Chapter 1-15 Web Links Links:

Chapter 1: Computing Basics

1.1 | The Basics of Computer Hardware

1.1.1 | Major components of a personal computer Tech Encyclopedia What's in Your Computer
1.1.2 | Information flow in an idealized computer
1.1.3 | The relationship of NICs to PCs
1.1.4 | The installation of a NIC in a PC Configuring a PC NIC - IRQ Installing a Network Interface Card
1.1.5 | PC components versus laptop components

1.2 | The Basics of Computer Software

1.2.1 | Lab: Configuring network settings required to connect a PC to a network
1.2.2 | Lab: Verify Web browser configuration Netscape Microsoft Flash Player Exploring the World Wide Web
Browser Basics
1.2.3 | Troubleshooting lab: hardware and software

1.3 | Binary Numbers

1.3.1 | Binary numbers represent alphanumeric data
1.3.2 | Bits and bytes How Bytes and Bits Work
1.3.3 | The Base 10 (decimal) number system How Bytes and Bits Work ASCII Bit Positioning
1.3.4 | The Base 2 (binary) number system How Bytes and Bits Work
1.3.5 | Converting decimal numbers to binary numbers How Bytes and Bits Work
1.3.6 | Converting binary numbers to decimal numbers How Bytes and Bits Work

1.4 | Basic Networking Terminology

1.4.1 | Networks and networking
1.4.2 | Data networks
1.4.3 | Data networking solutions
1.4.4 | Local area networks PlanetIT: LAN Index Data Communications InfoWorld Network Magazine
LAN Times
1.4.5 | Wide area networks

1.5 | Digital Bandwidth

1.5.1 | Digital bandwidth measurements Digital Communications
1.5.2 | Three analogies to describe digital bandwidth
1.5.3 | Media bandwidth differences
1.5.4 | Data throughput in relation to digital bandwidth
1.5.5 | Data transfer calculation
1.5.6 | The importance of bandwidth

Chapter 2: The OSI Model

2.1 | General Model of Communication

2.1.1 | Using layers to analyze problems in a flow of materials The OSI Reference Model
2.1.2 | Source, destination, and data packets The OSI Reference Model
2.1.3 | Media The OSI Reference Model
2.1.4 | Protocol The OSI Reference Model
2.1.5 | The evolution of ISO networking standards Networking Research Links and Standards The Development of Communication Networks

2.2 | The OSI Reference Model

2.2.1 | The purpose of the OSI reference model The OSI Seven Layers Model
2.2.2 | The names of the seven layers of the OSI reference model The OSI Seven Layers Model
2.2.3 | Descriptions of the seven layers of the OSI reference model The OSI Seven Layers Model
2.2.4 | Encapsulation The OSI Seven Layers Model
2.2.5 | Names for data at each layer of the OSI model

2.3 | Comparison of the OSI Model and the TCP/IP Model

2.3.1 | The importance of the TCP/IP reference model The Internet Engineering Task Force Introduction to the Internet Protocols
2.3.2 | Names and descriptions of the layers of the TCP/IP reference model Introduction to the Internet Protocols
2.3.3 | TCP/IP protocol graph Introduction to the Internet Protocls
2.3.4 | Comparison of the OSI model and the TCP/IP model Introduction to the Internet Protocols
2.3.5 | Use of the OSI and the TCP/IP models in the curriculum Ethernet Web Site Introduction to the Internet Protocols

Chapter 3: Local Area Networks

3.1 | Basic LAN Devices

3.1.1 | The teaching topology Webopedia Network
3.1.2 | LAN devices in a topology
3.1.3 | NICs Blackbox Network Services Micro Warehours
3.1.4 | Media Blackbox Network Services Micro Warehours
3.1.5 | Repeaters Blackbox Network Services Micro Warehours
3.1.6 | Hubs Blackbox Network Services Micro Warehours Hubs
3.1.7 | Bridges
3.1.8 | Switches Cisco Systems
3.1.9 | Routers Cisco Systems
3.1.10 | Clouds
3.1.11 | Network segments

3.2 | Evolution of Network Devices

3.2.1 | Evolution of network devices
3.2.2 | Milestones in the history of networking
3.2.3 | Evolution of networking devices and the OSI layers

