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Contents

Preface.....................................................................................xxix Prerequisites .................................................................................xxix Who Should Study This Course? ..................................................xxx Key Topics......................................................................................xxx Course Objectives ..........................................................................xxx Exam Objectives ...........................................................................xxxi How to Study ................................................................................xxxi CACQ ..........................................................................................xxxii How to Become CompTIA Certified ...........................................xxxii

Introduction............................................................................xxxv

Module1Telephony.................................................................................... 1 Introduction .....................................................................................1 Terms ................................................................................................1

Lesson 1Telecommun�cat�ons Traffic Eng�neer�ng ........................................ 6 Trunks ...............................................................................................6 Trunk Direction .........................................................................7 Trunk Capacity ..........................................................................7 Trunk Transmission Type ..........................................................8 Analog Transmission ..........................................................8 Analog Bandwidth .............................................................9 Digital Transmission ...........................................................9 Digital Bandwidth ............................................................11 Types of Trunks ..............................................................................12 Special Access Trunks .....................................................................13 Tie Trunk .................................................................................13 Private Lines ............................................................................14 Foreign Exchange ....................................................................14 Ring Down ...............................................................................15 Trunk Pricing ............................................................................15

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Carried Load ....................................................................................16 Conversation Time ..................................................................17 Operating Time .......................................................................17 Holding Time ..........................................................................18 Constant Distribution .......................................................18 Exponential Distribution ..................................................18 Probability .......................................................................................19 Grade of Service ..............................................................................20 Trunk Usage Measurements ............................................................20 CCS ..........................................................................................21 Erlang ......................................................................................21 The Erlang B Traffic Formula ..........................................................22 Erlang C and Poisson Tables ..........................................................23 Poisson: Immediate Redial ......................................................23 Erlang C: Infinite Queue .........................................................24 No Formula Is Perfect .....................................................................24 Estimating Total System Capacity ..................................................24 Outbound Trunk Capacity ......................................................24 Tie Trunks ................................................................................25 VoIP Link Capacity ..................................................................26 PBX Processing Capacity .........................................................27 Adjusting To Changes .............................................................28 Data Prioritization ..........................................................................28 Protocol Reservation .......................................................................29 Session Fairness ...............................................................................30 Traffic Shaping ................................................................................30

Lesson 2Vo�ce System Fundamentals ......................................................... 34 Legacy Hybrid and IP Telephony Systems ......................................34 Key Systems .....................................................................................35 Key System Components .........................................................35 Cordless Key Systems ...............................................................36 Limitations of Key Systems ......................................................37 Hybrid Systems ................................................................................38 IP Telephony Systems ......................................................................38 Voice Transmission Fundamentals..................................................39 Encoding, Decoding, and Compression .........................................40 Digitizing the Voice .........................................................................40 Analog to Digital ......................................................................41 DTMF Signaling ........................................................................42 How a Call is Made .........................................................................43 Dial Tone ..................................................................................44 Entering a Telephone Number .................................................44 Call Routing .............................................................................44 Ringing .....................................................................................46 Ending the Call ........................................................................47 Long Distance Voice Routing ..........................................................47

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Signaling ..........................................................................................48 In-Band vs. Out-of-Band Signaling .........................................48 Signaling System 7 ..................................................................49

Lesson 3 Number and D�al�ng Plan Components ....................................... 52 Prefixes ...........................................................................................52 Telephone Numbering System .......................................................52 The Dwindling Supply of Numbers ........................................53 Assigning Telephone Numbers ...............................................54 Special Area Codes .........................................................................54 Special NXX Codes ..................................................................55 Special Information: 555 .........................................................55 Hearing-Impaired Services: 800-855 .......................................55 Service Codes, or N11 Numbers ..............................................55 Toll-Free: 800, 888, 877, etc. ...................................................56 Premium: 900 ..........................................................................56 700 Services .............................................................................56 Follow-Me: 500 ........................................................................56 Number Formats ............................................................................57 Number Blocking ...........................................................................57 Anonymous Call Blocking ......................................................57 Digit Translation ............................................................................58 Toll Fraud .......................................................................................58 ENUM .............................................................................................61 Local Number Portability (LNP) .....................................................65 Emergency Service ..........................................................................68

Lesson 4Converged Network Endpo�nts ................................................... 75 Voice Terminals ..............................................................................75 IP Phones ........................................................................................75 TDM Phones ...................................................................................76 Analog Phones ...............................................................................76 Dialup Hard Phone ........................................................................77 PC-Based Soft Phones .....................................................................77 Microphones and Headsets or Speakers .........................................77 USB Hand Sets ................................................................................78 SIP Phones ......................................................................................78 PDA Soft Phones .............................................................................78 WiFi Phones ...................................................................................78

Summary .................................................................................... 81

Qu�z ............................................................................................ 82

Module2NetworkEngineering................................................................ 89 Introduction ...................................................................................89 Terms ..............................................................................................90

