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CSS (CSG subscriber server)

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CSS (CSG Subscriber Server) is a key component in the Converged Services Gateway (CSG) architecture that is used in mobile networks. CSG is a platform that enables mobile operators to offer convergent services that work across multiple access networks such as 3G, 4G, and Wi-Fi. CSS is responsible for managing the subscriber information that is used by the CSG platform.

In this article, we will explain CSS in detail, including its functions, architecture, and how it works in the CSG environment.

Functions of CSS

The main functions of CSS are:

Authentication and Authorization

CSS is responsible for authenticating and authorizing subscribers who access the network through CSG. When a subscriber initiates a session, CSS validates the subscriber’s credentials and checks if the subscriber is authorized to access the requested service. CSS uses the subscriber’s profile to verify their credentials and authorization status.

Subscriber Profile Management

CSS stores and manages the subscriber profile, which contains the subscriber’s personal and service-related information. The subscriber profile includes information such as the subscriber’s name, address, phone number, and the services they are authorized to use. CSS ensures that the subscriber profile is up-to-date and accurate so that the CSG platform can use it to provide personalized services to the subscriber.

Service Configuration

CSS is responsible for configuring the services that are offered to subscribers. CSS manages the service configuration parameters such as service access point names (APN), Quality of Service (QoS) parameters, and IP addresses. These parameters are used by the CSG platform to provide the requested services to the subscriber.

Charging

CSS provides the charging information for the services that are used by the subscriber. CSS communicates with the charging system to generate charging records and to ensure that the subscriber is charged accurately for the services they use.

Roaming Management

CSS manages the roaming agreements between the home operator and the visited network. CSS ensures that the subscriber is authorized to use the visited network and manages the roaming parameters such as charging rates and QoS parameters.

Architecture of CSS

CSS is typically deployed as a cluster of servers that are located in the operator’s data center. The CSS cluster consists of one or more CSS servers that work together to provide the required functions. Each CSS server is responsible for a subset of the subscriber data and can communicate with other CSS servers to synchronize the subscriber data across the cluster.

The CSS architecture includes the following components:

Subscriber Data Repository (SDR)

The SDR is the database that stores the subscriber data. The SDR can be a relational database or a NoSQL database, depending on the operator’s preference. The SDR stores the subscriber profile and service-related information, such as the subscriber’s services and charging information.

CSS API

The CSS API provides the interface for the CSG platform to access the subscriber data. The CSS API includes the following components:

  • Authentication and Authorization API: This API provides the functions for authenticating and authorizing the subscriber.
  • Subscriber Profile Management API: This API provides the functions for managing the subscriber profile.
  • Service Configuration API: This API provides the functions for configuring the services that are offered to the subscriber.
  • Charging API: This API provides the functions for generating charging records.
  • Roaming API: This API provides the functions for managing roaming agreements.

High Availability and Load Balancing

To ensure high availability and scalability, the CSS cluster can be configured with load balancing and failover mechanisms. Load balancing distributes the subscriber requests across multiple CSS servers to ensure that the load is evenly distributed. Failover mechanisms ensure that the CSS service remains available even if one or more CSS servers fail.

How CSS Works in the CSG Environment

CSS works closely with the other components in the CSG environment to provide convergent services to subscribers. The following steps describe how CSS works in the CSG environment:

  1. Subscriber initiates a session: The subscriber initiates a session by requesting a service through their device.
  2. Device communicates with CSG: The device communicates with the CSG platform to request the service.
  3. CSG communicates with CSS: The CSG platform communicates with CSS to authenticate and authorize the subscriber.
  4. CSS validates subscriber credentials: CSS validates the subscriber’s credentials by checking the subscriber profile in the SDR.
  5. CSS checks authorization status: CSS checks the subscriber’s authorization status to ensure that they are authorized to access the requested service.
  6. CSS provides service configuration parameters: CSS provides the service configuration parameters such as APN and QoS parameters to the CSG platform.
  7. CSG provides service to subscriber: The CSG platform provides the requested service to the subscriber using the service configuration parameters provided by CSS.
  8. CSS generates charging records: CSS generates the charging records for the service that was used by the subscriber.
  9. CSS manages roaming agreements: If the subscriber is roaming, CSS manages the roaming agreements between the home operator and the visited network.
  10. CSS updates subscriber profile: CSS updates the subscriber profile in the SDR to reflect the services that were used by the subscriber and any charging information.

Benefits of CSS

CSS provides several benefits to mobile operators who use the CSG platform:

  1. Single Point of Management: CSS provides a single point of management for subscriber information, which simplifies the management of subscriber profiles.
  2. Converged Services: CSS enables mobile operators to offer convergent services that work across multiple access networks, such as 3G, 4G, and Wi-Fi.
  3. Personalized Services: CSS enables mobile operators to provide personalized services to subscribers based on their subscriber profile.
  4. Scalability and High Availability: CSS can be deployed as a cluster of servers that provides scalability and high availability to the CSG platform.

Conclusion

CSS is a key component in the Converged Services Gateway (CSG) architecture that is used in mobile networks. CSS is responsible for managing the subscriber information that is used by the CSG platform. CSS provides several benefits to mobile operators, including a single point of management, converged services, personalized services, and scalability and high availability. CSS works closely with the other components in the CSG environment to provide convergent services to subscribers.