If the path fails, the Admin Workstation attempts to establish a new link with the other side of the ICM system. Each physical node, that is, each computer, is managed by a Node Manager process. The Node Manager has responsibility for initializing nodes and for restarting failed processes on the node. The Node Manager is guided by registry values that are stored on each node. These values describe, among other things, which processes must be started and, if necessary, restarted on the node.
Processes can fail in different ways.
In the simplest case, a process terminates and the Node Manager is informed of the termination by the operating system on the node. In other cases, a process stops responding to messages, or its responses are unreasonably delayed. A standard message type, which is recognized by every ICM process, is used for this purpose. On receipt of a ping message, a process attempts to verify that it is performing normally. How this is done is specific to each process type.