Hong Kong's CSL Optimizes Network Management with ZOOMs

The rapid development of mobile packet services has good prospects for operators. However, due to the lack of an optimized service operation and management system, satisfactory profits cannot be obtained from these services. Operators instead tend to become bit pipe providers unable to guarantee QoS of high-priority services or restrict low-profit services. This leads to bandwidth waste. Optimized operation and management is therefore needed. 

The Policy and Charging Control (PCC) defined in 3GPP is aimed at optimizing operation and management. Its Application Function (AF)―the service feature identification system―is based on IMS architecture. Because standard AF only identifies SIP-based sessions, requirements of operators without IMS networks cannot be satisfied.

 In cooperation with CSL, Hong Kong’s largest mobile operator, ZTE has developed a flexible, efficient Optimized Operation and Management System (ZOOMs) to help the company manage its mobile packet services. Based on the PCC structure, ZOOMs provides Deep Packet Inspection (DPI) embedded in the Gateway GPRS Support Node (GGSN) to compensate for deficiency in AF.

ZOOMs consists of GGSN, User Behavior Analysis System (UBAS), Policy and Charging Rules Function (PCRF), Subscriber Profile Repository (SPR), self-help Portal Server, and Online Charging System/Offline Charging System (OCS/OFCS), as shown in Figure 1. Service streams are inspected via the DPI of GGSN, and user subscription, location, and access information, as well as more complex service software features can be obtained from the GGSN/SPR. Service analysis can be made by the UBAS; service control policies are issued by the PCRF and executed by the Policy and Charging Enforcement Function (PCEF) of GGSN; and services are charged by the OCS/OFCS.

All these subsystems work together to help CSL build a complete, flexible service control and management system. With smart service sensing and smart user behavior sensing at its core, the system provides control and management functions such as smart user behavior analysis, smart service billing, smart service bandwidth management, and smart service access control, as shown in Figure 2.

 CSL’s service policies have three requirements. First, users are divided into several classes according to the feature of their subscribed bandwidth, and these classes have different service access priorities. Second, user bandwidth can be limited but not banned. Third, differentiated control and service redirection are provided for family members. To meet these requirements, ZTE developed an optimized service operation and management solution to be implemented in three stages.

Stage 1: P2P service control and management

To ensure sufficient bandwidth for high-level user access, low-level user traffic (low-profit P2P) is monitored. Differentiated user (DiffUser) control not only alleviates network congestion caused by P2P services, but also helps users understand and accept CSL’s service policies.

Stage 2: User internal service resource management

After the first stage, CSL’s network resources were effectively controlled. In order to enhance customer satisfaction and increase profits, CSL decided to further manage its internal service resources and worked out more detailed and flexible service policies.

■    Control and manage users’ internal service resources based on their access priority. This avoids resource over-use by low-delay, low-bandwidth services and enhances high-delay, high-bandwidth service experience;

■    Alert users when their traffic is close to or reaches their subscribed amount;

■    Control total service access volume according to user daily or monthly traffic. If they have exceeded traffic flow for one day, lower user service and bandwidth classes and restore them back to normal the following day. This alleviates excessive daily traffic and ensures high QoS over the whole month; 

■    Help parents control their children’s access to specific services at specific times or restrict their access to certain services. Considerate service policy makes family users feel more satisfied;  

■    Remind users they do not have a subscription before they access specific services, and transfer them automatically to a subscription page with clearly specified charges;

■    Prompt when users access non-CSL services to inform them about the services they will access.

Stage 3: In-depth service control and management

To provide a more effective and rational basis for the existing PCC policy making system, CSL adopts UBAS―a professional service statistical and analysis system developed by ZTE. Through detailed and intuitive analysis, UBAS helps CSL pinpoint user behavior changes, develop optimized and differentiated policy rules, and launch more attractive services to enhance customer satisfaction. UBAS provides the following functions:

■    Packet service access analysis based on network elements, routing areas, cells, and access point name (APN);

■    Service or protocol utilization analysis to provide Top N service or protocol list, or Top N user list;

■    Specific service access analysis including P2P and VoIP monitoring;

■    Service access analysis based on user class or user group, including user preference analysis, Top N user analysis, and VIP user/brand service analysis;

■    Website traffic statistics and analysis;

■    Analysis of traffic/bandwidth usage caused by malicious attacks, and list of end-users affected by malicious attacks.

The complete architecture of CSL’s ZOOMs is shown in Figure 3.

ZTE’s optimized packet service operation and management solution allows CSL to create more flexible and differentiated service policies for effective management of its network resources. In this way, customer satisfaction is enhanced, and CSL’s leading position in the value chain is strengthened.