- Overview of Dial Interfaces, Controllers, and Lines
- Configuring Asynchronous Lines and Interfaces
- Asynchronous Call Queueing by Role
- Configuring Asynchronous Serial Traffic Over UDP
- Configuring and Managing Integrated Modems
- 1- and 2-Port V.90 Modem WICs for Cisco 2600 and Cisco 3600 Series Multiservice Platforms
- Call Tracker show Commands Extensions
- Cisco NM-8AM-V2 and NM-16AM-V2 Analog Modem Network Modules with V.92
- MICA and NextPort Modem Tech-Support Command Additions
- PIAFS Wireless Data Protocol Version 2.1 for Cisco MICA Modems
- V.92 and V.44 Support for Digital Modems
- V.92 Modem on Hold for Cisco AS5300 and Cisco AS5800 Universal Access Servers
- V.92 Modem on Hold for Cisco AS5350, Cisco AS5400, and Cisco AS5850 Universal Gateways and Cisco AS5800 Universal Access Servers
- V.92 Quick Connect for Cisco AS5300 and Cisco AS5800 Universal Access Servers
- V.92 Quick Connect for Cisco AS5350, Cisco AS5400, and Cisco AS5850 Universal Gateways and Cisco AS5800 Universal Access Servers
- V.92 Reporting Using RADIUS Attribute v.92-info
- Configuring and Managing Cisco Access Servers and Dial Shelves
- Configuring and Managing External Modems
- Modem Signal and Line States
- Creating and Using Modem Chat Scripts
- Cisco Modem User Interface
- Modem Script and System Script Support in Large-Scale Dial-Out
- Leased and Switched BRI Interface for ETSI NET3
- ISDN BCAC and Round-Robin Channel Selection Enhancements
- Configuring Virtual Asynchronous Traffic over ISDN
- Configuring Modem Use over ISDN BRI
- Configuring X.25 on ISDN
- Configuring X.25 on ISDN Using AO/DI
- Configuring ISDN on Cisco 800 Series Routers
- Cisco IOS Software Feature Removal
- Configuring ISDN PRI
- Dialing Number Enhancement
- ISDN BCAC and Round-Robin Channel Selection Enhancements
- Configuring ISDN Special Signaling
- Configuring Network Side ISDN PRI Signaling, Trunking, and Switching
- Preparing to Configure DDR
- Configuring Legacy DDR Spokes
- Configuring Legacy DDR Hubs
- Configuring Peer-to-Peer DDR with Dialer Profiles
- Dialer Map VRF-Aware for an MPLS VPN
- Dialer Persistent
- PPPoE Client DDR Idle-Timer
- Redial Enhancements
- Rotating Through Dial Strings
- Configuring Dialer CEF
- CEF Support for Dialer Profiles on Cisco 7500 Routers
- Configuring Snapshot Routing
- Reliable Static Routing Backup Using Object Tracking
- Configuring Dial Backup for Serial Lines
- Configuring Dial Backup Using Dialer Watch
- Dialer Watch Connect Delay
- VRF Aware Dialer Watch
- Configuring Dial Backup with Dialer Profiles
- ISDN Backup in MPLS Core
- Configuring Cisco Easy IP ..
- Configuring Virtual Template Interfaces
- Multiclass Multilink PPP
- Configuring Asynchronous Callback
- Configuring PPP Callback
- Configuring ISDN Caller ID Callback
- Configuring BACP
- Configuring an IP Local Pools Holdback Timer
- Configuring per-User Configuration
- Configuring Resource Pool Management
- Configuring Wholesale Dial Performance Optimization
- Large-Scale Dial-Out
- Dial-Out DS0 Level Trunk Group
- L2TP Large-Scale Dial-Out
- L2TP Large-Scale Dial-Out per-User Attribute via AAA
- Modem Script and System Script Support in Large-Scale Dial-Out
- Large-Scale Dial-Out (LSDO) VRF Aware
- Peer Pool Backup
- Dial Networking Business Applications
- Enterprise Dial Scenarios and Configurations
- Telco and ISP Typical Dial Scenarios and Configurations
- Modem Initialization Strings
Multiclass Multilink PPP
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This document describes the Multiclass Multilink PPP feature in Cisco IOS Release 12.2(13)T. It includes the following sections:
Feature Overview
Previous implementations of Cisco IOS Multilink PPP (MLP) include support for Link Fragmentation Interleaving (LFI). This feature allows the delivery of delay-sensitive packets, such as the packets of a Voice call, to be expedited by omitting the PPP Multilink Protocol header and sending the packets as raw PPP packets in between the fragments of larger data packets. This feature works well on bundles consisting of a single link. However, when the bundle contains multiple links there is no way to keep the interleaved packets in sequence with respect to each other.
The Multiclass Multilink PPP (MCMP) feature in Cisco IOS Release 12.2(13)T addresses the limitations of MLP LFI on bundles containing multiple links by introducing multiple data classes. Normal data traffic and delay-sensitive data traffic are divided into Class 0 and Class 1, respectively. Class 0 data traffic is subject to fragmentation just as regular multilink packets are. Class 1 data traffic can be interleaved but never fragmented. The next transmit sequence number, expected sequence number, unassigned fragment list, working packet, lost fragment timer, fast-switching mode, and all statistics are managed per class, rather than for the bundle as a whole.