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Lesson 1 General QoS Concepts .............................................................. 104 Network Requirements for Convergence .....................................105 Converged Network Architecture ................................................105 A Hybrid Approach to Convergence .....................................105 Parallel WAN Paths for QoS ..................................................106 Application-Level QoS ...........................................................107 Voice Quality ................................................................................107 The QoS Parameters .....................................................................108 Bandwidth .............................................................................109 Throughput ...........................................................................110 Delay ......................................................................................110 Encoding, Decoding, and Compression ........................111 Packetization ..................................................................111 Jitter .......................................................................................112 Jitter Buffers ....................................................................112 Measuring Jitter ..............................................................114 Wander ..................................................................................114 Packet Loss ............................................................................114 Availability ............................................................................115 Security ..................................................................................116 IP Header Features ........................................................................117 ToS Field ................................................................................117 IntServ ...................................................................................117 RSVP .............................................................................................117 CBQ ..............................................................................................118 COPS .............................................................................................118 MPLS .............................................................................................120 Policy Routing ..............................................................................122 RED ...............................................................................................122 WFQ .............................................................................................122 WRED ...........................................................................................123 DiffServ ..................................................................................123 DSCP Code Points .................................................................123 PHB ........................................................................................124 Standard PHBs ................................................................124 Custom PHBs ..................................................................125 DiffServ Domains ..................................................................125 IP Precedence ..........................................................................125 Traffic Prioritization ......................................................................125 802.1Q VLAN Standard .................................................................126 The VLAN Tag .......................................................................126 802.1Q as an Architecture .....................................................128 802.1Q Protocols ...................................................................128 802.1p Traffic Prioritization Standard ..........................................129 Priority Tags and Traffic Classes ............................................129 How 802.1p Prioritizes Traffic ...............................................130 Mapping 802.1p Traffic Prioritization to IP and ATM Networks .......................................................130

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Using QoS to Optimize Voice Quality in VoIP Networks ............131

Lesson 2 Network Performance ............................................................... 137 Network Performance Issues ........................................................138 Voice Quality ................................................................................139 Encoding and Decoding ........................................................139 Propagation ...........................................................................139 Packetization Delay ...............................................................140 Jitter .......................................................................................140 Voice Compression ................................................................140 Latency .........................................................................................140 Packet Loss ...................................................................................141 Port Settings ..................................................................................142 Bandwidth ....................................................................................143 Network Capacity Baselining .......................................................143 Tools for Testing Activity ......................................................144 Design and Modeling Tools ..................................................144 Simulation and Testing Tools ................................................145 Network Capacity Baselining .......................................................145 Packet Capture Functions .....................................................145 Network Baselining in “Monitor” Mode ...............................146 Troubleshooting in “Analyzer” Mode ...................................146 Basic Operation .....................................................................146 Building the Relational Names Database ..............................147 Interpreting the Baseline .......................................................148 Bottlenecks ...................................................................................152 Measuring Shared Resource Utilization ................................152 Measurement Tools ...............................................................153 Performance Monitor .....................................................153 Task Manager ..................................................................154 Network Monitor ...........................................................154 Applying the Tools .........................................................155 Output: Baseline Report .................................................155 Network Throughput ...................................................................155 Bandwidth .............................................................................156 Point-To-Point Links .............................................................156 Various Data Rates and Associated Applications ..................158 Bottlenecks ...................................................................................160 Response Time in a Client/Server Configuration .................160 NIC Delay ..............................................................................161 Physical Media Delay ............................................................161 Server Delay ...........................................................................161 Public Network Delay ............................................................161 CPU Utilization .....................................................................162 Link Utilization ............................................................................164 Capacity .................................................................................164 Bandwidth .............................................................................164 Throughput ..................................................................................166

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Impact to the Network when Adding/Modifying Converged Applications ...............................................................168

Lesson 3Sw�tches .................................................................................... 172 LAN Switching .............................................................................173 LAN Switch Features .....................................................................175 Switching Techniques ..................................................................176 Cut-Through ..........................................................................176 Store-and-Forward .................................................................176 Ethernet Switch Bandwidth .........................................................177 Multilayer Switch Technology .....................................................179 Layer 2 Switches ....................................................................179 Layer 3 Switches ....................................................................180 Comparing Layer 3 Switches and Routers ............................180 Examples of Layer 3 Switching Techniques ..........................181 Proprietary Methods .......................................................181 Packet-by-Packet Switching ............................................181 Layer 4-7 Switches .................................................................181 Multilayer Switches ...............................................................182 Process of Switching Frames ........................................................182 Learning Network Addresses .................................................183 Frame Forwarding/Filtering ..................................................184 Redundancy and Active Loops .....................................................185 Spanning Tree Algorithm .............................................................187 Selecting Switches ........................................................................188 Switch Configurations ..................................................................189 Switch Features and Backbone Switch Considerations ...............189 Number of Ports ....................................................................189 Support for Mixed Data Link Protocols ................................189 Virtual LAN Support ..............................................................189 Redundancy and Reliability ..................................................190 Network Management ...........................................................190 PoE .........................................................................................190 Summary of Switch Features ........................................................191

Lesson 4Phys�cal and Log�cal Port Sett�ngs .............................................. 197 Features Common to Both User Datagram Protocol and Transmission Control Protocol .............................................197 Demultiplexing Based on Port Number ................................198 Ports and Addressing .............................................................200 Well-Known Port Numbers ...................................................200

Lesson 5Network Class�ficat�ons and Topolog�es ..................................... 205 Network Classification .................................................................205 PANs ......................................................................................205 LANs ......................................................................................205 Campus Networks .................................................................206

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MANs .....................................................................................207 WANs .....................................................................................208 GANs .....................................................................................209 Network Topologies ......................................................................210 Bus Topology .........................................................................210 Star Topology .........................................................................211 Ring Topology .......................................................................212 Star Ring Topology ................................................................212 Point to Point Topology ........................................................214 Partial Mesh Topology ...........................................................214 Fully Meshed Topology .........................................................214 Network Cloud ......................................................................215

