Contents Preface...1 Prerequisites...1 Who Should Study This Course?...2 Key Topics...2 Course Objectives...3 How Do I Use This Course?...4 Real-World Scenarios...4 Pedagogy...4 Key Terms...4 Resources Available in Instructor-Led Settings...4 Why Choose WestNet?...5 Introduction...7 Course Overview...8 Module 1 Telecommunications Concepts and Components...9 Lesson 1 Local Exchange Components...16 The Telephone System Hierarchy...17 Class 5 Central Office: The Local Exchange...18 Class 4 Central Office...20 Tandem Central Offices...22 Class 1 Office...23 Class 5 Central Office Components...24 Switching and Routing...25 Semipermanent Circuit Connections...25 IXC POP...26 Billing...27 Customer Premises...27 Local Exchange Calling Options...27 LEC Does It All...27 CLEC Serves as Reseller...28 i
CLECs Switch and ILECs Wire...28 CLEC Does It All...29 Activities...30 Lesson 2 Central Office Switching...32 The Talking Path...32 Evolution of Telephone Switching...34 Manual Switching...35 Step-by-Step Switching and Rotary-Dial Telephones...37 Crossbar Switching...39 Later Electro-mechanical Switching...40 Digital Switches...41 Touch-Tone Signaling...41 How a Call is Made...43 Dial Tone...43 Entering a Telephone Number...43 Call Routing...43 Ringing...46 Ending the Call...46 Long Distance Voice Routing...46 Signaling...47 In-Band vs. Out-of-Band Signaling...47 SS7...48 Telephone Numbering System...48 The Dwindling Supply of Numbers...49 LNP...50 Assigning Telephone Numbers...51 Special Area Codes...51 Special NXX Codes...51 Special Information: 555...51 Hearing-Impaired Services: 800-855...52 Service Codes, or N11 Numbers...52 Toll-Free: 800, 888, 877...52 Premium: 900...53 International: 700...53 Follow-You: 500...53 Activities...54 Lesson 3 Trunks, Lines, and Loops...56 Telecommunications Terms...57 Loops...58 Lines...58 Trunks...59 Trunk Direction...59 Trunk Capacity...59 ii
Contents Analog Transmission...60 Channels and Bandwidth...61 Digital Transmission...62 PCM...64 Multiplexing...64 Digital Bandwidth...66 Special Access Trunks...66 Tie Lines...66 Private Lines...67 FX...67 Ring Down...68 Trunk Pricing...68 Activities...69 Lesson 4 Central Office Exchange...71 Centrex...71 Centrex Benefits...72 Technical Requirements for Centrex...73 Distance From CO Switch...73 Allocation of Call Paths...74 CPE...74 Centrex Features...74 Centrex vs. PBX...75 Activities...76 Lesson 5 Key Systems...78 Key System Components...78 Cordless Key Systems...80 Limitations of Key Systems...81 Hybrid Systems...81 Activities...83 Lesson 6 Buying a Telephone System...84 Planning: First steps...85 Analyze Current Traffic Flow...85 Identify Needs and Desires...85 Choosing a Switching System...85 Digital vs. Analog...86 Sizing a Telephone System...86 System Features...87 Selecting the Telephones...87 Multiline vs. Single-Line...87 Trunk Requirements...88 Cost...88 Features...89 Physical Issues...89 iii
Switch Capacity...89 Number Portability...90 Determining Required Applications...90 ACD Systems...91 Messaging Systems...91 Wireless Systems...92 CTI...92 IP Telephony...92 Finding the Right Vendor...93 Qualifying the Vendors...93 Submitting an RFP...93 Selecting the Vendor...94 Pricing...94 Vendor Experience...95 Shopping for Service and Support...95 System Setup...95 Warranty...96 Service Level Commitment...96 Technical Support...96 System Security...97 Preventive Maintenance...97 Activity...98 Summary...99 Quiz...101 Module 2 PBX and ACD Systems...109 Lesson 1 PBX Fundamentals...126 PBX Components...126 Trunks...127 Extension Lines...128 Equipment Cabinet...128 Telephones and Attendant Console...129 Administrative Terminal...129 Making a Call on a PBX...129 Call Routing...130 Supplementary PBX Features...131 DID...131 DISA...132 Station Set Features...133 Attendant Console Services...134 Administration and Management Reports...135 Call Detail Reports...135 Test Reports...135 Busy-Hour Studies...135 iv
