What is the difference between Flow Control and Error Control?

Let us understand the concept of flow control.

Flow Control

Flow control is an important procedure to control issues like congestion, overloading, loss of data, etc. Flow control is a service implemented by the receiving device to limit the data rate being sent by the transmitting machine. The stop and wait protocols are the simplest methods to control the data flow. Flow control is a must, particularly if the communicating machines have multiple transmission and reception data costs.

A simple method of flow control is Stop and Wait for Flow Control. In this, the sender will share one frame at a time with the receiver. The sender will stop and wait for the acceptance from the receiver. This time (i.e. the time joining message transmitting and acknowledgment receiving) is the sender’s waiting time, and the sender is idle during this time.

While sending the information from the sender to the receiver, the data flow required to be controlled. If the sender is sharing the data at a cost higher than the receiver can receive and process it, the data will get hidden. The Flow-control technique will help in providing that the data doesn't get hidden.

In this method, it is a technique for controlling sending data packets between two network devices where dependable and sequential delivery of data packets is needed, such as using the Data Link Layer (OSI model) or Transmission Control Protocol (TCP).

In the sliding window approaches, each data packet (for most data link layers) and byte (in TCP) involves a specific consecutive sequence number utilized by the receiving computer to locate data in the appropriate order. The goal of the sliding window technique is to use the sequence numbers to prevent duplicate information and to request missing information.

Error Control

This is the prominent service of the data link layer. It supports the protocols to recognize error frames and to support the communication of accurate frames. It includes sequencing frames and transmitting control frames for acknowledgment. A noisy channel can avoid scanning of bits, falling bits from a frame, introducing specific bits in the frame, frames final sinking, etc.

The error control is implemented in two steps as follows −

• Error Detection

• Retransmission of data

For error detection, there are various error detection code is shared by the sender with each PDU. The receiver knows that code and checks if the code in the received data is correct or not.

If any error is found, the receiver requests the sender to retransfer the data. On the other hand, if no error is detected, the receiver transmits an acknowledgment for correct receiving data to the sender.