this command, all Network Control Protocols (NCPs) for an 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.
This document describes the Multilink PPP Minimum Links Mandatory feature for Cisco IOS Releases 12.2(13)T, 12.2(14)S, and 12.2(15)B.
Feature History for the Multilink PPP Minimum Links Mandatory Feature
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Contents
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Information About Multilink PPP Minimum Links Mandatory
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How to Configure Multilink PPP Minimum Links Mandatory
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Configuration Examples for Multilink PPP Minimum Links Mandatory
Information About Multilink PPP Minimum Links Mandatory
You must understand the following concepts to configure this feature:
PPP Encapsulation
PPP, described in RFC 1661, encapsulates network layer protocol information over point-to-point links. You can configure PPP on the following types of physical interfaces:
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Asynchronous serial
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High-Speed Serial Interface (HSSI)
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ISDN
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Synchronous serial
When PPP encapsulation is enabled on physical interfaces, PPP can also be in effect on calls placed by the dialer interfaces that use the physical interfaces.
PPP supports option 3, authentication using Challenge Handshake Authentication Protocol (CHAP) or Password Authentication Protocol (PAP); option 4, Link Quality Monitoring (LQM); and option 5, Magic Number configuration options. Cisco IOS software always sends option 5 and negotiates for options 3 and 4 if so configured. All other options are rejected.
Magic Number support is available on all serial interfaces. PPP always attempts to negotiate for Magic Numbers, which are used to detect looped-back lines. Depending on how the down-when-looped command is configured, the router might shut down a link if it detects a loop.
Cisco IOS software provides the CHAP and PAP on serial interfaces running PPP encapsulation. For detailed information about authentication, refer to the Cisco IOS Security Configuration Guide.
Multilink PPP
The Multilink PPP feature provides load balancing functionality over multiple WAN links, while providing multivendor interoperability, packet fragmentation and proper sequencing, and load calculation on both inbound and outbound traffic. The Cisco implementation of MLP supports the fragmentation and packet sequencing specifications in RFC 1990. Additionally, you can change the default endpoint discriminator value that is supplied as part of user authentication. Refer to RFC 1990 for more information about the endpoint discriminator.
MLP allows packets to be fragmented and the fragments to be sent at the same time over multiple point-to-point links to the same remote address. The multiple links come up in response to a defined dialer load threshold. The load can be calculated on inbound traffic, outbound traffic, or on either, as needed for the traffic between the specific sites. MLP provides bandwidth on demand and reduces transmission latency across WAN links.
MLP is designed to work over synchronous and asynchronous serial and BRI and PRI types of single or multiple interfaces that have been configured to support both dial-on-demand rotary groups and PPP encapsulation.
How to Configure Multilink PPP Minimum Links Mandatory
This section contains the following procedures:
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Configuring PPP (required)
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Configuring Multilink PPP (required)
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Configuring Multilink PPP Minimum Links Mandatory (required)
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Verifying the Multilink PPP Minimum Links Mandatory Configuration (optional)
Configuring PPP
Perform this task to configure PPP.
SUMMARY STEPS
1.
enable
2.
configure terminal
3.
interface type slot/port
4.
encapsulation ppp
5.
ppp authentication {chap | chap pap | pap chap | pap} [if-needed] [list-name | default] [callin]
6.
exit
7.
username name password secret
DETAILED STEPS
Configuring Multilink PPP
Perform this task to configure MLP.
SUMMARY STEPS
1.
enable
2.
configure terminal
3.
interface multilink group-number
4.
ip address address
5.
encapsulation ppp
6.
ppp multilink
7.
ppp multilink links maximum links
8.
ppp multilink links minimum links
9.
bridge-group bridge-group-number
10.
no shutdown
DETAILED STEPS
Configuring Multilink PPP Minimum Links Mandatory
Perform this task to configure the minimum number of links in an MLP bundle required to keep that bundle active.
SUMMARY STEPS
1.
enable
2.
configure terminal
3.
interface multilink group-number
4.
ppp multilink
5.
ppp multilink links minimum links mandatory
DETAILED STEPS
Verifying the Multilink PPP Minimum Links Mandatory Configuration
Perform this task to verify configuration of the Multilink PPP Minimum Links Mandatory feature.
