Join Julio Appling for an in-depth discussion in this video Understanding the difference between bandwidth and throughput, part of Up and Running with Wireless Networking.
- You may often hear the term bandwidth used in the context of discussing Internet speeds. Bandwidth refers to the data transfer rate that can be handled by a medium. The data transfer rate is measured in bits per second, though given the immense number of bits that can be transferred by modern hardware, most outlets express this number as millions of bits, megabits, per second, or even billions of bits, gigabits, per second. Bandwidth is often prominently advertised by Internet service providers when touting their speeds, often with small accompanying text indicating actual speeds may vary.
Various factors, both within and out of your control, contribute to the actual speed of your Internet connection, which is why bandwidth is often advertised as speeds up to a certain number. To illustrate the concept of bandwidth, imagine cars traveling on a road. A high-bandwidth connection could be illustrated by a highway with five lanes traveling in each direction. A large number of cars can travel on the highway at once in both directions, and the cars can travel at high speeds. A two-lane road with one lane traveling in each direction will illustrate a much lower-bandwidth connection, where only one lane of cars may travel at the same time.
Provided that traffic remains at a minimum, the two-lane road still performs adequately, but has much lower capacity for handling large amounts of traffic, and is prone to slowdowns, or bottleneck, if the capacity is met. In contrast to bandwidth, throughput reflects the Internet connection speed while accounting for factors such as radio interference, distance the data needs to travel, cable quality, and other real-life variables that affect data transfer. In our highway analogy, even on a five-lane road, wet conditions, potholes, and other obstructions would slow down traffic.
While the bandwidth, the amount of traffic the highway could theoretically handle, remains the same, the throughput is reduced. While bandwidth represents the theoretical capacity, the throughput gives a better description of your actual Internet connection speed. So how does bandwidth factor into network performance? In our analogy, if there isn't a lot of traffic on a single-lane road, a single car could travel at the same speed as it could on the five-lane highway. Likewise, on our network, low-bandwidth actions such as text chat may see little difference in performance between high- and low-bandwidth connections.
On the other hand, bandwidth-intensive applications such as videoconferencing, online gaming, and streaming video can demand larger portions of available bandwidth, similar to how even a five-lane freeway can back up given enough traffic on the road. While it's good to have an idea of your bandwidth and throughput calculations, there's often little one can do to affect the speeds received by your modem, even though there are methods of calculating both throughput and bandwidth. It's not necessarily important that you calculate both of these. It's more important to establish a baseline to work from as you experiment with improving your wireless connection.