2.1 types and methods of Data transmission

Why are data packets used?

Faster to route

Packet switching stages

1. Data is broken down into packets 2. Packets are assigned a header 3. Each packet makes its way to the destination 4. Routers control the route for each packet 5. Packets arrive and are reordered accordingly

Full duplex

Data can travel in both directions

USB is serial or parallel?

Serial

Advantages of packet switching

Minimal interference and corruption as individual packets can be resent if lost or damaged

Saves time and bandwidth as whole file doesn't have to be resent in case of corruption

Quicker as each packet finds the fastest way around the network

Harder to hack as each packet travels across the network separately with minimal data

USB drawbacks

Only around 5 meters cable length

Older USB have limited transfer rates

Very old USB may not be supported in the future

USB benefits

Devices are automatically detected and drivers are automatically loaded for communication

Cable connectors fit only one way, preventing incorrect connection ensuring compatible data transmission

USB usage is standardized, a lot of support from online and retailers

High speed transmission

USB

Widely used standard for data transmission

Trailer contains

Additional security information

End of packet notification

What are the three main components of a packet?

Header, payload, and trailer

Data transmission

The process of sending data from one device to the other both with wires and wirelessly

Disadvantages of Parallel: Skew

Skew is the difference in arrival times of parallel data bits, causing timing misalignment

Disadvantages of Parallel: Crosstalk

Crosstalk is the unwanted coupling of a signal from one transmission line into another, causing interference and signal degradation

Examples of full Duplex

Local and wide area networks

Advantages of Half Duplex

Cheaper than full duplex for 2 way communication

Disadvantages of Parallel

Skew (difference in arrival times of parallel data bits, causing timing misalignment)

Crosstalk (unwanted coupling of a signal from one line to another, causing interference)

Expensive

Bandwidth

Maximum data which can be sent over a network connection over a period of time

Header contains

Source IP address

Destination IP address

Packet number

What does TCP stand for?

Transmission Control Protocol

Examples of Simplex

From computer to monitor

Wired data transmission

Serial (stream of bits sent along a single wire)

Parallel (multiple bits sent simultaneously, each in its own wire)

Payload contains

The actual data being transferred

Advantages of Simplex

Low cost

More simple

Example of serial transmission

USB

Examples of parallel transmission

Traditional printer cable

Examples of Half duplex

Printer cable which waits for data to be received before sending low ink message

Corruption

Data is changed or lost in some way, or data is gained that originally was not in the packet

Simplex

Data travels in one direction

Advantages of Full Duplex

Faster, 2 way simultaneous data transmission

What are packets?

Small chunks of data that make up a larger piece of data that has been broken down by the TCP protocol so that it can be transmitted over the internet

Wired data transmission: Serial

Stream of bits is sent along a single wire

Half Duplex

Data can travel in both directions, but only one at a time

Wired data transmission: Parallel

Multiple bits sent simultaneously, each in its own wire

Routing

Finding the most optimal path over a network

Advantages of Serial

Reliable over long distances

Cheaper

Less interference

Packet switching

The process in which data is broken down into packets and sent across the internet

Examples of USB usages

Keyboards

Mice

Mobiles