Abstract-Rapid growth in the evolution of wireless technologies and mobile user demands necessitates future wireless communication to be a conjunctive working of several heterogeneous networks with their complementary features. Roaming of mobile terminals with different access interfaces and technologies among dissimilar networks is inescapable depending upon the user demands. Anywhere, anytime, any type connectivity is the raising requirement for mobile users either for real time or non-real time services. Recent literature has brought out numerous vertical handoff protocols for the emergence of the best network. In this paper, we give an overview and categorization of various vertical handoff decision schemes with reference to their characteristics. We also have given a synthesis of various vertical handoff decision schemes against diverse parameters.