1、Extended Learning Module ENetwork BasicsINTRODUCTIONComputer network two or more computers connected so that they can communicate with each other and share information,software,peripheral devices,and/or processing power 4 Basic Principles of Networks1.Each computer must have a network interface2.The
2、 network usually has at least one connecting device3.The network must have communications media to transport information4.Each computer must have software to move information on the network HOME NETWORKSA typical home network setup has1.An Ethernet network card in each computer or a wireless card in
3、 each laptop2.Network cables to transmit signals,or radio waves for wireless3.A DSL or cable modem connection and a broadband/home router NETWORKS BY DISTANCELocal Area Network(LAN)network that serves a building or buildings in a contiguous area Wide Area Network(WAN)networks serving areas not immed
4、iately contiguousMetropolitan Area Network(MAN)networks within the same city or metropolitan area Broadband Internet ConnectionBroadband high-capacity telecommunications line capable of providing high-speed Internet serviceAll Internet access methods on the previous slide are broadband except the di
5、alup modem Digital Subscriber Line(DSL)Digital Subscriber Line(DSL)high-speed Internet connection using phone lines,which allows you to use your phone for voice communications at the same timeRuns at a higher frequency than voice conversations,so not supported on some older phone lines Cable ModemCa
6、ble modem uses your TV cable to deliver an Internet connectionSatellite ModemSatellite modem delivers Internet access by means of a satellite dishSatellite TV and modem may share same dish or may be separateConnects to computer or broadband router like cable modem NETWORK COMMUNICATIONS MEDIACommuni
7、cations media the paths in a network over which information travelsWired communications media transmit information over a closed,connected pathWireless communications media transmit information through the air Wireless Communications MediaInfrared uses red light to send and receive informationWi-Fi
8、or Wireless Fidelity-a standard for transmitting information in the form of radio waves over distances of about 100 feetWith directional antennas,the distance can be increased to several milesWi-Fi hotspots sites that offer wireless Internet access for your laptop or tablet.NETWORK SECURITYThe four
9、principles of network security are:1.Confidentiality2.Authenticity3.Integrity4.Availability Firewalls&Intrusion Detection SystemsFirewall protects a computer from intrudersIntrusion detection system(IDS)watches for and reports intrusion attempts Intrusion prevention system(IPS)type of IDS that also
10、takes action against intrusion attemptsEncryptionEncryption scrambles data so you cant read it without having the decryption keyVirtual Private Network(VPN)encrypts all network transmissions between two endpoints to protect confidentiality and integrity of data MalwareMalware software designed to harm your computer or security1.Virus software written with malicious intent to cause annoyance or damage2.Worm spreads itself from computer to computer via e-mail and other network traffic3.Spyware collects information about you and reports it to someone else without your permission
