|Note: UNet is deprecated, and will be removed from Unity in the future. A new system is under development. For more information and next steps see this blog post.
Unity’s multiplayer High Level API (HLAPI) is a system for building multiplayer capabilities for Unity games. It is built on top of the lower level transport real-time communication layer, and handles many of the common tasks that are required for multiplayer games. While the transport layer supports any kind of network topology, the HLAPI is a server authoritative system; although it allows one of the participants to be a client and the server at the same time, so no dedicated server process is required. Working in conjunction with the internet services, this allows multiplayer games to be played over the internet with little work from developers.
The HLAPI is a new set of networking commands built into Unity, within a new namespace: UnityEngine.Networking. It is focused on ease of use and iterative development and provides services useful for multiplayer games, such as:
The HLAPI is built from a series of layers that add functionality:
This section of the manual explains how to use the multiplayer HLAPI.