3.3 | Basics of Data Flow Through LANs

3.3.1 | Encapsulation and packets review Encapsulation Packets Data Encapsulation Encapsulation Slide
Encapsulation of PDUs
3.3.2 | Packet flow through Layer 1 devices Encapsulation Packets Data Encapsulation Encapsulation Slide
Encapsulation of PDUs
3.3.3 | Packet flow through Layer 2 devices Encapsulation Packets Data Encapsulation Encapsulation Slide
Encapsulation of PDUs
3.3.4 | Packet flow through Layer 3 devices Encapsulation Packets Data Encapsulation Encapsulation Slide
Encapsulation of PDUs
3.3.5 | Packet flow through clouds and through Layer 1-7 devices Encapsulation Packets Data Encapsulation Encapsulation Slide
Encapsulation of PDUs
3.3.6 | A data packet's path through all seven layers of a LAN Encapsulation Packets Data Encapsulation Encapsulation Slide
Encapsulation of PDUs

3.4 | Building LANs

3.4.1 | Readiness to build a small network
3.4.2 | Building a 2-node network with a cross-connect cable
3.4.3 | Building a 4-node hubbed network with file sharing capabilities Hubs
3.4.4 | Building a 4-node hubbed network with Internet access Hubs

Chapter 4: Layer 1 - Electronics and Signals

4.1 | Basics of Electricity

4.1.1 | A helium atom Helium
4.1.2 | Creating stable atoms
4.1.3 | Static electricity "Static Electricity" means "High Voltage"
4.1.4 | Electrical current including insulators, conductors, and semiconductors Forms of Energy
4.1.5 | Electrical measurement terms Electricity Fundamentals
4.1.6 | Analogy for voltage, resistance, and current
4.1.7 | Graphing AC and DC voltage
4.1.8 | Constructing a simple series electrical current
4.1.9 | Purpose of grounding networking equipment

4.2 | Basics of Digital Multimeters

4.2.1 | Safe handling and use of the multimeter Using a Multimeter
4.2.2 | Using a multimeter to make resistance measurements Using a Multimeter
4.2.3 | Using a multimeter to make voltage measurements Using a Multimeter
4.2.4 | Measuring simple series circuit Using a Multimeter
4.2.5 | Constructing a simple electrical communication system

4.3 | Basics of Signals and Noise in Communications Systems

4.3.1 | Comparing analog and digital signals
4.3.2 | Using digital signals to build analog signals
4.3.3 | Representing one bit on a physical medium
4.3.4 | Network signal propagation
4.3.5 | Network attenuation Connection Denied
4.3.6 | Network reflection
4.3.7 | Noise Tests on Conducted Electrical Noise
4.3.8 | Dispersion, jitter, and latency
4.3.9 | Collision
4.3.10 | Messages in terms of bits

4.4 | Basics of Encoding Networking Signals

4.4.1 | Historical examples of encoding
4.4.2 | Modulation and encoding Digital Encoding

Chapter 5: Layer 1- Media, Connections, and Collisions

5.1 | Most Common LAN Media

5.1.1 | STP Twisted Pair Cabling
5.1.2 | UTP Twisted Pair Cabling
5.1.3 | Coaxial cable
5.1.4 | Optical fiber Optical Fiber Cabling
5.1.5 | Wireless communication

5.2 | Cable Specification and Termination

5.2.1 | Purpose of LAN media specifications Industry Standards for Structured Cabling
5.2.2 | EIA/TIA standards Electronics Industries Alliance Industry Standards for Structured Cabling
5.2.3 | EIA/TIA 568 Industry Standards for Structured Cabling
5.2.4 | Networking media and terminations AMP ANIXTER Belden Panduit Wiring and Communication Products
Industry Standards for Structured Cabling
Cable Termination and Installation

5.3 | Making and Testing Cable

5.3.1 | Testing Ethernet 10BASE-T patch cables with a cable tester Cable Termination and Installation
5.3.2 | Making and testing Ethernet 10BASE-T straight-thru patch cable Cable Termination and Installation
5.3.3 | Making and testing Ethernet 10BASE-T console patch cable Cable Termination and Installation
5.3.4 | Making and testing Ethernet 10BASE-T crossover cable Cable Termination and Installation
5.3.5 | Features of an advanced cable tester Cable Termination and Installation
5.3.6 | Cable identification experiments using an advanced cable tester Cable Termination and Installation
5.3.7 | Length experiments using an advanced cable tester Cable Termination and Installation