Lesson 6 Rout�ng ..................................................................................... 221 Introduction to Routers ...............................................................221 How Routers Work ................................................................222 Multiprotocol Routing ..........................................................223 How Routers Move Packets Between Networks ...........................223 Routers Rebuild Frames .........................................................224 Internet Routers ....................................................................225 Broadcast Domains ................................................................225 Routers for Broadcast Containment ..............................227 Router Advantages and Disadvantages .................................227 Routing Tables ..............................................................................228 Building the Routing Table ...................................................229 Sample Network Routing Table .............................................232 Determining the Best Path ....................................................233 Related Devices .............................................................................236 Brouters .................................................................................236 Direct Routing ..............................................................................237 Indirect Routing ...........................................................................237 Static Routing ...............................................................................239 Default Routes ..............................................................................240 Dynamic Routing .........................................................................242

Lesson 7Protocols ................................................................................... 247 The TCP/IP Protocol Suite ............................................................247 TCP/IP Protocol Layers and the OSI Model .................................248 Network Interface Layer Protocols ........................................249 Internetwork Layer Protocols ................................................249 Transport Layer Protocols .....................................................250 Application Layer Protocols ..................................................250 Communication Using TCP/IP ....................................................251 Application Layer ..................................................................252 Transport Layer .....................................................................252 Network Layer .......................................................................253 Network Interface Layer ........................................................253 Destination Station ...............................................................254

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Features Common to Both UDP and TCP ...................................254 UDP ..............................................................................................255 UDP Service ...........................................................................255 Demultiplexing Based on Port Number ................................256 UDP Port Numbers ................................................................259 Frame Encapsulation .............................................................259 TCP ...............................................................................................260 Basic Data Transfer ................................................................260 Reliable and Sequenced Packet Delivery ...............................261 Flow Control .........................................................................261 Multiplexing and Demultiplexing ........................................261 Connection Establishment ...................................................261 Sockets ............................................................................261 IP ...................................................................................................262 Overview of IP .......................................................................263 IP Header Format and Field Descriptions .............................265 IP Packet Encapsulation ........................................................267 Real-time Transport Protocol .......................................................268 Time Stamping ......................................................................268 Sequencing ............................................................................269 Compressed RTP ...........................................................................269 How cRTP Works ...................................................................272 Routing cRTP Traffic ..............................................................273 Real-Time Transport Control Protocol .........................................274

Lesson 8Transm�ss�on Med�ums ............................................................... 280 Cables ...........................................................................................280 Copper Cable .........................................................................280 Coaxial Cable ...............................................................................281 10Base5 ..................................................................................283 10Base2 ..................................................................................284 Coaxial Cabling Characteristics ............................................285 Twisted Pair Cabling ....................................................................286 UTP Cable ..............................................................................287 STP Cable ...............................................................................289 USB Cables .............................................................................290 IEEE 1394 FireWire Cable ......................................................290 Other Twisted Pair Cabling Characteristics .................................291 Fiber Optic Cable ..........................................................................292 Digital Subscriber Line .................................................................295 How DSL Works .....................................................................297 DSL Physical Requirements ...................................................298 Satellites .................................................................................299 Geosynchronous Satellites .............................................299 Low Earth Orbit Satellites ..............................................300 Wireless Transmission ..................................................................301 How Wireless Transmission Works ..............................................301 The Electromagnetic Spectrum .............................................302

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Competition for the Finite RF Spectrum .....................................305 Wireless Networking Applications ...............................................305 Point-to-Point Microwave Systems .......................................306 Cellular Systems and Personal Communication Services .....306 Wireless LANs ........................................................................307 Short-Range Infrared Transmission .......................................307 Ethernet ........................................................................................308 Advantages and Disadvantages of Ethernet .................................308 Ethernet Configurations ..............................................................309 Fast Ethernet .................................................................................310 Gigabit Ethernet ...........................................................................311 Evolution-Data Optimized (EVDO) .............................................312 Cable Applications .......................................................................313 Coaxial Cable Applications ...................................................313 Optical Fiber Applications .....................................................313 Twisted Pair Cable Applications ............................................314 WLAN Applications ...............................................................314 Comparing Media .................................................................314 General Installation Guidelines ............................................315 Virtual Private Networks (VPNs) ..................................................316 VPNs in Action ......................................................................316 VPN Protocols .......................................................................319 Point to Point Tunneling Protocol (PPTP) .....................319 Layer 2 Tunneling Protocol (L2TP) ................................321 PPP Authentication Protocols ........................................321

Lesson 9S�gnal�ng Bas�cs ......................................................................... 326 Types of Signals ............................................................................326 Supervisory Signals .......................................................................327 Loop Start ..............................................................................327 Ground Start ..........................................................................329 E&M .......................................................................................330 Emulated Tie Trunks ..............................................................331 Wink Start .............................................................................331 Digital Signaling ....................................................................332 Address Signals .............................................................................333 Dial Pulse Signaling ...............................................................333 Dual Tone Multifrequency Signaling ....................................335 Alerting Signals ............................................................................335 Control Signals .............................................................................336 In-Band vs. Out-of-Band Signaling ..............................................336

Lesson 10Methods of Encod�ng, Decod�ng and Compress�on ................... 341 Analog to Digital ..........................................................................341 Voice Conversations .....................................................................343 Standards ......................................................................................343 H.261 .....................................................................................343 H.264/MPEG-4/AVC ..............................................................344

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Audio Codecs ........................................................................344 G.711 Companding Algorithms ....................................345 G.722 ..............................................................................347 G.729a ............................................................................347 MPEG, MP3 ..................................................................................348 MPEG.x .........................................................................................349 MPEG-1 .................................................................................349 MPEG-2 .................................................................................349 MPEG-4 ALS ..........................................................................350

Summary .................................................................................. 354

Qu�z .......................................................................................... 355

Module3Applications............................................................................. 365 Introduction .................................................................................365 Terms ............................................................................................366

