Communications and Networks 1 Communications What are computer

Communications and Networks 1

Communications What are computer communications? Ø Process in which two or more computers or devices transfer data, instructions, and information notebook computers smart phones servers Web-enabled PDAs GPS receivers desktop computers mainframe computers set-top boxes Tablet PCs

Communications What is needed for successful communications? Sending device — initiates instruction to transmit data, instructions, or information Communications device — connects the sending device to the communications channel Communications device — connects the communications channel to the receiving device Communications channel — media on which data, instructions, or information travel Receiving device — accepts transmission of data, instructions, or information

Uses of Computer Communications What are some uses of communications technology? Web Internet Instant Messaging Web Folders Chat Rooms E-Mail Newsgroups Video Conferencing FTP Fax Machine or Computer Fax/Modem

Uses of Computer Communications What are Internet telephony and Internet printing? Internet telephony enables you to talk to other people over the Internet Sometimes called Voice over IP Internet printing allows you to print to network printer from anywhere in the world

Uses of Computer Communications What are Web services? Ø Software that enables programmers to create applications that communicate with other remote computers

Uses of Computer Communications What are collaboration and groupware? Ø Collaboration is working with other users connected to a server § Ø Microsoft’s Net. Meeting allows collaboration Groupware is software that allows people to share information

Uses of Computer Communications What are public Internet access points and cybercafés? Ø Ø Public Internet access point allows wireless connection to Internet in public location Cybercafé is coffee house that provides computers with Internet access

Networks What is a network? Ø Collection of computers and devices connected via communications devices and transmission media

Networks What is a local area network (LAN)? Ø Network in limited geographical area such as home or office building § Metropolitan area network (MAN) connects LANs in city or town

Networks What is a wide area network (WAN)? Ø Ø Network that covers large geographic area using many types of media Internet is world’s largest WAN

Networks What is a client/server network? Ø One or more computers act as server and other computers, or clients, access server

Networks What is a peer-to-peer network? Ø Ø Simple network that connects fewer than 10 computers Each computer, or peer, has equal capabilities

Networks What is Internet peer-to-peer (P 2 P)? Ø Enables users to connect to each other’s hard disks and exchange files directly

Networks What is a bus network? Ø Ø All computers and devices connect to central cable, or bus Example of network topology (layout of devices in network) § Popular topologies are bus, ring, and star

Networks What is a ring network? Ø Ø Cable forms closed ring, or loop, with all computers and devices arranged along ring Data travels from device to device around entire ring, in one direction

Networks What is a star network? Ø Ø All devices connect to a central device, called hub All data transferred from one computer to another passes through hub

Networks What are Ethernet and token ring? Ethernet technology allows computers to contend for access to network § If two computers send data at same time, a collision occurs and computers must send again Token ring technology controls access to network by requiring devices to pass a special signal, called token

Networks What are TCP/IP and 802. 11? Ø TCP/IP (Transmission Control Protocol/Internet Protocol) technology transmits data by breaking it up into small pieces, or packets § Ø Commonly used for Internet transmissions 802. 11 is family of standards for wireless LANs

Networks What is Bluetooth? Ø Short-range radio waves transmit data between Bluetooth devices

Networks What are Ir. DA, RFID, and Wireless Applications Protocol (WAP)? Radio Frequency Identification (RFID) Ir. DA specification allows data to be transferred wirelessly via infrared light waves uses radio signals to communicate with a tag placed in an object Wireless Applications Protocol (WAP) allow wireless mobile devices to access Internet

Networks What is an intranet? Internal network that uses Internet technologies Makes information accessible to employees Typically includes connection to Internet Extranet allows customers or suppliers to access part of company’s intranet