IP Telephony Self-Study Cisco QOS Exam Certification Guide 2nd.1

Introduction......Page 20
“Do I Know This Already?” Quiz......Page 37
QoS: Tuning Bandwidth, Delay, Jitter, and Loss Questions......Page 38
Traffic Characteristics of Voice, Video, and Data Questions......Page 39
Planning and Implementing QoS Policies......Page 40
Foundation Topics......Page 41
QoS: Tuning Bandwidth, Delay, Jitter, and Loss......Page 43
Bandwidth......Page 44
The clock rate Command Versus the bandwidth Command......Page 46
QoS Tools That Affect Bandwidth......Page 47
Delay......Page 49
Serialization Delay......Page 50
Propagation Delay......Page 51
Queuing Delay......Page 53
Forwarding Delay......Page 54
Shaping Delay......Page 55
Network Delay......Page 56
Delay Summary......Page 58
QoS Tools That Affect Delay......Page 59
Jitter......Page 61
QoS Tools That Affect Jitter......Page 62
Loss......Page 63
QoS Tools That Affect Loss......Page 64
Summary: QoS Characteristics: Bandwidth, Delay, Jitter, and Loss......Page 66
Voice Traffic Characteristics......Page 67
Voice Basics......Page 68
Voice Bandwidth Considerations......Page 71
Voice Delay Considerations......Page 73
Codec Delay......Page 77
Considering the Effects of Packetization and Codec Delay......Page 78
De-Jitter Buffer Delay......Page 79
Voice Jitter Considerations......Page 82
Voice Loss Considerations......Page 84
Video Basics......Page 86
Video Bandwidth Considerations......Page 88
Video Delay Considerations......Page 90
Video Loss Considerations......Page 91
Data Traffic Characteristics......Page 92
IP Data Basics......Page 93
Data Bandwidth Considerations......Page 97
Data Delay Considerations......Page 98
Data Jitter Considerations......Page 99
Data Loss Considerations......Page 100
Comparing Voice, Video, and Data: Summary......Page 101
Step 1: Identify Traffic and Its Requirements......Page 102
Step 2: Divide Traffic into Classes......Page 103
Step 3: Define Policies for Each Traffic Class......Page 104
Foundation Summary......Page 105
Q&A......Page 113
QoS Exam Topics......Page 116
QoS Tools and Architectures......Page 117
“Do I Know This Already?” Quiz......Page 118
QoS Tools Questions......Page 119
The Differentiated Services QoS Model Questions......Page 120
The Integrated Services QoS Model Questions......Page 121
Introduction to IOS QoS Tools......Page 122
Classification and Marking......Page 123
Classification and Marking Tools......Page 125
Queuing......Page 126
Queuing Tools......Page 127
Shaping and Policing......Page 129
Shaping and Policing Tools......Page 131
Congestion Avoidance......Page 132
Link Efficiency......Page 133
Link-Efficiency Tools: Summary......Page 135
Call Admission Control......Page 136
Flow-Based QoS......Page 137
Class-Based QoS......Page 140
Proper Planning and Marking for Enterprises and Service Providers......Page 142
The Differentiated Services QoS Model......Page 145
DiffServ Specifications and Terminology......Page 146
DiffServ Per-Hop Behaviors......Page 150
The Class Selector PHB and DSCP Values......Page 152
The Assured Forwarding PHB and DSCP Values......Page 156
The Expedited Forwarding PHB and DSCP Values......Page 159
The Integrated Services QoS Model......Page 160
Comparison of the Three QoS Models......Page 163
Foundation Summary......Page 164
Q&A......Page 172
QoS Exam Topics......Page 174
MQC, QPM, and AutoQoS......Page 175
“Do I Know This Already?” Quiz Questions......Page 176
Cisco Modular QoS CLI......Page 177
The Cisco AutoQoS Feature......Page 178
Comparisons of CLI, MQC, and AutoQoS......Page 179
Cisco Modular QoS CLI......Page 180
The Mechanics of MQC......Page 181
Classification Using Class Maps......Page 182
MQC Example 1: Voice and Everything Else......Page 184
MQC Example 2: Matching ACLs and Using class-default......Page 185
Example 3: Matching Opposites with match not......Page 187
Example 4: Matching More Than One Thing......Page 188
Example 5: Complex Matching with match-class......Page 189
Performing QoS Actions (PHBs) Using policy-map Commands......Page 190
show Commands for MQC......Page 192
QoS Policy Manager (QPM)......Page 193
SNMP Support for QoS......Page 195
Cisco AutoQoS Feature......Page 196
AutoQoS VoIP Default Configuration......Page 197
More AutoQoS Configuration Options......Page 200
AutoQoS VoIP for Router PHBs......Page 201
AutoQoS VoIP for Cisco IOS Switches......Page 204
AutoQoS VoIP Configuration for IOS Switches......Page 205
AutoQoS VoIP for IOS Switch PHBs......Page 207
AutoQoS VoIP for 6500 Cat-OS......Page 208
Comparisons of CLI, MQC, and AutoQoS......Page 211