Lesson 1Messag�ng Appl�cat�ons ............................................................. 377 Voice Mail Systems .......................................................................377 Voice Mail Features ......................................................................378 Voice Mail/PBX Integration ..................................................378 Design Factors .......................................................................380 Unified Messaging .................................................................380 Broadcasting ..........................................................................381 Voice Mail Security ................................................................381 Automated Attendants .................................................................382 Text Messaging: E-Mail, News, and Chat .....................................382 E-Mail ...........................................................................................383 E-Mail Addresses ...........................................................................383 E-Mail Protocols ...........................................................................383 Simple Mail Transfer Protocol ...............................................384 UNIX-to-UNIX Encoding ......................................................385 Multipurpose Internet Mail Extension .................................385 Secure/MIME .........................................................................386 Post Office Protocol ...............................................................386 Mail Server Configuration ............................................................386 Store-and-Forward Mail Systems ..................................................387 Chatting .......................................................................................388 Instant Messaging ........................................................................390 Video Messaging ...........................................................................391 Unified Messaging ........................................................................391 Benefits of Unified Messaging ...............................................392 Unified Messaging Components ...........................................393 Accessing Separate Message Sources .....................................394 Challenges .............................................................................395

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Lesson 2Collaborat�on Appl�cat�ons ........................................................ 401 Audio Conferencing .....................................................................401 Types of Audio Conferencing ...............................................401 Audio Conference Connection Methods ..............................402 Internet Multimedia .....................................................................403 Basic IP Videoconferencing System .............................................403 Input: Microphone and Video Camera .................................404 Webcams ...............................................................................404 Video System Software ..........................................................405 Codec .....................................................................................405 Types of Videoconferencing Systems ...........................................406 ISDN-Based Video: H.320 ......................................................406 IP-Based Video: H.323 ...........................................................407 H.320 vs. H.323 .....................................................................408 Data Sharing .................................................................................409 Single or Dual Video Streams ................................................409 T.120 Series ............................................................................409

Lesson 3Computer Telephony Integrat�on and Call Center Automat�on ... 413 CTI in Action ................................................................................413 Evolution of CTI ...........................................................................415 Levels of Call Center Automation ...............................................416 PBX/ACD Routing .................................................................416 IVR Routing ...........................................................................416 CTI Software ..........................................................................418

Lesson 4Computer Telephony Integrat�on Concepts ............................... 423 Media Processing and Call Control .............................................423 First-Party Call Control .........................................................424 Third-Party Call Control .......................................................425 CTI Components ..........................................................................426 CTI Server ..............................................................................426 CTI Client Applications ........................................................426 CTI Link .................................................................................427 Key CTI Implementation Issues ...................................................428 Key Integration Steps ............................................................429 Enabling CTI in the Avaya Communication Manager ................429 MAPD Hardware ....................................................................430 ASAI Client Software .............................................................431 Call Vectoring Software .........................................................431

Lesson 5Web-Enabled Call Centers ......................................................... 435 Internet Callback ..........................................................................436 Tailors Information for Each Customer ................................436 Increases Site Revenue ...........................................................436 Captures Qualified Leads ......................................................436

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Uses Time Efficiently .............................................................436 Callback Architectures .................................................................436 Nonintegrated Callback ........................................................437 Integrated Callback ...............................................................438 Web-Integrated Call Centers .................................................440 Implementation Issues ..........................................................441 Web Chats ....................................................................................442 Customer Interaction ...................................................................443

Lesson 6Call Rout�ng .............................................................................. 446 Call Routing Patterns ...................................................................446 Reports .........................................................................................448 Configurations .............................................................................448 Stand-Alone ACDs .................................................................449 PC-Based ACDs ......................................................................449 UnPBX ACDs .........................................................................450 PBXs With ACD Functions ....................................................451 Central Office-Based ACDs ....................................................451 Nationwide Networks of ACDs .............................................452 Customer Handling Procedures ...................................................453 Waiting Time .........................................................................454 Recorded Announcements ....................................................454 On-Hold Entertainment ........................................................454 Program Control Statements .................................................454 Telephone System Instructions .............................................455 Priority Queuing ...........................................................................455 ANI Routing .................................................................................455 Elements of an ANI Transaction ...........................................456 DNIS Routing ...............................................................................458 ACD First ...............................................................................458 Server First .............................................................................458 SBR .........................................................................................460 Routing Rules .........................................................................462 Multiple Skill Queues .............................................................462 Multiple Skills Vs. Multiple Queues .......................................463 SBR Simulations .....................................................................463 EBR ................................................................................................464 Intelligent Call Queuing ..............................................................465 Call Queuing ................................................................................465 Call Recording ..............................................................................465

Lesson 7Interact�ve Vo�ce Response ........................................................ 470 Audio Computer Application ......................................................471 Data Input ....................................................................................471 Links to Outside Systems .............................................................471 Data Output .................................................................................472 Audio .....................................................................................472 Multimedia ............................................................................472

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Trend Toward Integrated Solutions ..............................................473 System Configurations .................................................................473 Behind the ACD ....................................................................473 In Front of the ACD ..............................................................474 LAN-Based IVR ......................................................................474 Carrier-Based IVR ..................................................................475 Common IVR Mistakes ................................................................476

Lesson 8Mob�l�ty Components ............................................................... 478 Softphone .....................................................................................478 Application Layer .........................................................................479 Transport Layer ............................................................................480 Network Layer ..............................................................................480 Network Interface Layer ...............................................................481 Destination Station ......................................................................481 Presence ........................................................................................481 Cellular Integration Services ........................................................482 Find-Me/Follow-Me: 500 Numbers ..............................................483

