Computer Science Ch. 7
Terms
undefined, object
copy deck
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"switched, dial-up" means . . .
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when you dial a telephone number, a circuit is temporarily established between the caller and callee
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dedicated point-to-point lines
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directly connect two machines without the use of of shared channels found on a LAN
- hub
- has a number of ports, with a wire leading from each port to an ethernet interface in the wall of a room in the building
- packet
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an information block with a fixed maximum size that is transmitted through the network as a single unit
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shared cable
- a wire is literally strung around and through a building
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star network
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has a single central node that is connected to all other sites, and it can route information directly to any other node in the LAN
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wireless local access network
- user transmits data to base station, base station connects to wired network such as dsl, cable modem
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wireless wide-area access network
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computer transmits messages to remote base station, which is usually a large antenna placed on top of a tower or building
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A bridge, also called a switch, is a . . .
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"smarter" version of a repeater that has knowledge about the nodes located on each separate network.
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A repeater is a device that . . .
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amplifies and forwards a signal.
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A digital subscriber line's wires are . . .
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the same as your home telephone wires.
- a modem modulates or alters . . .
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a standard analog signal called a carrier so that it encodes binary information
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A regional or national ISP might connect to . . .
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an international ISP, which provides global coverage.
- A user taps into a shared cable at it's nearest point, using a device called a ___________.
- transceiver
- A user's individual computer or a company's private network is connected to the world through . . .
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an Internet Service Provider, or ISP.
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an analog medium . . .
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the physical quantity used to represent information, usually voltage level, is continuous and can take on any value
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digital information is . . .
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a sequence of 0s and 1s
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Gigabit networking:
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transmission lines that support speeds in excess of 1 billion bits per second.
- If a DSL is assymetric, it means that . . .
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it does not have the same transmission speed in the download direction as in the upload direction.
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In a WAN, a message must . . .
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"hop" from one node to another to make its way from source to destination.
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In the bus topology,
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all nodes are connected to a single shared communication line.
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In the commercial and office environment, the most widely used broadband technology is . . .
- the Ethernet.
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In the ring topology,
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the network nodes are connected in a cirucular fashion, with messages ciruclating around the ring in either a clockwise or counterclockwise direction until they reach their destination.
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Individual networks are connected through a ______.
- router
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It is the job of the data link protocols to . . .
- determine the beginning and end of each message contained within a continuous raw data stream.
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It is the job of the network layer protocols to . . .
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deliver a message from the site where it was created to its ultimate destination.
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It is the job of the transport layer protocols to . . .
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assign port numbers to programs and remember which program goes with which port. It is also designed to eliminate errors in the data.
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The application layer protocols are . . .
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the rules for implementing the end-user services provided by a network, and they are built on top of the four protocol layers.
- The physical layer protocols govern . . .
- the exchange of binary digits across a physical communication channel.
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The ability to deliver data to users regardless of their location is called ___.
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mobile computing
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The concept of internetworking stated . . .
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that any WAN is free to do whatever it wants internally.
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The Ethernet uses ___ topology.
- bus
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The first level of hierarchy in the structure of an ISP:
- the local ISP, which individual users or company networks connect to.
- the high error rate and low capacity of a switched telephone line is called ___
- bandwidth
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The individual computers on the network are referred to as . . .
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nodes, hosts, or end systems
- The local ISP connects to . . .
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a regional or national ISP that interconnects all local ISPs in a single geographic region or country.
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The term broadband generally refers to . . .
- any communication link with a transmission rate exceeding 256,000 bps.
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The two main broadband options are . . .
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digital subscriber lines (DSL) and cable modems.
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The unit of transmission in a WAN is a ______.
- packet
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To connect to a network with a hub . . .
- a port is activated by flipping a switch and users can then simply plug their computers in to the wall socket.
- when a modem performs a demodulation, it . . .
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takes the received waveform, separates the carrier from the encoded digital signal, and passes the digital data on to the computer
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Wireless transmitters must be placed on top of hills or tall buildings because of . . .
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the curvature of the earth.