Aprendendo a Trabalhar Com o CMTS

Cisco CMTS Router Downstream and Upstream Features ConfigurationGuideFirst Published: February 14, 2008

Last Modified: June 16, 2014

Americas HeadquartersCisco Systems, Inc.170 West Tasman DriveSan Jose, CA 95134-1706USAhttp://www.cisco.comTel: 408 526-4000 800 553-NETS (6387)Fax: 408 527-0883

Text Part Number: OL-27606-08

C O N T E N T S

C H A P T E R 1 Cable Modem Upstream RF Adaptation 1

Prerequisites for Cable Modem Upstream RF Adaptation 2

Restrictions for Cable Modem Upstream RF Adaptation 3

Information About Cable Modem Upstream RF Adaptation 3

Related CMTS Software Features 4

How to Configure Cable Modem Upstream RF Adaptation 5

Troubleshooting Tips 9

Cable Modem Does Not Downgrade to the Secondary Logical Channel 9

Cable Modem Does Not Upgrade to the Primary Logical Channel 9

Verifying Cable Modem Upstream RF Adaptation 10

Configuration Examples for Cable Modem Upstream RF Adaptation 10

Example: Configuring Cable Modem Upstream RF Adaptation on the Cisco uBR10012

Router 10

Example: Configuring Cable Modem Upstream RF Adaptation on the Cisco uBR7200

Router 11

Example: Non-Default Timer Configuration 12

Additional References 13

Feature Information for Cable Modem Upstream RF Adaptation 13

C H A P T E R 2 Configuring Downstream Cable Interface Features on the Cisco CMTS Routers 17

Prerequisites for Configuring Downstream Cable Interfaces on the Cisco CMTS Routers 18

Activating Downstream Cable Address Resolution Protocol Requests 19

Activating Downstream Ports 21

Assigning the Downstream Channel ID 22

Verifying the Downstream Channel ID 22

Traffic Shaping 23

Downstream Traffic Shaping 23

Configuring Downstream Rate Limiting and Traffic Shaping 24

Cisco CMTS Router Downstream and Upstream Features Configuration Guide OL-27606-08 iii

Setting the Downstream Helper Address 25

Verifying the Downstream Helper Address 25

Setting the Downstream Interleave Depth 26

Verifying the Downstream Interleave Depth 26

Setting the Downstream Modulation 27

Verifying the Downstream Modulation 27

Setting the Downstream MPEG Framing Format 28

Verifying the Downstream MPEG Framing Format 28

Setting Downstream Traffic Shaping 28

Verifying Downstream Traffic shaping 29

Activating Host-to-Host Communication (Proxy ARP) 30

Activating Cable Proxy ARP Requests 30

Verifying Cable Proxy ARP Requests 30

Activating Packet Intercept Capabilities 31

Configuring Payload Header Suppression and Restoration 31

Setting Optional Broadcast and Cable IP Multicast Echo 32

Setting IP Multicast Echo 32

Verifying IP Multicast Echo 32

Access Lists and the cable ip-multicast echo Command 33

Setting IP Broadcast Echo 33

Verifying IP Broadcast Echo 34

Cable Interface Configuration Examples 34

Example: Subinterface Configuration 34

Example: Cable Interface Bundling 34

Example: Subinterface Definition on Bundle Master 35

Example: Cable Interface Bundle Master Configuration 35

Example: PE Router Configuration 35

Example: Router Configuration 39

Example: Configuring BGP Routing Sessions 40

Example: Configuring PE-to-PE Routing Sessions 40

Example: Configuring BGP PE-to-CE Routing Sessions 41

Example: Configuring RIP PE-to-CE Routing Sessions 41

Example: Configuring Static Route PE-to-CE Routing Sessions 42

C H A P T E R 3 Configuring Upstream Cable Interface Features on the Cisco CMTS Routers 43

Cisco CMTS Router Downstream and Upstream Features Configuration Guideiv OL-27606-08

Contents

Prerequisites for Configuring Upstream Cable Interfaces on the Cisco CMTS Routers 44

Prioritizing Upstream Traffic to Initialize Cable Modems 45

Configuring the Priority of the QoS Profile 46

Activating the Upstream Minimum Reserved Traffic Rate Plus Excess Traffic Rate 47

Activating Upstream Admission Control 48

Verifying Upstream Admission Control 49

Activating Upstream Differential Encoding 49

Verifying Upstream Differential Encoding 49

Activating Upstream Forward Error Correction 50

Verifying Upstream FEC 50

Activating the Upstream Ports 51

Activating Upstream Power Adjustment 52

Activating the Upstream Scrambler 53

Verifying the Upstream Scrambler 53

Activating Upstream Timing Adjustment 54

Verifying Upstream Timing Adjustment 54

Traffic Shaping 55

Upstream Traffic Shaping 55

Upstream Buffer Control for Maximum Queue Depth 56

Configuring Upstream Rate Limiting and Traffic Shaping 57

Setting Upstream Backoff Values 58

Setting the Upstream Channel Width 59

Verifying Upstream Channel Width 60

Copy and Paste Support for TDMA to A-TDMA Upgrade 61

Setting the Upstream Frequency 61

Verifying the Upstream Frequency 63

Setting the Upstream Input Power Level 63

Verifying the Upstream Input Power Level 64

Specifying Upstream Minislot Size 65

Verifying Upstream Minislot Size 65

Setting Upstream Traffic Shaping 66

Verifying Upstream Bandwidth Request Shaping 67


Configuring Upstream Drop Classifier 68

Setting Upstream Buffer Control Parameters 69

Cisco CMTS Router Downstream and Upstream Features Configuration Guide OL-27606-08 v

Contents

Verifying Upstream Buffer Control Parameters 70


Feature Information for Configuring UpstreamCable Interface Features on the Cisco CMTS

Routers 73

C H A P T E R 4 Cable Modem Steering on the Cisco CMTS Routers 75

Prerequisites for Cable Modem Steering 76

Restrictions for Cable Modem Steering 77

Information About Cable Modem Steering 78

Channel Redirection 79

Channel Restriction 79

Upstream Channel Descriptor TLV for Ranging Hold-off 80

Ranging Class ID 80

Cable Modem Exclusion for DOCSIS Load Balance 80

How to Configure Cable Modem Steering on the CMTS Router 80

Configuring a Channel Redirection 80

Configuring a Channel Restriction 81

Configuring an Upstream Channel Class ID 82

Configuring an Upstream Ranging Hold-off Priority Value 84

Configuration Examples for Cable Modem Steering 85

Example: Configuring a Channel Class ID and Ranging Hold-off Priority Value 85

Example: Clearing a Channel Redirection 85

Verifying and Troubleshooting Cable Modem Steering 86

Verifying a Channel Redirection 86

Verifying a Channel Restriction 87

Verifying an Upstream Ranging Class ID Configuration 88

Clearing Attribute Masks 92

Debugging Channel Redirection 92



Feature Information for Cable Modem Steering 95

C H A P T E R 5 DOCSIS 2.0 A-TDMAModulation Profiles for the Cisco CMTS Routers 99

Prerequisites for DOCSIS 2.0 A-TDMA Modulation Profiles for the Cisco CMTS Routers 100

Restrictions for DOCSIS 2.0 A-TDMA Services 101

Cisco CMTS Router Downstream and Upstream Features Configuration Guidevi OL-27606-08

Contents

Information About DOCSIS 2.0 A-TDMA Services 102

Modes of Operation 103

Modulation Profiles 105

Benefits 106

How to Configure DOCSIS 2.0 A-TDMA Services 106

Creating Modulation Profiles 106

Creating a TDMA Modulation Profile 106

Creating a Mixed Mode Modulation Profile 108

Creating an A-TDMA Modulation Profile 109

Configuring the DOCSIS Mode and Profile on an Upstream 110

Monitoring the DOCSIS 2.0 A-TDMA Services 112

Displaying Modulation Profiles 112

Displaying Cable Modem Capabilities and Provisioning 113

Configuration Examples for DOCSIS 2.0 A-TDMA services 114

Creating Modulation Profiles Examples 114

Example: DOCSIS 1.0/DOCSIS 1.1 TDMA Modulation Profiles 114

Example: Mixed TDMA/A-TDMA Modulation Profiles 115

Example: DOCSIS 2.0 A-TDMA Modulation Profiles 115

Assigning Modulation Profiles to Upstreams Examples 116

Example: Assigning DOCSIS 1.0/DOCSIS 1.1 TDMA Modulation Profiles 116

Example: Assigning Mixed TDMA/A-TDMA Modulation Profiles 117

Example: Assigning DOCSIS 2.0 A-TDMA Modulation Profiles 118


Feature Information for DOCSIS 2.0 A-TDMA Modulation Profiles for the Cisco CMTS

Routers 121

C H A P T E R 6 DOCSIS 3.0 Downstream Bonding for Bronze Certification 123

Prerequisites for DOCSIS 3.0 Downstream Bonding for Bronze Certification 124

Restrictions for DOCSIS 3.0 Downstream Bonding for Bronze Certification 125

Information About DOCSIS 3.0 Downstream Bonding for Bronze Certification 125

Receive Channel Profile 126

Receive Channel Configuration 126

RCC Template 126

Channel Assignment 126

Downstream Traffic Forwarding 127

Cisco CMTS Router Downstream and Upstream Features Configuration Guide OL-27606-08 vii

Contents

How to Configure RCC Encoding 127

Configuring an RCC Template 127

Configuring RCC Encoding 128

Assigning an RCC Template to a Cable Interface 130

Verifying the RCC Configuration 131

Verifying the MD-DS-SG Configuration 132

How to Configure Attribute Masks 132

Configuring Provisioned Attributes for a Cable Interface 134

Configuring Provisioned Attributes for a Modular Cable Interface 134

Configuring Provisioned Attributes for an Integrated Cable Interface 135

Configuring Provisioned Attributes for a Wideband Cable Interface 136

Verifying the Attribute-Based Service Flow Assignments 137

Enabling Verbose Reporting for Receive Channel Profiles 138

Configuration Example for an RCC Template 139


Feature Information for DOCSIS 3.0 Downstream Bonding for Bronze Certification 141

