Ch3 - Communication Systems Flashcards

1
Q

What are the 5 components of a communication system?

A
  1. Data source
  2. Transmitter
  3. Transmission medium
  4. Receiver
  5. Destination
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2
Q

What is a protocol?

A

A set of rules that govern the transfer of data between computers.

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3
Q

What is handshaking?

A

A discussion between two computers prior to communication to establish the protocol and settings to use for the communication.

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4
Q

What are the two methods of handshaking?

A
  1. Hardware flow control

2. Software flow control

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5
Q

What are the three levels of the Communication System Framework

A
  1. Application
  2. Communication Control and Addressing
  3. Transmission
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6
Q

What are the 5 layers of the TCP model?

A
  1. Application
  2. Transport
  3. Internet
  4. Data link
  5. Physical
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7
Q

What are the 7 layers of the OSI model?

A
  1. Application
  2. Presentation
  3. Session
  4. Transport
  5. Network
  6. Data link
    7, Physical
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8
Q

What is bandwidth?

A

The capacity of a channel or transmission medium.

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9
Q

What is the difference between Bits per second and Baud rate?

A

Bits per second is how many bits are transferred in a second whilst baud is how many symbols that can be transmitted in one second.

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10
Q

What are the three types of error checking studied?

A
  1. Parity
  2. Checksum
  3. Cyclic Redundancy Check ( CRC )
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11
Q

What are the two types of Parity checking?

A

Even and Odd

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12
Q

How does parity checking work?

A

A bit is added to the end of the message to make the total number of ‘1’s either even or odd in number.

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13
Q

What does EFTPOS stand for?

A

Electronic Funds Transfer at Point of Sale

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14
Q

What is Parallel transmission?

A

When data is transferred over multiple lines on the transmission medium simultaneously.

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15
Q

What is Serial transmission?

A

When data is transferred over a single line with all the bits transferred one after the other.

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16
Q

What is Asynchronous transmission?

A

Timing is not involved and start and stop bits are used to indicate when messages are being sent.

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17
Q

What is Synchronous transmission?

A

The sending of data is timed and synchronised to a clock. Start and stop bits are not required.

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18
Q

What is simplex?

A

When data may only be transferred in one direction over the medium.

19
Q

What is half-duplex?

A

When data may be transferred in both directions over the medium but only in one direction at a time.

20
Q

What is full-duplex?

A

When data may be transferred in both directions over the medium at the same time.

21
Q

List some common Applcation level protocols

A
  • HTTP
  • SMTP
  • SSL
22
Q

List some common Communication control and Addressing level protocols

A
  • TCP

- IP

23
Q

List some common Transmission level protocols

A
  • Ethernet

- Token ring

24
Q

What are three methods of error detection?

A
  • Parity
  • Checksum
  • Cyclic Redundancy Check ( CRC )
25
Q

How does parity work?

A

Parity is either even or odd and is achieved by adding a final bit to make the number of ‘1’s either even or odd.

26
Q

What is a LAN?

A

Local Area Network. A network with computers connected over a small geographic area.

27
Q

What is a WAN?

A

Wide Area Network. A network with computers connected over a large geographic area.

28
Q

What is packet switching?

A

A technique that divides messages into small data packets such that multiple paths may be used to transfer the data between the source and destination.

29
Q

What are the three main network topologies?

A
  • Bus
  • Ring
  • Star
30
Q

Describe a Bus network topology.

A

This is where every device connects to a common medium. Everyone shares the common medium to communicating.

31
Q

Describe a Star network topology.

A

This is where the devices all connect back to a single point which manages and directs all messages.

32
Q

Describe a Ring network topology.

A

All the computers are connected in a ring. Each device has two connections. Messages are passed around the network, one machine to another.

33
Q

What is a Network Interface Card?

A

NIC for short, it is the hardware that allows a computer or other device to connect to the transmission medium in order to send and receive messages.

34
Q

What type of servers exist on a network?

A
  • File server
  • Print server
  • Mail server
  • Web server
35
Q

What is a Router?

A

A device that connects two or more networks (that may be of different type. It is able to work out the path from a Sender to a Reciever on networks not directly connected to it to route packets to the intended destination.

36
Q

What is a Switch?

A

A device that directs data packets within a LAN. It knows which devices are directly connected to it by MAC address and sometimes by IP address.

37
Q

What is a Bridge?

A

A device that is able to connect two networks that are of the same type.

38
Q

What is a Gateway?

A

A device which can link two networks of different types.

39
Q

What is a Repeater?

A

A device which allows a connected to be extended by amplifying and resending the signal.

40
Q

What is a hub?

A

Similar to a switch but is not aware of the devices connected to it and just broadcasts all messages to every connected device. Largely been replaced with Switches.

41
Q

List the common wired transmission media

A
  • Twisted pair
  • Coaxial cable
  • Fibre optic cable
42
Q

Describe twisted pair

A

Pairs of wires are twisted around each other to shield and protect the signal. This is the most common LAN transmission medium with CAT 5 / 6 cables.

43
Q

Describe Coaxial cable

A

A single copper wire surrounded by an insulator, shielding and an outer insulator.

44
Q

Describe fibre optic cable

A

A very thin glass (or plastic) fibre is surrounded by cladding and an outer covering. Lasers are used to send light beams along the cable which is then read a the other end. Extremely fast but easily damaged if care is not taken.