Lesson 9 H.323 Standard for Packet Mult�med�a ...................................... 486 Overview of the H.323 Standard ..................................................486 Version 1: Videophone ..........................................................487 Version 2: Packet-Based Multimedia .....................................487 Version 3: Under Development ............................................487 Other Standards of the H.323 Family ..........................................487 Fundamental H.323 Network Components ................................488 Terminals ...............................................................................488 MCUs .....................................................................................489 Gateways ...............................................................................489 Gatekeepers ...........................................................................489 MGCP ...........................................................................................491 MGCP Network Components ...............................................491 MG ..................................................................................492 MGC ...............................................................................493 The H.323 Protocols and Their Effect on Voice Stream QoS ....................................................................493 H.323 Protocols .....................................................................493 Audio Codecs ........................................................................494 Silence Suppression ........................................................495 G.711 Companding Algorithms ....................................495 MOS ................................................................................496 Audio Codec Delays .......................................................497 DSPs ................................................................................498 DSP Delays ......................................................................498 RTP .........................................................................................498 Time Stamping ...............................................................498 Sequencing .....................................................................499 eRTCP ....................................................................................499

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RAS: H.225 .............................................................................500 Call Signaling: H.225 ............................................................500 Control Signaling: H.245 ......................................................500 H.323 Protocol Limitations ...................................................500 Document Conferencing: T.120 Series ..................................501 Integration with the Digital PSTN ...............................................501 ISDN/VoIP Integration ..........................................................501 Adding SS7 to VoIP ................................................................502 Network Infrastructure Requirements .........................................504

Lesson 10H.323 Call Process�ng ............................................................... 509 H.323 Call Progression Phases .....................................................509 Gatekeeper Discovery and Registration: H.225 RAS .............510 Call Setup and Signaling: H.225 ...........................................511 Control Signaling: H.245 ......................................................514 Call Termination: H.245/H.225 ............................................515 H.323v2 fastStart ..........................................................................517 SIP .................................................................................................518 SS7 to ITSP Call Progression .........................................................519

Lesson 11Sess�on In�t�at�on Protocol ......................................................... 525 SIP .................................................................................................525 SIP Messages .................................................................................527 Request Messages ..................................................................527 SIP Addresses ..................................................................528 Request Message Format ................................................528 Response Messages ................................................................529 Response Message Format ..............................................530 SIP Servers .....................................................................................531 Proxy .....................................................................................531 Redirect ..................................................................................531 Registrar .................................................................................531 SIP Clients ....................................................................................531 SDP ................................................................................................532 Creating a SIP Session ..................................................................533

Lesson 12R�ch Med�a Transm�ss�on Methods ............................................. 537 Webcasting ...................................................................................537 Audio and Video Streaming .........................................................538 Unicasting vs. Multicasting (audio and video) ............................539

Lesson 13V�deo Standards ........................................................................ 541 H.323 ............................................................................................541 H.320 ............................................................................................542 H.261 ............................................................................................542 H.263 and H.263+ ........................................................................543

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H.264 (MPEG-4 Part 10) or Advanced Video Coding (AVC) .......543 Advanced video coding for generic audiovisual services .....543 MPEG (MPEG-1, MPEG-2, MPEG-4) ............................................544 CIF/FCIF .......................................................................................544 SIF .................................................................................................544 QCIF .............................................................................................545 HD ................................................................................................545 G.711 Companding Algorithms ..................................................545 G.722 ............................................................................................547 G.724—ADPCM ...........................................................................547 G.729a .........................................................................................548 Document Conferencing: T.120 Series .........................................548 iLBC ..............................................................................................548 NTSC .............................................................................................548 PAL ................................................................................................549 SECAM ..........................................................................................549

Summary .................................................................................. 554

Qu�z .......................................................................................... 555

Module4HardwareandArchitecture..................................................... 563 Introduction .................................................................................563 Terms ............................................................................................564

Lesson 1The OSI Model Layers ............................................................... 575 The Physical Layer ........................................................................575 A Stream of Bits .....................................................................576 The Data Link Layer ..............................................................576 Frames Across a Link .............................................................577 Frame Addressing ..................................................................577 Data Link Layer Services .......................................................577 On the Transmitting Node .............................................577 On the Receiving Node ..................................................578 Data Link Layer Protocols .....................................................578 Data Link Layer Sublayers .....................................................578 The Network Layer .......................................................................579 Packets across a Network .......................................................579 Network Layer vs. Data Link Layer Addresses ......................580 Packet Routing ......................................................................581 Network Layer Services .........................................................582 Network Layer Protocols .......................................................582 The Transport Layer .....................................................................582 Transport Layer Services ........................................................583 Transport Layer Protocols .....................................................585 The Session Layer .........................................................................586 Session Layer Protocols .........................................................587

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The Presentation Layer .................................................................587 Computer Number Systems ..................................................588 The Binary Numbering System ......................................588 The Hexadecimal Numbering System ............................589 The Application Layer ..................................................................590 Common Application Layer Programs .................................591 E-Mail .............................................................................591 USENET Newsgroups ......................................................591 File Transfer and Access ..................................................592 Virtual Terminals ............................................................592 Web Browsers and Servers ..............................................593

Lesson 2Network Modules ..................................................................... 599 Centralized Network vs. Decentralized Network .........................599 Configuration of Converged Application Resources ............600 Branch vs. Edge Network Solutions .............................................600 Network Flattening vs. Tier Network ...........................................600

Lesson 3Routers and Sw�tches ................................................................ 605 Routers ........................................................................................605 Router Functionality ....................................................................606 Multiprotocol Routing .................................................................607 How Routers Move Packets Between Networks ...........................608 Routers Rebuild Frames .........................................................608 Internet Routers ....................................................................610 Broadcast Domains ................................................................610 Routers for Broadcast Containment ..............................611 Router Advantages and Disadvantages .................................612 Switches—Managed vs. Unmanaged ...........................................612 Switch Functionality ....................................................................613 Traffic Isolation With Switches ....................................................616