C H A P T E R 7 Downstream Channel ID Assignment on the Cisco CMTS Routers 145

Prerequisites for Downstream Channel ID Assignment on the Cisco CMTS Routers 146

Information About Downstream Channel ID Assignment on the Cisco CMTS Routers 147

Manual Downstream Channel ID Assignment on the Cisco CMTS Routers 148

Automatic Downstream Channel ID Assignment on the Cisco CMTS Routers 149

How to Configure Downstream Channel ID Assignment on the Cisco CMTS Routers 150

Configuring Manual Downstream Channel ID Assignment 150

Configuring Automatic Downstream Channel ID Assignment 151


Feature Information for Downstream Channel ID Assignment on the Cisco CMTS

Routers 154

C H A P T E R 8 Downstream Resiliency Bonding Group 155

Prerequisites for Downstream Resiliency Bonding Group 156

Restrictions for the Downstream Resiliency Bonding Group 156

Information About Downstream Resiliency Bonding Group 158

Finding a Best-Fit RBG for the Cable Modem 158

How to Configure Downstream Resiliency Bonding Group 159

Cisco CMTS Router Downstream and Upstream Features Configuration Guideviii OL-27606-08

Contents

Enabling Downstream Resiliency Bonding Group 159

Reserving a Resiliency Bonding Group for a Line Card 160

Verifying Downstream Resiliency Bonding Group Configuration 161

Verifying the Downstream Resiliency Bonding Group 161

Verifying a Reserved Resiliency Bonding Group 162

Wideband Modem Resiliency Versus Downstream Resiliency 162

Troubleshooting the Downstream Resiliency Bonding Group Configuration 165

Configuration Examples of the Downstream Resiliency Bonding Group Feature 166


Feature Information for Downstream Resiliency Bonding Group 172

C H A P T E R 9 IGMP-Triggered Dynamic Channel Change Load Balancing for DOCSIS 2.0 Cable Modems 173

Prerequisites for IGMP-Triggered DCC Load Balancing for DOCSIS 2.0 CMs 174

Restrictions for IGMP-Triggered DCC Load Balancing for DOCSIS 2.0 CMs 175

Information About IGMP-Triggered DCC Load Balancing for DOCSIS 2.0 CMs 175

Combined Optimization Technique 176

Deployment of the IGMP-Triggered DCC Load Balancing for DOCSIS 2.0 and DOCSIS 3.0

CMs 177

Interaction of IGMP-Triggered DCC Load Balancing With DOCSIS Load Balancing 178

Interaction of IGMP-Triggered DCC Load Balancing With Fairness Across DOCSIS

Interfaces 178

DOCSIS 2.0 Multicast Enhancement for VDOC 179

How to Configure IGMP-Triggered DCC Load Balancing for DOCSIS 2.0 CMs 180

Creating a Load Balancing Group 180

Creating a Load Balancing Rule 181

Creating a Load Balancing Policy 183

Configuring a Load Balancing Group 184

Verifying IGMP-Triggered DCC Load Balancing Operations 186


Feature Information for IGMP-Triggered DCC Load Balancing for DOCSIS 2.0 CMs 189

C H A P T E R 1 0 IGMP-Triggered VDOC Broadcast Support on the Cisco CMTS Routers 191

Prerequisites for Configuring VDOC Broadcast 192

Restrictions for Configuring VDOC Broadcast 193

Information About Configuring VDOC Broadcast 193

Cisco CMTS Router Downstream and Upstream Features Configuration Guide OL-27606-08 ix

Contents

Inter Line Card RF Spanning 194

RF Spanning of Bonding Groups Carrying Static Multicast Traffic 194

RF Spanning of Remote Bonding Groups 195

RCC Template 197

How to Configure VDOC Broadcast 198

Configuring the Primary and Secondary Bonding Group 198

Configuring the RCC Template 199

Configuring the Multicast Static Group 201

How to Configure Inter Line Card RF Spanning 203

Configuring RF Spanning of Bonding Groups Carrying Static Multicast Traffic 203

Configuring RF Spanning of Remote Bonding Groups 204

Configuration Examples for VDOC Broadcast 206

Example: Configuring the Primary and Secondary Bonding Groups 206

Example: Configuring the RCC Template 207

Example: Configuring the Multicast Static Group 208

Configuration Examples for Inter Line Card RF Spanning 209

Example: RF Spanning of Bonding Groups Carrying Static Multicast Traffic 209

Example: RF Spanning of Remote Bonding Groups 210

Verifying VDOC Broadcast and Inter Line Card RF Spanning 211


Feature Information for Configuring VDOC Broadcast 216

C H A P T E R 1 1 Load Balancing, Dynamic Channel Change, and Dynamic Bonding Change on the Cisco

CMTS Routers 219

Prerequisites 221

Prerequisites for Load Balancing 222

Prerequisites for Dynamic Channel Change for Load Balancing 222

Prerequisites for Dynamic Bonding Change for DOCSIS 3.0 Static Modem Count-Based

Load Balancing 223

Restrictions 223

Restrictions for Load Balancing 223

Restrictions for Dynamic Channel Change for Load Balancing 225

DCC Restrictions with N+1 Redundancy and Inter-Card Load Balancing 226

Restrictions for DOCSIS 3.0 Static Modem Count-Based Load Balancing 227

Cisco CMTS Router Downstream and Upstream Features Configuration Guidex OL-27606-08

Contents

Restrictions for Dynamic Bonding Change for DOCSIS 3.0 Static Modem Count-Based

Load Balancing 227

Restrictions for MRC-Only Cable Modems 228

Information on the Load Balancing on the Cisco CMTS 228

Feature Overview 228

DOCSIS 3.0 Static Modem Count-Based Load Balancing 229

Error Handling of Channel Assignment 231

Multiple Channel Load Balancing Operation 231

Using DOCSIS 3.0 Static Modem Count-Based Load Balancing With DBC 233

Using DBC to Change the Receive Channel Set 234

Using DBC to Change the Transmit Channel Set 234

Using DBC to Change the Downstream ID 234

Using DBC to Change the Security Association for Encrypting Downstream

Traffic 235

Using DBC to Change the Service Flow SID Cluster Assignments 235

Types of Load Balancing Operations 235

Methods to Determine When Interfaces Are Balanced 237

Modems Method 237

Utilization Method 238

Service-Flows Method 239

Using Both Static and Dynamic Load Balancing 240

Load Balancing Parameters 240

Load Balancing Groups 240

Support for 256 Legacy LBGs 242

Downstream Load Balancing Distribution with Upstream Load Balancing 242

Upstream Load Balancing for DOCSIS 3.0 Cable Modems in Single Upstream Mode 243

Disabling Upstream Load Balancing for DOCSIS 3.0 Modems 243

Disabling Upstream Load Balancing for DOCSIS 3.0 Modems 244

DOCSIS 3.0 Dynamic Load Balancing 244

Interaction with Spectrum Management 244

DOCSIS 2.0 Multicast Enhancement for VDOC 245

Benefits of Load Balancing 246

Exclude Cable Modems from Load Balancing Groups 246

How to Configure Load Balancing 247

Creating a Load Balancing Group 247

Cisco CMTS Router Downstream and Upstream Features Configuration Guide OL-27606-08 xi

Contents

Creating a Load Balancing Rule 248


Creating a Load Balancing Policy 249

Configuring a Load Balancing Group 250

Configuring the DOCSIS 3.0 Dynamic Load Balancing 251

Assigning Interfaces to a Load Balancing Group 252

Excluding Cable Modems from a Load Balancing Group 254

Disabling Load Balancing 256

Distributing Downstream Load Balancing with Upstream Load Balancing 256

Examples 257

How to Configure Dynamic Channel Change for Load Balancing 259

Configuring DCC for Load Balancing on the Cisco CMTS 259

Verifying Load Balancing Operations 260


Examples 262

Verifying Dynamic Bonding Change for Load Balancing 263

Debugging Load Balancing 264

Extended Load Balance Debugging 264

Configuration Examples for Load Balancing 265

Example: Load Balancing Group (Static Load Balancing) 265

Example: Load Balancing Group (Passive Load Balancing) 265

Example: Load Balancing Group (Dynamic Load Balancing) 265

Example: Interface Configuration 266

Example: Configuration for Upstreams and Downstreams 266

Example: Configuring Dynamic Channel Change for Load Balancing 268


Feature Information for Load Balancing, Dynamic Channel Change, and Dynamic Bonding

Change on the Cisco CMTS Routers 272

C H A P T E R 1 2 M-CMTS DEPI Control Plane 279

Prerequisites for M-CMTS DEPI Control Plane 280

Restrictions for M-CMTS DEPI Control Plane 281

Information About M-CMTS DEPI Control Plane 281

Benefits of M-CMTS DEPI Control Plane 282

DEPI Control Connections 282

Cisco CMTS Router Downstream and Upstream Features Configuration Guidexii OL-27606-08

Contents

DEPI Data Sessions 282

DEPI SSO 282

N+1 DEPI Redundancy 283

GigE Port-level Redundancy 284

Difference Between Manual DEPI and Control Plane DEPI Configuration 284

DEPI EQAM Statistics 284

How to Configure M-CMTS DEPI Control Plane 285

Configuring DEPI Control Plane on the M-CMTS Router 285

Configuring DEPI Control Plane on Cisco RFGW-10 289

Configuring N+1 DEPI Redundancy on the M-CMTS Router and Cisco RFGW-10 295

Configuring DLM on the M-CMTS Router 296

Disabling a DEPI Data Session on the M-CMTS Router 297

Configuration Examples for M-CMTS DEPI Control Plane 298

Example: DEPI Control Plane Configuration on the M-CMTS Router 299

Example: DEPI Control Plane Configuration on Cisco RFGW-10 299

Example: N+1 DEPI Redundancy Configuration on the M-CMTS Router 300

Example: GigabitEthernet Interface Configuration on the M-CMTS Router 300

Example: GigabitEthernet Interface Configuration on Cisco RFGW-10 300

Verifying M-CMTS DEPI Control Plane 301

Verifying DEPI Tunnel Information 301

Verifying DEPI Session Information 302

Verifying DLM Configuration Information 304


Feature Information for M-CMTS DEPI Control Plane 306

C H A P T E R 1 3 Restricted/General Load Balancing and Narrowband Dynamic Bandwidth Sharing with