SUMMARY STEPS
1.
enable
2.
show running-config [interface type number] [linenum]
3.
show interfaces multilink group-number
4.
show ppp multilink
5.
show interfaces multilink group-number stat
DETAILED STEPS
Examples
The following is sample output from the show running-config command that shows that the Multilink PPP Minimum Links Mandatory feature is configured on interface bri0:
Router# show running-config...interface multilink1ip address 10.0.0.0 255.255.255.0encapsulation pppppp authentication chapppp multilinkppp multilink max-links 100ppp multilink links minimum 10 mandatoryinterface BRI2/1no ip addressencapsulation pppdialer pool-member 2no fair-queueno cdp enableppp authentication chapppp multilinkinterface bri 0description connected to abc 81012345678902ip address 172.16.0.10 255.255.255.0encapsulation pppdialer idle-timeout 30dialer map ip 172.16.0.0 name cisco 81012345678901dialer-group 1ppp authentication papppp multilinkppp multilink links minimum 2 mandatory ! Indicates that the Multilink PPP Minimum Links Mandatory feature is enabled.Configuration Examples for Multilink PPP Minimum Links Mandatory
This section provides the following configuration examples:
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Configuring Multilink PPP: Example
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Configuring Multilink PPP Minimum Links Mandatory: Example
Configuring PPP: Example
The following example shows how to configure PPP on a serial interface with CHAP authentication:
interface serial 1/0encapsulation pppppp authentication chapexitusername abc password password1Configuring Multilink PPP: Example
The following example shows how to configure MLP. 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 multilink max-links 100ppp multilink links minimum 5bridge-group 2no shutdownConfiguring Multilink PPP Minimum Links Mandatory: Example
The following example shows how to configure an MLP bundle to be required to have at least five active sessions:
ppp multilinkppp multilink links minimum 5 mandatoryAdditional References
The following sections provide references related to the Multilink PPP Minimum Links Mandatory feature.
Related Documents
Related Topic Document TitleDial technologies configuration
Dial technologies commands
Cisco IOS Dial Technologies Command Reference, Release 12.2 T
PPP and multilink PPP configuration
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Configuring Media-Independent PPP and Multilink PPP
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Configuring PPP and Multilink PPP
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Criteria for Naming Multilink PPP Bundles
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Multichassis Multilink PPP (MMP)
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Router-to-Router Async Multilink PPP
Standards
Standards TitleNo new or modified standards are supported by this feature and support for existing standards has not been modified by this feature.
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MIBs
RFCs
Technical Assistance
Command Reference
This section documents the following modified commands. All other commands used with this feature are documented in the Cisco IOS Release 12.2 T command reference publications.
multilink min-links
The multilink min-links command is replaced by the ppp multilink links minimum command. See the ppp multilink links minimum command for more information.
ppp multilink links minimum
To specify the preferred minimum number of links in a Multilink PPP (MLP) bundle, use the ppp multilink links minimum command in interface configuration mode. To reset the default value, use the no form of this command.
ppp multilink links minimum links [mandatory]
no ppp multilink links minimum
Syntax Description
Defaults
0 links
Command Modes
Interface configuration
Command History
Usage Guidelines
This command affects only dial-on-demand dynamic bandwidth environments.
The value configured for the links argument specifies the minimum number of links that MLP will try to keep in a bundle. If a bundle contains fewer links than the number specified by the links argument, 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 the specified limit. 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 the mandatory keyword is configured, the minimum number of links specified by the links argument must be in the bundle. Whenever a link is added to or removed from the bundle, the number of links is checked against the specified minimum number. If the number of links in the bundle falls below the specified minimum, all NCPs will be disabled for the bundle. NCPs will be established if the number of links meets the specified minimum.
If the dialer max-call command is configured, MLP will not exceed its value even if the ppp multilink links maximum command is configured for a higher value. This restriction does not affect the number of links that you can configure; rather it affects what happens at run time.
Examples
The following example sets the minimum number of links to 12:
ppp multilink links minimum 12The following example sets the minimum number of links to 4 and specifies that the bundle must have at least four links to establish and maintain NCPs:
ppp multilink links minimum 4 mandatoryRelated Commands
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