5.4 | Layer 1 Components and Devices

5.4.1 | Ethernet 10BASE-T Blackbox Network Services
5.4.2 | Connectors
5.4.3 | Cabling
5.4.4 | Jacks
5.4.5 | Patch panels
5.4.6 | Transceivers
5.4.7 | Repeaters
5.4.8 | Multiport repeaters (hubs)
5.4.9 | OSI Layer 1 components and devices

5.5 | Collisions and Collision Domains in Shared Layer Environments

5.5.1 | Shared media environment
5.5.2 | Collisions and collision domains
5.5.3 | Signals in a collision
5.5.4 | Collisions as natural functions of shared media environments and collision domains
5.5.5 | Shared access as a collision domain
5.5.6 | Repeaters and collision domains
5.5.7 | Hubs and collision domains
5.5.8 | Hubs and repeaters as causes of collision domains
5.5.9 | The four repeater rule
5.5.10 | Segmenting collision domains

5.6 | Basic Topologies Used in Networking

5.6.1 | Network topologies
5.6.2 | Linear bus network topology
5.6.3 | Ring network topology
5.6.4 | Dual ring network topology
5.6.5 | Star network topology
5.6.6 | Extended star network topology
5.6.7 | Tree network topology
5.6.8 | Irregular network topology
5.6.9 | Complete (mesh) network topology
5.6.10 | Cellular network topology

Chapter 6: Layer 2 - Concepts

6.1 | LAN Standards

6.1.1 | Layer 2 The Data Link Layer DataLink Layer
6.1.2 | Comparing OSI Layer 1 and 2 with various LAN standards IEEE
6.1.3 | Comparing the IEEE model with the OSI model
6.1.4 | Logical Link Control (LLC)
6.1.5 | MAC sublayers Layer 2 - The Data Link Layer The Media Access Control ( MAC) Sublayer Functions
6.1.6 | LLC as one of four concepts of Layer 2

6.2 | Hexadecimal Numbers

6.2.1 | Hexadecimal numbers as MAC addresses OUIs Frequent Asked Questions Hex (hexadecimal) Explained
6.2.2 | Basic hexadecimal (hex) numbering
6.2.3 | Converting decimal numbers to hexadecimal numbers
6.2.4 | Converting hexadecimal numbers to decimal numbers
6.2.5 | Methods for working with hexadecimal and binary numbers

6.3 | MAC Addressing

6.3.1 | Data link layer MAC identifiers OUIs Frequent Asked Questions
6.3.2 | MAC address and NICs Hardware address How To
6.3.3 | How the NIC uses MAC addresses
6.3.4 | Layer 2 address encapsulation and decapsulation
6.3.5 | Limitations of MAC addressing

6.4 | Framing

6.4.1 | Why framing is necessary TechEncyclopedia
6.4.2 | Frame format diagram
6.4.3 | Three analogies for frames
6.4.4 | A generic frame format
6.4.5 | Frame start fields Ethernet Frame
6.4.6 | Address fields Ethernet Frame
6.4.7 | length/type fields Ethernet Frame
6.4.8 | Data fields
6.4.9 | Frame error problems and solutions
6.4.10 | Stop frame field

6.5 | Media Access Control (MAC)

6.5.1 | Definition of MAC MAC address
6.5.2 | Three analogies for MAC
6.5.3 | Deterministic MAC protocols Media Access Control Protocols
6.5.4 | Non-deterministic MAC protocols
6.5.5 | Three specific technical implementations and their MACs

Chapter 7: Layer 2 - Technologies
There are no web links for chapter 7.
Chapter 8: Design and Documentation

8.1 | Basic Network Design and Documentation

8.1.1 | General design process Cabling Glossary
8.1.2 | Network design issues Cabling Glossary
8.1.3 | General network design process What is Engineering Problem Solving? Cabling Glossary
8.1.4 | Network design documents Siemon Guidelines to Industry Standards Cabling Glossary

8.2 | Planning Structured Cabling: Wiring Closet Specifications

8.2.1 | Overview of wiring closet selection Cabling Glossary ANSI/EIA/TIA Standards
8.2.2 | Size Cabling Glossary
8.2.3 | Environmental Specifications Cabling Glossary
8.2.4 | Walls, floors, and ceilings Cabling Glossary
8.2.5 | Temperature and humidity Cabling Glossary
8.2.6 | Lighting fixtures and power outlets Cabling Glossary
8.2.7 | Room and equipment access Cabling Glossary
8.2.8 | Cable access and support Cabling Glossary

