Cisco 10000 Series User manual

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Cisco 10000 Series Router Quality of
Service Configuration Guide
February 25, 2013
Text Part Number: OL-7433-09

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Cisco 10000 Series Router Quality of Service Configuration Guide
Copyright ©2007-2009, Cisco Systems, Inc. All rights reserved.

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CONTENTS
About This Guide xxxv
Guide Revision History xxxv
Audience xl
Document Organization xl
Document Conventions xlii
Related Documentation xliii
Obtaining Documentation and Submitting a Service Request xliii
CHAPTER 1Quality of Service Overview 1-1
Benefits of Quality of Service Features 1-2
Restrictions and Limitations for Quality of Service 1-2
Modular QoS Command-Line Interface 1-2
Feature History for MQC 1-3
QoS CLI Migration from PRE2 to PRE3 1-3
Feature History for QoS CLI Migration from PRE2 to PRE3 1-4
QoS Management Information Base Support 1-4
QoS Implementation Guidelines 1-4
QoS Execution on the Router 1-4
QoS Configuration on an Interface 1-5
QoS Models 1-6
Overview of QoS Models 1-6
Model D.2 Definition 1-7
Model F Definition 1-7
Configuration Tasks 1-8
Configuration Steps on Subinterfaces for QoS Model D.2 1-8
Configuration Steps on Sessions for QoS Model D.2 1-8
Configuration Steps for QoS Model F 1-9
Configuration Examples 1-9
QoS Features, Commands, and Changes 1-11
Applying QoS Parameters Dynamically to Sessions 1-12
Applying Traffic Shaping Parameters Using RADIUS Profiles 1-12
dbs enable Command 1-12
default dbs enable Command 1-12

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Dynamic Bandwidth Selection Feature 1-13
Attaching QoS Service Policies 1-13
service-policy Command 1-13
Attaching ATM QoS Service Policies 1-14
Attaching Frame Relay QoS Service Policies 1-14
Attaching LAC QoS Service Policies 1-15
Attaching Virtual LAN QoS Service Policies 1-15
Attaching Virtual Access Interface QoS Service Policies 1-15
Classifying Traffic 1-15
class-map Command 1-15
match Commands 1-16
Class Map Feature 1-18
Configuring QoS for MPLS Traffic 1-18
MPLS CoS Multi-VC Mode 1-18
MPLS QoS Feature 1-19
MPLS Traffic Engineering—DiffServ Aware Feature 1-19
Control Plane Policing 1-19
Divert Cause Policer 1-19
Control Plane Policing—Platform Enhancement 1-20
Controlling Packet Queue Congestion 1-21
queue-limit Command 1-21
random-detect Command 1-22
random-detect basis Command 1-23
show pxf cpu queue interface summary 1-23
Tail Drop Feature 1-23
Random Early Detection Feature 1-24
Weighted Random Early Detection Feature 1-24
Distributing Bandwidth Between Queues 1-25
bandwidth Command 1-25
bandwidth remaining ratio Command 1-26
Distribution of Remaining Bandwidth Using Ratio 1-26
Dynamically Changing VC Weight and Watermark Values 1-26
Hierarchical Queuing Framework 1-27
Hierarchical Queuing Framework Feature 1-27
MQC Hierarchical Queuing with 3 Level Scheduler 1-27
Hierarchical Policies 1-27
Nested Hierarchical Policies 1-27
Three-Level Hierarchical Policies 1-28
Hierarchical Input Policing 1-28
IP Quality of Service for Subscribers 1-29

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MQC Support for IP Sessions 1-29
Per-Session Shaping for ATM Interfaces 1-29
Per Session Rate Limiting 1-29
Per User Multiservice Rate Limiting 1-29
Per Session Service Policy Using RADIUS 1-30
Per Session Shaping and Queuing on LNS 1-30
PPP Session Queuing on ATM VCs 1-30
Layer 2 Access Concentrator 1-30
Classification, Policing, and Marking on the LAC 1-30
LAC QoS 1-30
Link Fragmentation and Interleaving 1-31
interface multilink Command 1-31
multilink group Command 1-31
ppp multilink Command 1-32
ppp multilink fragment-delay Command 1-32
ppp multilink fragmentation Command 1-33
ppp multilink fragment disable Command 1-33
ppp multilink group Command 1-33
ppp multilink interleave Command 1-34
MLP Over ATM-Based LFI Feature 1-34
Multi-VC MLP Over ATM-Based LFI Feature 1-34
MLP Over Frame Relay-Based LFI Feature 1-35
MLP Over Serial-Based LFI Feature 1-35
FRF.12 Fragmentation Feature 1-35
Marking Traffic 1-36
set atm-clp Command 1-36
set cos Command 1-36
set discard-class Command 1-36
set fr-de Command 1-37
set ip dscp Command 1-37
set ip precedence Command 1-37
set mpls experimental Command 1-37
set mpls experimental imposition Command 1-38
set qos-group Command 1-38
Marking Feature 1-38
Modular QoS Command Line Interface 1-39
MQC Feature 1-39
QoS CLI Migration from PRE2 to PRE3 1-39
Overhead Accounting 1-39
ATM Overhead Accounting 1-40

