Chapter 5 Flashcards
What is byte stuffing
Some bytes are reserved for control characters. control characters play management role in frame. They are used for start of frame and end of frame. They are used in character oriented hardware. What happens in it that when we receive transmission, transmitter replace those control characters with some fixed characters.
What are 2 major types of data stuffing
- Byte stuffing
2. Bit stuffing
What are transmission errors
Interference or power surges may destroy data during transmission. There are 2 possibilities
- Bits may be lost.
- Bit values may be changed
What is error detection
Send additional information so that incorrect data can be detected and rejected
What is error correction
Send additional information so that incorrect data can be corrected and accepted
What is parity checking
We add some additional information of 1 bit (called parity bit). Receiver find that attached parity bits are same or not. If it is same then it is fine otherwise it will do error detection.
What are 2 types of parity bits
Even parity
Odd parity
What is even parity
The transmitter count the number of bits. If the all bits including parity bit are even then it is even parity.
What is odd parity
The transmitter count the number of bits. If the all bits including parity bit are odd then it is odd parity.
What is parity bit
A parity bit is an extra bit transmitted with the data item.
What are other methods of error detection
- The size of the additional information
- Computational complexity of an algorithm
- The number of bit errors that can be detected
What are 3 methods for error detection
- Parity Checking
- Checksum
- CRC (cyclic redundancy check)
`What is checksum
Transmitter treats data as a sequence of integers. It sum all integers and transmit the sum to the integer.
Does 8-bit, 16-bit, 32-bit can be checksum
Yes
Which error detection technique detects most number of errors and less complex
CRC
