There are two important factors that affect network speed: network bandwidth and network latency!

With the popularization of the Internet, users pay more and more attention to the speed of response. The faster the website, the higher the user stickiness and conversion rate.

Simply put, it is to increase the speed! There are many factors that affect the speed of the website. Here we mainly introduce the network communication aspects, namely "bandwidth" and "delay".

"Network bandwidth" and "network latency" are sometimes used interchangeably, but they actually describe two separate concepts. Understanding the difference between them is key to understanding front-end web performance.

What is bandwidth?

Bandwidth refers to the amount of data that can be transmitted per unit time (generally 1 second), and is what almost all Internet service providers call "speed" in business and marketing.

This can be a bit misleading, one of the most misunderstood concepts in networking is speed and capacity, many people think speed and capacity are the same thing.

When you hear someone say "I have 30 Mbps" or something similar, they are actually referring to the bandwidth capacity of their internet service, not the speed. The speed of a network is actually the result of bandwidth and latency.

Bandwidth actually refers to the width of the data pipe, not the speed at which data is transmitted.

Transfer rates are measured in latency, and the wider the pipe, the less latency you'll experience when loading web pages and transferring files.

Bandwidth is measured in Mbps, or megabits per second.

Your internet connection will have two bandwidth numbers: download speed and upload speed.

Most ISPs only talk about download speeds because that's what matters most to most people. Unless you're sending files, upload speeds are even lower.

What is latency?

Latency is the delay between when you click on something and when you see it.

This is the time it takes for your request for data to reach a server (like a website) and for the data to be returned to you.

Latency is measured in milliseconds, abbreviated "ms", and can be measured using your computer's ping command.

When you run the ping command, a small piece of data (usually 32 bytes) is sent to another computer, measuring the round-trip time in milliseconds. The ping command measures the time it takes for a packet of data to leave the source computer, travel to the destination computer, and return to the source computer.

What is the difference between bandwidth and latency?

Let's assume some scenarios so that it's easier to explain the difference:

(1) If your bandwidth is good but latency is bad:

Web pages take a long time to start loading, but once the initial connection is made, the rest of the page loads instantly.

(2) If latency is good but bandwidth is poor:

Web pages may begin loading almost instantly, but pages load slowly, one chunk at a time.

Think of your internet as a water pipe, where you send water out one pipe and back in another. Bandwidth is like the size of the pipe and the amount of water it can send or receive at any one time. Latency is like the water pressure; it's how fast the water can move through the pipe.

In other words, as bandwidth increases, the amount of data that can flow through it in a given time also increases, just as an increase in the diameter of a pipe increases the amount of water that can flow through it in a given period of time.