Voice over IP is emerging as the new standard in telephony. It inexpensively routes calls worldwide and consumers are embracing it. Inexpensive communications opens the door for unsolicited calls. In this paper we investigate spam in VoIP, discuss properties of the technology that make it vulnerable to spam and propose the use of techniques which impose cost to spammers as an effective approach...

Internet Protocol (IP) based communication is fast becoming a viable alternative for voice communications. The Intelligent Network (IN) represents the world wide accepted basis for the uniform provision of advanced telecom services. Mobile Agents offer unique opportunities for structuring and implementing open distributed service architectures, facilitated by the dynamic downloading and movemen...

We apply some of the existing web server redundancy techniques for high service availability and scalability to the relatively new IP telephony context. The paper compares various failover and load sharing methods for registration and call routing servers based on the Session Initiation Protocol (SIP). In particular, we consider SIP server failover techniques based on the clients, DNS (Domain N...

Differentiated Services (DiffServ) are not yet fully adapted and integrated with mobile environments, especially when Mobile IP [7] is used as the mobility management protocol in the Internet. When a mobile node visits a foreign network and requests services based on Service Level Agreements (SLAs), the DiffServ Internet Service Providers (ISPs) must care about how to charge the mobile user. In...

Wireless access to Internet services will become typical, rather than as it is today, the exception. Such a vision presents great demands on mobile networks. Mobile IP represents a simple and scalable global mobility solution but lacks support for fast hando control and paging found in cellular telephony networks. In contrast, second and third generation cellular systems o er seamless mobility ...

Voice over Internet Protocol (VOIP) is one of the most notable applications of internet. Some other well known terms used for VOIP in literature include IP telephony or Internet telephony. It can be a better replacement for the traditional telephone systems because of its high resource utilization as well as low cost. Beside this, wireless LAN Network (WLAN) has emerged as a robust networking t...

An Internet telephony system is basically a computer-form of a conventional telephone to support real-time voice communication between two or more users who are connected to the Internet. Internet telephony circumvents expensive international telephone toll charges by using Internet as an intermediary medium to transport voice signals between two users. In doing so, transcontinental telephone c...

The growing popularity of IP telephony systems has made them attractive targets for spammers. Voice call spam, also known as Spam over Internet Telephony (SPIT), is potentially a more serious problem than email spam because of the real time processing requirements of voice packets. We explore a novel mechanism that uses duration of calls between users to combat SPIT. CallRank, the scheme propos...

Voice over IP (VoIP) is a key technology, which provides new ways of communication. It enables the transmission of telephone calls over the Internet, which delivers economical telephony that can clearly benefit both consumers and businesses, but it also provides a cheap method of mass advertising. Those bulks unsolicited calls are known as SPam over Internet Telephony (SPIT). In this paper we i...