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Telecom 101 Third Edition
ISBN 978-1-894887-01-4 400 pages, 177 diagrams, full index. Published January 2008
Part I Fundamentals of Telecommunications
The first part covers the Public Switched Telephone Network, equipment and call centers, the telecom business, carriers, digital voice transmission, T1, fiber and SONET backbones, how digital circuits and services are provided, muxes vs. switches vs. routers and wireless … the groundwork for understanding everything.
Chapter 1 Introduction
Chapter 1 is an introduction. We discuss the approach taken in organizing the topics, and suggestions for how to use the material. This chapter contains an initial framework for understanding telecom circuits and services, and introductory terminology, jargon and buzzwords.
1.1 Our Approach
1.2 How the Text is Organized
1.3 How to Use This Text
1.4 The Three Answers
1.4.1 Answer Number 1: Money
1.4.2 Answer Number 2: History
1.4.3 Answer Number 3: It's All Pretty Much the Same Thing
1.5 Telecommunications Services from the User's Point of View
1.5.1 Access Circuits
1.5.2 Network Connection
1.5.3 Billing Plan
1.6 The Network “Cloud”
1.7 Telecom Circuits from the Phone Company's Point of View
1.7.1 Access Network
1.7.2 Switching Centers
1.7.3 Transmission Network
1.8 What's Next
Chapter 2 Fundamentals of Telephony
Whether you're interested in telecom, datacom, wireless, Wide Area Networking or Voice over IP, everything begins with the Public Switched Telephone Network and Plain Ordinary Telephone Service. We'll begin with a model for the PSTN, explaining analog circuits and circuit switching, as well as common telephony buzzwords and jargon, and an overview of SS7.
2.1 History of Telecommunications
2.1.1 Invention of the Telephone
2.1.2 Local Phone Companies
2.1.3 The Bell System
2.1.4 The Rest of the World
2.2 PSTN: Public Switched Telephone Network
2.2.1 Basic Model of the PSTN
2.2.2 Loops
2.2.3 Remotes
2.2.4 Trunks and Circuit Switching
2.3 Analog Signals and Analog Circuits
2.4 Capacity Restrictions on the Loop
2.4.1 What is Speech?
2.4.2 The Voiceband
2.4.3 Bandwidth
2.5 Problems with Analog Transmission
2.5.1 Attenuation and Amplifiers
2.5.2 Noise
2.6 Plain Ordinary Telephone Service
2.6.1 Twisted Pair
2.6.2 Components of a Telephone
2.6.3 Supervision
2.6.4 Call Progress Tones
2.7 Network Addresses: Telephone Numbers
2.7.1 Area Codes
2.7.2 Pulse Signaling
2.7.3 DTMF Address Signaling
2.8 SS7: Signaling System 7
2.8.1 Advanced Intelligent Network (AIN)
2.8.2 AIN Services
2.9 Summary
Chapter 3 Telecom Equipment
We’ll round out our discussion of telephony with a practical overview of different types of equipment that can be connected to the telephone network. Without bogging down on details, we'll sort out switches, PBXs, ACDs, IVRs, Call Centers and modems, including a discussion of DSL and how it is provided.
3.1 Telephone Switches
3.1.1 PBXs
3.1.2 Centrex
3.2 Computer-Telephony Integration
3.2.1 Voice Mail
3.2.2 IVR: Interactive Voice Response System
3.2.3 ACD: Automated Call Distributor
3.2.4 Inbound Call Centers
3.3 Modems and DSLAMs
3.3.1 Voiceband Modems
3.3.2 Bits per Hertz?
3.3.3 DSL: “Digital Subscriber Lines”
3.3.4 DSL Equipment
Chapter 4 The Telecommunications Industry
A practical overview of the telecommunications industry: service providers and alliances, competitive forces, structure and regulation; resellers, IXCs, LECs and CLECs.
