OpenIGTLink version 2 Summary

The header format will not be changed.
Simple querying mechanism is defined. See querying mechanism in version 2.
The protocol version 2 continue to focus on message formats. Supporting tools (simulators and interfaces for specific applications e.g. 3D Slicer, Matlab) and transportation layer (use of UDP or other network communication middleware) should be discussed separately.
(TBD)Xenios proposed to introduce a "footer" field in addition to header and body in the OpenIGTLink message format. The idea is to use footer as an area, which can be used by the developers to put application-specific information. In most case, this "footer" approach does not violate the rules in version 1 protocol.

OpenIGTLink Protocol Rules

The OpenIGTLink protocol is a network communication protocol works in the Application Layer in the OSI model.
The minimum unit in data transfer in OpenIGTLink protocol is an OpenIGTLink message.
An OpenIGTLink message consists of header and body sections. The header format is consistent and can be interpreted by all software that has OpenIGTLink interface. The header contains device type (or data type) name, which specifies the format of the body.
The OpenIGTLink protocol is stateless.