Foundation Summary......Page 212
Q&A......Page 217
QOS Exam Topics......Page 220
“Do I Know This Already?” Quiz Questions......Page 221
Classification and Marking Concepts Questions......Page 222
Classification and Marking Tools Questions......Page 223
Classification Issues when Using VPNs Questions......Page 225
Classification......Page 226
Class-Based Marking......Page 227
Classification with NBAR......Page 229
IP Header QoS Fields: Precedence and DSCP......Page 231
LAN Class of Service (CoS)......Page 235
Other Marking Fields......Page 237
Summary of Marking Fields......Page 238
Classification and Marking Design Choices......Page 239
Class-Based Marking (CB Marking) Configuration......Page 245
Network-Based Application Recognition (NBAR)......Page 253
CB Marking show Commands......Page 257
Miscellaneous Features of Class-Based Marking......Page 262
Classification and Marking Before Entering the VPN Tunnel......Page 263
Classification and Marking on the Router Creating the VPN Tunnel......Page 264
Configuring QoS Pre-classification......Page 266
Foundation Summary......Page 271
For Further Reading......Page 275
Q&A......Page 276
QoS Exam Topics......Page 280
“Do I Know This Already?” Quiz......Page 281
Cisco Router Queuing Concepts Questions......Page 282
Scheduling Concepts: FIFO, PQ, CQ, and MDRR Questions......Page 283
Concepts and Configuration: WFQ, CBWFQ, and LLQ Questions......Page 284
Cisco Router Queuing Concepts......Page 286
Software Queues and Hardware Queues......Page 289
Queuing on Interfaces Versus Subinterfaces and Virtual Circuits (VCs)......Page 296
Summary of Queuing Concepts......Page 298
FIFO Queuing......Page 299
Priority Queuing......Page 302
Custom Queuing......Page 303
Modified Deficit Round-Robin......Page 304
Weighted Fair Queuing (WFQ)......Page 307
WFQ Classification......Page 308
WFQ Scheduler: The Net Effect......Page 309
WFQ Scheduler: The Process......Page 310
WFQ Drop Policy, Number of Queues, and Queue Lengths......Page 314
Special WFQ Queues......Page 315
WFQ Configuration......Page 316
Class-Based WFQ (CBWFQ)......Page 322
CBWFQ Configuration......Page 325
Low Latency Queuing (LLQ)......Page 339
LLQ Configuration......Page 341
LLQ with More Than One Priority Queue......Page 346
LLQ and the bandwidth remaining percent Command......Page 348
Comparisons of WFQ, CBWFQ, and LLQ......Page 351
Foundation Summary......Page 352
For Further Reading......Page 357
Scheduling Concepts: FIFO, PQ, CQ, and MDRR......Page 359
Concepts and Configuration: WFQ, CBWFQ, and LLQ......Page 360
QoS Exam Objectives......Page 364
“Do I Know This Already?” Quiz......Page 365
Shaping and Policing Concepts Questions......Page 366
Configuring Class-Based Shaping......Page 367
Configuring Class-Based Policing......Page 369
Traffic Policing and Traffic Shaping Concepts......Page 371
When and Where to Use Shaping and Policing......Page 372
Policing: When and Where?......Page 373
Traffic Shaping—When and Where?......Page 376
How Shaping Works......Page 379
Traffic Shaping with No Excess Burst......Page 384
Traffic Shaping with Excess Burst......Page 385
Traffic-Shaping Adaption......Page 387
Where to Shape: Interfaces, Subinterfaces, and VCs......Page 389
Queuing and Traffic Shaping......Page 390
How Policing Works......Page 393
CB Policing: Single-Rate, Two-Color (1 Bucket)......Page 394
CB Policing: Dual Token Bucket (Single-Rate)......Page 396
CB Policing: Dual Token Bucket (Dual Rate)......Page 397
Summary of CB Policing Mechanics......Page 399
Policing, but Not Discarding......Page 400
Class-Based Shaping Configuration......Page 401
Setting Bc to Tune Tc......Page 405
Tuning Shaping for Voice Using LLQ and a Small Tc......Page 408
Shaping to a Peak Rate......Page 413
Miscellaneous CB Shaping Configuration: Adaptive Shaping......Page 414
Miscellaneous CB Shaping Configuration: Shaping by Percent......Page 415
Comparing CB Shaping and FRTS......Page 417
Class Based Policing Configuration......Page 418
Policing a Subset of the Traffic......Page 423
CB Policing Miscellany......Page 426
Policing by Percentage......Page 427
CB Policing Defaults for Bc and Be......Page 429
Policing by Percent......Page 430
CB Policing Configuration Summary......Page 431
Foundation Summary......Page 432
Traffic Policing and Traffic Shaping Concepts......Page 442
Class Based Shaping Configuration......Page 444
Class Based Policing Configuration......Page 445
QoS Exam Objectives......Page 446
“Do I Know This Already?” Quiz......Page 447
Congestion-Avoidance Concepts and RED Questions......Page 448