Downstream Dynamic Load Balancing 309

Prerequisites for Restricted/General Load Balancing andNarrowbandDynamic Bandwidth Sharing

with Downstream Dynamic Load Balancing 310

Restrictions for Restricted/General Load Balancing and NarrowbandDynamic Bandwidth Sharing


Information About Restricted/General Load Balancing and Narrowband Dynamic Bandwidth

Sharing with Downstream Dynamic Load Balancing 313

Service-Based Load Balancing 313

RLBG/GLBG Assignment 315

Cisco CMTS Router Downstream and Upstream Features Configuration Guide OL-27606-08 xiii

Contents

Channel Assignment 316

Upstream Load Balancing for DOCSIS 3.0 Cable Modems in Single Upstream Mode 322

Narrowband LB with DBS 323

Auto-generate DOCSIS 2.0 GLBG 323

Independent Upstream/Downstream Throughput Rules 323

How to Configure Restricted/General Load Balancing and Narrowband Dynamic Bandwidth

Sharing with Downstream Dynamic Load Balancing 324

Configuring DOCSIS 3.0 and 2.0 RLBG and DOCSIS 2.0 GLBG 325

Configuring DOCSIS 3.0 GLBG 328

Configuring a DOCSIS 3.0 General Load Balancing Group 328

Configuring Default Values of DOCSIS 3.0 Load Balancing Group 330

Configuring Cable Modems to RLBG or a Service Type ID 331

Configuring Rules and Policies 331


Configuring Load Balancing Parameter for a Cable Modem Movement Failure 333

Creating and Configuring TLV type Tag 333

Configuration Examples for Restricted/General Load Balancing and Narrowband Dynamic

Bandwidth Sharing with Downstream Dynamic Load Balancing 335

Example: Configuring a Tag 335

Example: Disabling Load Balancing 336

Verifying Restricted/General Load Balancing and Narrowband Dynamic Bandwidth Sharing



Feature Information for Restricted/General Load Balancing and Narrowband Dynamic

Bandwidth Sharing with Downstream Dynamic Load Balancing 342

C H A P T E R 1 4 RSVP-Based Video on Demand Support Over DOCSIS 347

Prerequisites for Configuring RSVP-Based Video on Demand Support Over DOCSIS 348

Restrictions for Configuring RSVP-Based Video on Demand Support Over DOCSIS 348

Information About RSVP-Based Video on Demand Support Over DOCSIS 349

How to Configure RSVP-Based Video over DOCSIS 350

Configuring the RSVP Service Class 350

Displaying the RSVP-DOCSIS Flow Data 350


Feature Information for RSVP-Based Video over DOCSIS 352

Cisco CMTS Router Downstream and Upstream Features Configuration Guidexiv OL-27606-08

Contents

C H A P T E R 1 5 S-CDMA and Logical Channel Support on the Cisco CMTS Routers 355

Prerequisites for S-CDMA and Logical Channel Support 356

Restrictions for S-CDMA and Logical Channel Support 357

Information About S-CDMA and Logical Channel Support 358

S-CDMA Services 358

Modulation Profiles 359

Benefits 360

Logical Channels 361

Spectrum Management on Logical Channels 361

Load Balancing on Logical Channels 362

How to Configure S-CDMA and Logical Channel Support 362

Creating Modulation Profiles 362

Creating a DOCSIS 2.0 S-CDMA Modulation Profile 362

Configuring a Global Modulation Profile 363

Creating a DOCSIS 3.0 S-CDMA Modulation Profile 364

Configuring the DOCSIS Mode and Profile on an Upstream 365

Configuring the Logical Channel Support 368

Monitoring the S-CDMA and Logical Channel Support 369

Displaying Modulation Profiles 369

Displaying Cable Modem Capabilities and Provisioning 370

Displaying the Logical Channel Support 370

Configuration Examples for S-CDMA and Logical Channel Support 372

Creating Modulation Profiles Examples 372

Example: DOCSIS 2.0 S-CDMA Modulation Profiles 372

Example: Global Modulation Profiles 373

Example: DOCSIS 3.0 S-CDMA Modulation Profiles 373

Assigning Modulation Profiles to Upstreams Examples 374

Example: Assigning DOCSIS 2.0 S-CDMA Modulation Profiles 374

Example: Assigning Global Modulation Profiles 375

Example: Assigning DOCSIS 3.0 S-CDMA Modulation Profiles 377

Example: Creating Logical Channels 377


Feature Information for S-CDMA and Logical Channel Support on the Cisco CMTS Routers 380

Cisco CMTS Router Downstream and Upstream Features Configuration Guide OL-27606-08 xv

Contents

C H A P T E R 1 6 Spectrum Management and Advanced Spectrum Management for the Cisco CMTS 383

Prerequisites for Spectrum Management and Advanced Spectrum Management 384

Restrictions for Spectrum Management 386

Shared Spectrum Groups 387

Cisco IOS Releases and Cable Interface Line Card Support 387

Dynamic Upstream Modulation 388

Fixed-Frequency Spectrum Groups with Advanced Spectrum Management 388

Limitations on Upstream Modulation Parameters for PacketCable VoIP Calls 388

N+1 Redundancy Support 389

Intelligent and Advanced Spectrum Management Support 389

Information About Spectrum Management 390

Spectrum Management Measurements 391

Signal and Carrier Noise Ratios 391

Differences Between the MER (SNR) and CNR (CNiR) Values 392

Additional Measurements 394

Upstream Signal Channel Overview 394

Upstream Segments and Combiner Groups 396

Frequency Management Policy 397

Noise Impairments 397

Spectrum Groups and Frequency Hopping 398

Guidelines for Spectrum Management 398

Guided and Scheduled Spectrum Management 399

Frequency Hopping Capabilities 399

Dynamic Upstream Modulation (MER [SNR]-Based) 401

Feature Overview 401

Criteria for Switching Modulation Profiles 402

Input Power Levels 403

Intelligent and Advanced Hardware-Based Spectrum Management 404

Intelligent Spectrum Management Enhancements 404

Advanced Spectrum Management Support Using the Cisco uBR10-MC5X20S/U/H

BPE 404

Benefits 406

Guided and Scheduled Spectrum Management Benefits 406

Intelligent and Advanced Spectrum Management Benefits 407

Cisco CMTS Router Downstream and Upstream Features Configuration Guidexvi OL-27606-08

Contents

How to Configure Spectrum Management 408

Guided and Scheduled Spectrum Management Configuration Tasks 408

Creating and Configuring Spectrum Groups 408

Assigning a Spectrum Group to One or More Upstream Ports 411

Configuring Shared Spectrum Groups (Fiber Node Groups) for DOCSIS 3.0 412

Configuring Dynamic Upstream Modulation (MER [SNR]-Based) 412

Verifying Frequency Hopping 416

Intelligent and Advanced Spectrum Management Configuration Tasks 419

Configuring and Assigning Spectrum Groups 419

Configuring Dynamic Upstream Modulation (CNR-Based) 419

Configuring Proactive Channel Management 421

Configuring Proactive Channel Management for Releases Prior to 12.3(13a)BC 422

Configuring Proactive ChannelManagement for Release 12.3(13a)BC, 12.2(33)SCC,

and Later 424

Verifying the Spectrum Management Configuration 427

Monitoring Spectrum Management 430

Using CLI Commands 431

Using SNMP 433

ccsSNRRequestTable 433

ccsSpectrumRequestTable 434

ccsSpectrumDataTable 435

ccsUpSpecMgmtTable 435

ccsHoppingNotification 437

Configuration Examples 438

Spectrum Group and Combiner Group Examples 438

Example: Verifying Spectrum Group Creation 438

Example: Time-Scheduled Spectrum Group 438

Example: Verifying Spectrum Group Configuration 439

Example: Determining the Upstream Ports Assigned to a Combiner Group 439

Example: Combiner Group 440

Example: Other Spectrum Management Configurations 441

Dynamic Upstream Modulation Examples 442

Verifying Your Settings 443

Example: Modulation Profiles 443

Example: Input Power Level 444

Cisco CMTS Router Downstream and Upstream Features Configuration Guide OL-27606-08 xvii

Contents

Advanced Spectrum Management Configuration Examples 445

Example: Advanced Spectrum Management for the Cisco uBR7200 Series Router 445

Example: Advanced Spectrum Management for the Cisco uBR10012 Router 448


Feature Information for Spectrum Management and Advanced Spectrum Management on

CMTS 451

C H A P T E R 1 7 Support for Extended Upstream Frequency Ranges 457

Prerequisites for Extended Upstream Frequency Ranges 458

Restrictions for Extended Upstream Frequency Ranges 458

Information About Extended Upstream Frequency Ranges 458

Frequency Ranges Currently in Use 459

Extended Frequency Support for Downstreams 459

Extended Frequency Support for Upstreams 459

How to Configure the Upstream Frequency Range 460

Configuring DOCSIS Upstream Frequencies 460

Configuring Extended DOCSIS Upstream Frequencies for Japan 462

Configuring EuroDOCSIS Upstream Frequencies 464

Configuration Examples for Extended Upstream Frequency Ranges 465

Example: Configuring North American (DOCSIS) Frequency Range 465

Example: Configuring Japanese Frequency Range 467

Example: Configuring European (EuroDOCSIS) Frequency Range 470


C H A P T E R 1 8 Upstream Bonding Support for D-PON on the Cisco CMTS Routers 475

