Administering Cisco QOS for IP Networks

Mike Flannagan, Syngress

ISBN:1928994210, Edition: 1, 2001-03-15

Price: $59.95

Contents

Foreword ~ xxiii

Chapter 1 Cisco IOS Feature Review ~ 1

Introduction ~ 2
IP Address Classes and Classful IP Routing ~ 2
Classes A, B, and C ~ 5
Class D Addresses (Multicast) ~ 8
RIPv1 and IGRP ~ 10
RIPv1 ~ 11
IGRP ~ 13
Variable-Length Subnet Mask (VLSM) Review ~ 17
Why Do We Need VLSM? ~ 19
Common Uses for Subnetting ~ 20
Standard Access Control Lists (ACLs) ~ 21
Filtering Traffic ~ 24
Configuration Examples ~ 25
Extended Access Control Lists (ACLs) ~ 25
Benefits of Extended ACLs ~ 30
Common Ports Used with Extended ACLs ~ 30
Configuration Examples ~ 32
Network Address Translation (NAT) ~ 35
Controlling NAT with ACLs ~ 39
Dynamic versus Static Translations ~ 39
Configuration Example ~ 40
Route Maps ~ 40
Where to Use Route Maps ~ 41
Controlling Traffic with Route Maps ~ 41
Configuration Example ~ 41
Summary ~ 43
FAQs ~ 44

Chapter 2 EIGRP A Detailed Guide ~ 47

Introduction ~ 48
Reviewing Basic Concepts of IGRP ~ 48
How Does EIGRP Work? ~ 50
Using Distance Vectors for Path Selection ~ 50
Defining the Four Basic Components of EIGRP ~ 57
Establishing Protocol-Dependent Modules ~ 57
Establishing Neighbor Discovery/Recovery ~ 58
Managing Reliable Transport Protocol ~ 59
Establishing DUAL Finite State Machine ~ 59
Implementing Packet Types ~ 60
Configuring EIGRP’s Distributed
Update Algorithm (DUAL) ~ 64
Choosing a Path Selection ~ 64
Handling Failure and Recovery ~ 72
Configuring Basic EIGRP ~ 75
Verifying Configuration with Show Commands ~ 84
Configuring Advanced EIGRP ~ 87
Summarizing EIGRP Addresses ~ 88
Redistributing EIGRP and OSPF ~ 97
Unequal Cost Load Balancing ~ 103
Recognizing Caveats ~ 108
Stuck-in-Active ~ 108
Auto-Summarization ~ 109
Troubleshooting EIGRP ~ 110
Troubleshooting Stuck-in-Active Routes ~ 110
Troubleshooting Auto-Summarization ~ 115
Troubleshooting not-on-common-subnet ~ 117
Summary ~ 119
FAQs ~ 120

Chapter 3 Introduction to Quality of Service ~ 123

Introduction ~ 124
Defining Quality of Service ~ 124
What Is Quality of Service? ~ 125
Applications for Quality of Service ~ 126
Three Levels of QoS ~ 127
Understanding Congestion Management ~ 129
Defining General Queuing Concepts ~ 130
Leaky Bucket ~ 131
Tail Drop ~ 132
Token Bucket ~ 133
First In First Out Queuing ~ 134
Fair Queuing ~ 136
Priority Queuing ~ 138
Custom Queuing ~ 139
Understanding Congestion Avoidance ~ 141
Congestion Avoidance in Action ~ 142
Pros and Cons of Congestion Avoidance ~ 142
Introducing Policing and Traffic Shaping ~ 143
Traffic Shaping ~ 144
Generic Traffic Shaping ~ 145
Frame Relay Traffic Shaping ~ 145
Summary ~ 145
FAQs ~ 146

Chapter 4 Traffic Classification Overview ~ 147

Chapter 5 Configuring Traffic Classification ~ 181

Introduction ~ 182
Configuring Policy-based Routing (PBR) ~ 182
Using PBR to Route Specific Packet Types ~ 184
Defining Committed Access Rate (CAR) ~ 185
Configuring Distributed CAR (DCAR) ~ 188
Marking and Transmitting Web Traffic ~ 188
Remarking the Precedence ~ Bit
and Transmitting Web Traffic ~ 189
Marking and Transmitting Multilevels of CAR ~ 190
Marking and Rate Limiting ISPs ~ 191
Rate Limiting by Access List ~ 193
Using CAR to Match and Limit by MAC Address ~ 194
Monitoring CAR ~ 196
Configuring Cisco Express Forwarding ~ 196
Enabling CEF ~ 197
Monitoring CEF ~ 198
Troubleshooting Cisco Express Forwarding
Caveats and Bugs ~ 200
Configuring Basic Network-based Application
Recognition (NBAR) ~ 201
Creating an NABR Class Map ~ 202
Creating a Policy Map ~ 203
Applying the Policy Map to an Interface ~ 203
Configuring Complex NBAR ~ 204
Integrating NBAR with Class-based Weighted Fair Queuing ~ 206
Creating a Class Map to Identify NBAR ~ 207
Configuring Class Policy in the Policy Map ~ 207
Attaching the Policy to an Interface ~ 208
Configuring NBAR with Random Early Detection ~ 209
Configuring System Network Architecture Type of Service ~ 211
Mapping SNA CoS to IP ToS ~ 211
Prioritizing SNA Traffic ~ 212
Summary ~ 213
FAQs ~ 215

