The flashcards below were created by user
anb110
on FreezingBlue Flashcards.
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half duplex connection
transmits data in both directions, but in only one direction at a time
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full duplex connection
transmits data in both directions and at the same time
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DTE (Data Terminal Equipment)
the device, such as a workstation or a terminal, that connects to a DCE.
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DCE (Data Communications Equiment)
the device, such as a modem, that terminates a data transmission line (circuit terminating device)
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bus
a high-speed connection to which multiple devices can attach
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2 Data Connections that Firewire supports
- -Asynchronous
- connection
- -Isochronous
- connection
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Is Firewire hot pluggable?
yes
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SCSI (Small Computer System Interface)
specially designed interface that allows for a very high speed transfer of data between the disk drive and the computer (disk drives, tape drives, CDs, DVDs, [more permanent nature])
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How many devices can you connect to one SCSI adapter?
7
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InfiniBand
serial connection or bus that can carry multiple channels of data at the same time; network of high-speed links and switches
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How many devices can an InfiniBand handle?
thousands
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How many devices can Fibre channel support?
126
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Where are start bits added?
start bits added to signal the beginning of the frame (0)
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Where are stop bits added?
stop bits added to the signal at the end of a frame (1)
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synchronous connection
the unit of transmission is a sequence of characters ; technique for maintaining synchronization between a receiver and the incoming data stream
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What is a point-to-point connection?
direction connection between a terminal and a mainframe computer; single wire runs between the two devices and no other terminals or computers share this connection
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Does a point-to-point connection require polling?
no
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de facto standard
a standard that has not been approved by a standards-making organization but has become a standard through wides-spread use
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Is asynchronous connection most complex example of a data link protocol?
no
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Is a start bit always 1?
no
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flags
start and end sequences typically 8 bits in length
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Real time application examples
streaming voice, video, music
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A medium can be divided in what 3 ways?
- Frequency
- division multiplexing
- Time
- division multiplexing
- Code
- division multiplexing
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FDM (Frequency division multiplexing)
one of the simplest, assignemnt of nonoverlapping frequency ranges to each "user" of a medium
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How does FDM work?
a channel is assigned to each user, and a tuner separates one channel from the next and presents each as an individual data stream to you, the viewer
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What does FDM assign each user?
a separate channel
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What is a demultiplexor?
a multiplexor that un-multiplexes the data stream and delivers the individual streams to the appropriate devices
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Which two multiplexing techniques use guard bands and therefore waste unused transmission space?
FDM,
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2 types of TDM
STDM (Synchronous time division multiplexing), STDM (statistical time division mulitplexing)
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How does Synchronous TDM work?
- accepts input from a fixed number of devices and transmits their data in an unending
- repetitious pattern
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When was T-1 service created? What was its original purpose?
1960's to provide a high-speed connection between AT&T's switching centers
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Who developed SONET in the US?
ANSI
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Which multiplexing technique supports SONET?
synchronous
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How does WDM work?
- involves fiber-optic systems and the transfer of multiple streams of data over a single
- fiber using multiple, colored laser transmitters
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What medium does WDM multiplex on?
single fiber-optic line
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Does WDM support multiple concurrent signals?
yes
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When is statistical TDM a good choice?
when trying to save space
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At what layer of TCP/IP is multiplexing done?
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How many users does TDM allow to transmit at a time?
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How many channels does TDM send over one line?
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Discrete multitone is found in what systems?
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Code division multiplexing is based on what?
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Is noise a problem with both analog and digital signals?
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White noise also called what?
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How can white noise be prvented for both analog and digital signals?
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Is white noise dependent on the temperature of the medium?
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Impulse noise is known as what?
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Is crosstalk a problem with fiber optic cable?
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How can crosstalk be prevented?
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Why are echo suppressors used?
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At what OSI layers is error detection done?
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Parity checks are used with what types of connections?
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Cyclic checksum is also known as what?
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LRC is also known as what?
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CRC treats each data packet as what?
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What is frame relay used for?
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Which medium is least prone to generating errors?
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What is the most common form of error control?
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Which protocol is stop-and-wait technique used with?
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What is sliding windows function?
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Window size of 7 would allow how many data packets at a time?
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What is forward error correction?
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Is attenuation a form of error?
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