Prerequisites for Upstream Bonding Support for D-PON 475

Restrictions for Upstream Bonding Support for D-PON 476

Information About Upstream Bonding Support for D-PON 477

D-PON on Upstream Scheduling 478

How to Configure Upstream Bonding Support for D-PON 478

Verifying the Upstream Bonding Support for D-PON 479


Feature Information for Upstream Bonding Support for D-PON on the Cisco CMTS

Routers 481

Cisco CMTS Router Downstream and Upstream Features Configuration Guidexviii OL-27606-08

Contents

C H A P T E R 1 9 Upstream Channel Bonding 483

Prerequisites for Upstream Channel Bonding 484

Restrictions for Upstream Channel Bonding 484

Information About Upstream Channel Bonding 485

Multiple Transmit Channel Mode 486

Multiple Receive Channel Mode 486

Dynamic Range Window and Transmit Power Levels for Upstream Channel Bonding 487

Extended Transmit Power 487

Reduced Transmit Channel Set 489

T4 Multiplier 489

Fiber Node Configuration for Upstream Channel Bonding 489

New TLVs for Upstream Channel Bonding 490

Upstream Weighted Fair Queuing 491

Class-Based Weighted Fair Queuing 491

Activity-Based Weighted Fair Queuing 491

Custom Weight for Service Flow Priorities 491

Upstream Scheduler and Service Flows 492

Distribution of Traffic across all Channels in a USBG 493

DOCSIS 3.0 Load Balancing with USBG Smaller than Cable Modem Capabilities 493

Cisco uBR10-MC5X20H Line Card Rate Limiting 494

SID Tracking 494

Service ID Clusters 494

How to Configure Upstream Channel Bonding 495

Enabling MTC Mode on a Cisco CMTS Router 495

Default MTC Mode Configuration on a Cisco CMTS Router 495

Enabling MTC Mode for All CMs 495

Creating a Bonding Group 496

Adding Upstream Channels to a Bonding Group 497

Adding Upstream Channel Ports to a Fiber Node 498

Configuring the Class-Based Weighted Fair Queuing 499

Configuring the Activity-Based Weighted Fair Queuing 500

Configuring Custom Weights for Service Flow Priorities 501

Configuring the SID Cluster 501

Configuring the Channel Timeout for a Cable Modem 503

Cisco CMTS Router Downstream and Upstream Features Configuration Guide OL-27606-08 xix

Contents

Configuring Cable Upstream Resiliency 504

Configuring Rate Limiting on the Cisco uBR10-MC5X20H Line Card 505

Enabling Upstream Related Events for CM Status Reports 505

Modifying the Bonding Group Attributes 506

Modifying the Ranging Poll Interval on Upstream Channels 507

Configuring the Reduced Channel Set Assignment 508

Configuring DOCSIS Extended Transmit Power Feature 509


Configuration Example for Upstream Channel Bonding 510

Example: Enabling MTC Mode for a Single CM Using the CM Configuration File 511

Verifying the Upstream Channel Bonding Configuration 511

Verifying Weighted Fair Queuing for Upstream Service Flows 515

Verifying Rate Limiting for Upstream Bonded Service Flows 515

Verifying Extended Power Transmission 516


Feature Information for Upstream Channel Bonding 518

C H A P T E R 2 0 Upstream Scheduler Mode for the Cisco CMTS Routers 525

Prerequisites for the Upstream Scheduler Mode for the Cisco CMTS Routers 526

Restrictions for Upstream Scheduler Mode for the Cisco CMTS Routers 527

Information About Upstream Scheduler Mode for the Cisco CMTS Routers 527

Upstream Peak Traffic Rate 528

Upstream Bandwidth Request Rate Limiting 528

How to Configure Upstream Scheduler Modes 529

How to Configure Exempted Priority for BRRL feature 530


Feature Information for Upstream Scheduler Mode for the Cisco CMTS Routers 532

C H A P T E R 2 1 Upstream Utilization Optimization on the Cisco CMTS Routers 535

Prerequisites for Upstream Utilization Optimization 536

Information about Upstream Utilization Optimization 537

How to Configure Upstream Utilization Optimization 537

Configuring Upstream Utilization Optimization Globally 537

Configuring Upstream Utilization Optimization Locally Per Upstream 538

Verifying Upstream Utilization Optimization Configuration 539

Cisco CMTS Router Downstream and Upstream Features Configuration Guidexx OL-27606-08

Contents


Feature Information for Upstream Utilization Optimization 541

C H A P T E R 2 2 Wideband Modem Resiliency 543

Prerequisites for Wideband Modem Resiliency 543

Restrictions for Wideband Modem Resiliency 544

Information About Wideband Modem Resiliency 544

CM-STATUS Messages 545

RF Channel Event Dampening Time 545

Response of CMTS to RF Impairment Recovery 545

Trigger Thresholds for Downstream Events 546

How to Configure Wideband Modem Resiliency 548

Specifying Trigger Thresholds for Downstream Events 548

Specifying Persistence Time for RF Channels 548

Changing Default CM-STATUS Configuration 549

Verifying Wideband Modem Resiliency 550

What to Do Next 551

Modifying CM-STATUS Reports for Events 552

Enabling SNMP Traps for Wideband Resiliency Events 553

Enabling Wideband Resiliency Trap Notifications 554

Setting the Trap Interval 555

Configuration Example for Wideband Modem Resiliency 555


Feature Information for Wideband Modem Resiliency 557

Cisco CMTS Router Downstream and Upstream Features Configuration Guide OL-27606-08 xxi

Contents

Cisco CMTS Router Downstream and Upstream Features Configuration Guidexxii OL-27606-08

Contents

C H A P T E R 1Cable Modem Upstream RF Adaptation

First Published: June 13, 2011

The CableModemUpstreamRFAdaptation feature uses per cable modem physical layer statistics to identifyand automatically move cable modems to another logical upstream channel within the same physical port.This is to prevent unnecessary channel-wide parameter changes, which reduces throughput, disrupts trafficflow for all modems, and makes some modems to go offline in extreme cases.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest featureinformation and caveats, see the release notes for your platform and software release. To find informationabout the features documented in this module, and to see a list of the releases in which each feature issupported, see the Feature Information Table at the end of this document.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support.To access Cisco Feature Navigator, go to http://tools.cisco.com/ITDIT/CFN/. An account on http://www.cisco.com/ is not required.

Contents

Prerequisites for Cable Modem Upstream RF Adaptation, page 2

Restrictions for Cable Modem Upstream RF Adaptation, page 3

Information About Cable Modem Upstream RF Adaptation, page 3

How to Configure Cable Modem Upstream RF Adaptation, page 5

Troubleshooting Tips, page 9

Verifying Cable Modem Upstream RF Adaptation, page 10

Configuration Examples for Cable Modem Upstream RF Adaptation, page 10

Additional References, page 13

Feature Information for Cable Modem Upstream RF Adaptation, page 13

Cisco CMTS Router Downstream and Upstream Features Configuration Guide OL-27606-08 1
http://tools.cisco.com/ITDIT/CFN/http://www.cisco.com/http://www.cisco.com/

Prerequisites for Cable Modem Upstream RF Adaptation Multiple logical channels must be configured.

Logical channels should be enabled per upstream.

Logical channel 0 is the preferred primary logical channel, and logical channel 1 is the preferred secondarylogical channel. This increases interoperability with other CMTS applications such as load balancingand upstream channel bonding.

The table below shows the hardware compatibility prerequisites for this feature.

The hardware components introduced in a given Cisco IOS Release are supported in all subsequent releasesunless otherwise specified.

Note

Table 1: Cable Hardware Compatibility Matrix for Cable Modem Upstream RF Adaptation

Cable Interface CardsProcessor EnginePlatform

Cisco IOS Release 12.2(33)SCFand later releases

Cisco uBR10-MC5X20H

Cisco UBR-MC20X20V1

Cisco uBR-MC3GX60V2


PRE2

PRE4

Cisco IOS Release 12.2(33)SCHand later releases

PRE5

Cisco uBR10012 UniversalBroadband Router


Cisco uBR-MC88V3


NPE-G2

Cisco uBR7246VXR UniversalBroadband Router


Cisco uBR-MC88V


NPE-G2


1 The Cisco UBR-MC20X20V cable interface line card has three variantsCisco UBR-MC20X20V-0D, Cisco UBR-MC20X20V-5D, and CiscoUBR-MC20X20V-20D. The Cisco UBR-MC20X20V-0D line card supports 20 upstreams and zero (no) downstreams. The Cisco UBR-MC20X20V-5D linecard supports 20 upstreams and 5 downstreams, and the Cisco UBR-MC20X20V-20D line card supports 20 upstreams and 20 downstreams.

2 The Cisco uBR-MC3GX60V line card is not compatible with PRE2.3 The Cisco uBR-MC88V cable interface line card is not compatible with NPE-G1. You must use NPE-G2 with the Cisco uBR-MC88V cable interface line

card.

Cisco CMTS Router Downstream and Upstream Features Configuration Guide2 OL-27606-08

Cable Modem Upstream RF AdaptationPrerequisites for Cable Modem Upstream RF Adaptation

Restrictions for Cable Modem Upstream RF Adaptation Logical channel 1 cannot be part of an upstream bonding group.

TheUpstreamChannel Bonding (USCB) feature coexists with the CableModemUpstreamRFAdaptationfeature; however, cable modems in the multiple transmits channel (MTC) mode are excluded.

Cable modems that use the multiple receive channel (MRC)mode withoutMTCmay participate in cablemodem upstream RF adaptation because these cable modems can be moved using the dynamic channelchange (DCC) method.

Advanced spectrum management is not supported in multiple logical channel configurations.

Dynamic channel-width configurations are not supported.

A pair of logical upstream channels configured with a mix of DOCSIS modes (i.e. SCDMA on logicalchannel 0 and ATDMA on logical channel 1) is supported, however, the CMTS will request that thecable modem uses the initialization technique 1 for the DCC.

