🤔 What is Throughput? (Basic Idea)
When data is sent over a network:
Not all data sent actually reaches the destination
Some packets may be delayed or lost
📌 Throughput tells us how much data is actually delivered successfully.
🧠 Simple Definition
📌 Throughput is the amount of data successfully transmitted from source to destination per unit time over a network.
🧠 One-Line Understanding
Throughput = “How much useful data the network really delivers.”
🧠 Real-Life Analogy
🚰 Water Pipe Example
Pipe capacity = Bandwidth
Actual water flowing = Throughput
👉 Even if pipe is wide, leaks and blocks reduce actual water flow.
📌 Same with networks.
🧭 Where Does Throughput Matter?
Throughput is important in:
File downloads 📥
Video streaming 🎥
Cloud services ☁️
Database communication 💾
🧮 Throughput Formula
Throughput = Total Data Successfully Received / Total Time🧠 Example
Data received = 10 MB
Time taken = 5 seconds
👉 Throughput = 2 MB/s
📊 Units of Throughput
Bits per second (bps)
Kbps, Mbps, Gbps
📌 Same units as bandwidth, but meaning is different.
⚖️ Throughput vs Bandwidth
This comparison is almost guaranteed in exams.
Feature | Bandwidth | Throughput |
|---|---|---|
Meaning | Maximum capacity | Actual delivered data |
Nature | Theoretical | Practical |
Affected by | Link capacity | Congestion, delay, loss |
Always fixed? | Yes | No |
Example | 100 Mbps link | 30 Mbps actual |
📌 Throughput ≤ Bandwidth (Always)
🧠 Why Throughput is Always Less Than Bandwidth
Throughput is reduced due to:
⏱️ Delay
📦 Packet loss
🔁 Retransmissions
🚦 Congestion
🔐 Protocol overhead
🧩 Factors Affecting Throughput
🚦 1. Network Congestion
Too many packets
Router queues overflow
📌 Congestion → packet drops → lower throughput
📦 2. Packet Loss
Lost packets must be retransmitted
Increases time
📌 TCP retransmissions reduce throughput significantly.
⏱️ 3. Network Delay (Latency)
High delay slows acknowledgements
Reduces data rate
📌 Especially impacts TCP.
📏 4. Bandwidth of the Link
Higher bandwidth → higher possible throughput
But only if network is uncongested
🔁 5. Protocol Used
Protocol | Throughput Impact |
|---|---|
TCP | Reliable but slower |
UDP | Faster but unreliable |
📌 TCP trades speed for reliability.
🔐 6. Encryption & Security Overhead
SSL/TLS adds headers
Encryption consumes CPU
📌 Slight reduction in throughput.
🖥️ 7. Hardware Limitations
Slow routers
Weak NICs
CPU bottlenecks
📌 Hardware caps throughput.
🧠 Throughput in TCP (Quick Insight)
TCP throughput depends on:
Window size
Round-trip time (RTT)
Packet loss rate
📌 Larger window + lower RTT = higher throughput.
🎯 Why Throughput Is Important
Low throughput causes:
Slow downloads 📥
Video buffering 🎥
Poor cloud performance ☁️
Bad user experience 😡
📌 Users feel throughput, not bandwidth.
🧠 Good vs Poor Throughput (Approx.)
Application | Required Throughput |
|---|---|
Web browsing | Low |
HD video streaming | 5–10 Mbps |
4K video | 25+ Mbps |
File transfer | As high as possible |
🛠️ How to Improve Throughput (Preview)
Reduce congestion
Increase bandwidth
Use QoS
Optimize routing
Upgrade hardware
📌 Covered in troubleshooting topics next.
🧠 Memory Tricks
Bandwidth = Road width 🛣️
Throughput = Cars actually moving 🚗
Loss & delay kill throughput ❌
⭐ One-Line Summary
🔹 Throughput measures the actual amount of data successfully delivered over a network per unit time and is always less than or equal to bandwidth.