Free roaming for Yota subscribers at 0: how does it work?

We launched a service due to which Yota customers will not be left without communication in international roaming with a zero balance. Now, after the traffic and funds in the account are over, you can continue to exchange text messages for free in the most popular messengers: WhatsApp, Viber, Telegram, Facebook Messenger, and iMessage. Why they, how this service is implemented and in what cases is activated, read under the cut.



The service is activated in international roaming automatically in any of the three cases:

• the balance reaches zero
• there are not enough funds in the account to connect the Internet traffic package while roaming,
• the user does not extend the package of Internet traffic in roaming.

Correspondence in instant messengers will be free while the client is roaming and he does not have enough funds in the account. Not limited to text traffic, to transfer media files - pictures, video, audio - you need to activate a package of Internet traffic or use the service of megabyte rating. Text messages can be of any size, smiles and stickers will also be available - they are transmitted in the form of tags, not images.

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Recall that when using a Yota SIM card for a smartphone in any of 55 popular countries, if you pay 20 MB, another 20 MB is provided to Yota customers as a gift. Even in 174 countries, the “5 + 5” rule applies: if you pay 5 MB, the same amount is provided for free. Since the introduction of this service, the number of Yota users using mobile Internet in roaming has increased fivefold.

Selection of instant messengers

Five messengers, the text traffic of which we do not take into account in international roaming, were not chosen by chance - these are the most popular applications among Yota users. Most often, our customers choose WhatsApp (45%) and Viber (28%), Telegram (8%) and Facebook Messenger (4%) go by a large margin. At the same time, Viber leads among our users in Moscow (40%) and St. Petersburg (46%).

Technical implementation

To highlight the text traffic of five messengers, we use the DPI software complex developed by Procera Networks, which we modified. On its basis, a pricing system, traffic redirection and much more are implemented. This is a network module responsible for processing traffic and providing access to the Internet.



Procera Networks provides signatures with which DPI performs client traffic analysis and extracts from the general flow what we need: Viber, WhatsApp, p2p, etc. We have completed the basic functionality of DPI, since standard signatures did not meet our requirements. This is a standard practice for mobile operators; DPI developers cannot take into account all the conditions and requirements. For example, by default in Viber it was impossible to separate voice data from text. Together with Procera Networks, we analyzed the traffic dumps, and made changes to the signatures of the selected instant messengers. After that, it became possible to extract the text data of five messengers from the general user traffic.



The testing phase took several months. It was necessary to check the correctness of traffic accounting for different operating systems and applications. Debugging has become the most difficult stage of work. The greatest difficulty was with Telegram, which was updated almost every week. The protocol he used often changed, so I had to periodically adjust the signature.



Our colleagues, who went on vacation, took part in testing the “in the fields” service. A curious incident is connected with this. Our traffic control service reported that one of the clients pumped free traffic for a million rubles. Having understood, they found out that this is our employee who tested the service in Ukraine. It turns out that with inter-operator calculations, the cost of a megabyte in Ukrainian roaming exceeded 10 thousand rubles, although this does not affect our users.

Conclusion

We launched a product, thanks to which our customers can actively use the smartphone while traveling, without fear of remaining without communication if the traffic ends. Yota users today can send free text messages in WhatsApp, Viber, Telegram, Facebook Messenger and iMessage in international roaming with a zero balance or the termination of the Internet traffic package.