Interactive Network Simulations

Many of the network simulations found online seem to be either dead, require plugins, or just aren't very useful or easy to use. So I made a few. Suggestions or additions welcome:

• Single-hop simulator - Two nodes, A and B, with a single unidirectional link between them.
• Bidirectional (simplex) link - Two nodes, A and B, with a single bi-directional simplex link between them.
• Duplex link with acknowledgements - Two nodes, A and B, communicating over a duplex link, with acknowledgements.
• Switching simulator - Shows the difference between cut-through switching and store-and-forward (a.k.a. packet) switching.
• Mismatched-link simulator - What happens when links in a path have mismatched bandwidths?
• Bottleneck-link simulator - A path with a bottleneck link.
• Queues and bottleneck-links - Three links, with intermediate finite-sized queues.
• Multiplexing a shared link - Three connections sharing a single bottleneck link.
• Packet-switching network - Statistical multiplexing with multiple connections.