Question

I want to develop simple Serverless LAN Chat program just for fun. How can I do this ? What type Architecture should I use?

Last year I have worked on TCP,UDP Client/ Server application Project.It was simple (Server listens to certain port/socket and Client connect to server’s port etc..) But I have no idea about how to develop ‘Serverless’ LAN Chat program. How can I do this? UDP,TCP,Multicast,Broadcast? or Should program behave like both server and client?

Answer 1

The simplest way would be to use UDP and simply broadcast your messages all over the network. A little bit more advanced version would be to only use the broadcast to discover other nodes in the network.

• Every node maintains a list of known peers.
• Messages are sent with TCP to all known peers.
• When a node starts up, it sends out an UDP broadcast to discover other nodes.
• When a node receives a discovery broadcast, it sends ‘itself’ to the source of the broadcast, in order to make it self known. The receiving node adds the broadcaster to it’s own list of known peers.
• When a node drops out of the network, it sends another broadcast in order to inform the remaining nodes that they should remove the dropped client from their list.

You would also have to consider handling the dropping out of nodes without them informing the rest of the network.