Introduction

VoIP technology has proved to be capable of providing high quality and dependable voice services. This achievement has resulted in increased deployments and volume of voice traffic within existing deployments. To live up to the set expectations, VoIP systems in large scale and critical deployments need to be well - managed.

“Well – managed” stands for successful integration, configuration operation and maintenance of VoIP services. To have those abilities - an efficient and first-rate management tool is required for both the network as well as the individual elements connected to it. An element management system (EMS) manages one or more of a specific type of telecommunications network element. The EMS allows the user to manage all the features of each element. This system communicates upwards towards higher-level network management systems (NMS), which manages the traffic aspects of the different types of elements in the network.

Despite their importance, Element Management Systems are often underdeveloped and overlooked by network equipment manufacturers in new technology markets - VoIP being no exception. The inherent complexity of developing a sophisticated EMS, which requires a wide range of knowledge and skill related to protocols, networking, graphical user interface development and database technologies in addition to a thorough knowledge of the element itself, details why it is preferable to favor the EMS provided by the MG/MS manufacturer.

Minimizing the Operational Expenses

The total cost of provisioning and continuing management for voice over IP must be less than that of Switched Circuit based service solutions, in order to make the business case work. Designed correctly, the EMS for the Media Gateway will not only support the business case for voice over packet, but could even improve it.

The role of EMS is to control and manage the gateway to ensure maximum usage of its resources. The EMS extracts relevant aspects of the detailed knowledge it has of the gateway into an information model that communicates this data via the northbound interface to the higher-level management system.

A first rate management tool needs to have characteristics which ensure smooth operations while minimizing the operational costs. The following section highlights some of these characteristics:

Ease of integration into the service provider’s infrastructures:
By assuring seamless integration with the Network Management System, the EMS of the Media Gateway allows for direct management of the Media gateway, giving the carrier’s maintenance personnel the visibility and control over this network element through a bi-directional configuration management interface.

A successful implementation of this function enables NMS operators to open a window on their NMS workstation directly into the EMS so that the EMS screen appears together with the related NMS screen. Operators performing management of the Media Gateway must be capable of modifying the state of the system while having visibility of the impact of that change at all relevant parts in the network in order to have effective and efficient execution of operations.

Providing Reliability and Availability:
The deployment of a mission critical application, such as voice services into the core network has to be supported by ongoing management of the network and its elements. In order to provide the required availability for Media Gateways, faults should be detected and indicated on the screen as soon as they occur, accompanied with all relevant information related to this condition.

Performance Management:
A common tactic used to prevent deterioration of the service is to detect the issues well in advance - at a stage which is still not critical to the overall network and system operation. It calls for a performance measurement mechanism, which enables the Network Operator/Service Provider to assess actual performance against planned patterns. Appropriate preventive actions can be taken based on analysis of the acquired data.

Straightforward Management Methodology:
In order to provide straightforward management, the EMS needs to include predictive analysis of events with intelligent association of complex cause and effect relationships. This capability provides valuable insight into service affecting conditions. The EMS also needs to enable rapid service activation with quick troubleshooting by fast problem detection, isolation, and renewing service of a faulty module.

Straightforward management also dictates the need for an appropriate User Interface. The significance of the user interface cannot be underestimated. The graphic user interface must provide a logical and simple format to the operator – so that he can handle the vast amount of information and complex parameter sets for managing a large variety and number of diverse media gateways, deployed in a real–live network.

To visualize devices in such a way that complements the network manager workflow, the user interface needs to be friendly, intuitive and have comprehensive functions – to ensure an uncomplicated tool to deploy and manage the Media Gateways, while minimizing the learning curve for new operators.

An EMS designed according to the above mentioned principles will result in a management tool which has a significant potential cost savings and revenue generation opportunity for service providers thereby making the EMS an invaluable part of the network.

EMS Basics

The EMS allows the service provider to perform the full range of management activities on a large number of Media Gateways that are necessary for operation, administration and maintenance (OA&M) of voice over broadband services within the network. The EMS of the Media Gateway allows for direct management, giving the carrier’s Maintenance personnel the visibility and control over this network element through a bi-directional management interface via the EMS. The operator can manage the equipment regardless of its location, whether it is at the central office or network operations center. EMS has to include Fault and Alarm management, configuration, accounting, performance and security management, which are functions that the EMS can apply to each of the connected elements.

