MIS lecture 10
Terms
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- network
- consiss of two or more connected computers
- network interface card (NIC)
- each computer on the network contains a NIC
- the connection medium for linking network components can be:
- a telephone wire, coaxial cable, or radio signal in the case of cell phones and wireless local area networks
- network operating system (NOS)
- routes and manages communications on the network and coordinates network resources
- switch or hub
- networks contain a switch or a hub acting as a connection point between the computers
- hub
- hubs are simple devices that connect network components, sending a packet of data to all other connected devices
- switch
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more intelleigence than a hub and can filter and forward data to a specified destination
- used within individual networks - router
- a special communications processor used to route packets of data through different networks, ensuring that the message sent gets to the correct address
- key digitital networking technologies
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client/server computing
packet switching
tcp/ip and connectivity - client/server computing
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A distributed computing model in which much of the processing power is located within small, inexpensive client computers
the powerful clients are linked to one another through a network that is controlled by a network server computer
the server sets the rules of communication for the network and provides every client with an address so others can find it on the network - packet switching
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in packet-switched networks, messages are first broken down into small bundles of data, called packets
these packets are sent along different communication paths and then the packes are reassembled once they reach their destinations
packet switching makes more efficient use of the communications capacity of the network
the packets include information for directing the packet to the right address and for checking transmission errors along with the data - TCP/IP and Connectivity
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TCP/IP is the communications protocol used by the Internet and all Internet devices
TCP/IP provides for breaking up diginital messages into packets, routing them to the proper addresses, and then reassembling them into coherent messages
TCP/IP uses a suite of protocols: TCP and IP - Transmission Control Protocol (TCP)
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handles the movement of data between computers
establishes a connection between the computers, sequences the transfer of packets, and acknowledges the packets are sent - Internet Protocol (IP)
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responsible for the delivery of packets
includes the disassemblingn and reassembling of packets during transmission - Protocol
- a set of rules and procedures governing transmission of information between two points in a network
- The four layers of the TCP/IP reference model for communication
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application
transport
internet
network interface - the different kinds of physical transmission media used by the networks are:
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twisted wire
coaxial cable
fiber opticds and optical networks
wireless transmission - Modem
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stands for modulation/demodulation
a device that translates digital signals from a computer into analog form so that they can be transmitted over analog telephone l ines. the modem also is used to translate analog signals back into digital form for the receiving computer - analog signal
- represented by a continuous waveform that passes through a communications medium and has been used for voice communication
- types of networks
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local area network (LAN)
campus area network (CAN)
metropolitan area network (MAN)
wide area network (WAN) - Three basic network topologies
- Bus , Star, and Ring
- topology
- the way in which components are connected
- Star network
- all devices on the network connect to a single hub
- Bus networks
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one station transmits signals, which travel in both directions along a single transmission segment
- all of the signals are broadcast in both directions to the entire network
- all machines on the network receive the same signals , and software installed on the clients enables each client to listen for messages addressed specifically to it
- most common Ethernet topology - Ring networks
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connects network components in a closed loop
- messages pass from computer to computer in only one direction around the loop, and only one station at a time may transmit - frame relay
- packages data into frames for high speed transmission over reliable circuits that require less error checking than packet switching
- asynchronous transfer mode (ATM)
- parcels data into uniform 53-byte cells for high-speed transmission; can transmit data, video, and audio over the same nework
- integrated services digital network (ISDN)
- dial-up network access standard that can integrate voice, data, and video services
- digital subscriber line (DSL)
- series of technologies for high-capacity transmission over copper wire
- cable modem
- service for high-speed transmission of data over cable TV lines that are shared by many users
- T lines
- dedicated lines for high-speed secure data transmission and internet connection
- three characteristics of the internet
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- a network composed of computers and other devices that are logically linkned together by a unique address space based on the Internet Protocol
- a network where network devices are able to support communications using TCP/IP or other compatible protocols
- a network that provides high-level services layered on a communication and network infrastructure - The Domain Name System
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every device connected to the intenet has a unique 32-bit numeric IP address
- a domain name system (DNS) converts IP addresses to English-like domain names
- the domain name is the name that corresponds to the unique 32-bit numeric IP address for each computer connected to the internet
- DNS servers maintain a database containing IP addressed mapping to their corresponding domain names
- to access a computer on the Internet, users need only specify its domain name - Internet Governance
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no one owns the intenet
there are intnet policies by the following organizations:
- internet architecture board (IAB)
- internet corporation for assigned names and numbers (ICANN)
---moreee - person to person messaging, document sharing
- usenet newsgroups
- discussion groups on electronic bulletin boards
- listservs
- discussion groups using email listservers
- telnet
- logging onto one computer system and doing work on another
- FTP
- transferring files from computer to computer
- world wide web
- retrieving, formatting, and displaying info using hypertext links
- Intranet
- an internal organizational network that provides access to data across a business firm
- extranet
- allow authorized vendors and customers to have limited access to its internal intranet
- groupware
- provides capabilities for supporting enterprise-wide communication and collaborative work
- teamware
- enables companies to implement collaboration applications easily that can be accessed using Web browser software
- electronic conferencing tools
- provides a virtual conference table where participants can view and and modify documents and slides or share their thoughts and comments using chat, audio, or video
- internet telephony
- enable companies to use Internet technology for telephone voice transmission over the Internet or private neworks
- voice over IP (VoIP) technology
- uses internet protocol (IP) to deliver voice information in digital form using packet switching
- unified messaging systems
- combine voice mail, email, and faxes so that they can all be obtained from one system
- virtual private network
- based on the Internet Protocol provides a secure connection between two points across the internet, enabling private communications to travel securely over the public infrastructure