Enterprise NMS Architectures
From NMSWiki
Network Management Architectural Model
Hierarchical Approach to Network Management
Layering of network management not only allows NMS systems to better communicate, 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. For example, it is not feasible to have someone watching every syslog event that occurs on the network. Instead, we rely on systems at the Network Management Layer to filter through all events and show us only those events deemed as most important. The Service Management Layer, meanwhile, is used to further summarize events from the Network Management Layer and to tie multiple network management systems together. A good NMS system will also provide de-duplication of these network events in order to further reduce the amount of unnecessary messages seen by operations personnel.
Hierarchical Model Overview
This model shows the major components that make up a comprehensive NMS system and provides a high-level integration scenario. Cisco Advanced Services encourages {CUSTOMER} to adopt a layered, hierarchical network management system. This type of architecture involves data flow and integration of multiple NMS tools to be effective. Those tool and data relationships are depicted in the following diagram.
The underlying hierarchical philosophy is to get the organization to a basic level of integrated network management. This foundation of network management can be characterized as addressing the ITIL model via the three functional areas/layers making up the left-hand side of the figure above: Element Management, Network Management, and Service Management,
Element Management Layer
The first level, the Element Management Layer, is used to define individual network elements used in deployment. In defining this layer, we accept that for each anomaly that occurs in the network, potentially multiple devices can be affected by the event and independently alert network management systems that an event has occurred, resulting in multiple instances of the same problem.
Network Management Layer
In the middle of the diagram is the Network Management Layer. This function takes input from multiple elements (which in reality might be different applications), correlates the information received from the various sources (also referred to as root cause analysis), and identifies the event that has occurred. These is a level of abstraction above Element Management in that operations personnel are not “weeding” through potentially hundreds of Unreachable or Node Down alerts, but instead are focusing on the event, such as "an area-border router has failed."
Service Management Layer
At the top of Figure1 is the Service Management Layer. This layer is responsible for adding intelligence and automation to filtered events, event correlation and communication between databases and incident management systems. The goal is to move {CUSTOMER}’s network management environment and the operations personnel from Element Management (managing individual alerts) to Network Management (managing network events) to Service Management (managing identified problems).
Benefits of Hierarchical Layers: From a practical perspective, integrating these elements involves:
- Assembling a robust set of event correlation rules that consistently and accurately identify the source of an event.
- Opening a trouble ticket in an Incident Management application that operational personnel begin working on.
This enables an operations organization to:
- Pro-actively manage the network.
- Identify and correct potential network issues before they become problems.
- Prevent a loss of network connectivity, thus ensuring organizational productivity.
- Focus on the solution instead of the problem.
