Network replication

Now that we've talked a bit about servers and clients, let's learn more about how information moves between them.

The first and most important concept to talk about is replication. Replication is a process by which an actor or a variable value that exists on one system is communicated to another connected system so it can be used there as well.

 

This brings up an important point: only those items that you choose to replicate will be communicated to the other connected systems, and this is deliberate. Unreal's networking infrastructure is designed for efficiency, and a major way to maintain that efficiency, especially if you have a lot of players, is to send only the information you absolutely need to send over the network, and send it only to those who actually need to receive it. Think about a massively-scoped game such as Fortnite. It simply could not run if every single piece of data about every connected player was being sent to every other player. Unreal can handle...