1. Chapter 2 Accessing the Internet

2. Learning Objectives
Describe how the last mile connects users to the Internet.
Examine the difference between bandwidth, throughput, and latency.
Explain the different hardware and software requirements for connecting to the Internet.
Contrast the different types of wired and wireless Internet connection methods.
Evaluate Internet Service Providers and determine best practices.

3. Chapter Focus Internet Infrastructure
Bandwidth, Throughput, and Latency
Hardware and Software Requirements for Connecting to the Internet
Wired Internet Connections
Wireless Internet Connections
Choosing an Internet Service Provider

4. Internet Infrastructure
The Last Mile
The last portion of any telephone connection from a central office to an end user
Most homes still have standard telephone service
POTS – plain old telephone service
Uses twisted-pair cables
Usually slowest portion of Internet connection

5. Internet Infrastructure
The Last Mile

6. Internet Infrastructure
Internet Service Providers (ISPs)
Provides Internet access and Web development and hosting
Internet Access Providers (IAPs)
Provides Internet access only
Network access points (NAPs)
ISPs and IAPs connect to an Internet backbone through an NAP
Smaller ISPs and IAPs may connect first to larger ISPs and IAPs, who will in turn connect to an NAP

7. Internet Infrastructure
The Internet Backbone
High-speed lines that form the core network of the Internet
First Internet backbones supported by ARPANET and later NSFnet
Now supported by the private sector – a number of different companies
Lines include T1, T3, OC-1, and OC-3 cables

8. Internet Infrastructure
T1 cables
Contain two twisted-pair cables
Bandwidth of Mbps
T3 cables
Contain 28 T1 lines
Bandwidth of Mbps

9. Internet Infrastructure
OC-1 and OC-3 cables
OC – Optical Carrier
Contains fiber-optic cable
OC-1
Bandwidth of Mbps
OC-3
Bandwidth of Mbps

10. Internet Infrastructure
Twisted-pair cable

11. Internet Infrastructure
Fiber-optic cable

12. Internet Infrastructure Review
Why do the last mile and the hardware in a central office often present a stumbling block to fast and reliable Internet connections?
What is the difference between an ISP and an IAP?
How do fiber-optic cables work?
What is a network access point (NAP)?

13. Bandwidth, Throughput, and Latency
Expresses the theoretical maximum amount of data that an Internet connection can transmit in one second
Internet bandwidth
Measured in bits per second
Expressed in decimal format

14. Bandwidth, Throughput, and Latency
Relative Bandwidth Size

15. Bandwidth, Throughput, and Latency
One bit (binary digit)
A single digit – zero or one
Kilobit
1,000 bits
Megabit
1,000 kilobits
Gigabit
1,000 megabits

16. Bandwidth, Throughput, and Latency
Bandwidth Measurements
bps – bits per second
Kbps – kilobits per second
File Size Measurements
Byte – eight bits
KB – kilobytes

17. Bandwidth, Throughput, and Latency
Bandwidth Speeds
Symmetrical
Uploading or downloading are the same
Asymmetrical
Uploading and downloading speeds are different
Usually more bandwidth for downloading compared to uploading

18. Bandwidth, Throughput, and Latency
Measures actual transmission speed per second
As opposed to bandwidth which measures theoretical rate
Measures only useable data transmitted and does not include data used for network overhead

19. Bandwidth, Throughput, and Latency
Time between transmission and reception of data across a network
Usually measured in milliseconds (ms)
Causes of latency
Device delays
Network congestion
Long route necessary for satellite signal to travel between earth and outerspace
Ping
Program to measure latency

20. Bandwidth, Throughput, and Latency Review
How do bandwidth, throughput, and latency differ from each other?
What kind of Internet connection is most affected by high latency rates?
How are bandwidth, file storage, and latency measured?
What is the difference between symmetrical and asymetrical Internet connections?

21. Hardware and Software Requirements for Connecting to the Internet
Hardware Requirements
Computer
Modem
Cable for connecting the modem
Specific requirements depends on the type of Internet connection that will be used

22. Hardware and Software Requirements for Connecting to the Internet
Modem (modulator – demodulator)
Originally named for purpose
To convert digital computer data into analog data to be sent over an analog phone line, then on the receiving side, convert back to digital data
Satellite modems
Transmit data using radio waves
Other types
ISDN, xDSL, and cable modems
Different modem types are not interchangeable

23. Hardware and Software Requirements for Connecting to the Internet
Current computer operating system that will support TCP/IP
Windows Vista, Linux, Mac OS, and others
Web browser
program

24. Hardware and Software Requirements for Connecting to the Internet Review
How does a modem work?
What kind of software is needed to connect to the Internet?
What basic hardware requirements are necessary for connecting to the Internet?

