Via Mobile Computing for Field Work:
ConteXtML, a simple XML based protocol for exchanging contextual information, FieldNotes and map data between a mobile client and a server. The current implementation passes messages as HTTP content and the server uses a Java servlet accessed via an Apache v1.3 web server extended with the JServ Servlet Engine module v1.0. The servlet uses JDBC to interact with a database server.
This work is from 1999, now the trend is locative packets