8.3 | Planning Structured Cabling: Identifying Potential Wiring Closets

8.3.1 | Topology as floor plan Cabling Glossary
8.3.2 | Selecting potential locations Cabling Glossary
8.3.3 | Determining number of wiring closets Cabling Glossary
8.3.4 | Identification practice Cabling Glossary

8.4 | Planning Structured Cabling: Selection Practice

8.4.1 | Building description
8.4.2 | Closet A
8.4.3 | Closet B
8.4.4 | Closet C
8.4.5 | Closet D
8.4.6 | Closet E
8.4.7 | Closet F
8.4.8 | Closet G
8.4.9 | Closet H
8.4.10 | Closet I
8.4.11 | Closet J

8.5 | Planning Structured Cabling: Horizontal and Backbone Cabling

8.5.1 | Catchment area problems Cabling Glossary Industry Standards for Structured Cabling
8.5.2 | MDF location in multi-story building Cabling Glossary Industry Standards for Structured Cabling
8.5.3 | Example of where you would use multiple wiring closets Cabling Glossary Industry Standards for Structured Cabling
8.5.4 | Cabling for MDF and IDF connections Cabling Glossary Industry Standards for Structured Cabling
8.5.5 | Backbone cabling media Cabling Glossary Industry Standards for Structured Cabling
8.5.6 | EIA/TIA 568 requirements for backbone cabling Cabling Glossary Industry Standards for Structured Cabling
8.5.7 | Maximum distance for backbone cabling Cabling Glossary Industry Standards for Structured Cabling

8.6 | Planning Structured Cabling: Electricity and Grounding

8.6.1 | Differences between AC and DC
8.6.2 | AC line noise
8.6.3 | Electrostatic discharge
8.6.4 | Grounding electrical current in computer equipment
8.6.5 | Purpose of grounding computer equipment
8.6.6 | Safety ground connections
8.6.7 | Safety ground connection problems

8.7 | Planning Structured Cabling: Cabling and Grounding

8.7.1 | Causes of ground potential problems
8.7.2 | Networking devices and dangerous circuits
8.7.3 | Faulty ground wiring problems
8.7.4 | Avoiding potentially dangerous circuits between buildings
8.7.5 | How fiber optic cable can prevent electrical shocks
8.7.6 | Reasons for using UTP for backbone cabling between buildings

8.8 | Design Practice No. 1: Wiring Plan for Ethernet Star Topology LAN

8.8.1 | Overview Cabling Glossary
8.8.2 | Main building: first floor Cabling Glossary
8.8.3 | Main building: second floor Cabling Glossary
8.8.4 | East building: first floor Cabling Glossary
8.8.5 | East building: second floor Cabling Glossary
8.8.6 | West building: first floor Cabling Glossary
8.8.7 | West building: second floor Cabling Glossary

8.9 | Design Practice No. 2: Multiple Earth Ground Problems

8.9.1 | Overview Cabling Glossary
8.9.2 | Company A: MDF location Cabling Glossary
8.9.3 | Company A: backbone media Cabling Glossary
8.9.4 | Company A: IDFs and ICCs Cabling Glossary
8.9.5 | Company A: HCC locations Cabling Glossary
8.9.6 | Company A: drawing horizontal cabling runs Cabling Glossary
8.9.7 | Company B: MDF location Cabling Glossary
8.9.8 | Company B: backbone media Cabling Glossary
8.9.9 | Company B: drawing horizontal cabling runs Cabling Glossary

8.10 | Network Power Supply Issues: Power Line Problems

8.10.1 | Power problem classifications
8.10.2 | Normal mode and common mode
8.10.3 | Typical power line problems
8.10.4 | Sources of surges and spikes
8.10.5 | Surge and spike damage
8.10.6 | Surge and spike solutions
8.10.7 | Sag and brownout solutions
8.10.8 | Oscillation solution

8.11 | Network Power Supply Issues: Surge Suppressors and Uninterruptible Power Supply (UPS) Functions

8.11.1 | Surge Suppressors: networking device locations
8.11.2 | Surge Suppressor: for power panel locations
8.11.3 | UPS: for certain LAN devices
8.11.4 | UPS: for certain electrical problems
8.11.5 | UPS: components
8.11.6 | UPS: differences in UPS features
8.11.7 | UPS: description and operation