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Ethernet Overhead Accounting 1-40
Traffic Shaping Overhead Accounting for ATM 1-40
Oversubscribing Physical and Virtual Links 1-41
atm over-subscription-factor Command 1-41
Interface Oversubscription Feature 1-41
ATM Virtual Circuit Oversubscription Feature 1-42
map-class frame-relay Command 1-42
Frame Relay PVC Oversubscription Feature 1-42
Virtual LAN Oversubscription Feature 1-43
queue-depth Command 1-43
weight Command 1-43
Weighting Feature 1-44
Policing Traffic 1-44
police Command (Single-Rate) 1-44
police percent Command 1-45
police Command (Two-Rate) 1-45
show atm vp Command 1-46
Percent-Based Policing Feature 1-46
Policing Feature 1-46
Single-Rate Color Marker Feature 1-47
Two-Rate Three-Color Marker Feature 1-47
ATM VP Average Traffic Rate 1-48
Prioritizing Traffic 1-48
priority Command 1-48
priority level Command 1-49
Child Service Policy Allowed Under Priority Class 1-49
Multi-Level Priority Queues 1-49
Priority Queuing Feature 1-49
PVC Bundles 1-50
bump Command 1-50
bump Command (Frame Relay VC-bundle-member) 1-51
bundle Command 1-51
class-bundle Command 1-51
class-vc Command 1-51
dscp Command (Frame Relay VC-bundle-member) 1-51
exp Command 1-51
frame-relay vc-bundle Command 1-51
mpls experimental Command 1-52
oam-bundle Command 1-52
precedence Command 1-52

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precedence Command (Frame Relay VC-bundle-member) 1-52
protect Command 1-52
protect Command (Frame Relay VC-bundle-member) 1-52
pvc-bundle Command 1-53
pvc Command (Frame Relay VC-bundle) 1-53
PVC Bundles Over ATM and Frame Relay Feature 1-53
ATM PVC Bundle Enhancement—MPLS EXP-Based PVC Selection Feature 1-53
Frame Relay PVC Bundles with QoS Support for IP and MPLS Feature 1-53
QoS Policy Maps 1-53
policy-map Command 1-54
qos match statistics Command 1-54
Policy Maps Feature 1-54
Policy Map Scaling Phase 2 1-54
Qos Policy Propagation through the Border Gateway Protocol 1-55
Shaping PPPoE Over VLAN Sessions Using RADIUS 1-55
Per Session Queuing and Shaping for PPPoE Over VLAN Support Using RADIUS Feature 1-55
Shaping Traffic 1-55
atm pvp Command 1-56
pvc Command 1-56
shape Command 1-56
shape percent Command 1-57
vbr-nrt Command 1-57
ATM VC/VP Shaping Feature 1-57
Class-Based Traffic Shaping Feature 1-58
Frame Relay Traffic Shaping Feature 1-58
Hierarchical Shaping Feature 1-58
Percentage-Based Traffic Shaping Feature 1-58
Traffic Shaping Overhead Accounting for ATM Feature 1-59
Sharing Bandwidth Fairly During Congestion 1-59
Bandwidth Fair Queuing Feature 1-59
Class-Based Weighted Fair Queuing Feature 1-59
Class-Based Weighted Fair Queuing for Virtual Access Interfaces Feature 1-60
Simultaneous Policy Maps 1-60
Simultaneous QoS Policy Map on Interface and PPP Session—A-DSLAM Case 1-60
VLAN Tag-Based Quality of Service 1-60
Related Documentation 1-61
CHAPTER 2Classifying Traffic 2-1
Traffic Classification Using Class Maps 2-1