Lesson 4Med�a Servers ........................................................................... 621 S8700 Media Server ......................................................................621 Availability/Reliability ...........................................................622 Multi-Connect vs. IP-Connect ..............................................624 Interoperability .....................................................................624 S8500 ............................................................................................624 S8300 Media Server with G700 Gateway .....................................625 Survivability ..........................................................................625 S8100 ............................................................................................626

Lesson 5Gateways .................................................................................. 630 Media Gateways ...........................................................................630 G350 ......................................................................................631 G600 ......................................................................................631 G650 ......................................................................................631

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TDM/IP Gateway ..........................................................................631 Traditional Separate Networks ..............................................631 Partial Integration Networks .................................................632 How Packet Telephony Works ...............................................633 Internet Telephony ................................................................634 SIP Gateway ..................................................................................635

Lesson 6Gatekeepers .............................................................................. 638 Gatekeepers ..................................................................................638

Lesson 7Pr�vate Branch Exchange ........................................................... 641 PBX Components .........................................................................641 Trunks ....................................................................................642 Making a Call on a PBX ...............................................................643 Calling on an IP PBX .............................................................643 Call Routing .................................................................................644 Supplementary PBX Features .......................................................645 Direct Inward Dialing ............................................................645 Direct Inward System Access .................................................647 PBX Enhancements ......................................................................647 Voice Response ......................................................................647 Voice Recognition .................................................................647 Automatic Call Distributor ...................................................648 Other Auxiliary Equipment ..................................................648 Call Management System .....................................................648 PBX Costs and Requirements .......................................................648 Hybrid PBX ...................................................................................649 IP Only PBX ..................................................................................649 IP PBX Features ......................................................................650

Lesson 8Router F�rewalls ......................................................................... 655 LAN Firewalls ................................................................................655 Internet Firewalls ..........................................................................656 Firewall Features ....................................................................656 Types of Firewalls .........................................................................657 Network Layer Firewalls ........................................................657 Application Firewalls .............................................................658 Hybrid Firewalls ....................................................................659

Lesson 9CSU and DSU ............................................................................ 662 Channel Service Unit (CSU) .........................................................662 Data Service Unit (DSU) ...............................................................662 Connecting to Digital Networks ..................................................663 DTE/CSU Interface .......................................................................663 Smart Jack .....................................................................................664 Subrate Facilities ...........................................................................664 Digital Data Services (DDS) ..........................................................664

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Lesson 10Network Term�nat�on Dev�ce One (NT1) .................................... 669 NT1: Network Termination Device, Type 1 .................................669

Lesson 11Adm�ss�on Control and Traffic Shap�ng ...................................... 672 Admission Control .......................................................................672 Traffic Shaping .............................................................................674 Traffic Smoothing ..................................................................675 Traffic Burst Shaping .............................................................676 Aggregated vs. Class-based Traffic Shaping ...........................677 Network Admission Policies .........................................................677 Admission Control and Traffic Shaping Applications .................678

Lesson 12Sess�on Border Controller .......................................................... 684 Session Border Controller Overview ............................................684 Types ......................................................................................685 Install Locations ....................................................................685 Features ..................................................................................685 Security ...........................................................................685 Translation ......................................................................686

Lesson 13In-l�ne Power Components ........................................................ 688 In-line Power Components (Power over Ethernet) .....................688 PoE ...............................................................................................690

Lesson 14Access Po�nts ............................................................................. 694 What Is a Wireless Access Point? .................................................694 Wireless APs ..................................................................................695 Access Point Modes ......................................................................695 Root Mode .............................................................................696 Bridge Mode ..........................................................................696 Repeater Mode .......................................................................697 Common Access Point Options ...................................................698 Fixed or Detachable Antennas ..............................................698 Advanced Filtering Capabilities ............................................699 Removable (Modular) Radio Cards .......................................699 Variable Output Power ..........................................................700 Varied Types of Wired Connectivity .....................................700 Access Point Configuration and Management ............................701 Mounting .....................................................................................703

Lesson 15Modems ................................................................................... 707 Modem Concepts .........................................................................708 Analog Modem Standards ............................................................709 Cable Modem Technology ...........................................................711 How Cable Modems Work ....................................................711

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Cable Modem Pros and Cons ................................................713 DSL ...............................................................................................713 xDSL Implementation ...........................................................715 xDSL Pros and Cons ..............................................................716 DSLAMs ........................................................................................717

Summary .................................................................................. 722

Qu�z .......................................................................................... 723

Module5Management........................................................................... 731 Introduction ..................................................................................731 Terms ............................................................................................732

Lesson 1Converged Network Analys�s and Problem Solv�ng .................... 742 Network Troubleshooting Steps ...................................................742 Identify the Exact Issue .........................................................742 Re-create the Problem ...........................................................743 Isolate the Cause ...................................................................743 Formulate and Implement a Correction ...............................743 Test the Solution ...................................................................743 Document the Problem and Solution and Provide Feedback ............................................................744 Troubleshooting Methods ............................................................744 A Network Problem Example ................................................745 Digging Deeper ......................................................................746 The Fix ...................................................................................748