4.1 US Domestic Telcos
4.1.1 LECs and LATAs: Local Exchange Carriers
4.1.2 IXCs: Inter-Exchange Carriers
4.1.3 Resellers
4.1.4 Consolidation
4.2 Canadian Telephone Companies
4.3 Trunks and Switching Centers
4.4 Network Access for Long-Distance
4.4.1 POP: Point of Presence
4.4.2 Equal Access
4.5 CLECs: Competitive Local Exchange Carriers
4.5.1 DSL from CLECs
4.5.2 Voice over DSL
Chapter 5 Digital Communications
This chapter will give you a real understanding of what "digital" means, and how it is implemented. We'll explain what a "DS0" is, and take a practical tour of digital circuits, including T1, T3, SONET and ISDN. At a high level, we'll see how voice, data and video can be integrated.
5.1 Why Digital?
5.1.1 Multiplexing
5.1.2 Noise Performance
5.1.3 Storage and Processing
5.1.4 Integration and Convergence
5.2 Analog and Digital: What do we really mean?
5.2.1 Analog
5.2.2 Bandwidth: Analog Circuits
5.2.3 Digital
5.2.4 Bandwidth: Digital Circuits
5.3 Continuous vs. Discrete Signals
5.3.1 Continuous and Analog
5.3.2 Discrete and Digital
5.4 Voice Digitization (Analog-Digital Conversion)
5.4.1 Quantization
5.4.2 Sampling
5.4.3 Coding
5.4.4 End to End: Analog-Digital-Analog
5.4.5 Quantization Errors
5.5 DS0: Voice Digitization on the PSTN
5.5.1 Quantization: 256 Levels
5.5.2 Sampling: 8,000 Samples per Second
5.5.3 Coding: 8 Bits Per Sample
5.5.4 The DS0 Rate
5.6 The Digital Hierarchy: Standard Line Speeds
5.6.1 DS1
5.6.2 DS3
5.6.3 STM
5.7 Technologies: Digital Carrier Systems
5.7.1 T1
5.7.2 T3: “Asynchronous” DS3 Multiplexing
5.7.3 SONET: Synchronous DS3 Multiplexing
5.7.4 SDH
5.7.5 T1 vs. DS1 and T3 vs. DS3
5.8 ISDN
5.8.1 ISDN Basic Rate Interface (BRI)
5.8.2 ISDN Primary Rate Interface (PRI)
5.8.3 PBX Trunks on T1 vs. ISDN PRI
5.9 Using Digital Circuits: Applications
5.9.1 Voice on Digital Circuits
5.9.2 Voice Compression
5.9.3 Data Applications
5.9.4 Digital Video
5.10 Summary: Integration: Voice, Video, Data
Chapter 6 Transmission Systems
Time Division Multiplexing (TDM) and digital carrier systems are the technologies at the heart of telecommunications networks. We'll provide you with a basic understanding of how transmission systems work, both over copper wires and over fiber, and an overview of SONET and optical networking. We'll explain the "network cloud": how circuits are actually provided by carriers, the difference between multiplexers, switches and routers and what services these are used for.
6.1 Time Division Multiplexing
6.1.1 Channelized or “Synchronous” TDM
6.1.2 “Statistical” TDM or “Bandwidth on Demand”
6.2 Channelized TDM: Channels and Framing
6.2.1 Subrate Multiplexing
6.3 Anatomy of a Service
6.3.1 Access Circuits
6.3.2 Network Connection
6.3.3 Billing Plan
6.4 Common Carriers' Transmission Networks
6.4.1 The Network “Cloud”
6.4.2 Fiber Optics
6.4.3 Representing Bits on Fiber
6.4.4 Fiber and Fiber Cable Construction
6.4.5 Redundancy and Protection: Rings
6.4.6 Dark Fiber
6.5 SONET: “Backbone” Transmission Networks
6.5.1 SONET and the Optical Carrier
6.5.2 SONET Rings
6.5.3 DWDM: Dense Wave Division Multiplexing
6.5.4 Next: Fiber Access
6.6 How Circuits are Actually Provided
6.6.1 Inside the Cloud: Core and Edge
6.7 Network Equipment
6.7.1 Multiplexers
6.7.2 Switches
6.7.3 Routers
6.7.4 ATM Switches or ATM Routers?
6.8 Summary
Chapter 7 T1
This chapter covers T1 technology and application in detail. We'll cover T1's origins, concepts such as framing and AMI line codes, and understand what repeaters are for and why this is superior to analog. We'll also cover B8ZS and clear channels, HDSL, cross-connects, fractional T1 and CSU/DSUs.
