1.3 Data Transmission Flashcards
Three parts of a packet
Header, message, Footer
Bit
Is the smallest unit of data that a computer can process and store. 1 binary digit long
How many physical states does a bit have?
2
Byte
Is a unit of data that is eight binary digits long
How many physical states does a byte have?
256
Serial transmission
Is the process of sending one bit of data after another.
Parallel transmission
Is the process of sending multiple bits of data at the same time.
What are the three main duplex modes?
Simplex, Half-Duplex, full Duplex
Full duplex
Data can travel in both directions at the same time
Half-Duplex
Data can travel in both directions but only one at a time
Simplex
Data can only travel in one direction
Multiplexing
Several independent data sources are combined and sent along a single route to a single destination
Circuit switching
In circuit switching a path across a network is setup in advance and all packets are sent down the same route in order. The route cannot be used by any other traffic during that time.
Disadvantages of Circuit switching
If a link fails the whole circuit will also fail.
After a link fails a new route will need to be planned.
Advantages of circuit switching
There is no delay in receiving data.
All data received is already whole and in order.
Once a secure connection is made data is transferred at a constant rate
Packet switching
Allows packets to take independent routes through the network, each packet decides on it own route, which is decided depending on which lines are available and how heavy the current load is.
Disadvantages of Packet switching
Packets may not arrive in order, requiring more processing.
Not ideal for applications that require constant use, such as phone calls.
High volume networks can lose data packets during high traffic times.
Advantages of Packet switching
More efficient than Circuit switching.
Does not require the use of a dedicated channel.
Reduces lost data packets because packet switching allows for resending of individual packets.
What are the two different types of data contained within a packet?
Control information and Actual data
What control information in a packet contains?
Source and Destination Addresses, Order Number of Packet, Control Signals, Error Control Bits.
Where is Control information found?
Header and Footer
Network Collisions
Is the detection of two sets of data simultaneously, the two sets of data are discarded once the collision is detected. The computers then wait a short, random, time before sending the discarded packets again.
Routing
The determination of the route data packet will take ensuring that the packets are delivered as quickly as possible.
What does an IP packet contain both of?
A Header and Data
What are the five parts of a TCP/IP Packet?
Sender IP Address, Receiver IP Address, Check Sum, Packet Number, Packet Content
Sender IP Address
Is the IP Address of the computer or device sending the data packet.
Receiver IP Address
Is the IP Address of the computer or device receiving the data packet.
Check Sum
Is a a value that represents the number of bits in a transmission message, it is used to determine the integrity of the message (If the message is whole).
What are the two different Packet Numbers?
- Indicates how many packets a piece of information was split into.
- Indicates the place of the individual packet as a part of the complete information.
Packet Content
This is the Content of the packet.
