Concepts

There are several layers that enable lightyear to act as a games networking library. Let's list them from the bottom up (closer to the wire):

• IO: how do we send raw bytes over the network between two peers? The Link component can be added to an entity to interact with the IO layer. Usually you will directly add the io component itself (WebTransportClientIO, UdpIO, CrossbeamIO, etc.), which will add the Link component.

• Transport: how do provide reliability/ordering guarantees for the bytes we want to send over the Link? The Transport component can be added to provide Channels. These channels can be used to define the send_frequency, priority, ordering, reliability characteristics for the bytes you want to send.

• Messages: how do you go from raw bytes to rust types? The MessageManager/MessageSender/MessageReceiver components will be required to serialize/deserialize from rust types into raw bytes that you can send over the Link or Transport. It is also responsible for mapping Entities from the remote World to the local World.

• Connection: how do we get a persistent connection on top of a link? A Link can be ephemeral, for example if it's simply an UDPSocket. Sometimes you want a more long-term identifier for the different peers that you are linked to. For example so that when a client disconnects and reconnects you can recognize them as the same client even if their socket port changed. Currently we have two layers that can give you a persistent connection: Netcode or Steam.

• Replication: how do you replicate components between the remote World and the local World

• advanced replication: prediction, interpolation, etc.