With increasing acceptability of Net-centric computing, expansion of the Internet, and the trend towards replacing the traditional shared-media, frame-based LANs with switch-based frameworks, network management gets even more complex.

The importance of having an up-and-running corporate network needs no explanation. Everyone understands the importance of a five 9 reliability. But what is important is making that a reality. There exist failure points—faulty software in routers and switches, increased bandwidth traffic that crashes servers, human errors, configuration problems, power failures, major carrier outages, and even the applications that run on the networks hinder the network. The answer then is management—end-to-end management of networks, systems, desktops, and applications.

All this appears very easy, simple, and cheap. But the reality is that it only gets more complex. Today, converged networks are around. The strain on the network and enterprise management will only compound as voice over IP and IP telephony, next-generation IP switches, routers, and PBXs and software-controlled switches, virtual routers and hubs and servers are getting deployed. So the challenge for network managers will not be just performance but also managing mission-critical networks.

Technology Options
Along with the complexity, the scope of network management is also getting broadened. In general, network management is a service that employs a variety of tools, applications, and devices to assist human network managers in monitoring and maintaining networks.

Network management system (NMS) is an integrated conglomeration of tools for network management. It consists of the incremental hardware and software additions implemented among existing components. The software used in accomplishing the network management tasks resides on the host computers and communication processors (e.g. bridges, routers etc). It is designed to view the entire network as a unified architecture, with addresses and labels assigned to each point and the specific attributes of each element and link known to the system. The active elements of the network provide regular feedback of status information to the network-control center.

n Common NM Functions: International Organization for Standardization (ISO) describes the functions common to most network-management architectures and protocols as FCAPS model. This model consists of five conceptual areas—fault management, configuration management, accounting management, performance management, and security management.

Fault Management: It deals most commonly with events and traps as they occur on the network. It enables detection, isolation, and correction of abnormal operation.

Configuration Management: The facilities that exercise control over, identify, collect data from, and provide data to managed objects for the purpose of assisting in providing for continuous operation of interconnection service.

Accounting Management: It enables charges to be established for the use of managed objects and costs to be identified for the use of those managed objects.

Performance Management: The facilities needed to evaluate the behavior of managed objects and the effectiveness of communication activities.

Security Management: Address those aspects of OSI security essential to operate OSI network management correctly and to protect managed objects.

n NM Architectures: Most of the 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 can also 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). Management proxies are entities that provide management information on behalf of other entities.

n Functionality Levels: Network management systems have four basic levels of functionality, each having a set of tasks defined to provide, format, or collect data necessary to manage the objects. These levels are:

Managed Objects: Managed Objects are the devices, systems and/or any other network element requiring some form of monitoring and management. E.g. routers, concentrators, hosts, servers.

Element Management System (EMS): An EMS manages a specific portion of the network. Element Managers may manage async lines, multiplexers, EPABXs, proprietary systems or an application.

Manager of Managers Systems (MoM): MoM systems integrate together the information associated with several element management systems, usually performing alarm correlation between EMS’s.

User Interface: The information gathered, be it the real time alarms and alerts or the trend analysis graphs and reports, is distributed to the whole MIS organization to keep people informed and to enable team communications.