7.1 T1 History and Current Applications
7.2 Basic T1 Circuit Components
7.3 T1 Framing
7.3.1 Superframe Format
7.3.2 ESF
7.4 Pulses and Line Code: AMI
7.4.1 Repeaters
7.5 Synchronization: Bit-Robbing
7.5.1 56 kb/s for Data
7.6 B8ZS and 64 kb/s Clear Channels
7.7 How T1 Is Provided
7.7.1 HDSL
7.8 Fractional T1 and Cross-Connects
7.9 Subrate Data Circuits 1.2 kb/s to 56 kb/s
7.9.1 CSUs, DSUs and CSU/DSUs
Chapter 8 Wireless Communications
We'll round out your knowledge of telecom fundamentals with wireless. We'll cover jargon and buzzwords in the mobility business, the idea of cellular, and sort out different cellular technologies, understand CDMA vs. TDMA/GSM and 3G 1x vs. UMTS and 1XEV-DO vs. HSPA. We’ll conclude with an overview of satellite communications, Wi-Fi and WiMAX.
8.1 Radio Transmission
8.2 Mobile Networks
8.3 AMPS: Analog Cellular
8.4 PCS: Personal Communication Services
8.4.1 Wireless PBXs
8.5 Digital Cellular: Voice Communications
8.6 Sharing the Radio Bands
8.6.1 AMPS
8.6.2 TDMA, GSM and GPRS
8.6.3 CDMA
8.7 3G
8.8 Satellite-Based Services
8.8.1 Geosynchronous Satellites
8.8.2 Low Earth Orbit
8.9 Wireless LANs
8.9.1 IEEE 802.11 Standards
8.10 802.16 WiMAX
Chapter 9 Voice Services and Jargon
This chapter provides a summary and overview of voice communication services from carriers, and explains jargon like VPNs, WATS and AIN.
9.1 Local Voice Services
9.1.1 POTS and Party Lines
9.1.2 CLASS Services
9.1.3 Local Measured Service
9.1.4 Public Coin Telephone Service
9.1.5 Directory Services
9.1.6 Business Services
9.1.7 Access
9.2 Long Distance Voice Services
9.2.1 Operator Services
9.2.2 Foreign Exchange
9.2.3 OPX: Off-Premise Extension
9.2.4 Tie Line
9.2.5 Private Networks
9.2.6 WATS
9.2.7 AIN Services
9.2.8 Virtual Private Voice Networks
Part II Understanding Data Communications
The second part covers datacom basics including the crucial concepts of IP packets and LAN frames; all about modems including DSL and cable modems, data over digital cellular and finishes with LANs: building blocks for Part III.
Chapter 10 Introduction to Data Communications and Networking
We'll start off on the right foot with a solid grounding in data communications and networking basics, introducing and defining key concepts explored in subsequent chapters. We'll start at the beginning, reviewing the components of a data circuit: DTEs, DCEs and physical connections, then explore practical examples of circuits and networks, allowing you to categorize and compare the different types of equipment and circuit configurations.
10.1 Information Theory
10.2 Data Circuit Model
10.3 DTE: Data Terminal Equipment
10.3.1 Dumb Terminals
10.3.2 Intelligent Terminals
10.4 Analog and Digital Data Circuits
10.4.1 Analog Data Circuits
10.4.2 Unloaded Circuits
10.4.3 Wet vs. Dry Circuits
10.4.4 Broadband or Wideband Analog
10.4.5 Digital Circuits
10.4.6 Fiber: Analog or Digital?
10.5 DCE: Data Circuit-Terminating Equipment
10.5.1 Analog DCE: Modems
10.5.2 Digital DCE: CSUs, DSUs, and More
10.6 Point-to-Point Circuits
10.6.1 Parallel
10.6.2 Serial
10.7 Multidrop Circuits
10.7.1 IBM Mainframe Circuits
10.7.2 Cable Television Distribution
10.8 LANs: Local Area Networks
10.9 Wide Area Networks
10.9.1 Basic Components of a WAN
10.9.2 Routers, Network Addresses and Packets
10.10 TCP/IP for Networking
Chapter 11 How Data is Formatted for Transmission
In this chapter, we'll put in place a solid understanding of the key concepts of IP packets and LAN frames, beginning with the fundamentals, to ensure that you have a solid foundation on which to build an understanding of routers, bandwidth-on-demand services and the Internet.
