Overview of Management Layers:

An Operational Support System(OSS) consists of various systems, including an element-management system (EMS), a network management system (NMS), and a performance-monitoring system, to ensure that the correct level of service is being provided to end users. An OSS uses fault, configuration, performance, and accounting information to ensure that the customer service is performing properly.

Network management is defined as a collective set of management functions that can be applied to a network.
These functions are commonly referred to as FCAPS:
• Fault management
• Configuration management
• Accounting management
• Performance management
• Security management

These functions exist as part of the telecommunications management network (TMN) framework. The TMN layers are the framework that defines how management is logically separated in an OSS. Developed within the International Telecommunications Union (ITU), the TMN framework breaks down the management functions into different layers that represent a hierarchical structure.

The TMN framework has four layers:
•Element Management Layer (EML) The bottom of the pyramid, referred to as the EML, is responsible for managing each individual element of the network. The EML communicates management data, such as alarms, collected from the network elements to the next-highest layer: Network Management.

•Network Management Layer (NML) The NML has the responsibility of ensuring end-to-end connectivity, network reliability, and capacity planning. It carries out these responsibilities by having access to the management data that the EML provides.

The NML has complete visibility of the entire network, which consists of different technologies for example, Asynchronous Transfer Mode (ATM), digital subscriber line (DSL), Synchronous Optical Network (SONET), and so on or a subsection of the network, such as all the Multiservice Provisioning Platform (MSPPs). The NML is also responsible for collecting any failures or performance degradations in the network that violate an SLA or help to provide advance warning of an SLA violation.Failures can be reported as alarms, error rates, and performance levels. Thus, the NML has the responsibility to report service-affecting problems to the Service Management Layer (SML).

•Service Management Layer (SML) The SML is responsible for managing the services within MSPP networks, such as Ethernet over SONET. The SML normally includes the contractual aspects of services that are provided to the end customers. Customer network management and service-layer management are supported at this layer.

•Business Management Layer (BML) The BML’s responsibilities include billing and company policies. Policy-management applications reside at this layer.

It is important to realize that, in many implementations of the Telecommunications Management Network (TMN) framework, management data might not be passed from a layer to the layer directly above it in all cases. Management data might pass from one layer to any layer above it, or to another system within the same layer, if required. For example, an EMS might support both EML and NML functions within the EMS system.

Network Management System: Preface

A Network Element Manger(NEM) or Element Management System(EMS) is concerned with remote connectivity to network devices (or ‘elements’) offering essential configuration and monitoring tools. While NEM or EMS is concerned with the individual device and its current state, managing the coordinated configuration of multiple devices, for example to route a service across the network, is usually done by ‘higher-level’ OSS systems such as a Network Management System.

A NMS will typically provide access to all the functionality of an NEM, either directly connecting to devices itself or by interfacing to the NEM. The NMS improves on the NEM in providing a more complete view of how devices work together to carry traffic and services across the network. The NMS can display configured service routes and simplifies the process of configuring new routes across multiple devices. NMS simplifies the task of introducing new devices which will often require ‘neighboring’ devices to be reconfigured.

Here we will be discussing about the Network Management System NetAct. NetAct is used to manage both the radio and core telecom networks under the following sections;
• Fault management
• Configuration management
• Performance management
• Security management

NetAct Architecture

NetAct is a Network Management system that is used for managing Network Elements. It provides the following functionalities:
• Administration and configuration of Network Elements.
• Collecting alarms, measurements and radio network parameters from network elements
• Remote management of managed networks (2G, 3G, etc.)

External Southbound interfaces are used to exchange data between NetAct and network elements or lower-level network management systems. Whereas, northbound interfaces are used to exchange data between NetAct and higher-level network management or other systems.

A NetAct system is connected to one or more Network Element(s) and / or Element Management System(s) and used for online monitoring and administration of the NEs. NetAct is the main connection point of Network elements and takes care of storing collected information like alarms from NE’s.

NetAct Start Page is the single point of entry for all NetAct applications which are grouped based on functional area. The applications are implemented as either a web interface or a Java client. It is possible to remove the grouping and display all applications on the Start page.

Three Tier Architecture

Going deep into the architecture, NetAct can be said to be a three-tier architecture. NetAct consists of a presentation tier, business logic tier and data tier. The advantages being:
-Client applications can be implemented more lightweight and platform independent.
-Each tier can be upgraded or scaled independently.
-Each tier can have independent fault tolerance strategies.

Presentation tier hosts client applications with graphical user interfaces; web applications and rich Java clients. Client applications on the presentation tier are communicating with business logic tier, but not allowed to communicate with the data tier. Physically the presentation tier is a user workstation that is usually a laptop or small desktop computer that is used also for other purposes.

Business logic tier hosts the NetAct specific business logic and data access, which can be implemented with different technologies. Business logic tier is not allowed to have persistent data storages for any business sensitive data. This layer is implemented by having VM nodes for hosting the components of the Business logic layer.

Data tier hosts the data storages of the NetAct; database and directory server. The data tier is free of NetAct specific business logic and other in-house software. This is implemented by having a single VM node for DB and another VM node for LDAP(Lightweight Directory Access Protocol).

Software Layers / Product Architecture

NetAct software is divided into three layers that represent a particular type of functionality: OSS applications, OSS application platform and computing platform.

Computing Platform:
Computing platform contains most of third-party software components; like operating system, persistent data storages and J2EE application server; NetAct specific hardware. Computing platform does not contain any NetAct specific business logic.

OSS Application Platform:
OSS application platform provides generic (network management domain independent) services for the use of OSS applications. Also called OSS middleware and services, comprises many important NetAct system services like Authorization, Credential Access etc.

Common OSS Components:
• Fault Management
The fault management monitoring tools in NetAct Monitor can be used to manage alarms from various network elements and types like the RNC, BTS, FTM, OMS, Cells etc, to perform root cause analysis, to troubleshoot faults that cause disruptions in network services, and to improve the quality of the network services for subscribers. (Full form of terms used : RNC-Radio Network Controller<3G>, BTS- Base Transceiver Station<WBTS-3G/MRBTS-4G or LTE>, FTM-Fiber Termination Module, OMS-Operation & Maintenance Server)

• Configuration Management
Purpose of the configuration management is to model the telecom network structure (a.k.a. network topology) and manage domain-independent network parameters.

• Performance Management
Purpose of the performance management is to collect & store measurements from telecom network and pre & post-process measurements. Measurement collecting and storing applications are used to collect measurements from telecom network and store them in the measurement repository (a.k.a. PM database). Measurement parameters may be anything like CPU or memory usage by each of the VMs for a particular time period specified.

Performance management consists of the following features: Measurement collecting and storing, measurement processing, post-processing, visualization and administration.

• Security Management
Purpose of the security management is to manage security related information and helps to enforce the security related policies.

OSS Applications:
Contains all the network management domain specific functionalities like applications, mediations and adaptations. Also contains the domain-agnostic applications like the Service Management applications.

Sources:
Work Experience, Online learning