e-Squirt is a simple protocol allowing to sense and control other devices and to build many complex interactions between devices and their environment, as can be shown in the various CoolTown demos. The dumb description of the protocol is that it allows passing URLs between devices over the IrDA medium.
IrNET is a protocol allowing to carry TCP/IP traffic between two IrDA peers in an efficient fashion. It is a thin layer, passing PPP packets to IrTTP and vice versa. It uses PPP in synchronous mode, because IrTTP offer a reliable sequenced packet service (as opposed to a byte stream). In fact, you could see IrNET as carrying TCP/IP in a IrDA socket, using PPP to provide the glue.
This Java Infrared Socket API provides a way of communicating through infrared medium on a Linux computer using the Java language. Thus, Java application developers can develop applications involving infrared access much easily.
The overall goal of this project is to make an implementation of the IrDATM standards specifications for the Linux kernel.