Numbering System in Message Flow (Communication) Diagrams: Part 1

In any integration project message flow diagrams are one of the most important artifacts along with mapping sheets (among participating systems and CIM- common information model or EBO -Enterprise Business Object).

In Message Flow Diagrams (or Communication Diagram) flow of information depicted and is depicted in terms of numbers for chronological order. This simple number scheme is only good for very simple systems. In any enterprise class systems or integration scenario information may not flow among participating systems in linear chronological order due to asynchronous communication, multi threading, multi processing, clustering, human intervention, etc.
To handle such common scenarios, I have developed a simple scheme which has worked for me in very complex integration scenarios and while architecting/designing products of varying complexities.

Reference

1. http://en.wikipedia.org/wiki/Communication_diagram
2. http://www.xpdian.com/Thecommunicationdiagram.html
3. http://searchsoftwarequality.techtarget.com/definition/collaboration-diagram
4. http://www.uml-diagram.org/communication-diagrams.html
5. http://www.agilemodeling.com/style/collaborationDiagram.htm
6. http://www.modelgoon.org/?p=231