Data Transmission and Error Handling

The physical layer in a network is responsible for transmitting data bits without understanding their meaning.

A data frame acts like an envelope for data, containing the message and additional information.

Creating a data frame always adds extra bits for headers and trailers, increasing the total number of bits to be transmitted.

Both the sender and receiver of a data link frame must use the same protocol to ensure proper communication.

The payload is the actual data being transmitted within a data link frame.

The transport layer header contains a port number to identify the receiving application.

The header fields in a data link frame vary depending on the protocol used.

The MAC address is usually found in the data link layer header, not the transport layer header.

Long messages can be broken down into smaller, independent packets, each traveling independently across a network.

White noise is a constant, random fluctuation in signal strength.

White noise is caused by the random motion of molecules in a medium.

Removing impulse spike interference can be difficult.

Impulse noise can cause errors that make it difficult to recover the original digital signal.

Both analog and digital signals are susceptible to noise interference.

Telephone crosstalk was more common before fiber optics and shielded wires were widely adopted.

Echo errors often occur at junctions or connections where signals reflect back.

NAK (Negative Acknowledgment) is a signal sent by a receiver to indicate that it has not received a packet correctly.

Sliding Window Protocols have been used for data transmission optimization since the 1970s.

A parity bit only increases the Hamming distance to 3, not 4. The additional bit provides error detection, but it doesn't significantly change the distance.

In a stop-and-wait system, the receiver acknowledges each packet individually before the sender can send the next one. It cannot acknowledge multiple packets at once.

A sliding-window protocol enables the receiver to acknowledge multiple packets at once, allowing for more efficient data transmission.

Packet sniffers are tools used to capture network packets and analyze them.

The data contained within a data link package is called the payload. It's the actual information being transmitted.

The data link layer is responsible for transmitting data bits across a network, but doesn't understand or interpret the meaning of the data itself.

A common location for error detection is the network access/data link layer of the TCP/IP model.

Parity checks are simple error-detection techniques used in various systems, including data storage.

Even parity ensures that the sum of binary 1s in a string, including the parity bit, is an even number.

A single-bit error represents a common type of error that occurs in data transmission, typically around 50 to 60 percent of the time.

Error bursts are more complex errors that occur in groups, affecting multiple bits at once. They represent a significant percentage of transmission errors, typically around 10 to 20 percent.

Longitudinal parity, also known as horizontal parity, involves adding a parity bit to each column of data bits, ensuring error detection across the entire transmission.

Arithmetic checksums are calculated by adding all the individual characters in a message, creating a unique value used for error detection.

A generator polynomial is an industry-standard bit string used to generate a Cyclic Redundancy Check (CRC) remainder, which helps detect errors in data transmission.

Jitter is the variation in the timing of data transmission. It is usually caused by delays in the network. While it might require a faster transmission rate, the core reason for jitter is timing variations, not necessarily the need to speed up the data transfer.

Repeaters amplify the signal but do not alter the signal's quality. Attenuation is the weakening of the signal over distance, which can be caused by various factors. Repeaters can strengthen the signal, but it can't erase the inherent signal degradation.

Noise interference during transmission often forces the transmitting device to slow down to ensure accurate signal delivery. The transmission rate adjustment is a response to noisy conditions and doesn't cause noise itself.

Filters and regeneration aim to reduce noise, but they don't completely eliminate it. Noise is inherent in any communication system and can't be fully prevented.

TCP (Transmission Control Protocol) is a reliable protocol that ensures data is delivered correctly. Error detection is one of its core functions, performed at both ends of the connection to ensure data integrity.

Simple parity checks the number of 1s in a character and adds a parity bit to make the total even or odd. Simple parity can only detect an odd number of errors, not an even number. It can detect a single error but not two.

CRC (Cyclic Redundancy Check) treats data as a large polynomial and performs a mathematical operation to detect errors. CRC is very effective, catching a highly significant number of errors in data transmissions.

CRC is a highly reliable error detection method, achieving a near-perfect rate in catching errors. It is a sophisticated method that utilizes mathematical computations to identify potential errors.

A protocol where a sender can transmit multiple packets before waiting for an acknowledgment (ACK) from the receiver. The window size defines the maximum number of packets that can be sent at once.

The receiver informs the transmitter what data packet it expects next using this protocol.

The receiver sends an ACK to indicate that it has received a packet successfully. The number in the ACK indicates the next expected packet.

A method of error correction where the receiver uses redundant information to identify and fix errors in the received data.

The process of sending data in a network with a clearly defined beginning and end. This package contains the data and control information.

The header of this layer contains addresses for both the sender and receiver.

A data unit that is transmitted across a network. It's not a traditional hardware component, but a logical concept. It's often used to describe a block of data sent across a network

The maximum window size refers to the maximum number of packets that can be sent before an acknowledgment is needed.