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Feature History for Class Maps 2-2
System Limits for Class Maps 2-2
PRE3 Class Maps and QoS Scalability 2-3
class-map Command 2-3
Syntax Description 2-4
class-map Command History 2-4
Usage Guidelines for the class-map Command 2-4
qos match statistics Command 2-4
Syntax Description 2-4
Command Default 2-5
qos match statistics Command History 2-5
Usage Guidelines for the qos match statistics Command 2-5
Defining Match Criteria Using the match Commands 2-5
match Commands History 2-9
Usage Guidelines for match Commands 2-10
Class-Default Class 2-11
Restrictions and Limitations for Traffic Classification 2-11
Classifying Traffic Using a Class Map 2-11
Creating a Class Map 2-12
Configuration Examples for Classifying Traffic 2-12
Verifying Traffic Classification 2-13
Verification Example 2-13
Defining QoS Policy Actions 2-13
Related Documentation 2-14
CHAPTER 3Configuring QoS Policy Actions and Rules 3-1
QoS Policies 3-1
Feature History for QoS Policies 3-2
Defining QoS Actions Using a Policy Map 3-2
System Limits for Policy Maps 3-2
8K Policy Maps 3-3
policy-map Command 3-3
Syntax Description 3-4
Usage Guidelines for the policy-map Command 3-4
Types of QoS Actions 3-4
Input and Output Policy Actions 3-4
Policy Map Actions—Releases Prior to Cisco IOS Release 12.0(17)SL 3-7
Policy Map Actions—Cisco IOS Release 12.0(17)SL and Later Releases 3-10
Policy Map Actions—Cisco IOS Release 12.0(20)ST and Later Releases 3-10

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Policy Map Actions—Cisco IOS Release 12.0(22)S and Later Releases 3-11
Policy Map Actions—Cisco IOS Release 12.2(31)SB2 and Later Releases 3-11
Policing Actions 3-11
QoS Inheritance 3-12
ATM Service Categories 3-13
Constant Bit Rate 3-13
Unspecified Bit Rate 3-14
Variable Bit Rate 3-15
Traffic Subject to QoS Policies 3-17
ATM Virtual Circuits Without QoS Policies 3-17
QoS Performance 3-18
Configuring QoS Policies 3-18
Creating a Policy Map 3-19
Configuration Examples for Creating a Policy Map 3-19
Defining QoS Actions in a Policy Map 3-20
Attaching Service Policies 3-20
Verifying QoS Policy Configurations 3-20
Verification Example for Service Policies 3-22
Related Documentation 3-23
CHAPTER 4Attaching Service Policies 4-1
Interfaces Supporting QoS Service Policies 4-1
Attaching ATM QoS Service Policies 4-2
Feature History for ATM QoS 4-2
ATM QoS Inheritance 4-2
service-policy Command 4-3
Syntax Description 4-3
service-policy Command History 4-3
service-policy Command Modes 4-4
Usage Guidelines for the service-policy Command 4-4
Restrictions and Limitations for Attaching ATM Service Policies 4-5
Attaching ATM QoS Service Policies to ATM Interfaces, Subinterfaces, and PVCs 4-5
Attaching QoS Service Policies to an ATM Interface 4-6
Attaching QoS Service Policies to an ATM Point-to-Point Subinterface 4-7
Attaching QoS Service Policies to an ATM PVC 4-8
Attaching QoS Service Policies to an ATM PVC Range and an ATM PVC in a Range 4-9
Attaching Frame Relay QoS Service Policies 4-11
Feature History for Frame Relay QoS 4-12

