11 Data Transmission

Data Transmission

The process of sending and receiving data across a network.

The Internet

Global network of interconnected computers.

Infrastructure

Underlying physical and virtual systems that enable connectivity, transmission and communication.

Network Devices

Essential hardware components to manage data flow.

Protocols and standards

Rules and conventions that govern how data is transmitted.

Wireless systems

Cellular networks and Wi-Fi that allow for mobile and local access.

Internet Exchange Points (IXPs)

Locations where different networks connect and exchange traffic improving efficiency and connectivity.

HTTP

Hypertext transfer protocol.

IP

Internet protocol.

TCP

Transmission control protocol.

FTP

File transfer protocol.

VoIP

Voice over internet protocol.

POP3

Post office protocol 3.

SMTP

Simple message transfer protocol.

Data Packets

Essential units of data used in networking to facilitate efficient communication.

Contents of a Packet

Includes source address, destination address, sequence number, control signals, and error control bits.

Source Address

Address of the origin of the packets.

Destination Address

Device intended to receive the packet.

Sequence Number

Used to keep track of the order of the packets during transmission.

Control Signals

Indicate various types of information that manage the transmission process.

Error Control Bits

Used for error detection and correction.

Checksum

Used for error detection by adding together the binary values using a mathematical algorithm.

Parity Bits

Simple error checking that adds an extra bit to indicate the number of set bits is odd or even.

Serial Transmission

Data is sent one bit at a time over a single wire.

Synchronous Transmission

Data is sent in a continuous stream with both sender and receiver synchronized to a clock.

Asynchronous Transmission

Data is sent without a shared clock signal, framed with start/stop bits.

Parallel Transmission

Multiple bits are sent at the same time using multiple wires.

Duplexing

Methods of communication including simplex, half-duplex, and full-duplex.

Simplex

Data can only be sent one way.

Half-Duplex

Data can be sent and received but only one at a time.

Full-Duplex

Data can be sent and received at the same time.

Multiplexing

Combines multiple signals or data into one over a shared medium.

Time-Division Multiplexing (TDM)

Each stream is assigned a time slot, which wastes bandwidth.

Circuit Switching

Establishes a dedicated communication path or circuit between two endpoints.

Packet Switching

Breaks down data into smaller packets sent over the network.

Routing Traffic

Determines the path data takes over a network using a route table.

Dijkstra's Algorithm

Calculates the lowest cost of the shortest path in a network.

CSMA/CD

Carrier Sense Multiple Access and Collision Detection (CSMA/CD) is the protocol to deal with collisions.

Collision Detection on Ethernet

On an ethernet network, collisions are detected by: A device transmits a signal when the medium is clear.

Collision Signal

If a collision occurs a collision signal is generated and is picked up by the sender.

Jam Signal

The sender transmits a jam signal which stops all transmissions of signal within affected areas.

Random Wait Time

The sender waits a random period of time before re-transmitting.

Bandwidth

Maximum amount of data that can be in a single cable.

Higher Bandwidth

Higher bandwidth allows for more data.

Bandwidth Measurement

Not a measure of speed.

Transmission Time

Transmission will always cross a cable in the same amount of time regardless of size.

Large Bandwidth Advantage

The advantage of having a larger bandwidth is that large files can be transferred without fragmentation.

Small Files Impact

Have no overall impact on the performance.

Bit Rate

Numerical expression of bandwidth.

High Bit Rate Requirement

High bit rate connections are required for large data to be sent in a short time.

Video Call Bit Rate

Video calls require high bit rate.

Low Bit Rate Impact

Low bit rate doesn't always impact the content delivery.

Network Connection

A device becomes a part of a vast network when connected.

Protocol Independence

Each network can decide its protocols.