11.1 Basics
11.1.1 Bits
11.1.2 Bytes
11.1.3 Words
11.1.4 Control and Data
11.2 Number Systems
11.2.1 Decimal
11.2.2 Binary
11.2.3 Hexadecimal
11.2.4 Common Use for Hexadecimal
11.3 “Asynchronous”
11.3.1 Coding, Framing and Error Control
11.3.2 ASCII Code Set
11.3.3 Extended ASCII
11.3.4 EBCDIC
11.3.5 Framing: Start and Stop Bits
11.3.6 Parity Checking
11.3.7 No Parity
11.4 Frames:“Synchronous”
11.4.1 Exchanging Frames
11.4.2 Components of a Frame
11.4.3 CRC: Cyclic Redundancy Checking
11.5 Packets
11.6 Packets vs. Frames
11.7 IP Packets
Chapter 12 Modems
Understand how modems transmit 1s and 0s over analog circuits. We'll explain the techniques all modems use, jargon like baud rate and half duplex, and review current voiceband modem standards and what connection speeds to expect.
12.1 Data over the PSTN
12.1.1 Recap: Circuit-Switching and the PSTN
12.1.2 Recap: The Voiceband
12.1.3 Why Not Use Pulses?
12.2 Representing Data in the Voiceband
12.2.1 Amplitude Shift Keying (ASK)
12.2.2 Frequency Shift Keying (FSK)
12.2.3 Phase Shift Keying (PSK)
12.2.4 Quadrature PSK
12.2.5 Quadrature Amplitude Modulation
12.2.6 Trellis-Coded Modulation
12.2.7 Theoretical Maximum
12.3 Modulation Summary
12.4 Voiceband Modem Standards
12.4.1 V.34 Modems
12.4.2 “56K” Modems
12.5 Negotiation and Handshaking
12.6 Modem Control and the AT Command Set
12.7 Modem Jargon and Buzzwords
12.7.1 Baud vs. Bits/Second
12.7.2 Half-Duplex and Full-Duplex
12.8 Factors Limiting Modem Data Rates
12.8.1 Crosstalk and NEXT
12.8.2 Harmonics
12.8.3 A/D Conversion Noise
12.8.4 Voice Compression
12.8.5 Impulse Noise: Spikes
Chapter 13 Broadband Modems
An in-depth overview of high-capacity or "broadband" technologies: DSL and Cable modems, and discuss the age-old question: which is faster? We'll also explore the next generations of DSL, how data over digital cellular works as well as reviewing broadband wireless.
13.1 DSL
13.1.1 ADSL vs. SDSL vs. XDSL
13.1.2 DSLAMs and Co-Location
13.1.3 “Always On”
13.1.4 Advantages of DSL
13.1.5 DSL Modulation Techniques
13.1.6 Loop Length Limitations
13.1.7 Next Generations of DSL
13.1.8 VDSL and OPI DSLAMs
13.2 Cable Modems
13.2.1 CATV Network Architecture
13.2.2 Two-way Communications
13.2.3 Sharing the Access Circuit
13.3 Which Is Faster, Cable Modem Or DSL?
13.4 Data over Analog Cellular
13.5 Data over Digital Cellular
13.5.1 Recap: Digital Cellular for Voice
13.5.2 Communicating Data Instead of Voice
13.5.3 Navigation Servers
13.5.4 WAP and XML
13.5.5 3G
13.6 WiFi and WiMAX
Chapter 14 Understanding LANs
LANs: Local Area Networks are the technology used to connect computers - and in the future telephones - inside the building. We'll complete this module with a basic, solid understanding of LANs: Ethernet and the original idea of a bus, how this changed to 100 Mb/s and now Gigabit Ethernet connected with LAN switches. You'll learn about categories of cables, hubs and switches, and as a preview of Part III, how to interconnect LANs using routers and TCP/IP.
