Types and Methods Flashcards
what is data transmission?
centre of all digital communication
why is breaking down data into chunks necessary?
allows data to be transmitted faster from the sender to the reciever
what is a data packet
small unit of data that can be transmitted from sender to receiver through a network communication protocol
what is the structure of a packet
header, payload, trailer
what does the header do and what does it contain
information is used by routers to determine source and destination of packet. Contains: sender’s IP address, reciever’s IP address, packet number
what does the header do and what does it contain
information is used by routers to determine source and destination of packet. Contains: sender’s IP address, reciever’s IP address, packet number
what does the payload do and what does it contain
carries the actual data. contains: data/part of message
what does the trailer do and what does it contain
tells receiver that the end of the packet has been reached. contains: bits to shows end of packet
advantages of packet switching
take different routes, transmission errors can be detected
disadvantages of packet switching
packets may be dropped if they reach their TTL
what factors determine which method is best for transmitting each piece of data
number of bits, number of wires, direction of data
what is serial transmission
one single wire is used to connect, bits are transmitted one at a time
advantages of serial
more reliable over long distance. bits arrive in order so wont be mixed up, chances of bits being lost is slim
what is parallel transmission
multiple wires are used to connect the sending device and the receiving device, several bits sent at a time
advantages of parallel
faster than serial
disadvantages of parallel
bits may arrive out of order, expensive method to implement over longer distance because it requires multiple wires
disadvantages of series
slow
What does USB stand for
universal serial bus
what type of transmission does USB use
serial
devices that use USB cables to transfer data
digital cameras, keyboards and printers, and most external storage devices
why is USBC better than USB
because data is transferred in both direction instead of one
what is USB
communication interface that has become a standard for connecting devices to their parent or host controllers
advantages of USB
it is universal, transfer power too,
disadvantages of USB
multiple different cables
What method does USB implement
asynchronous
how many pins is the USB composed of
4 (two for connecting wires that transmit data and two for connecting wires that carry the power
step by step of connecting USB to computer
device is detected due to change in voltage lines, speed type and configuration are determined, computer loads driver, computer prompts user to install driver if not already available
benefits of USB
- once plugged in, device drivers install automatically (sell configuration)
- connectors can only be connected in one way which ensure user connects it in the right manner (avoid damage)
- transmission rates are supported
- newer USB connectors are compatible with older USB standards
methods for error checking
automatic repeat request (ARQ), echo check
how does ARQ wrok
acknowledgment detects whether transmission is correct or not. If not data is resent until time out is reached
what is acknowledgment
message sent by receiver to sender indicating data has come through. A positive acknowledgement suggests that transmission was completed without error, while a negative acknowledgement indicates that transmission had some errors
timeout
time allowed to elapse
how does echo check work
data sent from sender to reciever and data received is sent back to sender. compares sets for transmission
error free transmition includes
direction, method of transmition, method of syncropnization
direction can be
simplex, half duplex or full duplex
transmission can be
series or parallel
synchronization can be
synchronous or asynchronous
what is simplex
one sending to another, onedirection
what is half duplax
two diretion but only one at a time
what is full duplex
two direction at the same time
synchronous transmission
a continuous and consistent timed transfer of data blocks. These types of connections are used when large amounts of data must be transferred very quickly from one location to the other.
asynchronous transmission
the transmission of data in which each character is a self-contained unit with its own start and stop bits and an uneven interval between them. Asynchronous transmission is also referred to as start/stop transmission
example of simplex
keyboard, monitor
example of half duplex
walkie talkie
example of full duplex
telephone
