The remainder of the process proceeds off-line. Here, too, the repair process can be as simple as replacing the entire node, or the technician may choose to further locate the failed component within the node. This diagnostic is done in an off-line system with full resources available to the repair process. A node-based system is relatively immune to mistakes made during this process. This requires a more finely grained fault management.
Location is done with an on-line diagnostic.
This diagnostic should not interfere with the operating portion of the system. The goal is to keep as much of the system operating as possible to avoid total outages. A typical metric for on-line fault identification is 95 percent fault location accuracy. Isolation is critical. Recovery is more complicated for two reasons.