Common flow control mechanisms Which of the following are considered flow control techniques in networking?

Introduction / Context:
Flow control regulates the rate of data transmission between sender and receiver to prevent buffer overflows and ensure reliable delivery. It operates at multiple layers, from link-layer buffering to transport-layer schemes like sliding windows, and network-level strategies that avoid sustained congestion.

Given Data / Assumptions:

• (1) Buffering, (2) Cut-through, (3) Windowing, (4) Congestion avoidance.
• Goal: identify techniques that actively manage data flow or backpressure.

Concept / Approach:

Buffering absorbs bursts and smooths traffic at ingress/egress queues. Windowing (for example, TCP sliding window) limits the amount of unacknowledged data in flight, dynamically adjusting to receiver capacity. Congestion avoidance (such as RED/WRED, TCP congestion window adjustments) proactively reduces offered load before buffers overflow. Cut-through is a switching method that reduces latency by forwarding frames before full reception; it is not a flow control mechanism.

Step-by-Step Solution:

Verification / Alternative check:

Observe TCP throughput under packet loss: window reductions and slow-start demonstrate flow control plus congestion control working together to stabilize traffic.

Why Other Options Are Wrong:

• Options A and C include cut-through, which does not regulate flow.
• Option D ignores buffering and congestion avoidance, both recognized techniques.
• Option E omits windowing, a core mechanism in TCP/IP.

Common Pitfalls:

• Confusing low-latency switching (cut-through) with rate regulation.
• Assuming congestion avoidance is only QoS; it is integral to flow stability.

Final Answer:

1, 3 and 4 (Buffering; Windowing; Congestion avoidance)