Requirement gathering for software development project is the most crucial stage and thus requirement engineering (RE) occupies the chief position in the software development. Countless techniques concerning the RE processes exist to make sure the requirements are coherent, compact and complete in all respects. In this way different aspects of RE are dissected and detailed upon. A comparison of RE in Agile and RE in Waterfall is expatiated and on the basis of the literature survey the overall Agile RE process is accumulated. Agile being a technique produces high quality software in relatively less time as compared to the conventional waterfall methodology. The paramount objective of this study is to take lessons from RE that Agile method may consider, if quality being the cardinal concern. The study is patterned on the survey of the previous research reported in the coexisting literature and the practices which are being pursued in the area.

Computation is spanning from PC to Mobile devices. The Mobile Ad hoc Networks (MANETs) are optimal choice to accommodate this growing trend but there is a problem, security is the core issue. MANETs rely on wireless links for communication. Wireless networks are considered more exposed to security attacks as compared to wired networks, especially; MANETs are the soft target due to vulnerable in nature. Lack of infrastructure, open peer to peer connectivity, shared wireless medium, dynamic topology and scalability are the key characteristics of MANETs which make them ideal for security attacks. In this paper, we shall discuss in detail, what does security mean, why MANETs are more susceptible to security attacks than wired networks, taxonomy of network attacks and layer wise analysis of network attacks. Finally, we shall propose solutions to meet the security challenges, according to our framed security criteria.