More than ten years ago, researchers at Google published a paper with the seemingly heretical title “More Bandwidth Doesn’t Matter (much)”. We published our own blog showing it is faster to fly 1TB of data from San Francisco to London than it is to upload it on a 100 Mbps connection. Unfortunately, things haven’t changed much. When you make purchasing decisions about home Internet plans, you probably consider the bandwidth of the connection when evaluating Internet performance. More bandwidth is faster speed, or so the marketing goes. In this post, we’ll use real-world data to show both bandwidth and – spoiler alert! – latency impact the speed of an Internet connection. By the end, we think you’ll understand why Cloudflare is so laser focused on reducing latency everywhere we can find it.
The grand summary of the blog that follows is this:
- There are many ways to evaluate network performance.
- Performance “goodness” depends on the application -- a good number for one application can be of zero benefit to a different application.
- “Speed” numbers can be misleading, not least because any single metric cannot accurately describe how all applications will perform.
To better understand these ideas, we should define bandwidth and latency. Bandwidth is the amount of data that can be transmitted at any single time. It’s the maximum throughput, or capacity, of the communications link between two servers that want to exchange data. The “bottleneck” is the place in the network where the connection is constrained by the amount of bandwidth available. Usually this is in the “last mile”, either the wire that connects a home, or the modem or router in the home itself.