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The Benefits of a Converged Enterprise Network Management System

By Paul Woodruff


As enterprise networks evolve and become more of a service delivery mechanism for real-time enterprise applications, such as IP telephony, converged network management tools need to lead the way.

In the past, the approach to network management has been predominantly reactive. Network devices (switches, routers, and servers) notified the network operators of an issue with the network; then, the issue with the network was diagnosed and resolved. The amount of time associated with diagnosing and resolving the issue ranged from minutes to hours, or even longer. Reducing the amount of downtime is crucial to enterprises, especially in light of the emphasis on real-time applications today. The inability to quickly diagnose voice-related problems on the network can have far reaching implications that impact internal communications and, more importantly, external customer contact and communications.

With the IETF Internet draft Real-Time Control Protocol � Extended Reports (RTCP-XR), if call quality of an in-progress call falls below a defined threshold, the network operator is immediately, and automatically, notified of the loss of call quality. This relieves the extended amount of time required to resolve the issue, which keeps networks running more efficiently. It is imperative that next generation network management applications be able to deliver a truly converged view of the network in order to allow enterprises to quickly diagnose issues related to real-time voice applications to minimize downtime and customer impact.

A converged view provides an end-to-end view of the network. This view (also called the physical view) includes the VoIP system components, IP Phones, the data infrastructure (switches, routers, subnets), as well as the physical connectivity between the devices. The status monitoring of devices continues to the converged view of the network. For the first time, the network operator has a complete view of the converged network and the interconnectivity associated with the devices. With a color coded device, status alarm devices in error can be quickly identified and the impact of the error determined, such as the failure of a router and how this would affect the VoIP calls within a given subnet.

Converged networks require the network infrastructure and its overlaid services (VoIP) to be monitored proactively, in a way that identifies issues with the VoIP call quality. An Enterprise Network Management System (ENMS) delivers functionality to monitor all in-progress VoIP calls and receive real-time information from the IP telephony solution on call quality using standards-based technology. ENMS provides enterprises with the ability to have a true end-to-end view of the converged network. ENMS is able to discover and monitor data infrastructure and VoIP system components (call servers, signaling servers, and gateways, as well as the VoIP endpoints).

In the near future, enterprises of all sizes will be expanding IP telephony deployments.

The rate of evolution, and whether this evolution begins in the WAN or the LAN, will vary from enterprise to enterprise, as will the acceptance of the technology and the degree to which applications are integrated. But, the net result is the same: what we traditionally think of as separate voice and data networks will be comverged and run over a single IP infrastructure.

Even though voice is sometimes characterized as �just another application,� the fundamental aspects of voice conversations place requirements on the network that are quite different from data applications. These requirements boil down to providing toll quality voice, which is measured in terms of clarity and loss.

Users assume that voice quality over an IP network will be as good as traditional voice. Another assumption is that IP telephony works well on network transport infrastructures designed for low latency and high reliability. However, IP telephony deployed over a poorly designed network results in poor voice quality. Making IP telephony work goes beyond tuning the data network infrastructure. For instance, the appropriate voice coder/decoder (codec) must be chosen for converting analog voice to digital voice.

While the days of assuming that IP telephony is synonymous with poor quality are gone, it remains incumbent upon the VoIP service and technology providers to convince potential users of its high voice quality. This, of course, is in stark contrast to traditional voice networks, where basic quality is assumed and there is no requirement for proactive voice quality monitoring.

Real proof of quality is quantitative and, to address this need, new capabilities, called Proactive Voice Quality Monitoring (PVQM) tools are being developed. These tools allow accurate measurement of voice quality at the IP client, providing continuous passive monitoring to ensure satisfied users of IP telephony solutions. PVQM goes far beyond the capabilities of traditional voice networks, providing a call-by-call analysis that alerts network management personnel to potential trouble spots before users are even aware that a problem exists. Because PVQM monitors call quality from the IP client itself, it provides true end-to-end quality assessment.

PVQM also has an active monitoring component to enable predictive analysis of potential degradation in voice quality. Potential problems can be addressed before users experience any actual call quality problems. Linking voice quality management with infrastructure management further simplifies the troubleshooting and diagnostic tasks associated with maintaining toll quality voice services. These PVQM capabilities provide the tools to take voice quality management beyond traditional telephony to a level that will become the norm for next generation voice networks.

The business implications for PVQM are tremendous. On one level, this capability removes a major barrier to IP telephony implementations by answering the question whether IP telephony sounds good, literally. More importantly, PVQM actually provides the enabling technology and metrics to include voice quality as a key parameter in a service level agreement (SLA), whether the corporate telecommunications department offers an SLA to internal users, or a service provider offers an SLA to external customers.

IP telephony is quickly growing in popularity because of the tactical and strategic advantages it brings to enterprise networks. From the tactical perspective, operations costs are contained and toll bypass can provide significant cost savings. More importantly, from a strategic perspective, IP telephony is an enabling technology that facilitates better customer relations and more productive employees via applications like collaborative computing, next-generation contact centers, and integrated messaging.

Nevertheless, in some circles, the willingness to move to this technology is stifled by concerns about voice quality. While the community of people who believe that IP telephony quality is good continues to grow, the �show me� concerns must still be met. Which is exactly what PVQM does.

What�s more, PVQM goes beyond addressing this objection. It doesn�t just level the playing field; it changes the rules of the game by demonstrating that IP telephony call quality is both quantifiable and actionable. By passively monitoring call quality, potential trouble spots are identified and can be corrected before users notice a problem.

This takes voice service delivery to the next level. IP telephony is not only demonstrated to be as good as traditional voice, but the capability for guaranteeing quality is taken to the next level. PVQM not only removes a barrier for IP telephony deployment, it clears the way for enterprises to move full speed ahead with converged networks for the 21st century.

Converged networks enable the network operator to quickly trace the route of the active call and view all devices, making their status, fault, and performance information readily available in a single console. This provides, and enables, a single point of contact for an enterprise to manage its converged network with all necessary tools and data on hand to quickly identify and resolve issues.

As VoIP deployments reach critical mass, the requirements for maintaining voice quality become essential to the end user�s Quality of Experience. ENMS proactively monitors voice calls and offers the ability to quickly identify quality issues in real-time. The tools embedded in ENMS allow organizations to quickly react to quality issues as well as identify the source of the issue, allowing corrective action to be taken, resulting in a decrease of time-to-resolution and improved operational efficiency of the organization. IT

Paul Woodruff is General Manager of the Enterprise Network and Service Management business unit within Nortel (News - Alert). For more information, please visit the company at

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