Information About Cable Modem Upstream RF AdaptationThe Cable ModemUpstream RF Adaptation feature moves a single cable modem or a group of cable modemsto a more robust channel when a user-defined set of per cable modem PHY statistics does not meet a set ofuser-specified thresholds. Similarly, it releases a single cable modem or a group of cable modems from thesecondary channel when the user-defined set of per cable modem PHY statistics exceeds a set of user-specifiedthresholds.

The following relocation methods are used while moving a cable modem to and from the secondary logicalupstream channel:

UCC for DOCSIS 1.0 cable modems.

DCC initialization technique 2 for DOCSIS 1.1 and newer cable modems. Initialization technique 2performs periodic ranging. The cable modem is kept online and allowed to start on the new channel withperiodic ranging.

DCC initialization technique 1 for any configuration where at least one logical channel uses the SCDMADOCSIS mode. The initialization technique 1 broadcasts the initial ranging. The cable modem is keptonline and re-registration is avoided, but this technique requires completion of initial ranging.

The following PHY statistics are used while moving a cable modem to and from the secondary logical upstreamchannel:

Ranging burst Modulation Error Ratio (MER)

Data burst MER for JIB3-based line cards

Correctable and uncorrectable Forward Error Correction (FEC)

The cable modems to be relocated from the primary logical upstream channel to the secondary channel aremarked as downgrade candidates. Similarly, the cable modems to be relocated from the secondary logicalupstream channel to the primary channel are marked as upgrade candidates. Tracking individual cable modem


Cable Modem Upstream RF AdaptationRestrictions for Cable Modem Upstream RF Adaptation

statistics prevents a cable modem or a small group of cable modems from lowering the available bandwidthfor the larger population of cable modems.

Following are the step-by-step timer-based events that occur during RF adaptation:

1 General timer eventThe PHY statistics of the cable modems on the RF adapt-enabled channel arechecked. The cable modems that fail or exceed the set threshold are flagged as either downgrade or upgradecandidates.

2 Candidate timer eventThe PHY statistics of the cable modems that are flagged as downgrade or upgradecandidates are checked again to verify if the impairment still exists.

3 Relocation timer eventThe cable modems that continue to fail or exceed the threshold are relocated.

After a line card switchover, the cable modems remain online on either the primary or secondary logicalupstream channel depending on the state of the cable modem prior to the switchover. The upgrade anddowngrade candidate cable modems, and the cable modem movement history from primary to secondarylogical upstream channel and vice versa are not retained after a line card switchover. The Cable ModemUpstreamRFAdaptation feature is not affected by a PRE switchover and the candidate information and historyis retained during a PRE switchover.

The Cable Modem Upstream RF Adaptation feature is disabled by default. For information about how toenable this feature, see How to Configure Cable Modem Upstream RF Adaptation, on page 5.

Related CMTS Software FeaturesThe Cable Modem Upstream RF Adaptation feature via spectrum management integrates with and leveragesfrom the following CMTS software features:

Multiple Logical Channels, on page 4

CMTS PHY Measurement, on page 5

Multiple Logical Channels

The ability to use a multiple logical channel configuration to relocate cable modems with PHY impairmentsis a key capability of the Cable Modem Upstream RF Adaptation feature. In a cable modem upstream RFadaptation configuration, the logical channels are used as:

Logical Channel 0This is the default primary logical channel that cable modems registers on. Theprimary logical channel should be configured with performance options such as 64 QAM modulationprofile irrespective of the index value.

Logical Channel 1This is the default secondary logical channel. The secondary logical channel shouldbe configured with robust options, such as QPSK-based modulation profile irrespective of the indexvalue.

You can configure the primary and secondary logical channel. Whenmultiple logical channels are configured,the upstream-related commands are categorized into physical port level and logical channel level groups.Logical channel level commands use the format of cable upstream port logical-channel-index, where portdenotes the physical port number, and logical-channel-index denotes the logical channel index number.

The following logical channel-level configuration options have an impact on the Cable Modem Upstream RFAdaptation feature:


Cable Modem Upstream RF AdaptationRelated CMTS Software Features

DOCSIS mode. In the case of SCDMA, change in parameters like codes-per-minislot may also impactrobustness.

Modulation profile.

Equalization-coefficient (that is pre-equalization).

For more details on the Multiple Logical Channel feature, see S-CDMA and Logical Channel Support on theCisco CMTS Routers .

CMTS PHY Measurement

The CMTS PHY measurements collected on a per cable modem basis is used during RF adaptation. For acable modem upstream RF adaptation, the MER (also referred to as Signal-to-noise Ratio [SNR]), and FEC(both correctable and uncorrectable) measurements provide an accurate indication about the effect of anyPHY impairments on a single cable modem.

The Cable Modem Upstream RF Adaptation feature uses the following thresholds:

rf-adaptSets the RF adaptation percentage threshold.

snr-profilesSpecifies the MER (SNR) threshold in dB.

hysteresisSpecifies the hysteresis value.

corr-fecSpecifies the allowable number of correctable FEC errors for the upstream.

uncorr-fecSpecifies the allowable number of uncorrectable FEC errors for the upstream.

All the above thresholds are configured at the physical port level to ensure that the same collection ofthresholds is used for both upgrade and downgrade.

Note

How to Configure Cable Modem Upstream RF AdaptationThis section describes how to configure a physical upstream and its associated logical channels for cablemodem upstream RF adaptation.

Before You Begin

Multiple logical channels must be configured.

The cable modem upstream RF adaptation is not applicable for modems that are registered in MTCmode.Restriction

DETAILED STEPS

PurposeCommand or Action

Enables privileged EXEC mode.enableStep 1


Cable Modem Upstream RF AdaptationHow to Configure Cable Modem Upstream RF Adaptation
http://www.cisco.com/en/US/docs/ios/cable/configuration/guide/cmts_d30_scdma_lc_ps2209_TSD_Products_Configuration_Guide_Chapter.htmlhttp://www.cisco.com/en/US/docs/ios/cable/configuration/guide/cmts_d30_scdma_lc_ps2209_TSD_Products_Configuration_Guide_Chapter.html


Example:Router> enable

Enter your password if prompted.

Enters global configuration mode.configure terminal

Example:Router# configure terminal

Step 2

(Optional) Sets the timer for cable modem upstream RF adaptation.cable rf-adapt timer general timeStep 3

Example:Router(config)# cable rf-adapt timer general1

general timeSpecifies the period when the RF adaptationprocess examines the physical layer statistics of all modems onRF adaptation-enabled upstream channels. The valid range isfrom 1 to 300 seconds.

(Optional) Sets the timer for cable modem upstream RF adaptation.cable rf-adapt timer candidate timeStep 4

Example:Router(config)# cable rf-adapt timercandidate 2

candidate timeSpecifies the period when the RF adaptationprocess examines the physical layer statistics of modems flaggedas downgrade or upgrade candidates, or both. The valid rangeis from 1 to 300 seconds.

(Optional) Sets the timer for cable modem upstream RF adaptation.cable rf-adapt timer relocation timeStep 5

Example:Router(config)# cable rf-adapt timerrelocation 300

relocation timeSpecifies the period when the RF adaptationprocess performs a single relocation of a candidate modem fromits current upstream channel to the appropriate destination. Thevalid range is from 1 to 300 seconds.

Enters interface configuration mode.interface cable {slot/cable-interface-index |slot/subslot/cable-interface-index}

Step 6

slotSlot where the line card resides.

Example:Router(config)# interface cable 8/0/0

Cisco uBR7225VXR routerThe valid value is 1 or 2.

Cisco uBR7246VXR routerThe valid range is from 3 to6.

Cisco uBR10012 routerThe valid range is from 5 to 8.

subslot(Cisco uBR10012 only) Secondary slot number of thecable interface line card. The valid subslot is 0 or 1.

cable-interface-indexDownstream port of the CiscouBR10-MC5X20 and Cisco uBR-MC88V line cards, or MACdomain index of the Cisco UBR-MC20X20V and CiscouBR-MC3GX60V line cards.

Cisco uBR7225VXR and Cisco uBR7246VXRroutersThe valid port value is 0 or 1.




Cisco uBR10012 routerThe valid range for the CiscoUBR-MC20X20V and Cisco uBR-MC5X20 line cards isfrom 0 to 4. The valid range for the CiscouBR-MC3GX60V line card is from 0 to 14.

Enables multiple logical channels on the physical upstream channelintended for RF adaptation.

cable upstreamportmax-logical-chans code

Example:Router(config-if)# cable upstream 0max-logical-chans 2

Step 7

portUpstream port. The valid range is from 0 to 3.

codeNumber of logical channels per port. The valid valuesare 1 and 2.

Enables RF adaptation on the physical upstream channel.cable upstream port rf-adaptStep 8

Example:Router(config-if)# cable upstream 0 rf-adapt


(Optional) Sets the RF adaptation percentage threshold.cable upstream port threshold rf-adaptthreshold1-in-percent

Step 9


Example:Router(config-if)# cable upstream 0threshold rf-adapt 25

rf-adaptSpecifies the ratio of candidate cable modems to totalnumber of upstream cable modems, which disables further RFadaptation.

threshold1-in-percentRF adapt disable threshold in percentage.The valid range is from 1 to 50.

You can bypass the RF adapt disable threshold by setting itto 0.

Note

(Optional) Specifies the MER (SNR) threshold in dB.cableupstreamportthresholdsnr-profilessnr-threshold1snr-threshold2

Step 10

snr-threshold1MER (SNR) threshold for the primarymodulation profile specified for the upstream. The valid rangeis from 5 to 35 dB, with a default value of 25 dB.

Example:Router(config-if)# cable upstream 0threshold snr-profiles 25 0

You can bypass the primary MER (SNR) threshold(snr-threshold1-in-db) by setting it to 0.

Note

snr-threshold2MER (SNR) threshold for the secondarymodulation profile specified for the upstream. The valid rangeis from 5 to 35 dB, with a default value of 25 dB. For the CableModem Upstream RF Adaptation feature, it is recommended toset this value to 0.

snr-threshold2 is ignored by the Cable ModemUpstream RF Adaptation feature.