25. Wired Internet Connections
Includes any method that uses cable or wires to connect to the Internet
Dial-up connections (POTS)
ISDN
xDSL
Cable
Leased lines
Broadband over power line (BPL)

26. Wired Internet Connections
Dial-up Internet Access (POTS)
Bandwidth between 28.8 and 56 Kbps
Referred to as narrowband
Accelerated Internet
Uses standard modems and POTS
Employs compression and caching technologies to increase:
Throughput
Web page loading up to 5 times faster
Reduce text and image file sizes

27. Wired Internet Connections
Integrated Services Digital Network (ISDN)
Integrates voice and data
Multiple digital channels
Users can talk on the phone and surf the Internet over a single telephone wire
Bandwidth of 64 Kbps or 128 Kbps
Distance-related
Users must be located within 18,000 of central office (CO)

28. Wired Internet Connections
Digital Subscriber Line (DSL)
High-speed Internet service using POTS twisted-pair cable
xDSL
Represents different members of DSL services
Asymmetric Digital Subscriber Line (ADSL)
Most common DSL service
Can carry simultaneous voice and data if splitter is installed
Bandwidth up to 9 Mbps
Always-on connection

29. Wired Internet Connections
Discrete Multitone (DMT) Modulation

30. Wired Internet Connections
Cable
Utilizes coaxial cable used to provide cable television service to connect users to the Internet
All cable Internet users share bandwidth with other users on the same channel
Bandwidth depends on how many users are connected
Always-on asymmetric Internet connection

31. Wired Internet Connections
Leased Lines
Dedicated line remains separate from the phone line
Offers always-on symmetrical bandwidth with identical speeds for data uploads and downloads
Most commonly leased lines are T1 and T3 lines
Very large businesses may lease an optical carrier line such as an OC-3

32. Wired Internet Connections
Broadband over power line (BPL)
Delivers Internet data over electrical power lines and into homes
Bandwidth Kbps to 3 Mbps
Limited availability in US, Canada, and Europe
Future is uncertain

33. Wired Internet Connections Review
Is there a fixed or agreed-upon definition for the term broadband Internet?
What are the differences among the different types of DSL technologies?
How does a cable modem Internet connection work?
How does an accelerated Internet connection work?

34. Wireless Internet Connections
Uses radio waves to connect computers equipped for wireless
IEEE most common series of specifications
Commonly called Wi-Fi
To operate wirelessly a computer must have:
Wireless network interface card (NIC)
Or adapter installed
Or factory equipped with wireless technology

35. Wireless Internet Connections
Security
Open connection
Allows anyone with a wireless NIC access to the connection
Secure connection
Connection can be made secure by using a 128-bit encryption system known as Wired Equivalency Privacy (WEP)

36. Wireless Internet Connections
Fixed Wireless Service
Broadcasts data in the form of microwave frequencies from a tower or series of towers
Broadcasting range is up to 35 miles
Line of sight technology
Between 256 Kbps and 1 Mbps downloading
Between 512 Kbps uploading

37. Wireless Internet Connections
Wireless LAN (WLAN)
To connect a computer or series of computers to an ADSL or cable modem to access the Internet
Connection is to a transceiver known as a wireless access point
Wireless equipment
To provide wireless Internet access for a home or business
Or to create a public hotspot

38. Wireless Internet Connections
Cellular Phone Internet Access
Work by dividing geographic regions into a grid of cells
Users travel through one cell to another cell
First generation (1G) were analog networks
Wireless Application Protocol (WAP)
Microbrowser designed for small screens found on hand-held devices such as PDAs
Wireless Markup Language (WML)
Used to develop pages to be shown in microbrowser

39. Wireless Internet Connections
Satellite Internet Access
Offers broadband Internet
Popular in rural or remote areas
Users need:
Small dish
Satellite modem
Coaxial cable connection

40. Wireless Internet Connections Review
How can a wireless local area network (WLAN) be connected to a wired Internet service?
How does a satellite Internet connection work?
What are some different methods that can be used to access the Internet using cellular service?

41. Choosing an Internet Service Provider
The first step begins with a needs assessment
Considerations
Hours per week or month of usage needed
Cost of disk storage if Web site hosting is needed
addresses provided
Ability to access account on the road
Minimum hardware and software required
Possibility of Online Service Provider (OSP)
America Online (AOL)
CompuServe
Support service provided
References

42. Choosing an Internet Service Provider Review
What is the first thing you should do before evaluating what kind of Internet service is best for you?
What is an OSP?
How does an OSP differ from an ISP or IAP?