Node Handler

The nodehandler is the central experiment controller. A central NodeHandler process communicates with NodeAgents, one on each active node in the testbed. The NodeHandler is hosted on one of the testbed's utility servers. Applications are loaded and executed by a NodeAgent on instructions from the NodeHandler. These instructions will also include the initial property settings for the applications.

In addition to providing interfaces for experiment execution, nodehandler also provides the following built in applications:

• load - Install a given disk image on the nodes in a testbed
• save - Saving node image
• tell - Switch ON/OFF the nodes in a testbed?
• stat - Returns the status of the nodes in a testbed?