ABSTRACT
Voice over Internet Protocol (VoIP) is emerging as an alternative to regular public telephones. IP telephone service providers are moving fast from low-scale toll bypass deployments to large-scale competitive carrier deployments, thereby giving an opportunity to enterprise networks a choice of supporting less expensive single network solution rather than multiple separate networks. Broadband-based residential customers also switch to IP telephony due to its convenience and cost-effectiveness. Contrary to traditional telephone system (where the end devices are dumb), the VoIP architecture pushes intelligence towards the end devices (i.e., PCs, IP phones etc.) giving an opportunity to create many new services which cannot be envisaged using traditional telephone system. This fl exibility, coupled with the growing number of subscribers, VoIP becomes an attractive and potential target to be abused by malicious users, hackers, and criminals alike to harass the legitimate users and to capitalize on its weaknesses.
