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The FCAPS Model of Network Management

The networking industry uses the FCAPS model to characterize the scope of work management. The acronym is derived from recommendation M.3400 publis by the International Telecommunications Union (ITU)†. FCAPS is expanded into a of five aspects of management.

Abbreviation Meaning
F Fault detection and correction
C Configuration and operation
A Accounting and billing
P Performance assessment and optimization
S Security assurance and protection

Fault Detection And Correction

Fault detection accounts for a major part of the operational aspect of network management. A manager monitors network equipment to detect problems, and takes appropriate steps to correct the problem. Possible faults include software failures (e.g., an operating system crash on a server), link failures (e.g., someone accidentally cuts an optical fiber), and equipment failures (e.g., the power supply fails on a router).

Often, users report failures by citing a high-level symptom such as “I just lost access to a shared disk.” A manager must investigate to determine whether the problem lies with software, security (e.g., a new password), a server, or a link. We say that a manager performs root-cause analysis. Often, a manager can determine the cause by correlating many reports. For example, if many users at one site suddenly start to complain that a variety of services are unavailable, a manager might suspect that the problem lies in a shared connection that all services use.

Configuration And Operation

It may seem that configuration is a trivial aspect of network management because configuration only needs to be performed once — after it has been created, a configuration can be saved so a device automatically installs the configuration during a reboot. In fact, configuration is complex for three reasons. First, a network contains many devices and services, and the configurations must be consistent across all devices. Second, as new equipment and services are added or policies change, a network manager must consider all configurations to insure the entire network implements the changes correctly. Third, current tools allow a manager to configure individual devices and individual protocols; there is no easy way to configure a set of heterogeneous devices.

Accounting And Billing

In many corporate intranets, accounting and billing is trivial. The corporation charges the cost of running a network to a central account, much like the cost of electrical power or telephone service. In ISP networks, however, accounting and billing can consume more of a manager’s time than any other aspect of management. For example, if an ISP offers tiered service with bounds on the traffic that can be sent, a system must account for each customer’s traffic separately. Often, service agreements specify that the fee a customer pays depends on a measure such as the total bytes a customer sends per day. Thus, it is important to measure all of a customer’s traffic and keep detailed records that can be used to generate a bill.

Performance Assessment And Optimization

A manager performs two types of performance assessment: diagnostic assessment to detect problems and inefficiencies and trend assessment that allows a manager to anticipate the need for increased capacity. Diagnostic assessment looks for ways to maximize the utilization of an existing network. For example, if a manager finds a path with low utilization, the manager might look for ways to shift traffic onto the path. Trend assessment looks for ways to increase the performance of the network to meet future needs. For example, most managers watch utilization on the link between their organization and the Internet, and make plans to increase the capacity of the link when the average utilization climbs above 50%.

Security Assurance And Protection

Because it crosses layers of the protocol stack and spans multiple devices, security is among the most difficult aspects of network management. In particular, security follows the weakest-link analogy: the entire security of a site can be compromised if the configuration is incorrect on one device. Moreover, because attackers continually devise new ways to break security, a network that is secure at a given time may be compromised later unless a manager makes changes.


Published on Sun 21 August 2016 by Rolf Gupta in Networking with tag(s): fcaps