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Frame Relay QoS Inheritance 4-12
map-class frame-relay Command 4-12
Syntax Description 4-12
map-class frame-relay Command History 4-13
Usage Guidelines for the map-class frame-relay Command 4-13
Restrictions and Limitations for Frame Relay QoS Service Policies 4-13
Creating and Attaching QoS Policies to Frame Relay Interfaces, Subinterfaces, and Data-Link
Connection Identifiers 4-14
Attaching a QoS Service Policy to a Frame Relay Interface or Point-to-Point Subinterface 4-14
Attaching a QoS Service Policy to a Frame Relay DLCI 4-17
Attaching Virtual LAN QoS Service Policies 4-20
Feature History for VLAN QoS 4-20
VLAN QoS Inheritance 4-21
Restrictions and Limitations for Attaching QoS Services to VLAN Subinterfaces 4-21
Attaching QoS Policies to VLAN Interfaces and Subinterfaces 4-21
Attaching QoS Service Policies to Physical Interfaces with VLAN Subinterfaces 4-22
Attaching QoS Service Policies to VLAN Subinterfaces 4-23
Attaching Virtual Access Interface QoS Service Policies 4-23
Feature History for VAI QoS 4-24
VAI QoS Inheritance 4-24
Restrictions and Limitations for Attaching QoS Services to a VAI 4-25
Attaching QoS Policies to VAIs Using Virtual Template Interfaces 4-25
Applying a QoS Service Policy to a Virtual Template Interface 4-26
Applying a Virtual Template Interface to a BBA Group 4-27
Attaching a BBA Group to an Interface or Subinterface for PPPoE Sessions 4-28
Attaching Layer 2 Access Concentrator QoS Service Policies 4-30
Feature History for LAC QoS 4-30
LAC QoS Inheritance 4-30
Restrictions and Limitations for Attaching LAC QoS 4-31
Attaching QoS Policies to LAC ATM Virtual Circuits 4-31
Applying QoS on Layer 2 Tunnel Packets 4-32
Verifying and Monitoring QoS Service Policies 4-32
Verification Example for QoS Service Policies 4-34
Related Documentation 4-36
CHAPTER 5Distributing Bandwidth Between Queues 5-1
Bandwidth Distribution Between Queues 5-1
Feature History for Bandwidth Distribution Between Queues 5-2
Interfaces Supporting Bandwidth Distribution 5-2

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Unused Bandwidth Allocation 5-3
Traffic Classes That Can Use Excess Bandwidth 5-3
Bandwidth Calculations 5-4
Bandwidth Allocation to PVCs 5-5
Class-Default Bandwidth Guarantee 5-6
Committed Rate Data 5-6
Bandwidth and Priority Service 5-7
Queuing Modes 5-8
Restrictions and Limitations for Bandwidth Distribution 5-9
Configuring Bandwidth Distribution Between Queues 5-10
Configuration Examples for Configuring Bandwidth Distribution 5-10
Configuration Example for Kilobits per Second-Based Bandwidth 5-11
Configuration Example for Percentage-Based Bandwidth 5-11
Configuration Example for Bandwidth-Remaining-Based Bandwidth 5-11
Verifying and Monitoring Bandwidth Distribution 5-12
Verification Example for Bandwidth Distribution 5-13
Distribution of Remaining Bandwidth Using Ratio 5-14
Feature History for Bandwidth-Remaining Ratios 5-14
Bandwidth-Remaining Ratio 5-14
Prerequisites for Distribution of Remaining Bandwidth Using Ratio 5-15
Restrictions for Distribution of Remaining Bandwidth Using Ratio 5-15
Configuring Bandwidth-Remaining Ratios 5-15
Configuring and Applying Bandwidth-Remaining Ratios to Subinterfaces 5-16
Configuring and Applying Bandwidth-Remaining Ratios to Class Queues 5-18
Configuration Examples for Distribution of Remaining Bandwidth Using Ratio 5-20
Configuring Bandwidth-Remaining Ratios on Ethernet Subinterfaces: Example 5-21
Configuring Bandwidth-Remaining Ratios on ATM Subinterfaces: Example 5-21
Configuring Bandwidth-Remaining Ratios on Class Queues: Example 5-22
Verifying Bandwidth Remaining Ratios: Example 5-22
Related Documentation 5-26
CHAPTER 6Policing Traffic 6-1
Traffic Policing 6-2
Feature History for Traffic Policing 6-2
Policing Actions 6-3
Single-Rate Color Marker for Traffic Policing 6-4
Feature History for the Single-Rate Color Marker 6-5
Configuration Commands for the Single-Rate Color Marker 6-5
police Command (Single-Rate) 6-6

