Throughput vs. Bandwidth: Key Differences Explained

This article clarifies the distinction between throughput and bandwidth, two often confused terms in networking.

Bandwidth

• Definition: Bandwidth measures the maximum amount of data that can pass through a channel (wired or wireless) within a fixed time interval.
• Mediums:
  • Wired mediums include DSL, ADSL, and fiber optic cables.
  • Wireless mediums include WLAN, satellite links, GSM, CDMA, LTE (4G), and 5G.
• Capacity: Bandwidth indicates the total capacity of a transmission medium.
• Analog Perspective: In the analog world, it represents the range of frequencies within a band used for signal transmission.
• Units:
  • Analog domain: MHz, KHz, Hz.
  • Digital domain: Mbps, Kbps, bps (bits per second).
• Analogy 1: The total water-carrying capacity of a pipe under full force or maximum flow rate conditions.
• Analogy 2: The total number of vehicles that can pass through a 4-lane highway during heavy traffic (rush hour).

Throughput

• Definition: Throughput measures the actual amount of data that successfully passes through a channel (wired or wireless) in a fixed time interval.
• Actual Capacity: It represents the real-world capacity of the transmission medium under practical conditions, which is usually less than the bandwidth.
• Calculation: Network throughput is generally calculated by dividing the size of a file being uploaded or downloaded by the time it takes to transfer in seconds. A common method involves transferring a large file and recording the transfer time.
• Units: Mbps, Kbps, bps (bits per second).
• Types: Throughput is categorized into uplink (or upstream) and downlink (or downstream) based on the direction of data flow. Data flowing from your computer to your ISP (Internet Service Provider) is uplink, while data flowing from the ISP to your computer is downlink.
• Measurement Tools: Software like IPerf, netperf, Netcps, JDSU QT600, and bwping can measure throughput.
• Analogy 1: The actual amount of water coming out of a pipe under less force or a low flow rate.
• Analogy 2: The actual number of vehicles passing through a 4-lane highway under low traffic conditions. This is typically less than the maximum possible throughput (bandwidth).

Throughput vs. Bandwidth: Key Differences Summarized

Here’s a concise comparison highlighting the differences between throughput and bandwidth:

• Throughput and bandwidth are not the same; throughput is usually less than bandwidth.
• Bandwidth refers to the maximum data a channel can handle, while throughput refers to the actual data that successfully passes through it.
• Example: Your ISP advertises a 50 Mbps broadband connection, but you consistently get 20 Mbps. In this case, the throughput is 20 Mbps, while the bandwidth is 50 Mbps (the maximum potential throughput).