Assignment 1 Solution
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Getting a packet from the source to destination through several connected networks is known as
routing.
- Simple parity checking can NOT detect
- an odd number of errors.
- an even number of errors.
- more than one error.
- any errors.
- Which is true about synchronous and asynchronous connections?
- Asynchronous transmissions are generally used for large amounts of
data.
- Asynchronous transmissions are often combined with a clock signal.
- Synchronous transmissions require synchronisation bits at the end.
- Synchronous transmissions have a larger overhead than asynchronous
transmissions.
- What will happen if a receiver confirms receipt of a message but the
confirmation is lost before it reaches the sender?
- ACK
- NAK
- ready
- resend
- timeout
- Which type of serial connection will generally have the highest
performance?
- simplex
- half-duplex
- full-duplex
- multiplex
- A parallel cable must be short because over a long distance the signals on
the wires can become out of sync. This is known as skew.
- A modem converts from digital to analog signals
when sending data from a computer to an older telephone line. [2]
- Which type of multiplexing uses a round robin scheme?
- Time division multiplexing
- Frequency division multiplexing
- Statistical multiplexing
- Which of the following would NOT generally improve data
transmission on cables?
- Using shorter cables
- Using shielding or insulation
- Using a medium with low electrical resistance
- Decreasing the number of cable twists per metre
- Which category of UTP cable can be used for both Ethernet and Fast
Ethernet? category 5
- Which type of connector is most commonly used for LANs?
- D
- BNC
- RJ-11
- RJ-45
- How many pairs of wires are in most UTP cables used today? four
- What is the most important difference between the Internet and an
Intranet?
- the number of users who have access
- the geographical distances covered
- the network protocols used
- the network software used
- Which is NOT an advantage of client-server networks over
peer-to-peer networks?
- centralised administration
- initial investment
- performance
- strong user-based security
- Which of these peripherals is NOT generally shared on the network?
- printer
- hard disk
- modem
- monitor
- Which workstation operating system has built-in network server
capabilities?
- Windows for Workgroups 3.11
- Windows NT Workstation
- Windows 2000 Professional
- Linux
- The way that two different devices are connected is the
- interface
- medium
- protocol
- topology
- A signal transmitting at 2.5 MHz can encode 8 bits per cycle. What is the
bandwidth of the signal?
20 Mbits/sec
- Which type of network topology requires the least amount of cable?
- bus
- mesh
- ring
- star
- Which type of server lists many types of resources available on the
network?
- file
- directory
- print
- mail
- Which is NOT generally a result of installing a network?
- increased peripheral cost
- need for administrator
- organisational changes
- security holes to plug
- What type of device is used to lengthen a LAN size by strengthening the
signal?
- bridge
- gateway
- repeater
- router
- In order to make content available on the Internet you need to use a
- web browser
- web client
- web page
- web server
- Which of the following can NOT get you connected to the Internet?
- an Internet café
- an Internet or online service provider
- an isolated local area network
- a standalone computer with a modem
- A disadvantage of protocols is that they tend to limit
- communication
- innovation
- interconnection
- standardisation
- Which type of network was NOT originally standardised by the IEEE
802 committee because of speed?
- FDDI
- MAN
- token bus
- token ring
- wireless
- Which OSI layer is primarily responsible for the following tasks?
- application: displaying a retrieved web page in a web browser
- network: getting a message from the sender's LAN to the receiver's LAN
- data link: retransmitting after detecting a collision on a LAN
- data link: passing a token to the next workstation
- transport: the sender breaking a long message into pieces
- transport: the receiver reassembling the pieces in the right order
- physical: specifying the number and voltage of pins for a cable connector
- application: software to read USENET newsgroups
- physical: translating between bits of information and electronic signals
- application: displaying the user's original message, exactly as it was sent
- Which will most reduce the quality of analog data to be sent on a network?
- long sampling period
- many bits per sample
- mpeg compression
- non-linear digitising
- Which type of modulation is likely to be most adversely affected by
resistance during transmission over long distances?
- amplitude
- frequency
- phase
- Which type of noise is likely to be a problem on a LAN with thick co-axial
cable and properly functioning terminators?
- impulse noise
- cross-talk
- echo
- white noise
- What percent overhead would be used to perform both vertical and
longitudinal redundancy checks on just two bytes of data? [2]
(8 bits + 2 bits) / (8 bits + 2 bits + 16 bits) = 10/26 = 38.5%
- Which type of error correction is most commonly used at the end of message
packets in popular OSI model compliant network protocols?
- vertical redundancy check
- longitudinal redundancy check
- cyclical redundancy check
- checksum
- Which is NOT a reason why forward error correction is rarely used
in data communication and networking?
- Few forward error correction algorithms have been invented
- Sending the data to reconstruct the message would be a large overhead
- The amount of processing required to reconstruct the message would be
large
- The error correction data could itself be damaged
- It is faster and easier to just resend the data
- Which is NOT a general characteristic of connectionless protocols?
- Used for high data rates
- High error rates are common
- Performed at lower OSI levels
- Used in LANs
- How are the RTS and CTS pins of a V.24 modem interface commonly used?
- transmitting data
- flow control
- error checking
- unused
- Which indicator light on an external modem would tell you that your
dial-up connection has succeeded?
- DSR
- Ground
- CD
- DTR
- The letter A is represented the same in ASCII and EBCDIC except for the
- least significant bit
- most significant bit
- parity bit
- start bit
- The purpose of a preamble is
- to delimit the start of the data
- to make the packet meet the minimum length requirement
- to provide synchronisation
- to provide error checking
- The purpose of bit stuffing in HDLC synchronisation is
- to detect errors in the data
- to distinguish the data from the start and end of the message
- to make the message have the required length
- to make start and stop flags composed of long strings of 1s or 0s