Chapter 6 Queuing and Congestion Avoidance Overview ~ 217

Chapter 7 Configuring Queuing and Congestion Avoidance ~ 239

Introduction ~ 240
Configuring FIFO Queuing ~ 240
Enabling FIFO ~ 240
Verifying FIFO Operations ~ 242
FIFO with RED ~ 243
Configuring Priority Queuing ~ 244
Enabling Priority Queuing ~ 244
A Closer Look at the Protocol Classification ~ 245
Applying Your Priority List to an Interface ~ 247
Configuring the Queue Limits ~ 247
Verifying Your Configuration ~ 248
Troubleshooting Priority Queuing ~ 250
Configuring Custom Queuing ~ 252
Enabling Custom Queuing ~ 252
Adjusting Byte Counts and Queue Sizes ~ 254
Applying Your Configuration to an Interface ~ 254
Verifying Your Configuration ~ 255
Troubleshooting Custom Queuing ~ 257
Configuring Weighted Fair Queuing ~ 259
Enabling Weighted Fair Queuing ~ 259
Verifying Your Configuration ~ 260
Troubleshooting Weighted Fair Queuing ~ 262
Configuring Random Early Detection ~ 263
Enabling Random Early Detection ~ 263
RED with Other Queuing Mechanisms ~ 264
Verifying Your Configuration ~ 266
Troubleshooting Random Early Detection ~ 267
Summary ~ 267
FAQs ~ 268

Chapter 8 Advanced QoS Overview ~ 271

Introduction ~ 272
Using the Resource Reservation Protocol (RSVP) ~ 272
What Is RSVP? ~ 273
What RSVP Is Not ~ 275
How Does RSVP Work? ~ 275
Session Startup ~ 276
Session Maintenance and Tear-Down ~ 278
What Kind of QoS Can I Request with RSVP? ~ 279
Reservation Styles and Merging Flows ~ 280
Why Do I Need RSVP on My Network? ~ 282
Advantages of Using RSVP ~ 283
Disadvantages of Using RSVP ~ 283
Using Class-Based Weighted Fair Queuing (CBWFQ) ~ 284
How Does CBWFQ Work? ~ 284
Why Do I Need CBWFQ on My Network? ~ 286
RSVP in Conjunction with CBWFQ ~ 290
Using Low Latency Queuing (LLQ) ~ 291
How Does LLQ Work? ~ 291
Classifying Priority Traffic ~ 292
Allocating Bandwidth ~ 292
Limitations and Caveats ~ 294
Why Do I Need LLQ on My Network? ~ 294
Using Weighted Random Early Detection (WRED) ~ 295
How Does WRED Work? ~ 295
WRED and IP Precedence ~ 296
WRED and RSVP ~ 297
WRED Algorithm ~ 297
Why Do I Need WRED on My Network? ~ 298
Using Generic Traffic Shaping and Frame
Relay Traffic Shaping ~ 299
Token Bucket ~ 299
How Does GTS Work? ~ 301
Why Do I Need GTS on My Network? ~ 301
How Does FRTS Work? ~ 303
Why Do I Need FRTS on My Network? ~ 305
Running in Distributed Mode ~ 307
Features Supported in Distributed Mode ~ 307
IOS Versions ~ 308
Operational Differences ~ 308
Restrictions ~ 308
Using Link Fragmentation and Interleaving ~ 309
How Does LFI Work? ~ 311
LFI with Multilink Point-to-Point Protocol ~ 312
How Can This Be Useful on My Network? ~ 313
Understanding RTP Header Compression ~ 313
How Does RTP Header Compression Work? ~ 314
When Would I Need RTP Header Compression? ~ 315
Summary ~ 315
FAQs ~ 318

