A shift in network maintenance - Testing and Diagnostics

Communications News, Sept, 2002 by Othmar Kyas

The explosion in size and complexity of communication networks, along with an increasing demand for high availability and performance, has led to a new generation of network test equipment. Traditional dispatched test tools are increasingly being complemented or replaced by remote diagnostic systems.

Today's networks frequently require highly specialized experts for maintenance and troubleshooting, who usually are concentrated in centers of expertise at a single location. The local network engineering sources focus on providing support for physical layer problems. In the case of complex application or network layer-related problems, experts are then brought in via remote accessible test systems, which are set up and connected by the local network staff. This allows for fast and efficient root cause identification, and provides an economic and efficient maintenance solution for high-availability networks with demanding applications.

The new network technologies and applications being deployed are the second driver for this trend. Application-based routing, quality-of-service mechanisms or streaming-media applications, such as voice, video or stock market data, have significantly changed the way in which networks are being used and operated. At the same time, new categories of problems have been arising, usually originating at OSI Layer 3.

Flexible, distributable analysis tools are emerging, which allow fur quick problem assessment and resolution in converged multiservice network conglomerates. The analysis tools deliver a set of new functionalities not found in traditional test systems:

Two-way interface to network monitoring and management systems. Single, stand-alone test systems can no longer perform the complicated measurement and troubleshooting tasks needed to deliver the required service levels for maintenance and fault recovery. For example, an interface between the test infrastructure and the management system enables the service-level agreement monitoring application to trigger the execution of measurements in order to isolate the root cause of a problem. Test systems, on the other hand, can alarm the network management system of fault conditions not directly visible at the OSS (operating systems support) level, triggering reconfigurations of network elements.

Integration of embedded network intelligence with measurement results. In switched environments, driven by sophisticated quality-of-service transport mechanisms, test systems must retrieve operational data from network elements and combine it with measurement results in order to he efficient.

To resolve many of the problems new-generation services introduce, the test system needs to he capable of analyzing data streams concurrently and of being time synchronized at a number of different locations in the network, correlating these results for a fast problem resolution.

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