Chapter 9: Structured Cabling Project

9.1 | Project Planning

9.1.1 | Network installation safety procedures Cabling Products Cabling Glossary
9.1.2 | Network documentation Cabling Products Cabling Glossary
9.1.3 | Network installation teams Cabling Products Cabling Glossary
9.1.4 | Work flow Cabling Products Cabling Glossary
9.1.5 | Scheduling materials flow Cabling Products Cabling Glossary

9.2 | RJ-45 Jack and Outlet Installation

9.2.1 | TIA/EIA-568-A standards Cabling Glossary Cable Termination and Installation
9.2.2 | RJ-45 jack Cabling Glossary Cable Termination and Installation
9.2.3 | Two methods for mounting an RJ-45 jack Cabling Glossary Cable Termination and Installation
9.2.4 | Surface-mounting an RJ-45 jack Cabling Glossary Cable Termination and Installation
9.2.5 | Advantages of surface-mounting an RJ-45 jack Cabling Glossary Cable Termination and Installation
9.2.6 | Factors to consider before flush-mounting an RJ-45 jack Cabling Glossary Cable Termination and Installation
9.2.7 | Preparing a drywall surface for a flush-mounted jack Cabling Glossary Cable Termination and Installation
9.2.8 | Preparing a plaster surface for a flush-mounted jack Cabling Glossary Cable Termination and Installation
9.2.9 | Preparing a wood surface for a flush-mounted jack Cabling Glossary Cable Termination and Installation
9.2.10 | Flush mounting a jack in a wall Cabling Glossary Cable Termination and Installation
9.2.11 | Procedure for placing the copper wires into a jack Cabling Glossary Cable Termination and Installation
9.2.12 | Procedure for punching wires down into a jack Cabling Glossary Cable Termination and Installation
9.2.13 | Installing RJ-45 jack and outlet Cabling Glossary Cable Termination and Installation

9.3 | Basics of Cable Installation

9.3.1 | Basics of installing UTP cable Cabling Glossary Cable Termination and Installation
9.3.2 | Documenting cable runs Cabling Glossary Cable Termination and Installation
9.3.3 | TIA/EIA-606 specifications for labeling cable Cabling Glossary Cable Termination and Installation
9.3.4 | Types of labels Cabling Glossary Cable Termination and Installation
9.3.5 | Preparing cable for routing and labeling Cabling Glossary Cable Termination and Installation
9.3.6 | Labeling cable ends Cabling Glossary Cable Termination and Installation

9.4 | Structured Cable Run Installation

9.4.1 | Easiest procedure for routing cable Cabling Glossary Cable Termination and Installation
9.4.2 | Mounting cable in raceway Cabling Glossary Cable Termination and Installation
9.4.3 | Running cable through existing raceway Cabling Glossary Cable Termination and Installation
9.4.4 | Personal safety precautions before installing cable Cabling Glossary Cable Termination and Installation
9.4.5 | Building safety Cabling Glossary Cable Termination and Installation
9.4.6 | Supporting horizontal cabling Cabling Glossary Cable Termination and Installation
9.4.7 | Stringing cable in an attic, or room with a dropped ceiling Cabling Glossary Cable Termination and Installation
9.4.8 | Fishing cable from above a wall Cabling Glossary Cable Termination and Installation
9.4.9 | Fishing cable from below a wall Cabling Glossary Cable Termination and Installation

9.5 | Stringing, Running, and Mounting Cable

9.5.1 | Installation tasks Cabling Glossary Cable Termination and Installation

9.6 | Basics of Wiring Closets and Patch Panels

9.6.1 | Wiring closet Cabling Glossary Cable Termination and Installation
9.6.2 | Reason for MDFs and IDFs Cabling Glossary Cable Termination and Installation
9.6.3 | Patch panel Cabling Glossary Cable Termination and Installation
9.6.4 | Structure of a patch panel Cabling Glossary Cable Termination and Installation
9.6.5 | Laying wires in a patch panel Cabling Glossary Cable Termination and Installation
9.6.6 | Punch tools Cabling Glossary Cable Termination and Installation
9.6.7 | Mounting a patch panel Cabling Glossary Cable Termination and Installation

