A Network Management System (NMS) is a combination of hardware and software used to monitor and administer a network. Individual network elements (NEs) in a network are managed by an element management system. According to Stephen B. Morris, we study the NMS under the following cases: FCAPS support ”“ basic NMS application areas; MIB support features; MPLS Support; policy support; reliability features, such as support for failure; programmability, integration with other software (Morris). The management station is a key function of NNM. This is the computer that performs the bulk of data collection like: collection of information from NEs via SNMP, processing and archiving data in a database, distribution to registered applications. Management station can delegate NE data collection to collection stations. A single management station can handle 5000 managed objects. Up to 60,000 objects can be managed if collection stations are deployed. For large networks, there can be more than one management station, and these can exchange information with one another. “Layering of network management not only allows NMS systems to communicate better, it reduces the amount of alerts seen by network operations support staff. At the lowest layer, it is nearly impossible to keep up with events displayed from each network element reported in the NMS architecture”¯ (Cisco).
The functions of a network node manager are:
”¢ Discovery and Mapping
”¢ Notification processing
”¢ Data Warehousing
”¢ Backup and Restore of firmware and configuration data
”¢ Java interface for remote access to management features
”¢ Remote administration of NMS
Newwork Discovery and Mapping is a feature that enables discovery of new network elements. Automatic discovery frees the user from potentially error prone task of manually entering and maintaining the details of deployed NEs. Large service providers deploy NMS from the point in time that they start to build their networks.
Discovery has three main phases:
”¢ initial discovery of previously unknown NEs (IP address of SNMP agent on the device, virtual connections, traffic profiles, route purposes etc);
”¢ incremental discovery of changes that occurred to previously discovered data;
”¢ discovery of removal ”“ when a Network Element is taken out of network, it is automatically removed from NMS. NNM provides and automatic discovery mechanism.
Discovery process uses SNMP based polling and ICMP requests to build a picture of the network. Discovery process populates an IP topology database using a series of tables like Network-level connectivity, Segments, Nodes, Interfaces. This grouping allows NNM to create logical maps of the NEs and to graphically indicate operational status using a color, such as green for up, red for down, etc. An icon representing a network can be expanded to show the constituent nodes. In other words, containment relationships are depicted clearly.
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