Chapter 7 – Computer

-links 2 or more computer systems to enable them to share data and resources-categories of computer networks (by geography) - LAN, WAN

-Local Area Network-uses cables, radio waves, infrared signals-Links computers in a limited geographic area (i.e.

office, home, campus, building) -Typically managed by a single person or organization-Can be wired or wireless

-Wide Area Network-Uses long-distance transmission media, including satellites and leased lines-Links computer systems (thousands of) miles apart-Usually not owned by a single organization-Internet is the world's largest WAN

-Metropolitan Area Network -cover a city or town -usually owned by a government or other organization (Wi-Fi Downtown Pittsburgh)

-Personal Area Network -composed of an individual's own personal devices (bluetooth headset, smartphone, printer)

-convert data into digital signals to transmit: modems, routers, Switches & Hubs, wireless access points, network interface cards (NICs)

-formats digital data to go over phone, cable, satellite, or cellular connections-Modulates signal, demodulates at other end-Uses modulation protocol

standard for how data is to be transmitted over that medium

Protocols define: data transfer rate, datacompression, error checking, and other details

-An expansion board or adapter that provides a connection between the computer and network-Electronics required to connect to a network-Wired or wireless-Can be USB, card, or built-in

-Receives and transmits radio signals-Joins wireless devices within a network (shop for "wireless access point", "wireless adapter") -communications heart --> access point

-Connect 2 or more networks-Complex; determine best route to transmit data to its destination-traffic cop -good for home network

-Connects devices within a single network-Hub is inexpensive, simpler than a switch

-High-speed computer that provides /manages network resources, (e.g.: Shared file space, communications/Internet access, security, authentication of users) -Uses a network operating system (like our Fedora LINUX server)-Also: Web servers, mail servers, media servers on Internet

-network composed of 2 types of devices clients and servers -Server provides data and resources to low-end client devices (most networks) -Relatively complex: ex: file server, print server, etc.

use network resources; relatively low speed

provide network resources

-All computers in the network are "equals"; NO central file server -Devices are "peers"-Each computer provides file services to others-P2P file-sharing sites on Internet (piratebay, frostwire, kazaa ..

.)-Easy to set up; not very efficient-No central "server"-Privacy and Security issues big concern: (viruses and malicious programs can easily be transferred)

-Reduced hardware costs-Sharing of resources-Sharing of information-Centralized data management / security-Easy to connect with others

-Loss of autonomy/control-Reduced privacy-Security threats-Loss of productivity

-Protocols are standards used by networks to permit communications-Network protocols define the technology used in the network (communication rules)

-most popular LAN protocol-For wired LANs-Uses inexpensive common wiring and switches

=most popular wireless LAN protocol-Uses radio waves through a central access point / router-Connects devices to the access point; does NOT connect devices directly to Internet-Router needed to connect to Internet

-Ethernet = WIRED technology (used by 85% of all networks)-Used in our lab, in DUQ Living Learning Centers-Inexpensive to superfast networks (Protocol/speeds: 100base-T, gigabit Ethernet, etc.)

-wireless LAN for devices in a limited area-Needs a central Access Point-802.11 is the tech standard-Up to ~300 feet-Prone to interference - from buildings, cell phones, etc.*Security issue - anyone can pick up radio signals

-Many networks combine wireless and wired protocols (similar to DUQ net) *NOTE roles of router, modem, access point --> KNOW THE DIAGRAM ON POWERPOINT

*depends on standard of Wi-Fi and the standard of internet -depends on too many factors, not simple

-latest standard -3 times the speed of 802.

11n~1.35 Gbps

- using Ethernet and simple twisted pair wires- RJ-45 connectors -Fast, efficient-Good for gaming and transferring large files-Speed depends upon devices, protocol setup, wiring

- using Wi-Fi and Wireless Access Point and wireless LAN cards

-Shared Internet connection-Share data (photos, music, games, etc.)-Share devices (printers, scanners...

)-Can be basis of home entertainment system

-Use Hub, Switch or Router-Advantages / Disadvantages?-Hub or Switch - can connect within 1 LAN -Router - can join 2 LANs (WiFi, Internet)

-Note positions of devices-Must run cables throughout house -Fast for multimedia -Each device needs a NIC

-WiFi - uses 802.11-Requires:-Wireless Access Point-Wireless adapter in each workstation-Using same 802.11x standard; if not the same, lowest standard applies

-WiFi - any wireless LAN that follows 802.11 standards-Last letter is important!-802.

11a, b, g, n, ac (Later letters offer faster speeds)

-802.11ac is latest standard (NOTE: 802.11ad just announced)-3X faster than 802.11n-For HD and multimedia

*Note devices-No need for cables -Can be MAC or PC-All same 802.

11x-Need router to join WiFi to Internet-Router acts as access point-Must set up security

-Faster/Not as fast -More secure/less secure (needs security set-up) -Simple to set up/no wires to run -Requires cabling/wires throughout home//flexiblility, mobility (limited range and subject to interference) -Equipment is less expensive

1.Determine your needs; most home networks will be peer to peer2.Select network technology Wired/Wi-Fi/hybrid? Which protocols (speed?)3.

Research and purchase networking hardware Do existing devices support selected standard? Purchase router, switch, modem, adapters...4.

Configure the network (Arrange the devices)

1. run wiring2. plug shared devices (including modem) into router3. Use Operating System settings to set up network on each PC

1. locate router/access point so devices can communicate (avoid interference)2. Setup router: password, SSID, security3.

Connect router to modem; connect wired devices like printers, scanners4. Use Op System settings to set up network on each PC/device

-SSID - WiFi network's name; use obscure name-Use passwords on home WiFi networks-Use security protocols-Allow only authorized devices to access-At a "hotspot" & in public:-Don't transmit confidential data-Someone may be intercepting-Turn off WiFi access when not in use

Trouble-shooting hints from page 336:-Blow lint and dust off router, adapter, modem-Shut Down & Restart the router (wait 10 seconds)-Unplug router from power source-Unplug and plug back in peripheral devices (start with modem)

-Most likely will be WIRELESS-Will integrate OTHER devices (not just computers):-Home entertainment systems -Security systems / doors and access-Lighting / temperature controls-Household appliances-Personal health monitors-Will demand faster Internet connections!