Internet and Computer Network-Basics

Internet and LAN Technology

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Chapter Contents

• Section A: Network Building Blocks

• Section B: Local Area Networks

• Section C: Internet Technology

• Section D: Internet Access

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Section A: Network Building Blocks

• Network Advantages and Challenges

• Network Classifications

• Geographic Scope: PANs, NANs, LANs, MANs, and WANs

• Organizational Structure: Client/Server and Peer-to-Peer

• Physical Topology

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Section A: Network Building Blocks

• Network Links

• Analog and Digital Signals

• Bandwidth

• Communications Protocols

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Network Advantages and Challenges

• Sharing networked hardware can reduce costs• Sharing networked hardware can provide access

to a wide range of services and specialized peripheral devices

• Sharing networked software can reduce costs• Sharing data on a network is easy• Networks enable people to work together

regardless of time and place

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Network Advantages and Challenges

• Networks may be vulnerable to unauthorized access from many sources and locations– More vulnerable than standalone computers

• Wireless networks can be tapped from a “snooping” computer

• Networked computers are susceptible to an increasing number of worms, Trojan horses, and blended threats

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Network Classifications

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Geographical Scope: PANs, NANs, LANs, MANs, and WANs

• Personal Area Network (PAN) – interconnection of personal digital devices

• Neighborhood Area Network (NAN) – connectivity spread over several buildings

• Local Area Network (LAN) – usually connects computers in a single building

• Metropolitan Area Network (MAN) – public high-speed network with range of about 50 miles

• Wide Area Network (WAN) – consists of several smaller networks

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Organizational Structure: Client/Server and Peer-to-Peer

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Physical Topology

• Arrangement of devices in a network

• Each connection point on a network is referred to as a node

• A bridge can connect two similar networks

• A gateway joins two dissimilar networks– Router

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Physical Topology

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Physical Topology

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Network Links

• Wired network– Twisted-pair cable– Coaxial cable– Fiber-optic cable

• Wireless network– RF signals– Microwaves– Infrared light

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Analog and Digital Signals

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Bandwidth

• The transmission capacity of a communications channel– High-bandwidth channel (broadband)

• Cable TV• DSL

– Low-bandwidth channel (narrowband)• Telephone system

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Communications Protocols

• Rules for efficiently transmitting data from one network node to another– Dividing messages into

packets– Affixing addresses to

packets– Initiating transmission– Regulating the flow of data– Checking for transmission errors– Acknowledging receipt of transmitted data

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Communications Protocols

• A packet is a “parcel” of data that is sent across a computer network– Circuit-switching technology vs. packet

switching technology• Voice over IP (VoIP)

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Section B: Local Area Networks

• LAN Standards

• Ethernet

• Wi-Fi

• HomePNA and HomePLC Networks

• Installing a LAN

• Using a LAN

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LAN Standards

• LAN Technologies are standardized by the IEEE– ARCnet– Token Ring technology– FDDI– Ethernet– Wi-Fi

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Ethernet

• Simultaneously broadcasts data packets to all network devices– IEEE 802.3– CSMA/CD protocol

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Ethernet

On an Ethernet, data travels on a “first come, first served” basis. If two workstations attempt to send data at the same time, a collision occurs.That data must be resent.

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Ethernet

• Varies in speed from 10 Mbps to 10 Gbps

• An Ethernet card is designed to support the Ethernet protocols

• Ethernet hubs link workstations via cables– Uplink port

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Wi-Fi

• Wireless networking technologies that are compatible with Ethernet

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Wi-Fi

• WEP (Wired Equivalent Privacy) encrypts data traveling over wireless networks

• Equipment required for a wireless network– Wi-Fi card– Wireless access point

• Bluetooth is a short-range wireless network technology

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HomePNA and HomePLC Networks

• HomePNA networks utilize existing telephone wiring to connect network devices– Special NICs and cables are required

• HomePLC networks transmit data over power lines as low-frequency radio waves

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Installing a LAN

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Using a LAN

In this drive mappingexample, a server’s driveC is mapped as drive Fby a workstation.After the mapping is complete,the server’s hard disk appears in the workstation’s directory asdrive F and can be used just as though it were a drive connected directly to the workstation.

