In other words, Latency is the time it takes for your packet to reach the server and come back and PING is a tool for measuring that time. However, the word "ping" itself can also have the same meaning as latency nowadays. Latency is the time it takes for a pack of data sent from a client to reach its destination and (for the response to) get back, while ping is a tool to measure latency. The word ping is generally used in the place of latency over the internet, while it's not technically 100% correct, I'll be using the the word ping in this guide for the sake of simplicity. You can read more about how networking in Source Engine works here: You can read more about Interpolation here: Interpolation prevents stuttering usually caused by packet loss, thus provides a smoother overall experience. What it basically does is provide a smooth visual (note the word visual) experience on client side. Your client tries to predict the cause and effect on the server you're playing on and show the results before waiting for confirmation from server. Lag Compensation is closely related to Prediction & Interpolation. You can read more about Lag Compensation in Source Engine here: In other words, lag compensation makes gameplay smoother for players with high latency. But what does the term "lag compensation" mean? Lag compensation tries to provide a smooth online gaming experience for low quality internet sessions or connections by countering the effects of high latency. Most modern video game engines (including Source Engine) feature comprehensive lag compensation.