In general, an NE can generate two types of maintenance information: 1. Information related to the quality or health of the transmission signal, and 2. Information related to its own internal hardware/software integrity.
The functional components of surveillance are performance monitoring and alarm/status monitoring, also known as alarm surveillance. In the national and international standards area for telecommunications operations, performance monitoring and alarm surveillance are classified as subcategories of the more general system management functional categories of performance management and fault management, respectively. Maintenance consists of both preventive and corrective procedures that are designed to (a) prevent troubles and identify potential troubles before they affect service, and (b) detect a network failure that impacts performance and make the appropriate repair(s). A typical seven-step maintenance process consists of: 1. Trouble Detection — Detect trouble by continuous monitoring, periodic tests, per-call or other pre-action tests, or other automatic processes. 2. Trouble Notification — Send notification of a specific event or condition to a local display or Operations System (OS). Trouble notifications include output messages and visual and audible alarms. 3. Service Recovery — Minimize the degradation of service by automatic or manual protection actions. 4. Trouble Verification — Determine whether the reported condition still exists. 5. Trouble Isolation — Isolate the trouble to its source, preferably to a single field-repairable element, e.g., circuit pack. 6. Repair — Fix or replace the faulty element. 7. Repair Verification and Return to Service — Verify that the trouble has been fixed and return the element to service.
Telcordia GR-474 establishes trouble-detecting and reporting criteria for signal transmission failures and internal hardware and/or softwa