The painless adding of OTT services to the Smile voLTE network, a case study Presented at TADSummit Lisbon 18th November Joachim Vanheuverzwijn CTO Securax Ltd (Zoiper) A case study on how the revolutionary African LTE operator SMILE and the Zoiper Softphone team designed their operator OTT services around Kamailio for streamlined interworking between OTT and voLTE while avoiding additional complexity in the core network.