NTT DOCOMO, has cloud shifted its mission critical system which manages authentication infrastructure used by 100 million users to the cloud, increasing the development speed by 4 times

NTT DOCOMO operates communication businesses such as 5G and broadband, smart life businesses including video services and finance, as well as other business domains. The system that plays a central role in the company's services is called “CiRCUS.” CiRCUS is a mission-critical system that manages essential functions such as internet connectivity and email as an ISP, as well as d account authentication functions with 100 million accounts.

Since it was built in 2003, the CiRCUS has been operated in an on-premises environment and has undergone continuous improvements. However, the challenges have emerged, such as the complexityof modifications due to the tightly coupled applications and the difficulty in dealing with fluctuations in traffic. Therefore, the company decided to shift to the cloud in order to eliminate technical debt, balance speed, quality, and cost, and adopt a way of working focused on creating value.

“The primary goal is to speed up development. In order to quickly provide the value that customers want, it was necessary to move away from regular quarterly development, adopt a cloud platform that can respond quickly to changes, and simultaneously implement drastic structural reforms, such as transitioning to an agile development system capable of keeping up with changes” says Mr. Noboru Horimoto, Manager in charge of Service Virtualization Infrastructure at the Cloud Design Office, Network Headquarters Service Design Department.

Mr. Horimoto immediately offered to the head of the organization when he was impressed by the AWS agility during his participation of AWS global event (re:Invent) in 2019, and he had built the foundation for a corporate common ID (business d account) that had been requested to be developed on the AWS. Starting with this initiative, we have been developing a cloud-based version called 'CiRCUS-Lite' since 2020, implementing some of the core functions and websites on AWS.

Regarding the reason for adopting AWS, Mr. Satoshi Uematsu, who is in charge of application infrastructure at the Network Division Service Design Department, explained, “The most important aspect is that it meets the stringent requirements demanded of telecommunications equipment. The deciding factor was that AWS data centers comply with the ISO 27001 information security management standard and are equipped to handle large-scale disaster recovery. We also appreciated the wide range of managed services that allowed us to reduce reliance on scratch development, and the scalability to adjust resources in response to service growth and event demands.”

The transition of services and functions to CiRCUS-Lite started with front-end components, prioritized according to development frequency, user trends, and the overall service roadmap and so on. Our basic principle for applications is to rebuild them based on a cloud-native architecture.

“With the end of i-mode in 2025 and the system's EOL in sight, we are reviewing the overall schedule and identifying which components will shift to the cloud and which will remain on-premises. The applications were designed to enhance agility through the adoption of a microservices architecture.” (Mr. Uematsu)

As a result, we built an ahamo website with a new rate plan in 2020, an API cooperation platform with over 1 billion daily accesses in 2022, d account authentication platform that performs 30 million authentications per day in 2023, and an irumo website, etc. were built on AWS, and 30 services and functions are being provided as of October 2024.

Among the refactored systems, the iconic service is an API collaboration platform called ‘Force.’ Mr. Keita Katsuno, in charge of Application Infrastructure at the Network Headquarters, Service Design Department, said, “FoRCE divides the front-end, authorization, and back-end into decoupled components, using serverless and managed services like Amazon ECS on AWS Fargate and AWS Lambda to ease development burdens. We also made the back-end DB a simple model that does not depend on data structures, and the latest information is provided by continuously synchronizing with the DB in the on-premises environment using AWS Database Migration Service (AWS DMS), contributing to the improving of the business value of DOCOMO's services.”

CiRCUS-Lite's development structure shifted to an agile model, delegating decision-making authority to Scrum teams organized by service units. At the same time, we reviewed the development and operations system and after that we adopted a DevOps approach, where Scrum teams handle everything from development to operations.

“Since it was the first approach to agile, the project team members first received training and worked on changing their mindset. As for DevOps, operations members became part of the Scrum teams, and the practice was gradually implemented by transferring operational responsibilities to the development team.” (Mr. Uematsu)

Development speed has increased significantly due to cloud shift and agile development.

“For FoRCE, the development speed has increased four times, and the release frequency has increased by 4 to 10 times, achieving 12 to 24 releases per year, or more than once a month. As a result, the service department is now able to provide the functions that customers are looking for at an early stage.” (Mr. Katsuno)

By utilizing the managed services, CiRCUS-Lite reduced development costs by 40%, deployment frequency has been reduced to weekly or monthly, with change lead times shortened to 1 week to 1 month.

“The benefits of increased flexibility outweigh the cost reductions, and by working with cutting-edge technologies, the engineers' motivation has also been enhanced.” (Mr. Uematsu)

Through agile development and DevOps, the mindset of the team members has shifted from "failure-free development" to "business growth" and "improving customer experience through development from the customer's perspective."

Ms. Saki Iwata, who joined the team in July 2021 as a new graduate and has been responsible for the development of services such as FoRCE, ahamo, and irumo in the Network Headquarters, Service Design Department, Application Infrastructure team, said, “With agile development, we can quickly make improvements and deliver them while listening to the real voices of our customers. In projects such as ahamo and irumo, we developed the services while considering the direction with the business department, using voices from social media as a reference. I find it rewarding to be part of a Scrum team with authority, working closely with the business department and vendors in an integrated development style."she recalls.

Regarding the future of CiRCUS-Lite, the plan is to continue meeting customer expectations by achieving high-frequency deployments through advanced release methods, implementing disaster recovery (DR) measures, transitioning to DevSecOps including security, and improving agility through platform engineering. For the entire CiRCUS system, we are working on structural reforms for on-premises systems while simultaneously shifting to the cloud, aiming for synergistic effects.

“AWS has greatly contributed to the development team through their ongoing support. We request continued support for the modernization of the entire CiRCUS system.” (Mr. Horimoto)