14.1 Categories of Cables
14.1.1 TIA-568A vs. TIA-568B
14.2 Bus Topology
14.2.1 Network Interface Cards and MAC Addresses
14.2.2 Frames and Logical Link Control
14.2.3 What Makes a LAN a LAN
14.2.4 Access Control: CSMA-CD
14.3 802.3 and Ethernet
14.4 Evolution of Ethernet
14.4.1 10BASE-5
14.4.2 10BASE-2
14.4.3 10BASE-T and Hubs
14.4.4 “Fast Ethernet”: 100BASE-T
14.4.5 Half-Duplex vs. Full Duplex
14.4.6 Gigabit Ethernet
14.5 “Gig-E” Applications
14.5.1 Gigabit Ethernet Passive Optical Network (EPON)
14.5.2 GPONs
14.6 802.5 / IBM Token-Passing Ring
14.7 Repeaters and Bridges
14.7.1 Old-Style Bridged LANs
14.8 Ethernet Switches
14.9 Interconnecting LANs with Routers
Part III Understanding IP and Networking
The third part brings it all together with a structured discussion of networking: protocol stacks, routers, IP addresses, bandwidth-on-demand services, Voice over IP (VoIP) and IP VPNs, the Internet, and finishes with a top-down review and templates for mainstream solutions.
Chapter 15 Understanding Protocol Stacks
We start by building a foundation for understanding networking by defining what needs to be done, and putting in place a structure for discussing how systems can interoperate via protocol stacks. We'll review the ISO Open Systems Interconnect (OSI) 7-layer reference model, give examples and explanations of protocols like SMTP, ASCII, HTTP, TCP, IP, 802.2 and 802.3 used for each layer, and practical insight into how a protocol stack works.
15.1 Choices for Connecting Systems
15.2 Protocols and Standards
15.3 ISO OSI Reference Model
15.4 OSI 7-Layer Model
15.5 Physical Layer
15.5.1 Physical Layer: Digital Technology Roundup
15.6 Data Link Layer
15.7 Network Layer
15.8 Transport Layer
15.9 Session Layer
15.9.1 Cookies: Session Restoration
15.9.2 Navigation and Profiling
15.10 Presentation Layer
15.10.1 Encryption
15.11 Application Layer
15.12 Protocol Stack in Operation
15.13 OSI Summary
15.13.1 Separability of the Layers
15.13.2 Peer Protocols
15.14 Standards Organizations
Chapter 16 IP Addressing
Obtain concise, detailed understanding of how IP addressing works: IP address classes, dynamic and static addresses, public and private addresses, Network Address Translation to connect multiple computers to one Internet connection, and IP version 6.
16.1 IP Version 4
16.1.1 Dotted-Decimal Notation
16.1.2 Address Classes
16.2 Dynamic IP Addresses
16.3 Static Addresses
16.4 Private IP Addresses
16.5 Network Address Translation
16.6 IP Version 6 (IPv6)
16.6.1 IPv6 Notation and Address Classes
Chapter 17 Private Networks using Routers and Dedicated Lines
The best way to understand routers and networks is with private networks, composed of routers connected with dedicated lines like T1s. We'll understand the functions routers perform, edge routers and packet filtering, and practical guidelines on how to order circuits and deal with carriers.
17.1 Chapter Roadmap
17.2 Traffic Aggregation via Channelized TDM
17.3 Statistical TDM Concepts
17.3.1 Overbooking
17.3.2 Addressing
17.4 T1 WAN: Integrated Data, Voice, Video
17.5 Edge Routers
17.5.1 Routing vs. Bridging
17.5.2 Packet Filtering
17.6 Private Wide-Area Packet Network
17.7 Dealing with Carriers
17.8 Troubleshooting
17.8.1 Fault Sectionalization
17.8.2 Bit Error Rate Testing (BERT)
17.8.3 In-Service Monitoring
17.8.4 Monitoring Higher Layers
Chapter 18 Bandwidth on Demand
Bandwidth on demand or "packet-switched" services have strong cost and flexibility advantages over dedicated lines. We’ll understand packet network concepts, how and why Virtual Circuits are implemented, and what the jargon and buzzwords really mean. You will understand the widely-used TCP/IP over Frame Relay and performance issues… which leads into understanding the need for Quality of Service (QoS) guarantees, ATM and MPLS.