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Using a LAN

• You can allow other network users to view and edit files in the folders you’ve designated as shared

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Using a LAN

• The Network Connection tool helps you troubleshoot connection problems

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Section C: Internet Technology

• Background

• Internet Structure

• ISP Infrastructure

• Internet Protocols

• IP Addresses

• Domain Names

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Background

• The Advanced Research Projects Agency designed ARPANET

• The Internet has an estimated 200 million nodes and 500 million users today

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Internet Structure

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Internet Structure

• Ping is used to find out whether a site is up and running

• The Traceroute utility records a packet’s path

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ISP Infrastructure

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Internet Protocols

• TCP and IP serve as the primary protocols responsible for message transmission on the Internet

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IP Addresses

• IP addresses are addresses that identify computers on the Internet– Static IP address– Dynamic IP address

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Domain Names

• Easy-to-remember names for Internet servers– Ends with an extension that indicates its top-

level domain

• Every domain name corresponds to a unique IP address– Domain Name System

• ICANN coordinates technical management of the Internet’s Domain Name System

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Domain Names

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Domain Names

The first step in registeringa domain name is to find out whether the name is currently in use or reserved for futureuse. If a domain name is notavailable, consider using a different top-level domain, such as biz instead of com.After you’ve found an available domain name you like, you can continue the registration process by filling out a simple online form.

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Section D: Internet Access

• Dial-up Connections• Cable Internet Service• DSL, ISDN, and Dedicated Lines• Wireless Internet Services• LAN Internet Access• Mobile Internet Access• Internet Connection Roundup

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Dial-up Connections

• Uses POTS to transport data between your computer and your ISP

• A modem converts digital signals from your computer into analog signals that can travel over telephone lines, and vice versa– Modulation / Demodulation

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Dial-up Connections

• Modems are still required, despite digital telephone technology

• Modem speed is measured as baud rate

• Many Internet connection methods provide faster downstream transmission rates than upstream rates

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Cable Internet Service

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Cable Internet Service

• Cable modems convert your computer’s signal into one that can travel over the CATV network

• Always-on connection

• Neighborhood network

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DSL, ISDN, and Dedicated Lines

• DSL is a high-speed, digital, always-on Internet access technology that runs over standard telephone lines– DSLAM– Most DSL installations require service

technicians• DSL modem

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DSL, ISDN, and Dedicated Lines

• ISDN connections are slower than DSL and cable Internet service, but faster than dial-up– ISDN terminal adapter connects a computer

to a telephone wall jack and converts signals to travel over ISDN connection

• T1, T3, and T4 lines are leased from the telephone company, and offer fast, high-capacity data transmission

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Wireless Internet Service

• Direct satellite service (DSS)

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Wireless Internet Service

• Fixed wireless Internet service broadcasts RF signals in order to offer Internet access to large areas– WiMAX– Wireless service providers are usually local or

regional businesses

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LAN Internet Access

• Cost-effective way to share one Internet connection among several computers

• To establish LAN Internet access, you need:– An operational wired or wireless LAN– A router or a hub with router capabilities– A high-speed Internet connection, such as DSL,

ISDN, or cable Internet– A modem that corresponds to your Internet

connection type

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Mobile Internet Access

• A Wi-Fi hotspot is a wireless broadband Internet service offered in a public location– WISP

• WAP is a communications protocol that provides Internet access from handheld devices

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Mobile Internet Access

• Handheld device services include:– Short message service (SMS)– Multimedia messaging (MMS)– Music fingerprinting– Games– City guides– E-mail– News, sports, stocks, and weather

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Mobile Internet Access

• Cellular service options

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Internet Connection Roundup

CHAPTER 5 COMPLETE

Internet and LAN Technology