As a variety of broadband applications have emerged in recent years, subscribers are no longer satisfied with the traditional Web browsing. They show increasing concern in broadband value-added services such as online video, online gaming, Webcast, P2P, instant messaging, and online stock trading. These services have high requirements on bandwidth, real-time delivery and stability. If their quality is poor, the subscriber satisfaction will lower dramatically. To better offer such services and improve broadband users' Quality of Experience (QoE), the broadband industry has been trying to find out an optimal broadband service assurance solution.

Key Problems
Network operators and subscribers are major players involved in broadband services. The operators deploy the broadband service assurance system and subscribers benefit from it. Therefore, the problems which draw most attention from the operators and subscribers are essential to building a robust broadband service assurance system.

Some analysis shows that broadband subscribers are most concerned about their QoE when using broadband services, which depends on the following three factors:

•  Availability
  After the subscribers subscribe to broadband services, operators should make an offer to them quickly and accurately (within specified bandwidth, traffic, period of time, etc.), so that the subscribers can have an easy and quick access.
• Stability
  Within the service period, operators should ensure that broadband services are offered through stable access links and at the required bandwidth.
• Timely handling of faults
  When faults occur in the services, operators should locate and remove them quickly and accurately.

Operators are most concerned about how to better serve subscribers at a low cost and generate considerable revenue, which depends on the following three factors:

• Quality
  The broadband services offered by operators should be highly available, stable, scalable and easy to maintain.
• Quick response
  Quick response involves fast service provisioning, fast service upgrading, fast fault handling, and prediction and prevention of potential faults.
• Low operation cost
  Operators hope to offer quality services and make quick response at a low cost. As the Operation and Maintenance (O&M) costs for broadband services are increasing, reducing OPEX has become the operators' major concern.

Key Techniques
To build a robust broadband service assurance system, it is necessary to first analyze the access network capability and service quality, provide complete functions such as capability estimation, service acknowledgement, operation monitoring and prediction, and service optimization, and then improve the fault diagnosis and complaint handling process. In this way, operators can definitely improve broadband users' QoE and thus increase customer satisfaction.

• Capability estimation
  The capability estimation process should be provided before the broadband access links are put into service or upgraded. With the capability estimation, operators are clear about whether the links subscribed to by the users can carry the services to be provisioned, and about the possible consequences such as service availability, configuration modification, and user QoE. The service capability estimation involves estimating connectivity, stability and available bandwidth of access links, and estimating the performance indices for carrying related services.
• Service acknowledgement
  The service acknowledgement process should be provided after the broadband access links are put into service. With the service acknowledgement, operators are clear about the service usage, and subscribers have an opportunity to verify the broadband services they are using, thereby improving user QoE. The broadband service acknowledgment involves acknowledging network bandwidth, network service quality, and quality of special broadband applications (such as IPTV).
• Operation monitoring and prediction
  The operation monitoring and prediction mechanism should be provided during the running of the broadband access network. By monitoring the quality of broadband services in an all-around way, operators can make dynamic evaluation regarding broadband services and solve the possible problems with service quality. Through the prediction of service quality, operators can know "sub-healthy" state of the services and find potential problems at the earliest time, thereby reducing complaints from subscribers and improving their satisfaction and service experience.
• Service optimization
  The service optimization process should be provided during the running of the broadband access network. By optimizing services, operators can improve stability of the existing services, deliver higher-bandwidth applications, and enhance the network capability. The service optimization involves optimizing the subscriber configuration, subscriber service quality, and subscriber line model, etc.
• Fault diagnosis and complaint handling
  The fault diagnosis and complaint handling process should be optimized to provide complete diagnosis for broadband services, achieve quick response, and reduce O&M costs. Through the home network diagnosis tool, subscribers or operators can quickly remove the home network faults, and thus reduce the home network failure rate, fault complaint rate and CPE return and repair rate. Through the fault pre-processing software, the customer service center can efficiently accept a fault complaint, locate the fault, and judge the fault type for quick and accurate handling, thereby greatly reducing the on-site O&M costs.

ZTE's EasyserviceTM System
ZTE has launched its EasyserviceTM (ZXESS), a broadband services supporting system, to guarantee the service quality of the broadband access network. With different software modules, EasyserviceTM implements functions such as estimation, acknowledgment, monitoring, prediction, analysis, diagnosis, and optimization of broadband services, and optimizes the O&M procedure, thereby helping operators reduce their O&M costs and improve subscriber satisfaction.

EasyserviceTM consists of five software modules: EasyAssistant, EasyCSM, EasyGateway, EasyCopper, and EasyOptical. EasyAssistant deployed in the user home helps the user implement self-maintenance of home network, diagnosis and repair of CPE/PC faults, monitoring and acknowledging of broadband service quality, and trial use of broadband value-added services. With EasyAssistant, subscribers can detect and remove most of the home network faults, thereby greatly reducing the fault complaint rate, the on-site maintenance work, and the CPE return and repair rate. EasyCSM is responsible for handling broadband complaints, quickly locating the broadband faults and judging the type of faults. Through the integrated diagnosis, expert knowledge base and network snapshot technology, EasyCSM helps customer service representatives quickly respond to all customer fault complaints and provide the best solutions. This can not only shorten the handling time of complaints, but also improve the quality of customer service. EasyGateway, the CPE remote management system, is responsible for automatic service provision and remote fault diagnosis. EasyOptical and EasyCopper are responsible for integrated operation and maintenance for PON and DSL networks, including fault diagnosis of broadband access devices and related lines, estimation of broadband access capability, monitoring and analysis of service performance indices, prediction of service quality, and optimization of subscriber services. With the subscriber-oriented broadband service access capability and service quality analysis technologies, EasyOptical and EasyCopper can help operators implement capability estimation before the service deployment, acknowledgement after the service deployment, and monitoring, prediction, fault diagnosis and repair during the service running. The five functional modules work together to build a subscriber-oriented broadband service assurance solution.

Conclusion
Ever since its launch, EasyserviceTM has attracted close attention of the operators, and is now efficiently guaranteeing their broadband service deployment. With further growth of broadband applications, EasyserviceTM will follow the latest trends in broadband and explore more means for service assurance, helping operators offer varieties of stable broadband services and subscribers improve their QoE.