These abilities are referred to as FCAPS (Fault, Configuration, Accounting- not relevant for Media Gateways and Servers - Performance and Security Management).

Fault Management
Fault management includes the Alarm Browser. An alarm browser may include many advanced features:

Features such as automatic and manual alarm clearing, various filtering and sorting options greatly facilitate the operator’s ability to process a large number of alarms in an effective manner. Displaying the alarms with colors according to their severity is a standard feature.

Fault management also includes the capability to forward traps to the NMS. All alarms and their subsequent handling by the operator are archived within the EMS data base. The amount of stored data depends on the disk space available.

Configuration Management
Configuration management entails all features related to monitoring Media Gateways status, Media Gateway Provisioning and Software Distribution (for small Media Gateways).

Monitoring Media Gateway status includes a summary of all the managed Media Gateways’ statuses – all which can be observed in one screen. The screen shows the element alarm severity according to the standard color scheme as well as the redundant modules and the switch-over state within each of the Media Gateways and Servers. In addition – the configuration manager provides the means to carry out provisioning and defining individual parameter values within the elements.
 

Mediant 8000 Media Gateway Status Panel

The EMS provides the means to define values to all parameters within the Media Gateways and Servers. As there are a large number of provisioning parameters - they are divided logically into several provisioning screens.

The EMS, being the access to many of the elements within the network, is considered a sensitive part. Therefore – the EMS has to include various measures to guarantee access only to authorized parties, such as:

• EMS-Based Authentication and Authorization
• Login and password to EMS application
• Centralized LDAP server based authentication
• Different Operator Security Levels – each with its allowed type of actions (Administrator Level for defining new users, Operation Level to perform changes and Monitor Level which allows for view only).

The EMS contains an embedded data base – which in addition to maintaining a record of all messages and alarms generated by the managed elements, also records the activity of the EMS operator. In this way – an operator’s mistakes can easily be tracked.

Performance Management

Performance Management collects performance data from the Media Gateways and Servers for viewing performance of these Network Elements There are two types of data collection: Real-time and Historic data ( also known as background monitoring).

Real-time data shows the current values of one or more performance measurements - presentable either in table format or in current view graphs. It highlights various system and network performance parameters, which can be used to troubleshoot network or system problems or to isolate an issue after it has been detected by the fault management system. The operator can simultaneously view up to 5 parameters – to compare these parameters over different entities (different blades / trunks of the same or different media gateways).

Historic data is used for long-term network analysis or planning purposes. The data can either be displayed on the screen or it can be exported to comma separated value (CSV) files for use by Network Management systems.



Interaction with Network Management

The EMS needs to integrate seamlessly with existing OSS systems. A successful implementation of this function enables a NMS operator to open a window on his NMS workstation screen - directly into the EMS client screen, watching both screens simultaneously.

Graphical User Interface

The EMS includes a user-friendly, intuitive Graphical User Interface (GUI) to provide operators with the specified Media Gateway status as well as with the overall network status for all Media Gateways managed by the EMS. Specifically it supports:

• One-Click Access to Element Provisioning & Actions
• Real-Time, Color-Coded Media Gateway status View

The EMS assists with various maintenance tasks – such as downloading of software versions into the connected elements, configuration, file downloading and diagnostic testing on the elements – in order to detect problems within the Media Gateway in advance, well before it impacts the overall service of this system.

Managing VoIP-based service is a complex undertaking.

Detailed planning of management systems is critical and must be concurrent with the rollout of the Media Gateways and servers. Standard management technologies are used however allowing the availability, reliability and all-round functionality designed for the AudioCodes Media Gateways, the specialized management product in the form of AudioCodes EMS, is indispensable.

Audiocodes provides a field-proven, standard-based EMS – presenting easy access to the operator and ensures smooth integration with the network management system. Using AudioCodes EMS provides many benefits:

• Improves operational efficiency
• Provides rapid diagnosis of media gateway faults
• Reduces service costs
• Introduces new services with faster time-to-market
• Allows for full utilization of media gateways and servers with rich feature list and complex OA&M requirements
• Allows for immediate deployment of the media gateway in the operator environment
• Always compatible with the latest media gateway software version
• Supports management of multiple media gateways and servers with different software versions
• Integrates easily with higher level management systems

The Audiocodes EMS is a mature, widely-deployed management solution- which lowers the effort, time, costs and risks for providing Voice Services with media gateway and media servers within large-scale and critical deployments.