Mobile Virtual Private Network Service Architecture

Defne’s Mobile Virtual Private Network (MVPN) service offers a range of advanced features and a robust infrastructure that integrates all the MSISDNs (Mobile Station International Subscriber Directory Numbers) of a particular entity into a cohesive, private network. Let’s delve into the key aspects of our MVPN service and the core modules that make it all possible.

Layer 1: Signalling Layer

The signalling layer is the backbone of our MVPN system, acting as the critical interface between our platform and the core network. This layer comprises two signalling servers that operate in an active-active mode, ensuring balanced load distribution and high availability.

• SIGTRAN (INAP) Signalling Stack: Handles signalling for Intelligent Network (IN)-based functions, essential for services like call routing and subscriber management.

• SIP Signaling Stack: Manages signaling for SIP-based functions, crucial for voice-related activities and VoIP services.

Each signaling server processes half of the incoming traffic from the core network, ensuring redundancy and continuous service. These servers connect to core network elements, such as Signal Transfer Points (STPs) or Mobile Switching Centers (MSCs) through SIGTRAN/M3UA for IN integration and to MSCs or Media Gateways (MGWs) for SIP integration.

Layer 2: Application Layer

The application layer is where the core functionalities of our MVPN service are executed. It hosts the media application, RespUS, responsible for establishing voice channels with MGWs using RTP (Real-time Transport Protocol).

• RespUS Media Application: Manages service scenarios and interacts with both the signaling layer for message exchange and the database layer for subscriber information.

• Active-Active Mode: Two application nodes run concurrently, ensuring continuous service and load balancing.

By leveraging the signaling layer's capabilities, the application layer ensures seamless communication within the network, enhancing the overall user experience.

Layer 3: Database Layer

The database layer is the repository of all critical data needed for the operation of our MVPN service. This includes subscriber information, company settings, and system configurations.

• MariaDB RDBMS: Our database servers run on MariaDB, ensuring robust and efficient data management.

• Galera Clustering: The database nodes operate in cluster mode, providing high availability and data consistency across the system.

This layer is pivotal for retrieving and storing data necessary for various network operations and service scenarios, ensuring that all subscriber and system information is readily accessible and up-to-date.

Test and Development Environment

To maintain the highest standards of service, our platform includes a dedicated testbed server. This server replicates the live environment, allowing administrators to test new features and updates thoroughly before deploying them on production servers.

• Integration with Test Core Network Nodes: Ensures that every module can be tested in a real-world scenario.

• Controlled Deployment: Administrators can safely deploy and test new functionalities on predefined numbers, minimizing the risk of disruptions.
  

Virtualization and Resource Management

All servers in our platform are virtualized, optimizing resource utilization and ensuring flexibility. However, it's crucial that these virtual servers are isolated from OS-based backup operations performed by the virtualization platform to prevent any impact on performance.

Seamless Integration with Operator’s Core Network

Our MVPN system is designed to integrate seamlessly with the served Mobile Operator’s core network. Calls to a specific short number range are redirected to the MVPN system. For IN integration, a mobile-originated (MO) trigger is defined for MVPN subscribers, ensuring efficient call handling and service delivery.

Core Modules of Our MVPN Solution

Our MVPN solution is composed of several key modules, each playing a crucial role in delivering our comprehensive service.

• Provisioning Module: Supports both SOAP and REST interfaces, managing provisioning activities with the operator's system and handling bulk service activations efficiently.

• Web GUI: Provides user interaction interfaces for operators, administrators, customer care representatives, and corporate clients. The Management GUI and Company Admin GUI run on Apache Tomcat, with the latter accessible via a proxy server for added security.

• Signaling Stack: Handles signaling with the core network over SIGTRAN, utilizing IN to control calls made by MVPN members to external numbers, ensuring seamless and controlled communication.

• Call Control Module: Manages calls using the SIP protocol, establishing RTP sessions between Media Servers and MSCs.

• Media Module: Manages RTP sessions for calls made to the MVPN platform, executing predefined scenarios, playing announcements, recording calls, and more to enhance functionality and user experience.

• Charging Module: Interacts with the prepaid charging system for real-time charging and generates Call Detail Records (CDRs) for each transaction.

• SNMP Traps: Sends predefined alarms to the network management station, ensuring prompt identification and resolution of any issues.

• Database Management: Uses MariaDB for storing configurations, call logs, SMPP parameters, and other essential data, with Galera clustering ensuring redundancy and high availability.

• Secure Access: Implements LDAP S/SSO login for secure access by Kyivstar admin and Customer admin, ensuring that only authorized personnel can access and manage the system.

• Reporting Module: Monitors internal activities and generates comprehensive reports to track performance, identify issues, and make informed decisions.

• Business Logic Module (BLM): Integrated with the Signaling Module to manage business logic for Mobile Originating (MO) calls, determining call connection parameters and handling number manipulation based on service features.

Conclusion

Our MVPN service offers a highly integrated, efficient, and flexible communication solution for telecom operators. By employing a robust three-layered system, we ensure seamless signaling, efficient application processing, and reliable data management. This architecture not only enhances service delivery but also guarantees high availability and scalability, meeting the dynamic needs.