Section: Software
Netquest system
Participants : Michel Bauderon, Stéphane Grumbach, Xin Qi, Kun Suo.
We have developed a system, Netquest[14] to be embedded on each node of a network, which evaluates in a distributed manner programs expressed in the Netlog language. The architecture of the system differs drastically from classical embedded systems such as TinyDB for instance. It relies on an embedded DBMS (e.g. MySQL), which handles all the data whether related to applications or to the network. The database also stores the protocols expressed in a declarative manner. The DBMS plays a fundamental role in the system which relies in particular on its transaction management. The main component is the Engine, which evaluates locally the Netlog programs, and generate messages to send, in addition to updates in the local database. Currently, Netlog in push mode has been implemented. Other versions of the engine will be developed in the near future for other types of programs and queries. Finally, the last component is a router, which handles the communication, in cooperation with the Engine. It accesses the database to find routes. It can also handle implicit destinations, which are to be evaluated by the engine. The use of an embedded linux together with a DBMS changes the way distributed systems can be programmed, and results in simplifications of the nodes development and maintenance, for its use of standard software components.
To facilitate protocol design in the Netlog language, protocols are developed through an interface which follows the Netquest protocol format, and performs some syntactic verification. Then the declarative protocol is transformed into SQL queries, and stored into the embedded DMBS.
The Netquest system has been installed as a library on the network simulator WSNet. WSNet is used to simulate wireless networks, test the Netquest system, as well as applications running on Netquest. To visualize the simulation result of Netquest on WSNet, we have developed a visualization tool to illustrate the message passing between network nodes, and the computation of the distributed query engine of the Netquest system in each node.
Netquest has also been ported on smart phones (with SQL Server) as well as on a network of iMote devices (with SQLite) in cooperation with Orange Labs in Beijing.
