Viettel moves 100 million subscribers to home-grown cloud-native charging in three months - with zero downtime

HANOI, Vietnam, Oct. 27, 2026 /PRNewswire/ -- Viettel High Technology Industries Corporation (Viettel High Tech), part of Viettel Group, has migrated more than 100 million subscribers and some 5,000 tariff plans at Viettel, Vietnam's largest mobile operator, to vOCS 4.0, its in-house cloud-native charging system. The three-month cutover ran on a live national network with no service disruption.

Replacing a charging system is one of the riskiest projects an operator can undertake, which is why many stick with legacy platforms. Viettel High Tech reduced the risk through real-time data synchronization, parallel running and a phased cutover, with instant rollback at every stage.

The project won the Telecom Review Excellence Awards 2026 prize for Best Technology Deployment in Asia, a first for a Vietnamese company.

What it means for operators:

• Scale: more than 300,000 transactions per second at latency below 5 milliseconds, across 2G–5G and fixed services on one platform
• Lower cost: up to 50% less hardware investment than the previous generation, by sharing infrastructure with the network
• Agility: new tariff plans in hours instead of days, new features three times faster and deployments about 30% faster
• Resilience: two active data centers about 2,000 km apart and automatic recovery in under two minutes

Viettel High Tech developed every core layer in-house, from a telecom-grade cloud-native platform and NFV-MANO orchestration to real-time charging, subscriber and balance management.

"Passing rigorous tests of real-time self-diagnosis and self-recovery is what allows an operator to keep its promise of 24/7 service to customers," said Luu Manh Ha, CEO of Viettel Networks, which operates the system on Viettel's network in Vietnam. "Above all, owning the charging system means an operator is not dependent on foreign vendors – it safeguards digital sovereignty and preserves business flexibility."

"The charging system is where an operator's business strategy turns into revenue in real time," said Nguyen Minh Quang, CEO of Viettel High Tech. "We believe vOCS 4.0 is ready to help operators worldwide capture the value of 5G and digital services."

In 2017, vOCS 4.0's predecessor, vOCS 3.0, replaced a foreign vendor's platform for 90 million Viettel subscribers. Across both generations, vOCS serves more than 220 million subscribers in 11 countries. Viettel High Tech now offers vOCS 4.0 to operators worldwide.