Lesson 2Common Symptoms and Problems ........................................... 752 Symptoms .....................................................................................752 Poor Voice Quality ................................................................753 MOS .......................................................................................753 Clipping .................................................................................754 Echo .......................................................................................754 Delay or Latency ...................................................................757 Audio Codec (Transcoding) Delays .......................................758 DSP ........................................................................................759 DSP Delays ......................................................................759 Encoding, Decoding, and Compression Delays ....................759 No Dial Tone .........................................................................759 Loss of Feature Set .................................................................760 Crosstalk ................................................................................760 Dropped Calls ........................................................................760 Blocked Calls .........................................................................761 Erlang B Formula ...................................................................762 Poisson Formula: Immediate Redial .....................................763 Erlang C Formula: Infinite Queue .........................................763

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Multiple Paths, Varied Traffic ................................................763 Poor Video Quality and Frame Loss ......................................763 Problems .......................................................................................764 Media Errors ..........................................................................765 Packet or Data Loss ................................................................765 Protocol Overhead ................................................................766 Protocol Mismatch ................................................................767 Jitter .......................................................................................767 Jitter Buffers ...........................................................................768 Measuring Jitter .....................................................................769 Wander ..................................................................................769 Port Settings ..........................................................................770 Security ..................................................................................770 Packet Re-ordering, MTU Issues, and Packetization .............771 Bandwidth Restrictions .........................................................772 Throughput ...........................................................................773 Hardware Failure ...................................................................774 Routing Misconfigurations ....................................................775 QoS Tags Being Dropped .......................................................775 IP Packet Loss ........................................................................776 Impact of Backup Over the Network ....................................776

Lesson 3Network Performance Mon�tor�ng Tools .................................... 780 LAN Monitoring Tools .................................................................781 Baselining .....................................................................................781 Software Tools for Baselining and Testing ...................................782 Built-In NOS Utilities ............................................................782 Protocol Analyzers .................................................................782 Types of Protocol Analyzers ..................................................783 Components of a LAN Protocol Analyzer .............................784 Protocol Analyzer Traces .......................................................784 The Dark Side of Protocol Analysis .......................................786 Reading a Protocol Analyzer Trace ........................................786 SNMP ............................................................................................789 SNMP Organization ...............................................................790 Architectural Elements ..........................................................790 Agents ....................................................................................791 Management Information Base ............................................791 Agent Components ...............................................................791 Traffic Monitors .....................................................................792 SNMP Proxy Agents ...............................................................792 Manager .................................................................................793 Modes of Network Management ...........................................794 Ping ...............................................................................................794 Ping Operation ......................................................................795 Pathping .......................................................................................798 Pathping Command Syntax ..................................................799 Pathping Example .................................................................800

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Contents

Traceroute .....................................................................................802 How Tracert Works ................................................................802 QoS Monitoring Tools ..................................................................805 LAN and WAN Bandwidth Monitoring Tools ..............................805 BERT – Bit Error Rate Tester ...................................................806 Testing Physical Media ..........................................................807 Copper Cables .......................................................................807 Tone Generator and Probe ....................................................807 Media Tester/Certifier .....................................................808 Lineman’s Test Set (Butt Set) ..........................................811 Optical Fiber .........................................................................812 Wireless LANs .......................................................................812 Voice/Video Quality Monitoring Tools ........................................813

Lesson 4LAN Protocol Analyzer Operat�ons ............................................. 816 Analyzers Overview ......................................................................816 Protocol Analyzer Features ....................................................817 Display Filters ........................................................................826

Lesson 5Traffic Management .................................................................. 831 Data Sources .................................................................................831 Gathering Data .............................................................................832 Experiments .................................................................................833 Experimental Conditions ......................................................833 Number of Experiments ........................................................834 Sampling .......................................................................................834 Bias ........................................................................................835 Sample Size ............................................................................835 Sample Spread .......................................................................835 Planning a Study ..........................................................................837

Lesson 6QoS Parameters, Router Parameters, Load Balanc�ng ................. 840 IP Header Features ........................................................................840 ToS Field ................................................................................840 IP Precedence .........................................................................841 DiffServ .........................................................................................841 DSCP Code Points .................................................................841 PHB ........................................................................................842 Standard PHBs ................................................................842 Custom PHBs ..................................................................843 DiffServ Domains ..................................................................843 IntServ ..........................................................................................843 RSVP .......................................................................................844 CBQ ..............................................................................................844 COPS .............................................................................................845 MPLS .............................................................................................845 Policy Routing ..............................................................................849

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Convergence+

PQ ................................................................................................849 RED ...............................................................................................849 Traffic Shaping .............................................................................849 WFQ .............................................................................................850 WRED ...........................................................................................850

Lesson 7Mean Op�n�on Score ................................................................. 854 Mean Opinion Score ....................................................................854

Lesson 8Adm�n�strat�on Tasks and Procedures ......................................... 858 Monitoring Log Files ....................................................................858 Reporting ......................................................................................859 Managing Configuration Changes ...............................................860 Policy Management (e.g., QoS, Admission Controls, Registration) .................................................................860 Patching, Upgrades, and Backups ................................................860 Grandfather/Father/Son ........................................................861 MAC (Moves, Adds, Changes) ......................................................861 Call Detail Record ........................................................................862

Summary .................................................................................. 865

Qu�z .......................................................................................... 866

Module6Security.................................................................................... 871 Introduction .................................................................................871 Terms ............................................................................................872

Lesson 1F�rewalls .................................................................................... 880 Firewalls ........................................................................................880 Firewall Functions ........................................................................881 Firewalls Components ..................................................................881 Packet Filtering Router ..........................................................882 Application Level Gateways ..................................................882 Circuit-level Gateway ............................................................884 Bastion Host ...................................................................884 Screened Subnet Firewall ..............................................................884