Note

(Optional) Specifies the hysteresis value.cableupstreamportthresholdhysteresishysteresis-value

Step 11




hysteresis-valueHysteresis value. The valid range is from 0to 10 dB, with a default value of 3 dB.Example:

Router(config-if)# cable upstream 0threshold hysteresis 3

You can bypass the hysteresis threshold by setting thevalue to 0.

Note

(Optional) Specifies the allowable number of correctable FEC errorsfor the upstream.

cable upstreamportthreshold corr-fecfec-corrected

Example:Router(config-if)# cable upstream 0threshold corr-fec 2

Step 12

fec-correctedAllowable number of correctable FEC errorsfor the upstream, given as a percentage of total packets receivedon the upstream during the polling period. It is given as apercentage of total packets received on the upstream during thepolling period. The valid range is from 1 to 30 percent, with adefault value of 3 percent.

You can bypass the corr-fec threshold by setting thevalue to 0.

Note

(Optional) Specifies the allowable number of uncorrectable FEC errorsfor the upstream.

cable upstreamportthresholduncorr-fecfec-uncorrected

Step 13

Example:Router(config-if)# cable upstream 0threshold uncorr-fec 10

fec-uncorrectedAllowable number of uncorrectable FECerrors for the upstream, given as a percentage of total packetsreceived on the upstream during the polling period. The validrange is from 1 to 30 percent of total packets, with a default of1 percent.

You can bypass the uncorr-fec threshold by setting thevalue to 0.

Note

(Optional) Specifies the primary upstream logical channel and thesecondary upstream logical channel.

cable upstream port logical-channel-indexrf-adapt [primary | secondary]

Step 14

Example:Router(config-if)# cable upstream 0 0rf-adapt primary


logical-channel-indexLogical channel index. The valid valuesare 0 and 1.

primarySets the logical channel as primary for RF adaptation.By default, the logical channel 0 is primary.

secondarySets the logical channel as secondary for RFadaptation. By default, the logical channel 1 is secondary.

When you set the primary channel, the secondarychannel is automatically set.

Note

Performs a no shutdown on logical channel 1.no cable upstream portlogical-channel-indexshutdown

Step 15




Example:Router(config-if)# no cable upstream 0 1shutdown

Exits the interface configurationmode and returns to privileged EXECmode.

end

Example:Router(config-if)# end

Step 16

What to Do Next

If you want to customize multiple logical channels, see S-CDMA and Logical Channel Support on the CiscoCMTS Routers.

Troubleshooting TipsFollowing are some scenarios that you may encounter while configuring or after configuring the CableModemUpstream RF Adaptation feature. Follow the recommended action to resolve these issue.

Cable Modem Does Not Downgrade to the Secondary Logical ChannelProblem A cable modem with PHY statistics less than the user-specified threshold is not downgraded to thesecondary logical channel.

Possible Cause The RF adaptation downgrade threshold has been met.

Possible Cause The RF adaptation downgrade threshold is exceeded while the cable modem is stillon the downgrade candidate list.

Possible Cause The RF adaptation downgrade threshold is exceeded after a group of cable modemsare moved to the secondary logical channel.

Solution Contact Cisco Technical Assistance Center (TAC).

Cable Modem Does Not Upgrade to the Primary Logical ChannelProblem A cable modem with PHY statistics greater than the user-specified threshold is not upgraded to theprimary logical channel.

Possible Cause The cable modem was upgraded or downgraded five times.

Possible Cause The SNR has not improved beyond the threshold and the hysteresis value.


Cable Modem Upstream RF AdaptationTroubleshooting Tips
http://www.cisco.com/en/US/docs/ios/cable/configuration/guide/cmts_d30_scdma_lc_ps2209_TSD_Products_Configuration_Guide_Chapter.htmlhttp://www.cisco.com/en/US/docs/ios/cable/configuration/guide/cmts_d30_scdma_lc_ps2209_TSD_Products_Configuration_Guide_Chapter.html

Solution You can delete the cable modem history from the CMTS database using the clear cable modemdelete command.

Verifying Cable Modem Upstream RF AdaptationPurposeCommand

To verify the downgrade candidate cable modems.show cable rf-adapt downgrade-candidates

To verify the upgrade candidate cable modems.show cable rf-adapt upgrade-candidates

To verify the RF adaptation historyshow cable modem rf-adapt

Configuration Examples for Cable Modem Upstream RFAdaptation

This section provides configuration examples for the Cable Modem Upstream RF Adaptation feature:

Example: Configuring Cable Modem Upstream RF Adaptation on the CiscouBR10012 Router

The following example shows how to configure the Cable Modem Upstream RF Adaptation feature on theCisco uBR10012 router.

!interface Cable8/0/0load-interval 30downstream Modular-Cable 1/1/0 rf-channel 0 upstream 0-3cable mtc-modeno cable packet-cachecable bundle 1cable upstream max-ports 4cable upstream bonding-group 700upstream 0upstream 1upstream 2upstream 3attributes A0000000

cable upstream 0 connector 0cable upstream 0 frequency 13000000cable upstream 0 channel-width 6400000 6400000cable upstream 0 max-logical-chans 2cable upstream 0 threshold snr-profiles 20 0cable upstream 0 threshold corr-fec 0cable upstream 0 threshold uncorr-fec 0cable upstream 0 threshold rf-adapt 0cable upstream 0 rf-adaptcable upstream 0 0 docsis-mode scdmacable upstream 0 0 spreading-interval 16cable upstream 0 0 codes-per-minislot 16


Cable Modem Upstream RF AdaptationVerifying Cable Modem Upstream RF Adaptation

cable upstream 0 0 active-codes 112cable upstream 0 0 range-backoff 3 6cable upstream 0 0 modulation-profile 321cable upstream 0 0 attribute-mask 20000000no cable upstream 0 0 shutdowncable upstream 0 1 docsis-mode atdmacable upstream 0 1 minislot-size 1cable upstream 0 1 range-backoff 3 6cable upstream 0 1 modulation-profile 223cable upstream 0 1 attribute-mask 20000000no cable upstream 0 1 shutdownno cable upstream 0 shutdowncable upstream 1 connector 1cable upstream 1 frequency 20000000cable upstream 1 channel-width 3200000 3200000cable upstream 1 load-balance group 80cable upstream 1 docsis-mode scdmacable upstream 1 spreading-interval 16cable upstream 1 codes-per-minislot 4cable upstream 1 active-codes 112cable upstream 1 range-backoff 3 6cable upstream 1 modulation-profile 321cable upstream 1 attribute-mask 20000000no cable upstream 1 shutdowncable upstream 2 connector 2cable upstream 2 frequency 26400000cable upstream 2 channel-width 3200000 3200000cable upstream 2 power-level 1cable upstream 2 load-balance group 80cable upstream 2 docsis-mode scdmacable upstream 2 spreading-interval 16cable upstream 2 codes-per-minislot 4cable upstream 2 active-codes 112cable upstream 2 range-backoff 3 6cable upstream 2 modulation-profile 321cable upstream 2 attribute-mask 20000000no cable upstream 2 shutdowncable upstream 3 connector 3cable upstream 3 frequency 32600000cable upstream 3 channel-width 3200000 3200000cable upstream 3 power-level 1cable upstream 3 load-balance group 80cable upstream 3 docsis-mode scdmacable upstream 3 spreading-interval 16cable upstream 3 codes-per-minislot 4cable upstream 3 active-codes 112cable upstream 3 range-backoff 3 6cable upstream 3 modulation-profile 321cable upstream 3 attribute-mask 20000000no cable upstream 3 shutdowncable sid-cluster-group num-of-cluster 2cable sid-cluster-switching max-request 1

...

...

Example: Configuring Cable Modem Upstream RF Adaptation on the CiscouBR7200 Router

The following example shows how to configure the Cable Modem Upstream RF Adaptation feature on theCisco 7200 router.

!interface Cable1/1load-interval 30downstream Integrated-Cable 1/1 rf-channel 0-3 upstream 0-3cable mtc-modeno cable packet-cache


Cable Modem Upstream RF AdaptationExample: Configuring Cable Modem Upstream RF Adaptation on the Cisco uBR7200 Router

cable bundle 2cable upstream max-ports 4cable upstream 0 connector 4cable upstream 0 frequency 20000000cable upstream 0 channel-width 6400000 6400000cable upstream 0 max-logical-chans 2cable upstream 0 threshold snr-profiles 26 0cable upstream 0 threshold corr-fec 5cable upstream 0 threshold uncorr-fec 2cable upstream 0 threshold hysteresis 4cable upstream 0 threshold rf-adapt 0cable upstream 0 rf-adaptcable upstream 0 0 docsis-mode atdmacable upstream 0 0 minislot-size 4cable upstream 0 0 range-backoff 3 6cable upstream 0 0 modulation-profile 221cable upstream 0 0 attribute-mask 20000000no cable upstream 0 0 shutdowncable upstream 0 1 docsis-mode atdmacable upstream 0 1 minislot-size 4cable upstream 0 1 range-backoff 3 6cable upstream 0 1 modulation-profile 222cable upstream 0 1 attribute-mask 20000000no cable upstream 0 1 shutdownno cable upstream 0 shutdowncable upstream 1 connector 5cable upstream 1 frequency 26600000cable upstream 1 channel-width 3200000 3200000cable upstream 1 docsis-mode atdmacable upsteram 1 minislot-size 4cable upstream 1 range-backoff 3 6cable upstream 1 modulation-profile 321cable upstream 1 attribute-mask 20000000no cable upstream 1 shutdowncable upstream 2 connector 6cable upstream 2 frequency 30000000cable upstream 2 channel-width 3200000 3200000cable upstream 2 docsis-mode atdmacable upsteram 2 minislot-size 4cable upstream 2 range-backoff 3 6cable upstream 2 modulation-profile 221cable upstream 2 attribute-mask 20000000no cable upstream 2 shutdowncable upstream 3 connector 7cable upstream 3 frequency 33500000cable upstream 3 channel-width 3200000 3200000cable upstream 3 docsis-mode atdmacable upsteram 3 minislot-size 4cable upstream 3 range-backoff 3 6cable upstream 3 modulation-profile 221cable upstream 3 attribute-mask 20000000no cable upstream 3 shutdownend

Example: Non-Default Timer ConfigurationThe following example shows how to configure non-default timer configuration.