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Two-Rate Three-Color Marker for Traffic Policing 6-8
Feature History for the Two-Rate Color Marker 6-9
Configuration Commands for the Two-Rate Color Marker 6-9
police Command (Two-Rate) 6-9
Percent-Based Policing 6-11
Feature History for Percent-Based Policing 6-11
police percent Command 6-11
Control Plane Policing 6-13
AToM Set ATM CLP Bit Using a Policer 6-13
Feature History for Set ATM CLP Bit Marking As a Police Action 6-14
AToM Set FR DE as Police Action 6-14
Feature History for AToM Set FR DE as Police Action 6-14
Set Layer 2 CoS as a Policer Action 6-15
Feature History for Set Layer 2 CoS as Policer Action 6-15
Set Inner CoS as a Policer Action 6-15
Feature History for Set Inner CoS as a Policer Action 6-15
Set Inner and Outer CoS as a Policer Action 6-16
Feature History for Set Inner and Outer CoS as a Policer Action 6-16
Dual Police Actions 6-16
Feature History for Dual Police Actions 6-17
Policing Support for GRE Tunnels 6-17
Interfaces Supporting Policing 6-17
Metering Traffic and Token Buckets 6-18
Metering Traffic Using Token Buckets (Single-Rate Policer) 6-18
Metering Traffic Using Token Buckets (Two-Rate Policer) 6-19
Committed Bursts and Excess Bursts 6-21
Committed Bursts 6-21
Committed Burst Calculation 6-22
Excess Bursts 6-22
Excess Burst Calculation 6-22
Deciding if Packets Conform or Exceed the Committed Rate 6-23
Data Included in the Policing Rate 6-23
Policing Rate Granularity 6-25
Avoiding Bandwidth Starvation Due to Priority Services 6-25
Bandwidth and Policing 6-26
Restrictions and Limitations for Traffic Policing 6-26
Configuring Traffic Policing 6-27
Configuring Single-Rate Traffic Policing Based on Bits per Second 6-28

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Configuration Examples for Configuring Single-Rate Traffic Policing Based on Bits per
Second 6-28
Configuring Percent-Based Policing 6-32
Configuration Examples for Configuring Percent-Based Policing 6-32
Configuring Two-Rate Policing 6-35
Configuration Example for Configuring Two-Rate Three-Color Policing 6-35
Marking Traffic Using Police Actions 6-36
Configuration Example for Marking Traffic Using Police Actions 6-36
Configuring Dual Police Actions 6-37
Configuration Example for Configuring Dual Police Actions 6-37
Configuration Examples 6-38
Configuration Example for Dual Actions—set-clp-transmit and set-mpls-exp-transmit 6-38
Configuration Example for Dual Actions—set-frde-transmit and
set-mpls-exp-imposition-transmit 6-39
Configuration Example of the set-cos-transmit Police Action 6-40
Verifying and Monitoring Traffic Policing 6-41
Verification Examples for Traffic Policing 6-41
Verifying Policing for a Specific Traffic Class 6-42
Verifying Policing on a Specific Interface 6-42
Verifying Dual Police Actions—set-clp-transmit and set-mpls-exp-transmit 6-43
Related Documentation 6-43
CHAPTER 7Marking Traffic 7-1
QoS Packet Marking 7-2
Feature History for QoS Packet Marking 7-3
Benefits of QoS Packet Marking 7-3
IP Precedence Marking 7-4
IP Precedence-Based Weighted Random Early Detection 7-4
set ip precedence Command 7-5
Syntax Description 7-5
set ip precedence Command History 7-5
Usage Guidelines for the set ip precedence Command 7-5
IP Differentiated Services Code Point Marking 7-6
DSCP Per-Hop Behavior 7-6
Assured Forwarding 7-7
Expedited Forwarding 7-7
Class Selector Code Points 7-7
DSCP Values 7-8
DSCP-Based Weighted Random Early Detection 7-9

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set ip dscp Command 7-9
Syntax Description 7-9
set ip dscp Command History 7-10
Usage Guidelines for the set ip dscp Command 7-10
Class of Service Marking 7-10
QinQ Class of Service Marking 7-12
set cos Command 7-12
Syntax Description 7-12
set cos Command History 7-12
Usage Guidelines for the set cos Command 7-12
QoS Group Marking 7-13
set qos-group Command 7-13
Syntax Description 7-13
set qos-group Command History 7-13
Usage Guidelines for the set qos-group Command 7-13
ATM Cell Loss Priority Marking 7-14
set atm-clp Command 7-14
set atm-clp Command History 7-14
Usage Guidelines for the set atm-clp Command 7-14
MPLS Experimental Marking 7-14
QinQ MPLS Experimental Marking 7-15
set mpls experimental imposition Command 7-15
Syntax Description 7-15
set mpls experimental imposition Command History 7-15
Usage Guidelines for the set mpls experimental imposition Command 7-16
Discard-Class Marking 7-16
set discard-class Command 7-16
Syntax Description 7-16
set discard-class Command History 7-16
Usage Guidelines for the set discard-class Command 7-17
Class-Based Frame Relay DE Bit Marking 7-17
History for the Class-Based Frame Relay DE Bit Marking Feature 7-17
Marking and Policing Traffic 7-18
Tunnel Header Marking 7-18
Feature History for Tunnel Header Marking 7-19
Restrictions and Limitations for Marking 7-19
Interfaces Supporting Marking 7-20
Classification and Marking Design Guidelines 7-21