Contents PBX Enhancements...136 Voice Response...136 Voice Recognition...136 Call Following...137 ACD...137 Other Auxiliary Equipment...137 PBX Costs and Requirements...138 Activities...139 Lesson 2 PBX Features and Functions...142 Call Accounting...142 Authorization Codes...143 Account Codes...143 Voice Mail Systems...144 FRL...145 Design Factors...145 Unified Messaging...146 Broadcasting...147 Voice Mail Security...147 Automated Attendants...148 CoR...148 Call Pickup...149 Call Park...149 Call Forwarding...149 Call Announcement...149 Call Waiting...149 DAU...149 Facility Test Call...150 Activities...151 Lesson 3 PBX Configurations...153 Overall Connectivity...154 Avaya DEFINITY Server with ACM System Components...155 Digital Networking...156 PN...156 PPN...156 EPN...156 CSS...156 SN...157 ATM SN...158 Main System Configurations...158 PN Components...159 TDM Bus...160 Packet Bus...160 Port Circuits...160 Interface Circuits...160 SPE...163 v
ACM Software Architecture...164 DEFINITY DCS Private Networks...164 LAN Gateway...164 IP Trunking...165 DCS Private Networks...165 DCS...166 Switch Components for DCS Networking...168 IP-Enabling DEFINITY Servers...169 IP Media Processor...170 CLAN...170 Upgrading DEFINITY Servers to S8700 Multi-Connect...170 Stage 1: Processor Replacement...171 Stage 2: IP Enable the PNs...171 Stage 3: Server Consolidation...172 Upgrade the Data Network...172 Activities...173 Lesson 4 DEFINITY Server Hardware...176 System Cabinets...176 Carriers...177 CMC1 Media Gateway...177 SCCI Media Gateway...178 MCC1 Media Gateway...179 Floor Area and Load...179 Floor Area...179 Floor Load...180 Floorplan Guidelines...181 CMC1 Configuration Guidelines...181 SCC1 Configuration Guidelines...182 MCC1 Configuration Guidelines...183 MDF...184 Environmental Conditions...184 Temperature...185 Altitude and Air Pressure...185 Humidity...186 Air Purity...186 Lighting...187 Radio Frequency Noise...187 Cabinet Power Requirements...187 AC Power...187 DC Power...188 Power Conditioning...188 Cabinet Power Components...189 DC Power Relay...189 Ring Generator...189 Fuses...189 vi
Contents Power Backup...189 UPS...190 Activities...191 Lesson 5 IP Telephony...192 Avaya Communication Manager...193 Media Servers...195 S8700 Media Server...195 Availability/Reliability...196 Multi-Connect vs. IP-Connect...197 Interoperability...198 S8500...198 S8300 Media Server with G700 Gateway...198 Survivability...199 S8100...199 Media Gateways...200 G350...200 G600...200 G650...201 IP Office...201 Supported Telephones...202 Analog...202 Digital...202 IP...203 Wireless...203 Activities...205 Extended Activities...206 Lesson 6 PBX Networking...208 Private Communications Networks...209 Cost Savings...211 Improved Efficiency...212 Enhanced User Satisfaction...212 Tandem Trunks and Tandem Switching...213 Network Configurations...213 Series...213 Star...215 Three-System Star...216 PBX Security...217 IP PBX Security...217 Activities...219 vii
Lesson 7 Basics of Automatic Call Distributor...222 Agents and Splits...222 What an ACD Does...223 Automatic-In Processing...224 DID Processing...224 Split Queue Processing...224 Announcements...224 Answer Supervision...225 Abandoned Call Search...225 Intraflow and Interflow...226 Call Distribution Methods...226 Vectors...227 Vector Flow...227 Vector Management...228 Call Flow Problems...228 Activities...230 Summary...232 Quiz...234 Module 3 Point-to-Point Telecommunications Protocols...243 Lesson 1 Physical and Logical Circuits...247 Circuits and Virtual Circuits...247 PVCs and SVCs...250 SVC Information Transfer...251 Connecting to WAN Circuits...252 DCE and DTE...252 DTE-to-DCE Protocols...253 Layer Upon Layer...253 Activities...256 Lesson 2 Summary of Data Rates...258 Point-to-Point Links...258 Analog Lines...259 DDS...259 SW56...259 High-Speed Services...259 Various Data Rates and Associated Applications...260 Bandwidth...261 Activities...263 viii
Contents Lesson 3 Dial-Up and Leased Lines...265 Dial-up Connections...265 Leased Lines...266 DDS...267 Activities...269 Lesson 4 T-Carriers...271 Digitizing Voice...271 T-Carriers...272 DS0 or Fractional T1...274 T1...275 T3 and North American Digital Signal Hierarchy...279 Circuit Costs...279 Activities...280 Lesson 5 Asymmetric Digital Subscriber Line...281 Digital Subscriber Lines and Internet Access...281 Options for Local High-Speed Internet Access...282 DSL...283 Physical Requirements...285 ADSL...286 Activity...290 Lesson 6 Cable Modems...292 Cable Modem Technology...292 ADSL or Cable Modem? The Subscriber s Perspective...294 Activities...296 Lesson 7 Synchronous Optical Network...297 The SONET Standard...297 SONET Advantages...298 SONET Protocol Architecture...299 Path Layer...299 Line Layer...300 Section Layer...301 Photonic Layer...301 SONET Multiplexing...302 SONET Frame Format...304 Virtual Tributaries...306 Clock Synchronization...307 SONET Network Elements...307 Add/Drop MUX/Demultiplexer...307 Broadband Digital Cross-Connect...308 Wideband Digital Cross-Connect...309 ix