Router# show running-config | in timercable rf-adapt timer general 60cable rf-adapt timer candidate 15cable rf-adapt timer relocation 5


Cable Modem Upstream RF AdaptationExample: Non-Default Timer Configuration

Additional ReferencesRelated Documents

Document TitleRelated Topic

Cisco IOS Master Commands List, All ReleasesCisco IOS commands

http://www.cisco.com/en/US/docs/ios/cable/command/reference/cbl_book.htmlCisco IOS CMTSCable Command Reference

CMTS cable commands

Technical Assistance

LinkDescription

http://www.cisco.com/cisco/web/support/index.htmlThe Cisco Support and Documentation websiteprovides online resources to download documentation,software, and tools. Use these resources to install andconfigure the software and to troubleshoot and resolvetechnical issues with Cisco products and technologies.Access to most tools on the Cisco Support andDocumentation website requires a Cisco.com user IDand password.

Feature Information for Cable Modem Upstream RF AdaptationUse Cisco Feature Navigator to find information about platform support and software image support.Cisco Feature Navigator enables you to determine which software images support a specific software release,feature set, or platform. To access Cisco Feature Navigator, go to http://tools.cisco.com/ITDIT/CFN/. Anaccount on http://www.cisco.com/ is not required.

The below table lists only the software release that introduced support for a given feature in a givensoftware release train. Unless noted otherwise, subsequent releases of that software release train alsosupport that feature.

Note


Cable Modem Upstream RF AdaptationAdditional References
http://www.cisco.com/en/US/docs/ios/mcl/allreleasemcl/all_book.htmlhttp://www.cisco.com/en/US/docs/ios/cable/command/reference/cbl_book.htmlhttp://www.cisco.com/en/US/docs/ios/cable/command/reference/cbl_book.htmlhttp://www.cisco.com/en/US/docs/ios/cable/command/reference/cbl_book.htmlhttp://www.cisco.com/en/US/docs/ios/cable/command/reference/cbl_book.htmlhttp://www.cisco.com/cisco/web/support/index.htmlhttp://tools.cisco.com/ITDIT/CFN/http://www.cisco.com/

Table 2: Feature Information for Cable Modem Upstream RF Adaptation

Feature InformationReleasesFeature Name

12.2(33)SCFCable Modem Upstream RFAdaptation


Cable Modem Upstream RF AdaptationFeature Information for Cable Modem Upstream RF Adaptation


The Cable Modem Upstream RFAdaptation feature uses the percable modem physical layerstatistics to identify andautomaticallymove cablemodemsto another logical upstream channelwithin the same physical port toprevent unnecessary channel-wideparameter changes.

In Cisco IOSRelease 12.2(33)SCF,this feature was introduced on theCisco uBR10012 router and CiscouBR7200 series routers.

The following sections provideinformation about this feature:

Information About CableModem Upstream RFAdaptation, on page 3

How to Configure CableModem Upstream RFAdaptation, on page 5

Verifying Cable ModemUpstreamRFAdaptation, onpage 10

Configuration Examples forCable Modem Upstream RFAdaptation, on page 10

The following commands wereintroduced or modified: cablerf-adapt timer, cable upstreamrf-adapt(logical channel), cableupstream rf-adapt, cableupstream threshold rf-adapt,show cable modem rf-adapt,show cable rf-adapt, cableupstream threshold hysteresis,cable upstream threshold, showcablemodem, show cablemodemaccess-group, show cablemodemcalls, show cable modemconnectivity, show cable modemcounters, show cable modemdocsis version, show cablemodem domain-name, showcable modem errors, show cable




modem flap, show cable modemipv6, show cable modem mac,show cablemodemmaintenance,show cable modem offline, showcable modem phy, show cablemodem primary channel, showcable modem registered, showcable modem rogue, show cablemodem summary, show cablemodem type, show cable modemunregistered, show cablemodemvendor, show cable modemwideband.



C H A P T E R 2Configuring Downstream Cable InterfaceFeatures on the Cisco CMTS Routers

First Published: February 14, 2008

Last Updated:May 12, 2009

Cisco IOS Release 12.2(33)SCA integrates support for this feature on the Cisco CMTS routers. Thisfeature is also supported in Cisco IOS Release 12.3BC, and this document contains information thatreferences many legacy documents related to Cisco IOS 12.3BC. In general, any references to Cisco IOSRelease 12.3BC also apply to Cisco IOS Release 12.2SC.

Note

The cable interface in the Cisco universal broadband routers serves as the cable TV radio frequency (RF)interface, supporting downstream and upstream signals. The downstream signal is output as anintermediate-frequency (IF) signal suitable for use with an external upconverter. Your cable plant, combinedwith your planned and installed subscriber base, service offering, and external network connections, determinesthe combination of cable interfaces, network uplink line cards, and other components that you should use.

The Cisco IOS software command-line interface (CLI) can be used to configure the Cisco cable interfaceline card for correct operation on the hybrid fiber-coaxial (HFC) cable network. This chapter provides aconfiguration summary for the various downstream cable interface features available on a Cisco CMTSrouter. Details about some of these features can be found in other chapters of this book.

The configuration commands and examples in this chapter may show slot numbering or references toeither Cisco uBR7200 series or Cisco uBR10012 Universal Broadband Routers. However, the featurescan be configured on either platform. Use the slot numbering appropriate for your CMTS routerconfiguration.

Note

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest featureinformation and caveats, see the release notes for your platform and software release. To find informationabout the features documented in this module, and to see a list of the releases in which each feature issupported, see the Feature Information Table at the end of this document.


Use Cisco Feature Navigator to find information about platform support and Cisco software image support.To access Cisco Feature Navigator, go to http://tools.cisco.com/ITDIT/CFN/. An account on http://www.cisco.com/ is not required.

Contents

Prerequisites for Configuring Downstream Cable Interfaces on the Cisco CMTS Routers, page 18

Activating Downstream Cable Address Resolution Protocol Requests, page 19

Activating Downstream Ports, page 21

Assigning the Downstream Channel ID, page 22

Traffic Shaping, page 23

Configuring Downstream Rate Limiting and Traffic Shaping, page 24

Setting the Downstream Helper Address, page 25

Setting the Downstream Interleave Depth, page 26

Setting the Downstream Modulation, page 27

Setting the Downstream MPEG Framing Format, page 28

Setting Downstream Traffic Shaping, page 28

Activating Host-to-Host Communication (Proxy ARP), page 30

Activating Packet Intercept Capabilities, page 31

Configuring Payload Header Suppression and Restoration, page 31

Setting Optional Broadcast and Cable IP Multicast Echo, page 32

Cable Interface Configuration Examples, page 34

Prerequisites for Configuring Downstream Cable Interfaces onthe Cisco CMTS Routers

The configuration of downstream cable interface features is supported on the Cisco CMTS routers in CiscoIOS Release 12.3BC and 12.2SC. The table below shows the hardware compatibility prerequisites for thisfeature.


Configuring Downstream Cable Interface Features on the Cisco CMTS RoutersPrerequisites for Configuring Downstream Cable Interfaces on the Cisco CMTS Routers
http://tools.cisco.com/ITDIT/CFN/http://www.cisco.com/http://www.cisco.com/

Table 3: Configuring Downstream Cable Interfaces on the Cisco CMTS Routers Hardware Compatibility Matrix

Cable Interface CardsProcessor EngineCMTS Platform

Cisco IOS Release 12.2(33)SCA

CiscouBR10-MC5X20S/U/H


PRE-2

Cisco IOS Release 12.2(33)SCHand later releases

PRE5

Cisco uBR10012 UniversalBroadband Router


Cisco uBR-MC28U/X

Cisco uBR-MC16U/X


NPE-G1

NPE-G2



Cisco uBR-E-28U

Cisco uBR-E-16U

Cisco uBR-MC28U/X

Cisco uBR-MC16U/X


NPE-G1


In most applications, default values for the commands used in these configuration steps are adequate toconfigure the Cisco CMTS router. You do not need to specify individual parameters unless you want todeviate from system defaults.

Note

Activating Downstream Cable Address Resolution ProtocolRequests

This configuration is required. Address Resolution Protocol (ARP) is an Internet protocol used to map IPaddresses to MAC addresses on computers and other equipment installed in a network. You must activateARP requests on the cable interface so that the Cisco uBR10000 series CMTS can perform IP address resolutionon the downstream path.

The default values for the commands used in this configuration step are adequate in most cases to configurethe Cisco uBR7200 series CMTS.

Note


Configuring Downstream Cable Interface Features on the Cisco CMTS RoutersActivating Downstream Cable Address Resolution Protocol Requests

DETAILED STEPS







Step 2

Enters cable interface configuration mode.interface cable5/0Step 3

Example:Router(config)# interface cable5/0

In this example, the interface is downstream port 0 on the cableinterface card installed in slot 1 of the Cisco uBR7200 seriesCMTS.

Enables ARP. This is the default.cable arp

Example:Router(config-if)# cable arp

Step 4

What to Do Next

To verify that cable ARP is activated, enter themore system:running-config command and look for thecable interface configuration information. If ARP is activated, it does not appear in this output. If ARP isdeactivated, it appears in the output asno cable arp.Router# more system:running-configBuilding configuration...

Current configuration:!interface cable5/0ip address 1.1.1.1 255.255.255.0no keepaliveno cable arpcable downstream annex Bcable downstream modulation 64qamcable downstream interleave-depth 32cable downstream symbol-rate 5056941cable upstream 0 frequency 15008000no cable upstream 0 shutdown

If you are having difficulty with verification, verify that you entered the correct port and cable interfaceline card slot number when you activated ARP and when you entered the show interface cable command.

