The problems associated with network expansion affect both day-to-day network operation management and strategic network growth planning.  Each new network technology requires its own set of experts.  In the early 1980s, the staffing requirements alone for managing large, heterogeneous networks created a crisis for many organizations.  An urgent need arose for automated network management (including what is typically called network capacity planning) integrated across diverse environments.

Most network management architectures use the same basic structure and set of relationships. End stations (managed devices), such as computer systems and other network devices, run software that enables them to send alerts when they recognize problems (for example, when one or more user-determined thresholds are exceeded).  Upon receiving these alerts, management entities are programmed to react by executing one, several, or a group of actions, including operator notification, event logging, system shutdown, and automatic attempts at system repair.

Management entities also can poll end stations to check the values of certain variables. Polling can be automatic or user-initiated, but agents in the managed devices respond to all polls. Agents are software modules that first compile information about the managed devices in which they reside, then store this information in a management database, and finally provide it (proactively or reactively) to management entities within network management systems (NMSs) via a network management protocol.  Well-known network management protocols include the Simple Network Management Protocol (SNMP) and Common Management Information Protocol (CMIP).

The goal of performance management is to measure and make available various aspects of network performance so that internetwork performance can be maintained at an acceptable level. Examples of performance variables that might be provided include network throughput, user response times, and line utilization.

Performance management involves three main steps. First, performance data is gathered on variables of interest to network administrators. Second, the data is analyzed to determine normal (baseline) levels. Finally, appropriate performance thresholds are determined for each important variable so that exceeding these thresholds indicates a network problem worthy of attention.

Management entities continually monitor performance variables. When a performance threshold is exceeded, an alert is generated and sent to the network management system.

Fault management involves first determining symptoms and isolating the problem. Then the problem is fixed, and the solution is tested on all important subsystems. Finally, the detection and resolution of the problem is recorded.