Benefits
The Multiclass Multilink PPP feature in Cisco IOS Release 12.2(13)T allows rapid delivery of real-time data over a bundle containing multiple links without loss of sequencing.
Restrictions
The ppp multilink multiclass command must be configured on each link that will be joining the bundle. Failure to configure this command could result in the peer refusing to allow mismatched links to join the bundle. The first link to join the bundle will determine whether MCMP is in effect for the bundle. Each subsequent link must negotiate the same MCMP parameters in order to join the bundle.
Because real-time traffic is encapsulated with multilink headers, the receiver will be required to buffer the packets when they arrive out of sequence. Therefore, the differential delay between the links must be small relative to the tolerable delay for such traffic. Otherwise, packets may be subject to additional delay while the receiver awaits the arrival of earlier sequence numbers sent over other links in the bundle.
The maximum number of links supported for an MCMP bundle is 64.
The Prefix Elision option specified in RFC 2686 is not supported.
Related Features and Technologies
Related Documents
Supported Platforms
- Cisco 2600 series
- Cisco 3600 series
- Cisco 3700 series
- Cisco 7200 series
- Cisco AS5300
- Cisco AS5350
- Cisco AS5400
Determining Platform Support Through Cisco Feature Navigator
Cisco IOS software is packaged in feature sets that are supported on 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 quickly 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.
To access Cisco 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 found at this URL:
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, if supported, Cisco Feature Navigator.
Supported Standards, MIBs, and RFCs
To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:
http://tools.cisco.com/ITDIT/MIBS/servlet/index
If Cisco MIB Locator does not support the MIB information that you need, you can also obtain a list of supported MIBs and download MIBs from the Cisco MIBs page at the following URL:
http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml
To access Cisco MIB Locator, 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 found at this URL:
Prerequisites
The dialer interface, BRI interface, PRI interface, multilink interface, or virtual template must be configured, and PPP encapsulation must be enabled. For information on completing these tasks, refer to the Cisco IOS Dial Technologies Configuration Guide, Release 12.2.
MLP LFI must be configured on the bundle. See the section “Configuring MLP LFI on a Bundle” in this document.
Configuration Tasks
See the following sections for configuration tasks for the Multiclass Multilink PPP feature. Each task in the list is identified as either required or optional.
- Configuring MLP LFI on a Bundle (required)
- Configuring MCMP on a Member Link (required)
- Verifying MCMP (optional)
Configuring MLP LFI on a Bundle
To configure MLP LFI on a dialer, multilink, or virtual template, use the following commands beginning in interface configuration mode:
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Enables interleaving of packets among the fragments of larger packets on an MLP bundle. |
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Router(config-if)# ppp multilink fragment delay milliseconds |
Specifies a maximum size, in units of time, for packet fragments on an MLP bundle. |
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Router(config-if)# ip rtp reserve lowest-udp-port range-of-ports [ maximum-bandwidth ] |
Reserves a special queue for real-time packet flows to specified destination User Datagram Protocol (UDP) ports, allowing real-time traffic to have higher priority than other flows. |
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For virtual templates only, applies the virtual template to the multilink bundle.1 |
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Configuring MCMP on a Member Link
To configure MCMP on a configured and operational member link, use the following commands in interface configuration mode:
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Verifying MCMP
To verify that the Multiclass Multilink PPP feature is configured correctly, enter the show ppp multilink EXEC command. The following output includes class-specific information for the PPP Multilink bundles:
Configuration Examples
This section provides the following configuration example:
- Configuring MCMP on a Dialer Example
- MCMP and MLP Interleaving and Queueing for Real-Time Traffic Examples
Configuring MCMP on a Dialer Example
The following partial example configures a dialer for MCMP; it does not show the configuration of the physical interfaces:
MCMP and MLP Interleaving and Queueing for Real-Time Traffic Examples
The following example enables MLP interleaving and MCMP on a dialer interface that controls a rotary group of BRI interfaces. This configuration permits IP packets to trigger calls.
The following example defines a virtual interface template that enables MLP interleaving and a maximum real-time traffic delay of 20 milliseconds. The bundle interface will be a virtual access interface cloned from the virtual template. MCMP is then configured on a member link, Serial0.
The following example configures MLP interleaving and a maximum real-time traffic delay of 20 milliseconds on a multilink interface. MCMP is then configured on a member link, Serial1, and the member link is restricted to joining only the designated multilink group interface.
Command Reference
The following commands are introduced or modified in the feature or features documented in this module. For information about these commands, see the Cisco IOS Dial Technologies Command Reference at http://www.cisco.com/en/US/docs/ios/dial/command/reference/dia_book.html . For information about all Cisco IOS commands, go to the Command Lookup Tool at http://tools.cisco.com/Support/CLILookup or to the Cisco IOS Master Commands List.
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