Suggest an editImprove this articleRefine the answer for “What is network bandwidth?”. Your changes go to moderation before they’re published.Approval requiredContentWhat you’re changing🇺🇸EN🇺🇦UAPreviewTitle (EN)Short answer (EN)**Network bandwidth** is the maximum amount of data that can be transmitted over a communication channel per unit of time; it is traditionally measured in bps, Kbit/s, Mbit/s, Gbit/s. **Key point:** bandwidth is the theoretical maximum, unlike throughput, which reflects the actual transmission speed.Shown above the full answer for quick recall.Answer (EN)Image**Network bandwidth** is the *maximum amount of data that can be transmitted over a communication channel per unit of time*. Traditionally measured in: - **bits per second (bps)** - **Kbit/s**, **Mbit/s**, **Gbit/s** Short phrasing for the interview: > **Bandwidth is the maximum data transmission speed that a network channel can provide.** --- ## A simple example for understanding Picture a pipe: - the wider the pipe, - the more water flows through it per second. In networking, the "width of the pipe" is the **bandwidth of the channel**. --- ## How bandwidth differs from other metrics ### 1. Bandwidth ≠ actual speed (Throughput) - **Bandwidth** is the theoretical maximum - **Throughput** is the real speed you get in practice Over a 1000 Mbit/s link, the actual traffic may run at 930-950 Mbit/s due to overhead, delays, and load. --- ### 2. Bandwidth ≠ latency - Bandwidth is *how much data can be transferred* - Latency is *how fast a packet travels the path* A comparison: - A road can be wide (large bandwidth) but long (high latency). --- ### 3. Bandwidth ≠ useful throughput (Goodput) Goodput is useful data without overhead traffic (TCP, headers). --- ## What bandwidth depends on ### 1. Type of transmission medium - twisted pair (Fast Ethernet 100 Mbit/s, Gigabit 1 Gbit/s) - fiber optic (10G, 40G, 100G+) - Wi-Fi (real speeds are lower than advertised) - mobile networks (4G, 5G) ### 2. Equipment characteristics - switch/router ports - radio modules - cable quality (Cat5e/6/6a, etc.) - frequencies and channels in Wi-Fi ### 3. Channel load The more users/packets, the lower the actual speed. --- ## Bandwidth examples (illustrated) | Technology | Bandwidth | |---|---| | Fast Ethernet | 100 Mbit/s | | Gigabit Ethernet | 1 Gbit/s | | 10G Ethernet | 10 Gbit/s | | Wi-Fi 5 | theoretically up to 3.5 Gbit/s | | Wi-Fi 6/6E | up to 9.6 Gbit/s | | 5G | up to 10 Gbit/s | --- ## Where bandwidth matters - **transferring large files** within a LAN - **4K/8K streaming** - **video conferencing** - **server load** - **cloud services** - **gaming platforms / multimedia** - **communication channels between data centers** If bandwidth is narrow, a "bottleneck" appears. --- ## How to explain this in an interview > **Network bandwidth is the maximum data transmission speed a communication channel can provide.** > **It is measured in bits per second and depends on the transmission medium, equipment, and network characteristics.** > **Bandwidth shows the theoretical maximum, unlike throughput, which reflects the real speed.** --- ## Cheat sheet (5 seconds before the interview) - Bandwidth = maximum data volume/second. - Measured in Mbit/s, Gbit/s. - Bandwidth ≠ throughput (real speed). - Depends on the medium (cable, Wi-Fi, fiber) and equipment. - Determines how "wide" the channel's pipe is.For the reviewerNote to the moderator (optional)Visible only to the moderator. Helps review go faster.