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Disaster recovery in large VoLTE deployments

Case study: Voice over LTE

In this case study from India, we describe how Nokia Core Networks Global Services was able to implement the largest VoLTE geo-redundancy disaster recovery solution rapidly and cost-efficiently for the 150+ million subscribers of Bharti Airtel. 

Who is Bharti Airtel?

Bharti Airtel, with 155 million subscribers, has one of the world’s biggest voice over LTE (VoLTE) services in the world, with operations across the Indian sub-continent. Dedicated to providing a world-class experience, Bharti turned to Nokia to help ensure a seamless and uninterrupted service experience for its customers.

VoLTE cloud solution benefits

When deployed as a cloud solution, VoLTE uses the data capacity of the 4G/LTE network and a cloud-based IMS server (Internet Multimedia Services) located in the core network to provide a full range of voice and, potentially, video communications. The quality of voice calls is much higher than traditional circuit-switched voice services and is now supported by all present generation Android and Apple smartphones.

VoLTE voice service benefits

VoLTE voice services are also capable of delivering highly flexible services to enterprise customers that integrate with enterprise unified communications systems. They can support field agents with the ability to combine data and video exchanges seamlessly into the call.

Bharti Emergency Alerts Service benefits

Services such as the Bharti Airtel Emergency Alerts Service, which allows subscribers to alert up to 10 loved ones with one call, also rely on the availability of the system during disaster situations. It is critical, therefore that these business- and mission-critical applications are highly reliable and secure, even in the case of disaster. 

How Nokia solution helped

The Nokia solution was designed to create N+1 redundancy, meaning that for all 12 hubs, there would always be one additional core available to replace the failure of a single regional hub. This 12+1 DR core, which provides the disaster recovery backup, includes all Nokia core network functions, including the IMS functions needed for VoLTE. In the case that one of the Bharti regional hubs fails, there is an automatic cutover to the redundant DR hub without service interruption.

“Nokia and Airtel together designed and deployed a unique disaster recovery (DR) solution specific to Airtel, which uses N+1 mode with a single DR hub able to support multiple active hubs. The best part is that the switchover from active hub to DR hub in case of any failure, happens automatically without any service impact. This has resulted in a highly available and resilient network with much better customer experience as the services remain available even in case of any partial or complete failure of any of the hubs. As a result, Airtel is confidently moving faster to convert the entire circuit-switched voice network to Nokia’s VoLTE IMS solution, thus improving VoLTE uptake in the Indian market.”
Rashim Kapoor
Senior Vice President – Core Networks, Bharti Airtel
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