WRED Questions......Page 449
ECN Questions......Page 451
TCP and UDP Reactions to Packet Loss......Page 452
Tail Drop, Global Synchronization, and TCP Starvation......Page 456
Random Early Detection (RED)......Page 458
Weighted RED (WRED)......Page 461
How WRED Weights Packets......Page 462
WRED and Queuing......Page 465
WRED Configuration......Page 467
WRED Summary......Page 480
ECN Concepts......Page 481
ECN Configuration......Page 484
Foundation Summary......Page 488
Congestion-Avoidance Concepts and Random Early Detection (RED)......Page 492
Explicit Congestion Notification......Page 493
QoS Exam Topics......Page 496
Link Efficiency Tools......Page 497
Compression Questions......Page 498
Link Fragmentation and Interleave Questions......Page 500
Payload and Header Compression......Page 502
Header Compression......Page 504
Class-Based TCP and RTP Header Compression Configuration......Page 505
Link Fragmentation and Interleaving......Page 509
Multilink PPP LFI......Page 512
Maximum Serialization Delay and Optimum Fragment Sizes......Page 513
Frame Relay LFI Using FRF.12......Page 515
Choosing Fragment Sizes for Frame Relay......Page 519
Multilink PPP Interleaving Configuration......Page 521
Frame Relay Fragmentation Configuration......Page 531
MLP LFI and FRF.12 Configuration: The Short Version......Page 542
Foundation Summary......Page 543
Compression Tools......Page 547
LFI Tools......Page 549
QoS Exam Topics......Page 550
“Do I Know This Already?” Quiz......Page 551
Classification and Marking......Page 552
Congestion Management......Page 553
AutoQoS......Page 555
Buffer Overflow (Overrun)......Page 557
The Cisco Catalyst 2950......Page 558
Layer 2 Header Classification and Marking......Page 559
Layer 2-to-Layer 3 Mapping......Page 560
Trust Boundaries......Page 563
CoS-Based Trust Boundaries......Page 564
Cisco IP Phone–Based Trust Boundaries......Page 565
Setting the Default CoS Value......Page 566
Configuring Trust Boundaries in an IP Telephony Environment......Page 567
Using MQC for Classification and Marking......Page 569
Verifying MQC Classification and Marking......Page 571
Congestion Management......Page 572
Strict Priority Scheduling......Page 573
WRR Scheduling......Page 575
Strict Priority and WRR Scheduling......Page 578
Policing......Page 580
AutoQoS......Page 584
Foundation Summary......Page 590
For Further Reading......Page 599
Q&A......Page 600
QOS Exam Topics......Page 604
“Do I Know This Already?” Quiz......Page 605
The Need for QoS Best Practices......Page 610
End-to-End QoS......Page 611
QoS Service Level Agreements......Page 612
Voice Traffic......Page 614
Video Traffic......Page 619
Data Traffic......Page 620
Classification and Marking Best Practices......Page 622
Congestion Management Best Practices......Page 625
Congestion Avoidance Best Practices......Page 628
QoS Case Studies......Page 630
Enterprise Campus QoS Implementations......Page 631
Enterprise (CE) to Service Provider (PE) WAN QoS Implementations......Page 640
Service Provider (PE) to Enterprise (CE) WAN QoS Implementations......Page 651
Service Provider Backbone QoS Implementations......Page 657
Foundation Summary......Page 661
For Further Reading......Page 670
Q&A......Page 671
QoS: Tuning Bandwidth, Delay, Jitter, and Loss Questions......Page 675
Q&A......Page 676
Classifying Using Flows or Service Classes Questions......Page 683
Q&A......Page 684
Cisco Modular QoS CLI......Page 688
Cisco AutoQoS Feature......Page 689
Q&A......Page 690
Classification and Marking Concepts Questions......Page 695
Classification and Marking Tools Questions......Page 696
Q&A......Page 697
Scheduling Concepts: FIFO, PQ, CQ, and MDRR Questions......Page 702
Concepts and Configuration: WFQ, CBWFQ, and LLQ Questions......Page 703
Q&A......Page 704
Concepts and Configuration: WFQ, CBWFQ, and LLQ......Page 706
“Do I Know This Already” Quiz......Page 712
Configuring Class-Based Shaping......Page 713
Configuring Class-Based Policing......Page 714
Q&A......Page 715
Class-Based Shaping Configuration......Page 720
Class-Based Policing Configuration......Page 722
WRED Questions......Page 725
ECN Questions......Page 726
Congestion-Avoidance Concepts and Random Early Detection (RED)......Page 727
Weighted RED (WRED)......Page 729
Explicit Congestion Notification......Page 731
Link Fragmentation and Interleave Questions......Page 732
Compression Tools......Page 733
LFI Tools......Page 737
Classification and Marking......Page 739
Policing......Page 740
Q&A......Page 741
“Do I Know This Already” Quiz......Page 748
Q&A......Page 750