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Recommended Values for Traffic Marking 7-21
Configuring Traffic Marking 7-22
Configuring IP Precedence Marking 7-22
Configuration Examples for IP Precedence Marking and Classification 7-23
Configuring IP DSCP Marking 7-24
Configuration Examples for IP DSCP Marking and Classification 7-25
Configuring Class of Service Marking 7-26
Configuration Examples for CoS Marking and Classification 7-27
Configuring QoS Group Marking 7-28
Configuration Examples for Configuring QoS Group Marking and Classification 7-28
Setting the ATM Cell Loss Priority Bit 7-29
Configuration Example for Setting the ATM CLP Bit 7-30
Configuring MPLS Experimental Marking 7-31
Configuration Examples for Configuring MPLS Experimental Marking and Classification 7-32
Configuring Discard-Class Marking 7-33
Configuration Examples for Configuring Discard-Class Marking and Classification 7-34
Configuring Tunnel Header Marking Using the set Command 7-35
Configuration Example for Tunnel Header Marking Using the set Command 7-35
Configuring Tunnel Header Marking Using the police Command 7-36
Example Configuration for Tunnel Header Marking Using the police Command 7-36
Verifying Traffic Marking 7-37
Verification Examples for Traffic Marking 7-38
Related Documentation 7-39
CHAPTER 8Prioritizing Services 8-1
Low-Latency Priority Queuing 8-1
Feature History for Low-Latency Priority Queuing 8-2
Bandwidth Starvation 8-3
Multi-Level Priority Queues 8-3
Feature History for Multi-Level Priority Queues 8-4
Child Service Policy Allowed Under Priority Class 8-4
Interfaces Supporting Priority Queuing 8-4
Queues per Policy Map 8-5
Restrictions and Limitations for Priority Queuing 8-5
Restrictions for Multi-Level Priority Queues 8-5
Configuring a Priority Queue 8-6
Configuring Multi-Level Priority Queues 8-7
Configuration Examples for Configuring Priority Queues 8-9

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Configuring a Priority Queue with a Guaranteed Bandwidth Based on Kilobits per Second:
Example 8-9
Configuring a Priority Queue with a Percent-Based Bandwidth Guarantee: Example 8-9
Configuring Multi-Level Priority Queues: Example 8-10
Unacceptable MPQ Configurations: Examples 8-10
Verifying and Monitoring Priority Queues 8-11
Verification Examples for Priority Queues 8-11
Verifying a Priority Queue: Example 8-11
Verifying Multi-Level Priority Queues: Example 8-12
Related Documentation 8-13
CHAPTER 9Shaping Traffic 9-1
Traffic Shaping 9-2
Feature History for Traffic Shaping 9-3
Class-Based Traffic Shaping 9-3
Feature History for Class-Based Traffic Shaping 9-4
System Limits for Class-Based Shaping 9-4
Restrictions and Limitations for Class-Based Shaping 9-4
Hierarchical Shaping 9-4
Feature History for Hierarchical Shaping 9-5
VP-Level Shaping 9-5
VC-Level Shaping 9-5
Shaped UBR PVCs 9-5
How Hierarchical Shaping Works 9-6
Hierarchical Shaping and Oversubscription 9-7
Active ATM VCs 9-7
Restrictions and Limitations for Hierarchical Shaping 9-8
Percentage-Based Traffic Shaping 9-8
History for the Percentage-Based Shaping Feature 9-8
Frame Relay Traffic Shaping 9-8
Feature History for Frame Relay Traffic Shaping 9-9
Restrictions and Limitations for Frame Relay Traffic Shaping 9-9
Configuration Commands for Traffic Shaping 9-9
Differences Between Traffic Shaping Mechanisms 9-10
Bandwidth and Traffic Shaping 9-10
Differences Between Shaping and Policing 9-11
Advantages and Disadvantages of Shaping and Policing for Bandwidth Limiting 9-11
Modifying the VC Weight and the VP Shaping Parameters 9-12
Example Scenarios of Traffic Shaping Usage 9-12

