The Photon Server is the central hub for communication for all your clients. It is a service that can be run on any Windows machine, handling UDP and TCP (TCP can be used by clients on platforms, that are not fully supporting UDP, and as for server-setups, that do not support UDP (like some cloud services) and in case of some paranoid firewall settings - use UDP (which can be sent reliable with Photon!) whenever you can and only use TCP as a fallback, as we can't guarentee feature completeness for TCP.

The Photon Server SDK includes a pre-built version that can be run out of the box. It also allows you to extend the server-side easily.

Get the Photon Server SDK at: https://www.photonengine.com/en/OnPremise/Download

The Lite Application

The Lite Application is the default implementation for room-based games on Photon and (hopefully) a flexible base for your own, more game-specific, extensions. It offers rooms, joining and leaving them, sending events to the other players in a room and handles properties.

It basically does everything you came to expect of Photon.

So why is this done in a separate project? Because this way we can could sperate the low level C++ server core and the high level C# server API, which comes in multiple so called Applications, that can be used for different needs.

On the client-side LitePeer is the counterpart for the server-side Lite Application.