DIS PDU Topics

DIS can be difficult to explain. We started with some very general and high level descriptions of DIS and what it does, and some limited information about networking and other simulation protocols. But for too many readers it's difficult to explain out to put together an entire DIS message.

DIS messages often contain several smaller-scale records or components--perhaps a field expressing position in distance from the center of the earth, or the rules used for dead reckoning. Those features, and more, are used in the Entity State PDU (ESPUD) DIS message. They've also been used in other messages, so explaining the message in multiple PDUS is distracting.

As another example, every DIS PDU contains a "header" section which contains field values. Some of them are the same--the version of DIS being used, for example--while some are different for other PDUs, including the number used to identify the type of PDU.

That's one part of it. Another is explaining what is happening with time between messages and other architectural choices. These will be discussed as well.

Unfortunately, this section can be long and involved. On the other hand, when it comes to explain a full PDU with several of these fields it's easier than that, and the explanations can be used in several PDUs. If trying to understand a PDU such as a position or shooting immediately read the corresponding PDU first, and back up and read any sections you must understand.