The migration
Viettel High Tech, part of Viettel Group, has moved more than 100 million subscribers and about 5,000 tariff plans at Viettel, Vietnam's largest mobile operator, onto vOCS 4.0, a charging platform the company built itself. The cutover took three months and ran on the live national network with no disruption to service, the company said.
The earlier generation, vOCS 3.0, replaced a foreign vendor's platform for 90 million Viettel subscribers in 2017, and across both generations vOCS serves more than 220 million subscribers in 11 countries, according to the company.
The method
Viettel High Tech said it handled the risk of the replacement with real-time data synchronisation, parallel running of the old and new systems and a phased cutover, with instant rollback available at each stage. The project received the Telecom Review Excellence Awards 2026 prize for Best Technology Deployment in Asia, which the company described as a first for a Vietnamese company.
The figures
The company said the platform processes more than 300,000 transactions per second at latency below 5 milliseconds, covering 2G to 5G and fixed services on one system. It said hardware investment is up to 50% lower than the previous generation because infrastructure is shared with the network, that new tariff plans can be introduced in hours rather than days, and that new features arrive three times faster and deployments about 30% faster. Two active data centres about 2,000 km apart allow automatic recovery in under two minutes, it said.
The executives
Luu Manh Ha, chief executive of Viettel Networks, which operates the system on Viettel's network in Vietnam, said passing tests of real-time self-diagnosis and self-recovery is what lets an operator keep a 24/7 service promise, and that owning the charging system means an operator is not dependent on foreign vendors. Nguyen Minh Quang, chief executive of Viettel High Tech, said the charging system is where an operator's business strategy turns into revenue in real time, and that he believes vOCS 4.0 is ready to serve operators worldwide.
Every core layer, from the cloud-native platform and NFV-MANO orchestration to charging, subscriber and balance management, was developed in-house, the company said. Viettel High Tech now offers vOCS 4.0 to operators worldwide.