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Interfaces Supporting Traffic Shaping 9-13
Configuring Traffic Shaping 9-13
Shaping a Traffic Class 9-14
Shaping Traffic at the VC-Level and Virtual Path-Level 9-15
Configuration Example for Traffic Shaping at the VC-Level and the VP-Level 9-17
Verifying Traffic Shaping 9-17
Verification Examples for Traffic Shaping 9-19
Configuration Examples for Traffic Shaping 9-21
Configuration Example for Class-Based Shaping 9-21
Configuration Examples for Hierarchical Shaping 9-21
Related Documentation 9-22
CHAPTER 10 Overhead Accounting 10-1
Overhead Accounting Features 10-1
Feature History for Overhead Accounting 10-2
ATM Overhead Accounting 10-2
MLP on LNS with HQoS and ATM Overhead Accounting 10-3
HQoS 10-3
Overhead Accounting 10-3
Traffic Shaping Overhead Accounting for ATM 10-4
Ethernet Overhead Accounting 10-4
Configuration Commands for Overhead Accounting 10-5
Subscriber Line Encapsulation Types 10-5
Overhead Calculation on the Router 10-5
Overhead Accounting and Hierarchical Policies 10-6
Restrictions and Limitations for Overhead Accounting 10-7
Configuring Overhead Accounting in a Hierarchical Policy 10-7
Configuration Examples for Overhead Accounting 10-10
Enabling ATM Overhead Accounting 10-10
Enabling ATM Overhead Accounting on the PRE3 and PRE4 for MLPoLNS 10-11
Enabling Ethernet Overhead Accounting on the PRE2 10-11
Enabling Ethernet Overhead Accounting on the PRE3 and PRE4 10-12
Verifying Overhead Accounting 10-12
Verification Examples for Overhead Accounting 10-13
Verifying ATM Overhead Accounting Using show policy-map 10-13
Verifying Overhead Accounting Using show running-config 10-14
Verifying Ethernet Overhead Accounting with User-Defined Option 10-14
Related Documentation 10-15

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CHAPTER 11 Managing Packet Queue Congestion 11-1
Queue Scaling Limits 11-1
Queue Limit 11-2
Queue Limit Packet Buffers 11-4
Default Queue Limit and Packet Buffers 11-4
queue-limit Command 11-4
Syntax Description 11-5
queue-limit Command History 11-5
Default Behavior for the queue-limit Command 11-5
Usage Guidelines for the queue-limit Command 11-6
Queue IDs and Interface Queues 11-6
Reserved QIDs 11-6
Queuing Outbound Traffic 11-7
Queuing Outbound Traffic on ATM Interfaces 11-7
Queuing Outbound Traffic on Frame Relay Interfaces 11-7
Queuing Outbound Traffic on Virtual LAN Interfaces 11-7
Controlling Congestion Using Tail Drop 11-8
Feature History for Tail Drop 11-8
Tail Drop and Random Early Detection 11-8
Controlling Congestion Using Random Early Detection 11-9
Feature History for Random Early Detection 11-9
Random Early Detection and Queue Limit 11-10
Determining Packet Drop Probability 11-10
Recommended Settings for RED Drop Probability 11-11
Controlling Congestion Using Weighted Random Early Detection 11-11
Feature History for Weighted Random Early Detection 11-12
Benefits of Using Weighted Random Early Detection 11-13
How WRED Works 11-13
WRED Drop Mode 11-13
WRED Drop Profiles 11-14
WRED Aggregate Drop Profiles 11-17
Usage Guidelines for the random-detect Command 11-18
Minimum and Maximum Thresholds 11-19
WRED and Queue Limit 11-20
Average Queue Size and the Exponential Weight Constant 11-21
Interfaces Supporting Layer 3 Packet Drop Policies 11-21
Restrictions and Limitations for Controlling Layer 3 Congestion 11-22
Configuring Layer 3 Queue Limit and Drop Policies 11-24