Terminating MUX...309 Regenerator...310 Activities...311 Summary...312 Quiz...314 Module 4 Switched Telecommunications Protocols...317 Lesson 1 Circuit- and Packet-Switched Networks...323 Data Link Layer Protocols...323 Reliable WAN Networks...324 Packet-Switched Networks...325 Circuit-Switched Networks...325 Activities...327 Lesson 2 Serial Line Internet Protocol and Point-to-Point Protocol...328 SLIP...328 SLIP Frame Delimiters...329 Drawbacks to SLIP...330 Compressed SLIP...330 PPP...331 Information Frames...331 Link Control Frames...332 Network Control Frames...332 Zero Bit Insertion...333 Activities...334 Lesson 3 Integrated Services Digital Network...335 Integrated Digital Networks...335 ISDN Services...336 Call-by-Call Service...339 Channel Bonding and NFAS...340 ISDN Signaling...341 DSS1...342 PSS1...343 Q.SIG and ISDN Supplementary Services...344 Activities...346 Lesson 4 Asynchronous Transfer Mode...347 The Need for ATM...348 Transfer Modes...348 STM...348 x
Contents PTM...349 ATM...350 Connection-Oriented Mode...351 Fixed-Length Data Cells...353 Header Details...354 B-ISDN and ATM...355 AAL...356 Convergence Sublayer (CS)...357 Segmentation and Reassembly (SAR) Sublayer...358 ATM Layer...359 Physical Layer...360 TC Sublayer...360 TC Cell Rate Decoupling...361 Physical Medium-Dependent Sublayer...361 Activities...362 Lesson 5 Frame Relay...363 What is Frame Relay?...364 Frame Relay Terms...366 Permanent and Virtual Circuits...367 Frame Relay Operation...368 Frame Relay Frame...368 Information Field...369 Frame Relay Header Field...369 Flow Control...370 Congestion...370 Management Frames...371 Frame Relay Addressing...371 Interconnecting LANs Using Frame Relay...374 Frame Relay Implementation Options...374 Private Frame Relay...375 Public Frame Relay...376 Hybrid Frame Relay...376 End-User Access to Frame Relay Networks...377 The Extra Hop Problem...379 Frame Relay vs. Private Line Networking...380 Frame Relay Services...382 Public Frame Relay Services...382 Bandwidth on Demand...383 Conditional Bursting...384 VoIP over Public Frame Relay Services...384 Cost Considerations...385 Carrier Choice Considerations...385 CIR...385 Congestion Control...386 Reports and Statistics...386 Frame Relay Network Requirements...386 Activities...387 xi
xii Lesson 6 Switched Multimegabit Data Service...393 SMDS Operation...393 Switched...393 Multimegabit...394 SNI...394 SMDS Protocols...395 SMDS Interface Protocol...396 SIP-1...396 SIP-2...396 SIP-3...396 DXI...397 Router Functions...398 DSU Functions...398 Advantages and Disadvantages...399 Activity...401 Lesson 7 X.25...403 X.25 Services...403 Addressing...404 X.25 Protocols...404 Layer 3: PLP...405 Layer 2: LAPB...405 Layer 1: X.21 and X.21bis...405 PAD...405 PLP...407 Overhead and Performance Limitations...409 Activity...411 Summary...412 Quiz...414 Module 5 Traffic Engineering...419 Lesson 1 Traffic Engineering Concepts...423 Carried Load...423 Conversation Time...424 Operating Time...425 Holding Time...425 Constant Distribution...426 Exponential Distribution...426 Probability...426 GOS...427 Trunk Usage...428 CCS...428 Erlang...428
Contents The Erlang B Traffic Formula...429 Erlang C and Poisson Tables...431 Poisson: Immediate Redial...431 Erlang C: Infinite Queue...431 No Formula is Perfect...431 Estimating Total System Capacity...432 Outbound Trunk Capacity...432 Tie Trunks...432 Voice Mail Capacity...434 Ports...434 Storage Time...435 PBX Processing Capacity...436 Adjusting to Changes...437 Activities...438 Lesson 2 Traffic Data Sources...441 Data Sources...441 Gathering Data...442 Experiments...443 Experimental Conditions...443 Number of Experiments...444 Sampling...444 Bias...445 Sample Size...445 Sample Spread...446 Planning a Study...447 Activities...448 Lesson 3 Busy-Hour Engineering...450 The Busy Hour...450 Constant Busy Hour...451 Bouncing Busy Hour...451 Grade of Service vs. Cost...451 Potential PBX Bottlenecks...452 Tone Detectors...453 Processor Occupancy...453 Time Slots...453 Modules...453 Consider All Traffic, All Paths...453 Activities...454 Summary...457 Quiz...459 Course Quiz...461 Glossary...471 xiii
Index...489 Overall Course Evaluation Survey...503 xiv