Tip


Configuring Downstream Cable Interface Features on the Cisco CMTS RoutersActivating Downstream Cable Address Resolution Protocol Requests

Activating Downstream PortsTo activate a downstream port on a Cisco uBR7200 series cable interface card for digital data transmissionsover the HFC network, complete the steps in the following table.

DETAILED STEPS







Step 2

Enters cable interface configuration mode.interface cable5/0Step 3

Example:Router(config)# interface cable5/0

In this example, the interface is downstream port 0 on the cableinterface card installed in slot 1 of the Cisco uBR7200 seriesCMTS.

Activates downstream digital data from the Cisco uBR7200series router.

Enter the following commands:Step 4

cable downstream if-outputDeactivates downstream digital data. This commandmutes theIF output of the cable interface card and shuts down theinterfaces.

no cable downstream if-output

Example:Router(config-if)# cable downstream if-outputRouter(config-if)# no cable downstreamif-output

Places the downstream port in the admin up state.no shutdown

Example:Router(config-if)# no shutdown

Step 5

Returns to privileged EXEC mode.endStep 6

Example:Router(config-if)# endRouter#

This message is normal and does not indicate an error.

%SYS-5-CONFIG_I: Configured from console byconsole


Configuring Downstream Cable Interface Features on the Cisco CMTS RoutersActivating Downstream Ports

What to Do Next

To determine if the downstream carrier is active (up), enter the show controllers cable command for thedownstream port that you just configured. For National Television Standards Committee (NTSC) 6 MHzoperations, see the following example:Router# show controllers cable5/0 downstream

Cable5/0 Downstream is upFrequency=96000000, Channel Width 6 MHz, 64-QAM, Symbol Rate 5.056941 MspsFEC ITU-T J.83 Annex B, R/S Interleave I=32, J=4

Assigning the Downstream Channel IDTo assign a numeric channel ID to the downstream port on the Cisco cable interface line card, use the followingcommand in cable interface configuration mode.Router(config-if)# cable downstream channel-id id

For Cisco IOS Release 12.2(33)SCB and later releases, the acceptable range is 1 to 255 (0 is reserved fornetwork management) and for releases prior to Cisco IOS Release 12.2(33)SCB, the acceptable range is0 to 255.

Note

The cable downstream channel-id command must be used with the following command:cable downstream frequency 54000000-1000000000 broadcast frequency - h

Note

These commands are used in instances where you want to send multiple downstream frequencies to a singleregion that contains CMs that can connect only to upstream ports on the same cable interface line card. Youmust configure unique channel IDs for each downstream that any CM is capable of receiving. The downstreamfrequency setting must match the setting on the upconverter.

After defining unique downstream IDs, test the CMs for correct operation. Cisco recommends that whenusing this feature, you re-test each subsequent software release of CM code to verify correct operationand to ensure reasonable acquisition time for new installations. Failure to use these commands in conjunctionor to test the involved CMs can result in customer service outages of indefinite duration.

Caution

Verifying the Downstream Channel IDTo verify the downstream channel ID, enter the show controllers cable command for the downstream portyou have just configured. See the following example:Router# show controllers cable5/0 downstream

Cable5/0 Downstream is upFrequency=96000000, Channel Width 6 MHz, 64-QAM, Symbol Rate 5.056941 MspsFEC ITU-T J.83 Annex B, R/S Interleave I=32, J=4Downstream channel ID: 1


Configuring Downstream Cable Interface Features on the Cisco CMTS RoutersAssigning the Downstream Channel ID

Traffic ShapingTraffic shaping basically uses queues to limit data surges that can congest a network. The data is buffered andthen sent into the network in regulated amounts to ensure that the traffic fits within the expected traffic envelopefor the particular connection.

Traffic shaping reduces the chance that information must be retransmitted to hosts on the cable plant. Whencable modems (CMs) have rate limits established, the CMTS typically drops data packets to enforce the ratelimit. Dropping packets from the requesting CM causes the host sending the information to retransmit itsinformation, which wastes bandwidth on the network. If both hosts sending and requesting information areon the cable plant, the upstream bandwidth is wasted as well.

Traffic shaping allows the CMTS to perform upstream and downstream rate limiting on the DOCSIS upstreamand downstream channels. Rate limiting restricts the data rate to and from a CM; the MAC scheduler supportstraffic-shaping capabilities for downstream and upstream traffic. Rate limiting ensures that no single CMconsumes all of the channel bandwidth and allows a CMTS administrator to configure different maximumdata rates for different subscribers. Subscribers requiring higher sustained rates and willing to pay for higherrates can be configured with higher sustained rate limits in their CM DOCSIS configuration file over regularsubscribers, who pay less and get lower rate limits.

Each time a packet belonging to a flow is transmitted on an output channel, the token-bucket policer functionchecks the rate limit status of the flow, passing the following parameters:

Token bucket maximum sustained rate in bits per millisecond.

Token bucket depth (maximum transmit burst) in bits.

Length of current packet to be sent in bits.

Pointer to the flows token bucket.

Pointer to the flows token bucket last update time stamp.

Variable to return the milliseconds buffering delay in case the packet needs to be shaped.

Maximum buffering delay that the subsequent traffic shaper can handle in milliseconds.

Every flow has its own shaping buffer where rate-exceeded packets are typically held back in first-in/first-out(FIFO) order for later releases transmission.

Token bucket policing with shaping is the per-upstream default rate limiting setting at the CMTS. Shapingcan be enabled or disabled for the token-bucket algorithm.

Tip

Downstream Traffic ShapingThe CMTS supports basic downstream traffic shaping by effecting data rate limiting on a per-modem basis.A downstream traffic shaping feature called downstream rate limiting with type of service (ToS) bits extendsthat capability by allowing the CMTS administrator to configure the ToS byte to calculate the data rate for aspecified flow.

Downstream rate limiting with ToS bits enables you to partition downstream traffic for a CM into multipleclasses of service and multiple data rates by using the three precedence bits in the ToS byte in the IP header


Configuring Downstream Cable Interface Features on the Cisco CMTS RoutersTraffic Shaping

to specify a class of service assignment for each packet. Those packets with the precedence bit set in the ToSfield are given higher priority. Using the ToS byte, you can calculate the data rate for a specified flow, inaddition to the data rate configured on a per-CM basis. By specifying a maximum data rate for a particularToS, you can override the common maximum downstream data rate.

The administrator can override the maximum common downstream data rate limits by configuring the ToSbyte.

Packets that contain ToS bytes that have not been configured for downstream data rates continue to use thecommon data rate limits.

Configuring Downstream Rate Limiting and Traffic ShapingTo configure downstream traffic shaping, use the following command in cable interface configuration mode.

PurposeCommand

Enables or disables rate limiting and traffic shapingon the downstream of a cable interface.

Router(config-if)# [no] cable downstreamrate-limittoken-bucket [shaping] weighted-discard[expwt]

Using Cisco IOS Release 12.0(5)T1 or higher, the software adds downstream calendar queuing routinesand grant shaping application of the calendar queues.

Note

Effective with Cisco IOS Release 12.2(33)SCF, the cable downstream rate-limit command is notsupported for Cisco uBR-MC88U line card in Cisco IOS software.

Note

Details for key command usage are provided below:

To enable rate limiting on the given downstream port using the token bucket policing algorithm, issuethe cable downstream rate-limit token-bucket command.

To enable rate limiting on the given downstream port using the token bucket policing algorithm withtraffic shaping, issue the cable downstream rate-limit token-bucket shaping command.

To enable rate limiting on the given downstream port using the token bucket policing algorithm with aspecific traffic shaping time granularity, issue the cable downstream rate-limit token-bucket shapinggranularity 8 command. Acceptable values are 1, 2, 4, 8, or 16 msecs.

To enable rate limiting on the given downstream port using the token bucket policing algorithm with aspecific maximum traffic shaping buffering delay, issue the cable downstream rate-limit token-bucketshaping granularity 8 command. Acceptable values are 128, 256, 512, or 1028 msecs.

To remove rate limiting on the given downstream port, issue the cable downstream rate-limittoken-bucket command.

To enable rate limiting on the given downstream port using a weighted packet discard policing algorithmand to assign a weight for the exponential moving average of loss rate value, issue the cable downstreamrate-limit weighted-discard 3 command. Acceptable values are 1 to 4.


Configuring Downstream Cable Interface Features on the Cisco CMTS RoutersConfiguring Downstream Rate Limiting and Traffic Shaping

Setting the Downstream Helper AddressSpecify an IP address of a Dynamic Host Configuration Protocol (DHCP) server where User Datagram Protocol(UDP) broadcast packets will be sent. You can specify a DHCP server for UDP broadcast packets from cableinterfaces, and a DHCP server for UDP broadcast packets from hosts. To set a downstream helper address,use the following commands in cable interface configuration mode.

DETAILED STEPS


Set the downstream helper address to the DHCP server at IP address10.x.x.x for UDP broadcast packets from cable modems.

cable helper-address 10.x.x.x cable-modem

Example:Router(config-if)# cable helper-address10.x.x.x cable-modem

Step 1

Use the IP address of the DHCP server. Both 10.x.x.x and172.56.x.x are private ranges.

Note

Set the downstream helper address to the DHCP server at IP address172.56.x.x for UDP broadcast packets from hosts.

cable helper-address 172.56. x.xhost

Example:Router(config-if)# cable helper-address172.56.x.x host

Step 2

Verifying the Downstream Helper AddressTo verify the downstream helper address setting, enter the show running-config command and look for cablehelper-address in the cable interface configuration information:Router# show running-config

Building configuration...Current configuration:!interface cable5/0ip address 10.254.254.254 255.0.0.0no ip directed-broadcastcable helper-address 192.168.1.1no keepalive

Perform these steps if you are having difficulty with verification:

Step 1 Check the cables, upconverters, RF levels, and frequencies if the cable inter