The reason why error detection occurs is explained briefly by the article provided by Wikipedia (Wikipedia, 2008). It states: Error detection is the ability to detect the presence of errors caused by noise or other impairments during transmission from the transmitter to the receiver.
Error correction also includes the additional ability to reconstruct the original message, with error-free data.
Two basic methods have been designed to handle the error correcting system. These are called the Automatic repeat-request (ARQ), and the Forward Error Correction (FEC). The ARQ sends that data with an error detection code, which the receiver user to check for errors. In the FEC method the transmitter includes an error-correcting code (ECC) and sends the coded message. The receiver never sends any data to the transmitter, it just decodes what it thinks is the most "likely" data.
The Network Layer deals with errors via a variety of means (Wikipedea, 2008). These are to ensure the QOS is maintained. These can be items such as the Parity check, which means that if any bits are corrupted in the message, they are replaced to the expected format. A checksum, which involves an algorithm to check the validity of the data, Hash functions, which perform a similar function and repetition schemes. The full list of methods is stated here:
The Transport Layer uses 2 two way error correction protocol, which involves a discussion between the sender and the receiver. This is where the receiver informs the transmitter to resend a message when an error occurs. ...