Table Of Contents
ATM Multilink PPP Support on Multiple VCs
Related Features and Technologies
Defining the Service Policy Using the MQC
Defining a Multilink MLP Bundle Interface
Defining the Virtual Templates for Member Links
Defining the PVCs and Making Them Bundle Member Links
Verifying ATM Multilink PPP Support on Multiple VCs
Monitoring ATM Multilink PPP Support on Multiple VCs
Defining the Service Policy Using the MQC Configuration: Example
Defining a Multilink MLP Bundle Interface Configuration: Example
Defining Virtual Templates for Member Links Configuration: Example
Defining PVCs and Making Them Bundle Member Links Configuration: Example
ATM Multilink PPP Support on Multiple VCs
First Published: 12.2(13)TLast Updated: February 28, 2006
History for the ATM Multilink PPP Support on Multiple VCs Feature
12.2(13)T
This feature was introduced.
12.2(28)SB
This feature was integrated into Cisco IOS Release 12.2(28)SB.
Finding Support Information for Platforms and Cisco IOS Software Images
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This document describes the ATM Multilink PPP Support on Multiple VCs feature. It includes the following sections:
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Monitoring ATM Multilink PPP Support on Multiple VCs
Feature Overview
The ATM Multilink PPP Support on Multiple VCs feature supports the transport of real-time (voice) and other (data) traffic on Frame Relay and ATM virtual circuits (VCs).
This feature facilitates traffic load balancing on high-speed virtual circuits, using multilink Point-to-Point Protocol (MLP) over Frame Relay and ATM. It facilitates traffic load balancing by using MLP to combine packet datagrams on high-speed VCs, as a means for transporting both the voice and data traffic more efficiently.
Load balancing operates at Layer 2 or Layer 3 (the network layer) of the Open System Interconnection (OSI) reference model. Layer 3 load balancing is independent of any link-layer technologies. The ATM Multilink Point-to-Point Protocol (PPP) Support on Multiple VCs feature implements load balancing at Layer 2 and depends on having MLP enabled at the link layer.
The ATM MLP functionality keeps track of packet sequencing, and this functionality buffers any packets that arrive early. With this ability, ATM MLP preserves packet order across the entire bundle.
In addition to MLP, low latency queueing (LLQ) and class-based weighted fair queueing (CBWFQ) are used to prioritize and differentiate the voice and data packets. LLQ and CBWFQ help to ensure that the voice and data traffic receive the proper quality of service (QoS) treatment (such the correct priority queue assignment) when the voice and data traffic are transmitted.
For more information about LLQ and CBWFQ, see the Cisco IOS Quality of Service Solutions Configuration Guide, Release 12.2.
Benefits
Facilitates More Efficient Traffic Load Balancing
The ATM Multilink PPP Support on Multiple VCs feature supports the transport of real-time (voice) and other (data) traffic on Frame Relay and ATM VCs.
Restrictions
The ATM Multilink PPP Support on Multiple VCs feature does not support the following commands and functionality. The configuration will accept these commands, but the commands have no effect:
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The ATM Multilink PPP Support on Multiple VCs feature does not support the link fragmentation and interleaving (LFI) functionality.
Related Features and Technologies
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Configuration Tasks
See the following sections for configuration tasks for the ATM Multilink PPP Support on Multiple VCs feature. Each task in the list is identified as either required or optional.
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Defining the Service Policy Using the MQC
The MQC allows you to create class maps and define service policies. Service policies are used to create classes and set match criteria for classifying traffic. To define a service policy using the MQC, use the following commands beginning in global configuration mode:
Step 1
Router(config)# class-map class-map-name
Specifies the name of the class map to be created. If match-all or match-any is not specified, traffic must match all the match criteria to be classified as part of the class map. Enters class-map configuration mode.
Step 2
Router(config-cmap)# match ip precedence ip-precedence-value [ip-precedence-value ip-precedence-value ip-precedence-value]1
Identifies IP precedence values as match criteria.
Step 3
Router(config-cmap)# exit
Exits class-map configuration mode.
Step 4
Router (config)# policy-map policy-name
Specifies the name of the policy map to be created. Enters policy-map configuration mode.
Step 5
Router (config-pmap)# class class-name
Specifies the name of the class map configured earlier. This class map is used to classify traffic. Enters policy-map class configuration mode.
Step 6
Router (config-pmap-c)# bandwidth {bandwidth-kbps | percent percent}1
Specifies a minimum bandwidth guarantee to a traffic class in periods of congestion. A minimum bandwidth guarantee can be specified in kbps or by a percentage of the overall available bandwidth. Enters class-map configuration mode.
Step 7
Router(config-cmap)# exit
Exits class-map configuration mode.
1 This is only an example of a command that can be used when configuring a class map or a policy map. Other commands are available. For more information, refer to the "Configuring the Modular Quality of Service Command-Line Interface" chapter of the Cisco IOS Quality of Service Solutions Configuration Guide, Release 12.2.