Chapter 9 Configuring Advanced QoS ~ 321

Introduction ~ 322
Enabling, Verifying, and Troubleshooting
Resource Reservation Protocol (RSVP) ~ 322
Enabling RSVP ~ 324
Verifying Your RSVP Configuration ~ 324
Troubleshooting RSVP ~ 327
Enabling, Verifying, and Troubleshooting
Class-Based Weighted Fair Queuing (CBWFQ) ~ 328
Enabling CBWFQ ~ 328
Defining Class Maps ~ 328
Creating Policies ~ 330
Attaching Policies to Interfaces ~ 334
Verifying Your CBWFQ Configuration ~ 334
Troubleshooting CBWFQ ~ 336
Configuring, Verifying, and Troubleshooting
Low Latency Queuing (LLQ) ~ 337
Configuring LLQ ~ 337
Verifying Your LLQ Configuration ~ 338
Troubleshooting LLQ ~ 339
Configuring, Verifying, and Troubleshooting
Weighted Random Early Detection (WRED) ~ 340
Configuring WRED ~ 340
Verifying Your WRED Configuration ~ 343
Troubleshooting WRED ~ 348
Configuring and Verifying Generic Traffic
Shaping (GTS) and Frame
Relay Traffic Shaping (FRTS) ~ 349
Configuring GTS ~ 351
Verifying Your GTS Configuration ~ 352
Configuring FRTS ~ 354
Enabling Frame Relay Traffic Shaping
on the Interface ~ 354
Configuring Traffic Shaping Parameters ~ 354
Configuring Queuing for the VC ~ 356
Applying Map Class to the Frame Relay Interface ~ 357
Verifying Your FRTS Configuration ~ 357
Understanding Distributed Technologies ~ 359
DCEF ~ 360
DWRED ~ 360
Configuring, Verifying, and Troubleshooting
Link Fragmentation and Interleaving (LFI) ~ 362
Configuring LFI ~ 362
Multilink PPP ~ 362
LFI and Frame Relay ~ 364
Verifying Your LFI Configuration ~ 365
Troubleshooting MLP ~ 366
Configuring, Verifying, and Troubleshooting
RTP Header Compression ~ 367
Configuring RTP Header Compression ~ 368
Verifying Your RTP Header Configuration ~ 368
Troubleshooting RTP Header Compression ~ 369
Summary ~ 370
FAQs ~ 372

Chapter 10 Overview: Border Gateway Protocol (BGP) ~ 375

Introduction ~ 376
The History of BGP ~ 376
Exterior Gateway Protocol (EGP) ~ 376
The Original Implementation ~ 377
The Current RFC ~ 378
Maximizing the Functionality of BGP ~ 380
The BGP Routing Process 380 BGP Finite State Machine Logic ~ 381
The Types of BGP Messages ~ 384
The Format of BGP Packets ~ 384
External BGP and the Internet ~ 393
What Is an Autonomous System? ~ 395
Does that Mean BGP Uses Hop Count? ~ 397
Weight ~ 397
How Do I Get There? ~ 398
Multiexit Discriminator (MED), the BGP Metric ~ 400
Local Preference ~ 401
The BGP Path Selection Process ~ 402
BGP Path Selection Example ~ 403
Redistributing BGP into Your IGP ~ 408
Redistributing the Default Route ~ 409
BGP Synchronization ~ 410
Defining Internal BGP, Route Reflectors, and Confederations ~ 411
Internal BGP ~ 412
Route Reflectors ~ 412
Confederations ~ 412
Advanced BGP Network Design ~ 414
Building Network Redundancy ~ 415
Common Design Methodologies ~ 417
Summary ~ 418
FAQs ~ 419

Chapter 11 Configuring Border Gateway Protocol ~ 421

Introduction ~ 422
Relevant RFCs ~ 422
Enabling BGP Routing ~ 423
Defining BGP for an Autonomous System ~ 424
Defining the Remote AS ~ 425
Public versus Private Autonomous Systems ~ 426
Enabling BGP Routing ~ 426
Configuring EBGP Neighbors ~ 427
Defining the Remote Version ~ 428
Removing Private AS Numbers ~ 429
Configuring IBGP Neighbors ~ 432
Peering to Loopback Interfaces ~ 432
Configuring Route Reflectors ~ 433
Configuring Confederations ~ 436
When Do I Need Route Reflectors and Confederations? ~ 438
Weight, MED, LOCAL PREF, and Other Advanced Options ~ 439
Route-Map, Match, and Set Commands ~ 441
Weight Attribute ~ 442
Setting the Weight Attribute Using ~ the
Neighbor Statement ~ 442
Setting the Weight Attribute Using Access Lists ~ 443
Setting the Weight Attribute Using Route Maps ~ 444
Multiexit Discriminate (MED) Attribute ~ 444
Setting the MED Attribute Using ~ the
Set Metric Command ~ 445
Setting the MED Attribute with ~ the
Default-Metric Command ~ 446
Local Preference Attribute ~ 446
Setting Local Preference with the Default
Local-Preference Command ~ 447
Setting the Local Preference Attribute with
the Set Local-Preference Command ~ 448
AS_Path Attribute ~ 448
Origin Attribute ~ 449
Next_Hop Attribute ~ 449
Other Advanced Options:
BGP Multiprotocol Extensions ~ 450
Summary ~ 454
FAQs ~ 455

Chapter 12 Multiprotocol Label Switching (MPLS) ~ 457