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Controlling Packet Dropping by Setting the Size of a Class Queue 11-24
Configuration Example for Controlling Packet Dropping by Setting a Queue Size 11-25
Dropping Packets Based on a Differentiated Services Code Point 11-26
Configuration Example for Configuring DSCP-Based WRED 11-27
Dropping Packets Based on IP Precedence 11-28
Configuration Example for Dropping Packets Based on IP Precedence 11-29
Dropping Packets Based on the Discard Class 11-29
Configuration Example for Dropping Packets Based on Discard Class 11-30
Dropping Packets Based on the ATM Cell Loss Priority 11-31
Configuration Example for Dropping Packets Based on the Cell Loss Priority 11-31
Verifying and Monitoring Layer 3 Packet Dropping 11-32
Verification Example for Queue Size and Packet Dropping 11-34
Verification Examples for DSCP-Based WRED 11-35
Verification Example for IP Precedence-Based WRED 11-36
Verification Example for Discard-Class-Based WRED 11-37
Verification Examples for ATM CLP-Based WRED 11-38
Controlling Packet Flow on Layer 2 Queues 11-39
Configuring the Depth of Layer 2 Queues 11-40
Related Documentation 11-40
CHAPTER 12 Sharing Bandwidth Fairly During Congestion 12-1
Class-Based Weighted Fair Queuing 12-1
Feature History for Class-Based Weighted Fair Queuing 12-3
Class-Default Class 12-3
CBWFQ and Bandwidth Allocation 12-3
CBWFQ and RSVP 12-4
Restrictions and Limitations for CBWFQ 12-4
Class-Based Weighted Fair Queuing for Virtual Access Interfaces 12-4
Feature History for CBWFQ for VAIs 12-5
Service Policy Inheritance 12-5
Restrictions and Limitations for CBWFQ for VAIs 12-6
System Limits for CBWFQ 12-6
Interfaces Supporting Class-Based Weighted Fair Queuing 12-7
Configuring Fair Bandwidth Sharing During Congestion 12-7
Defining Traffic Classes Using Class Maps 12-8
Configuration Example for Defining Traffic Classes Using Class Maps 12-8
Configuring Policy Actions for Traffic Classes Using Policy Maps 12-9
Configuring a Default Traffic Class Policy 12-9
Configuring a Class Policy and Dropping Packets Using Tail Drop 12-11

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Configuring a Class Policy and Dropping Packets Using WRED 12-12
Attaching Service Policies 12-15
Attaching a Service Policy to an Interface, Subinterface, or PVC 12-15
Attaching a Service Policy to a Virtual Access Interface 12-16
Modifying the Bandwidth for an Existing Policy Map Class 12-16
Modifying the Queue Limit for an Existing Policy Map Class 12-17
Deleting Classes 12-17
Deleting Policy Maps 12-18
Configuration Examples for Sharing Bandwidth Fairly 12-18
Configuration Example for Configuring CBWFQ and Attaching a Policy to an Ethernet Interface 12-18
Configuration Example for Configuring CBWFQ and Attaching a Policy to an ATM
Subinterface 12-19
Configuration Example for Configuring CBWFQ and Attaching a Policy to an RBE Subinterface 12-19
Verifying and Monitoring Class-Based Weighted Fair Queuing 12-20
Related Documentation 12-20
CHAPTER 13 Defining QoS for Multiple Policy Levels 13-1
Hierarchical Policies 13-2
Feature History for Hierarchical Policies 13-3
Benefits of Hierarchical Policies 13-3
Components Common to All Types of Hierarchical Policies 13-3
Child Policy 13-4
Parent Policy 13-4
service-policy Command 13-5
Types of Hierarchical Policies 13-6
Nested Hierarchical Policies 13-6
Restrictions and Limitations for Nested Hierarchical Policies 13-7
Three-Level Hierarchical Policies 13-8
Restrictions and Limitations for Three-Level Hierarchical Policies 13-9
Hierarchical Input Policing Policies 13-10
Restrictions and Limitations for Hierarchical Input Policing Policies 13-11
Hierarchical Policies and Oversubscription 13-11
Applying Child Policies Under Priority Classes 13-12
Interfaces Supporting Hierarchical Policies 13-12
Guidelines for Configuring QoS for Multiple Queues 13-13
Configuring QoS for Multiple Queues 13-13
Creating Fair Queues at Two Levels of Hierarchy 13-13
Creating Fair Queues at Three Levels of Hierarchy 13-15