9.7 | Range of Equipment for Testing Structured Cabling Projects

9.7.1 | Procedures for testing cable already installed Cabling Glossary Network Test Equipment
9.7.2 | Network operation testing Cabling Glossary Network Test Equipment
9.7.3 | Cable testing equipment Cabling Glossary Network Test Equipment
9.7.4 | Tests performed by cable testers Cabling Glossary Network Test Equipment
9.7.5 | Cable testers and distance measurements Cabling Glossary Network Test Equipment
9.7.6 | TDRs (time domain reflectometers) Cabling Glossary Network Test Equipment
9.7.7 | Wire maps Cabling Glossary Network Test Equipment
9.7.8 | Split pairs Cabling Glossary Network Test Equipment
9.7.9 | Signal attenuation Cabling Glossary Network Test Equipment
9.7.10 | Causes of near-end crosstalk Cabling Glossary Network Test Equipment
9.7.11 | Problem detected by a noise level test Cabling Glossary Network Test Equipment
9.7.12 | Using a cable tester to locate sources of outside interference Cabling Glossary Network Test Equipment
9.7.13 | Cable testing procedures Cabling Glossary Network Test Equipment

Chapter 10: Layer 3 - Routing and Addressing

10.1 | Importance of a Network Layer

10.1.1 | Identifiers RFC 941 Routing and the Network Layer Network Layer Functions
10.1.2 | Segmentation and autonomous systems
10.1.3 | Communication between separate networks
10.1.4 | Layer 3 network devices

10.2 | Path Determination

10.2.1 | Path determination Router
10.2.2 | Network layer addressing Router
10.2.3 | Layer 3 and computer mobility Router
10.2.4 | Comparing flat and hierarchical addressing Router

10.3 | IP Address within the IP Header

10.3.1 | Network layer datagrams IP Address Subnetting Tutorial IP Addressing Architecture
10.3.2 | Network layer fields IP Addressing Architecture
10.3.3 | IP header source and destination fields IP Addressing Architecture
10.3.4 | IP address as a 32-bit binary number Introduction to the Internet Protocols
10.3.5 | IP address component fields Introduction to the Internet Protocols

10.4 | IP Address Classes

10.4.1 | IP address classes
10.4.2 | IP address as decimal numbers
10.4.3 | Binary and decimal conversion review
10.4.4 | Converting decimal IP addresses to binary equivalents
10.4.5 | Converting binary IP addresses to decimal equivalents

10.5 | Reserved Address Space

10.5.1 | Purposes for network IDS and broadcast addresses IP Address Subnetting Tutorial
10.5.2 | Network ID
10.5.3 | Network ID analogy
10.5.4 | Broadcast address analogy
10.5.5 | Hosts for classes of IP addresses

10.6 | Basics of Subnetting

10.6.1 | Classical IP Addressing
10.6.2 | Subnetwork IP Address Subnetting Tutorial
10.6.3 | Purpose for subnetting
10.6.4 | Subnet mask
10.6.5 | Boolean operation: AND, OR, and NOT How Boolean Logic Works
10.6.6 | Performing the AND function

10.7 | Creating a Subnet

10.7.1 | Range of bits needed to create subnets
10.7.2 | Determining subnet mask size
10.7.3 | Computing subnet mask and IP address
10.7.4 | Computing hosts per subnetwork
10.7.5 | Boolean AND operation
10.7.6 | IP configuration on a network diagram Introduction to the Internet Protocols
10.7.7 | Host/subnet schemes Introduction to the Internet Protocols
10.7.8 | Private addresses

Chapter 11: Layer 3 - Protocols
There are no web links for chapter 11.
Chapter 12: Layer 4 - The Transport Layer
There are no web links for chapter 12.
Chapter 13: Layer 5 - The Session Layer
There are no web links for chapter 13.
Chapter 14: Layer 6 - The Presentation Layer
There are no web links for chapter 14.
Chapter 15: Layer 7 - The Application Layer

15.1 | Basics of the Application Layer

15.1.1 | Application processes The Application Layer of OSI
15.1.2 | Direct network applications Client/Server Frequently Asked Questions
15.1.3 | Indirect network support Redirectors
15.1.4 | Making and breaking a connection

15.2 | Domain Name System

15.2.1 | Problems with using IP addresses DNS: The Domain Name System
15.2.2 | The domain name server DNS: The Domain Name System

15.3 | Network Applications

15.3.1 | Internet applications
15.3.2 | E-mail message What is Email? Email Basics and Asynchronous Communication
15.3.3 | DNS function

15.4 | Application Layer Examples

15.4.1 | Telnet What is Telnet?
15.4.2 | File transfer protocol
15.4.3 | Hypertext transfer protocol Hypertext Transfer Protocol