Understanding Flow Control
Flow control is an essential mechanism in networking that helps manage the rate of data transmission between two devices. It ensures that a sender does not overwhelm a receiver with too much data at once, which could lead to data loss.
Where Flow Control Occurs
Flow control is primarily performed at the Data Link layer of the OSI (Open Systems Interconnection) model. Here’s why:
- Data Link Layer Functions:
- The Data Link layer is responsible for node-to-node data transfer and error detection.
- It manages access to the physical medium and ensures reliable transmission between directly connected devices.
- Flow Control Techniques:
- Techniques such as Stop-and-Wait, Sliding Window, and XON/XOFF are implemented at this layer.
- These techniques help regulate the amount of data sent before waiting for an acknowledgment from the receiver.
Other Layers Explained
- Network Layer:
- Primarily manages routing and forwarding of data packets.
- Flow control is not its primary function.
- Physical Layer:
- Concerned with the transmission of raw bitstreams over a physical medium.
- Does not provide flow control as it deals with the electrical and mechanical aspects of the network.
Conclusion
In conclusion, flow control is a critical function that takes place at the Data Link layer (option C), ensuring efficient and reliable communication between devices. Understanding this concept is crucial for networking professionals and those preparing for exams like SSC CGL.

Flow control is typically performed at the data link layer.