An operational network mainly refers to a metropolitan area network (MAN) or a broadband access network, and is the extension of the carrier-class IP bearer network and the backbone network within local (metro) area. It provides subscribers with direct access as well as services, and serves as the carriers' platform for full-service convergence and access.

 With the development of Internet services and the surging subscriber base, operational networks need to continue evolving and expanding. In the course of network evolution and expansion, the carriers are bound to encounter many challenges as shown below.

• Endless customer complaints about network quality: As the broadband Internet evolves, Internet users are in an era of amazing growth. Although the carriers make continuous efforts to expand their operational networks, they still fail to give a satisfactory answer to the requirements for increasing bandwidth. As a result, their network quality is perceived as rather poor, the committed bandwidth rate is unavailable, and the offline events and disconnection cases often occur. All these not only lead to a burst of customer complaints about the carriers' failure in meeting the service level agreement (SLA) for VIP subscribers, but affect customer satisfaction, and give rise to severe customer churn.

• Non-standard data over the existing network and improper network planning: With the increase of broadband networks on a large scale, some redundant data is seen in the configurations of devices over the existing networks. Many configurations go against the industry norms, which makes routine maintenance quite inconvenient. Besides, the network construction that is accomplished in a staged manner often easily incurs improper network planning, or even hidden network faults. For example, single-point of failure in the network architecture, poor network reliability and non-scalable IP address planning, or even overlapped IP addresses occur. In addition, an improper routing plan results in low running efficiency of the entire network; improper VLAN and QinQ planning easily causes broadcast storms and expansion difficulties. 

• Inefficient utilization of network resources: The development of services poses higher requirements on network device performance. The carriers are persistent in expanding their network capacity, but unfortunately, the utilization rate of network resources is still rather low. This situation is worsened by the carriers' unsatisfactory utilization of their own resources. On the one hand, service volumes continue growing and higher forwarding performance need to be supported by devices. On the other hand, they still have much room to increase the utilization of network resources. Despite the carriers' CAPEX that remains high, network performance is still unable to meet the requirements of service development.

In a word, the operational networks need an all-inclusive "health check-up" directed at the weaknesses and hidden faults over the existing networks, for the purpose of enhancing the KPIs of the networks and improving network over-all end-to-end performance.

The integrated solution for improving the performance of operational networks, guided by the advanced data network evaluation methodology, is developed to evaluate and optimize the carriers' networks by investigation & analysis and using professional evaluation and test tools and techniques. This solution is able to provide the carriers with the optimal network performance, as the whole, and the best utilization of resources, which is beneficial for improving the performance of the operational networks.

This solution consists of four integral parts: investigation and analysis, evaluation, optimization, and Re-evaluation. In this solution, an investigation and analysis on the carriers' networks is first carried out to analyze their requirements. In the stage of evaluation, professional evaluation tools, aided by the evaluation index library, can thoroughly detect the device and network faults over an operational network. Subsequently, a summary of how the network is running is made, followed by the steps of locating, analyzing and rectifying the faults over the existing network. When it comes to optimization, an optimization solution, based upon the results of network evaluation and the carriers' requirements for network capacity and quality, is drawn up and implemented. Finally, a check of how the optimization affects the network performance is performed.

This solution consists of four integral parts: investigation and analysis, evaluation, optimization, and Re-evaluation. In this solution, an investigation and analysis on the carriers' networks is first carried out to analyze their requirements. In the stage of evaluation, professional evaluation tools, aided by the evaluation index library, can thoroughly detect the device and network faults over an operational network. Subsequently, a summary of how the network is running is made, followed by the steps of locating, analyzing and rectifying the faults over the existing network. When it comes to optimization, an optimization solution, based upon the results of network evaluation and the carriers' requirements for network capacity and quality, is drawn up and implemented. Finally, a check of how the optimization affects the network performance is performed.