With the growing demands of system automation, technology integration, and non-human intervention technique, Internet-of-Things (IoT) has evolved as a boon and value-added services over pervasive computing. IoT comprises a highly complex system that integrates ubiquitous computing with lowpowered data capturing devices via a gateway. Along with various forms of unimaginable advantages, IoT is also associated with a huge list of ongoing problems. The prime objective of the paper is to gauge the effectiveness of existing works of literature being carried out towards mitigating the issues of IoT. The paper illustrates the most frequently explored research topic and less regularly explored topic in IoT for providing a true picture of existing research trends. The paper also idealizes some of the research gaps that have been extracted after reviewing the existing literature.