18.1 Bandwidth on Demand Service Concepts
18.1.1 Advantages
18.1.2 Disadvantages
18.2 Virtual Circuits
18.2.1 Switched Virtual Circuits (SVCs)
18.2.2 Permanent Virtual Circuits (PVCs)
18.2.3 Connection-Oriented Network Services
18.2.4 Connectionless Network Services
18.2.5 Connection-Oriented, Connectionless and Virtual Circuits
18.2.6 Reliable Network Service
18.2.7 Unreliable Network Service
18.3 X.25
18.3.1 X.25 Network and Packets
18.3.2 Packet Switches vs. Routers
18.3.3 PADs: Network Interface Devices
18.3.4 X.25 Protocol Stack
18.3.5 X.25 Performance
18.4 Frame Relay
18.4.1 Improvements on X.25
18.4.2 Relaying Frames Instead of Switching Packets
18.4.3 Unreliable Service
18.4.4 TCP/IP and Frame Relay
18.4.5 Frame Relay Performance
18.4.6 Committed Information Rate (CIR)
18.4.7 Burst Information Rate (BIR)
18.5 QoS Requirement for Voice in Packets
18.6 ATM
18.7 MPLS
18.8 TCP/IP Over MPLS
Chapter 19 IP Network Services
In this chapter, we focus on two primary services that can run on an IP/MPLS network: voice and secure data communications. We’ll begin with an introduction to Voice over IP components, jargon and buzzwords, and understand how VoIP will mesh with the PSTN covered in Part 1. You’ll also understand how IPsec protocols and equipment implement IP VPNs for secure business data communications over IP networks.
19.1 VoIP System Components
19.2 VoIP over the Internet: VSPs
19.2.1 Why Internet Telephony is Cheaper than POTS
19.2.2 DS0 Interconnect to the PSTN
19.3 Internet Telephony from LEC / CATV
19.4 Managed-IP Telephone Service (MIPT)
19.5 VPNs
19.5.1 Customer-Premise-Based VPNs
19.5.2 Carrier VPN Service
20 Understanding the Internet
Let's not forget the Internet! This chapter provides a concise explanation of the Internet, reviewing past and present, ISPs, who pays for it, TCP and IP, SMTP and MIME for e-mail, HTML, Web servers and browsers, the Domain Name System and more. We'll complete the picture with practical guidelines for connecting.
20.1 Internet History
20.1.1 Philosophy Behind the Internet
20.1.2 How Al Gore Invented the Internet
20.1.3 Historical Limitations
20.2 Internet Basics
20.2.1 Globally-Meaningful Network Addresses
20.2.2 Connectionless Network Service
20.3 Internet Today: Internet Service Providers
20.3.1 Who Pays for the Internet?
20.3.2 Resellers vs. Carriers
20.4 Commonly Used Internet Protocols
20.4.1 Network Protocols
20.4.2 Transport Protocols
20.4.3 Application Protocols
20.5 TCP and UDP
20.6 Domain Name System
20.7 MIME: E-Mailing Multimedia Files
20.7.1 Binary vs. Text
20.7.2 Transformations
20.7.3 Quoted-Printable and Base-64 Encoding
20.8 World Wide Web
20.8.1 Servers and Clients
20.8.2 Hyperlinks and URLs
20.9 HTML, HTTP and HTTPS
20.10 Web Browsers
20.11 Accessing the Internet: Home Connections
20.12 Access for an Organization
20.13 Current Internet Issues
20.13.1 IP Addressing
20.13.2 Router Table Update Overhead
20.13.3 Dial-Up Access
20.13.4 Quality of Service
21 Wrapping Up
The final chapter brings all of the concepts together with a top-down review. You’ll learn valuable insight in how technology should be deployed, and review mainstream services and solutions. We’ll conclude with a view toward the future: the IP Packet-Switched Telecommunications Network… the first diagram from the next Teracom textbook "IP Telecom"..
21.1 System Development Methodology
21.2 Top-Level Requirements
21.3 Design
21.4 Implementation: Circuits and Services
21.5 Access / Network Connection Combinations
21.6 Private Network WAN Design
21.7 Frame Relay WAN
21.8 Native IP WAN
21.9 The Future
Acronyms and Abbreviations
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