Defining a Multilink MLP Bundle Interface
The purpose of a multilink bundle interface is to combine more than one permanent virtual circuit (PVC). All configurations for PPP over ATM links are put into virtual templates, and the bundle parameters are put into the multilink bundle. To define a multilink MLP bundle interface, use the following commands beginning in global configuration mode:
Defining the Virtual Templates for Member Links
To define the virtual templates for member links, use the following commands beginning in global configuration mode:
Defining the PVCs and Making Them Bundle Member Links
To define the PVCs and make them bundle member links, use the following commands beginning in global configuration mode:
Step 1
Router(config)# interface atm slot/0
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Router(config)# interface atm slot/port
Specifies the ATM interface type and enters interface configuration mode.1
Step 2
Router(config-if)# no ip address
Removes an IP address or disables IP processing.
Step 3
Router(config-if)# load interval seconds
Changes the length of time for which data is used to compute load statistics.
Step 4
Router(config-if)# atm ilmi-keepalive [seconds]
Enables Interim Local Management Interface (ILMI) keepalives.
Step 5
Router(config-if)# pvc [name] vpi/vci
Creates an ATM PVC. Enters interface-ATM-VC configuration mode.
Step 6
Router(config-if-atm-vc)# vbr-nrt output-pcr output-scr output-mbs
Configures the variable bit rate (VBR)-non real time (NRT) QoS and specifies output peak cell rate, output sustainable cell rate, and output maximum burst cell size.
Step 7
Router(config-if-atm-vc)# tx-ring-limit ring-limit
Limits the number of particles or packets that can be used on a transmission ring on an interface. Use this command to tune the transmission ring to assign most of the packets to the Layer 3 queues.
Step 8
Router(config-if-atm-vc)# protocol ppp virtual-template number
Specifies that PPP is established over the ATM PVC using the configuration from the specified virtual template. Enters interface configuration mode.
Step 9
Router(config-if)# exit
Exits interface configuration mode.
1 To determine the correct form of the interface atm command, refer to your ATM network module, port adapter, or router documentation.
Verifying ATM Multilink PPP Support on Multiple VCs
To display information about ATM Multilink PPP Support on Multiple VCs, use the following privileged EXEC commands, as needed:
Monitoring ATM Multilink PPP Support on Multiple VCs
To monitor ATM Multilink PPP Support on Multiple VCs, use the following privileged EXEC commands, as needed:
Configuration Examples
This section provides the following configuration examples:
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Defining the Service Policy Using the MQC Configuration: Example
The following example shows a service policy that is configured using the MQC:
class-map match-all DATAmatch ip precedence 0class-map match-all VOICEmatch access-group 100policy-map CISCOclass VOICEpriority percent 70class DATAbandwidth percent 5access-list 100 permit udp any any precedence criticalDefining a Multilink MLP Bundle Interface Configuration: Example
The following example shows a Multilink bundle that is defined for the mulitilink interface:
interface Multilink1ip address 6.6.6.1 255.0.0.0load-interval 30no cdp enableservice-policy output CISCOppp multilink fragment disableppp multilink group 1!Defining Virtual Templates for Member Links Configuration: Example
The following example shows virtual templates that are defined for member links:
interface Virtual-Template1no ip addressload-interval 30ppp multilinkppp multilink group 1!interface Virtual-Template2no ip addressload-interval 30ppp multilinkppp multilink group 1Defining PVCs and Making Them Bundle Member Links Configuration: Example
The following example shows PVCs that are defined and configured as bundle members:
interface ATM6/0no ip addressload-interval 30atm ilmi-keepalivepvc 0/34vbr-nrt 1536 1536tx-ring-limit 5protocol ppp Virtual-Template1!pvc 0/35vbr-nrt 800 800tx-ring-limit 3protocol ppp Virtual-Template2!pvc 0/36vbr-nrt 800 400 94tx-ring-limit 5protocol ppp Virtual-Template1!pvc 0/37vbr-nrt 800 800tx-ring-limit 3protocol ppp Virtual-Template2!Additional References
The following sections provide references related to ATM Multilink PPP Support on Multiple VCs.
Related Documents
QoS Configuration Tasks
Cisco IOS Quality of Service Solutions Configuration Guide, Release 12.2
QoS Commands List
Cisco IOS Quality of Service Solutions Command Reference, Release 12.2
WAN Configuration Tasks
Cisco IOS Wide-Area Networking Configuration Guide, Release 12.2
WAN Commands List
Cisco IOS Wide-Area Networking Command Reference, Release 12.2
Standards
MIBs
None
To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:
RFCs
Technical Assistance
Command Reference
There are no new or modified commands for this feature. All other commands used with this feature are documented in the Cisco IOS Release 12.2 command reference publications.
Glossary
LFI—link fragmentation and interleaving. Method of fragmenting large packets and then queueing the fragments between small packets.
MLP—multilink PPP.
multilink PPP—See MLP.
QoS—quality of service.
VC—virtual circuit.
Any Internet Protocol (IP) addresses used in this document are not intended to be actual addresses. Any examples, command display output, and figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses in illustrative content is unintentional and coincidental.
© 2002, 2005-2006 Cisco Systems, Inc. All rights reserved.
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