Lesson 2Internet F�rewalls ....................................................................... 889 Types of Firewalls .........................................................................890 Network Layer Firewalls ........................................................890 Application Firewalls .............................................................891 Hybrid Firewalls ....................................................................892 Stance of a Firewall .......................................................................892 Everything Is Denied Unless Specifically Permitted .............892 Everything Is Permitted Unless Specifically Denied .............892

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Cost of a Firewall ..........................................................................893 Components of a Firewall System ................................................893 Building Block: Packet-Filtering Router ................................893 Service-Dependent Filtering ...........................................894 Service-Independent Filtering ........................................895 Source IP Address Spoofing Attacks ...............................895 Benefits of Packet-Filtering Routers ...............................896 Limitations of Packet-Filtering Routers ..........................896 Example 1: Packet-Filtering Router ................................897 Building Block: Application-Level Gateway (Proxy Server) ...........................897 Bastion Host ...................................................................898 Example 2: Telnet Proxy ................................................900 Benefits of Application-Level Gateways .........................901 Limitations of Application-Level Gateways ...................902 Building Block: Circuit-Level Gateway .................................902 Example 3: Screened Host Firewall ................................903 Example 4: Dual-Homed Bastion Host ..........................904 Example 5: “Demilitarized Zone” or Screened-Subnet Firewall ...........................................905

Lesson 3Authent�cat�on .......................................................................... 910 User Authentication .....................................................................910 Passwords ..............................................................................911 Smart Cards ...........................................................................912 Digital Certificates .................................................................912 Biometric Authentication .....................................................912 Message Digests and Digital Signatures ................................913 Wireless Authentication ...............................................................914 IEEE 802.1x ...................................................................................915 802.1x Authentication on a Wireless Network .....................915 EAP ...............................................................................................916 EAP Types ..............................................................................916

Lesson 4Prox�es ...................................................................................... 921 Web Servers ..................................................................................921 Web Caching Proxy ...............................................................923 Servers ..........................................................................................924 Proxy Server ...........................................................................924

Lesson 5V�rtual Pr�vate Networks ............................................................ 927 VPNs in Action .............................................................................927 Why Enterprises are Using VPNs .................................................930 Tunneling: The Underlying Technology for VPNs ......................930 Point-to-Point Tunneling Protocol (PPTP) ...................................931 Layer 2 Forwarding Protocol ........................................................932 Layer 2 Tunneling Protocol ..........................................................933

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Convergence+

PPP Authentication Protocols ......................................................933 Internet Protocol Security ............................................................934 Authentication Header (AH) .................................................935 Encapsulating Security Payload (ESP) ...................................936 Implementing IPSec ..............................................................936 Open Standards Help Ensure Interoperability .............................937 Providing Effective Security .........................................................937 User Authentication ..............................................................937 Extensible Authentication Protocol ......................................937 Token Card Support ..............................................................938 Data Encryption ...........................................................................938 Symmetric (Private-Key) Encryption ....................................938 Asymmetric (Public-Key) Encryption ....................................939 Key Management ..................................................................939 Digital Certificates .................................................................940 PPP Callback Control ...................................................................940 Filtering ........................................................................................940 Firewalls and VPNs .......................................................................940 User Administration .....................................................................941 RADIUS Servers ......................................................................941 Directory Service ...................................................................942 Authentication, Authorization, and Accounting (AAA) ..........................................................943 Considerations For Choosing a VPN Solution .............................943 VPN Tunnel ..................................................................................944

Lesson 6NAPT ........................................................................................ 948 NAT ...............................................................................................948 What Is Address Reuse? .........................................................948 A NAT Overview ...........................................................................950 NAT Address Spaces ...............................................................950 IP Address Translation ...........................................................951 Static Address Translation ............................................................951 Dynamic Address Translation ......................................................952 Enhanced Network Security ..................................................952 Masquerading/NAPT ....................................................................954 NAPT—Even More Security ...................................................957

Lesson 7Encrypt�on ................................................................................ 962 Commonly Used Encryption Systems .........................................962 Data Encryption Standard .....................................................962 Secure Sockets Layer ..............................................................963 Message Digests and Digital Signatures ................................963 Data Security .........................................................................964

Lesson 8IDS and IPS ............................................................................... 968 IDS ................................................................................................968

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Contents

Setting the Baseline ...............................................................969 IDS Features ...........................................................................969 IDS Sensors ............................................................................970 IPS .................................................................................................971 Types of IPSs .................................................................................971 Inline Network Intrusion Detection System .........................971 Application Firewalls .............................................................971 Layer 7 Switches ....................................................................972 Hybrid Switches ....................................................................972 Deceptive Applications .........................................................972

Lesson 9Ant�v�rus .................................................................................... 976 Antivirus .......................................................................................976 Malicious Programming ...............................................................977 Viruses ...................................................................................977 Boot Sector Virus ............................................................978 Multipartite Virus ...........................................................978 Macro Virus ....................................................................978 Stealth Virus ...................................................................978 Polymorphic Virus .........................................................979 Virus Hoax ......................................................................979

Lesson 10VLANs ....................................................................................... 981 Switched VLANs ...........................................................................981 Routed VLANs ..............................................................................982 VLAN Tagging ..............................................................................983 802.1Q-1998 VLAN Tag .........................................................984 ISL ..........................................................................................984 QoS ...............................................................................................985 802.1p Traffic Prioritization ..................................................986 802.1p Traffic Classes, IPT U3, L4 ..................................987 The Future of VLANs ....................................................................988

Lesson 11Dem�l�tar�zed Zone .................................................................... 991 Demilitarized Zone .......................................................................991 Screened Subnet Firewall .......................................................993

Summary .................................................................................. 996

Qu�z .......................................................................................... 997

Glossary................................................................................. 1005

CourseQuiz........................................................................... 1037

Index...................................................................................... 1063