This paper presents a new approach to provide computer telephony integration for mobile users and distribute services over the hybrid network domain. A new multimedia processing paradigm is presented in form of a distributed, agentbased architecture, called ‘Distributed Agent Network’, DAN, together with example services. The proposed architecture is designed to support user and data mobility, ...

Intrusion detection systems (IDS) provide security for network systems. They are used in computer networks to detect violations against security policies or unusual events that could lead towards a security thread. Telephone networks based on the internet protocol (IP) called IP telephony (IPT) are a recent development in network usage and will become a common application in the next years as t...

Voice over IP telephony reduces communications costs, but it is also subject to spam, i.e. unwanted, unsolicited calls. This paper discusses the problem of spam over IP telephony and reviews published techniques to reject likely nuisance callers. The techniques investigated include content filtering, black lists, white lists, gray lists, call rate monitoring, IP/domain correlation, reputation s...

This paper describes the author’s perspective on multimedia quality prediction methodologies for multimedia communications in advanced mobile and internet protocol (IP)-based telephony, and reports related experiments and trials. First, the paper describes the need for perceptual QoS (Quality of Service) assessment in which various quality factors in multimedia communications for advanced mobil...

SIP is a call control and signalling protocol that was adopted by the 3GPP to deliver IP multimedia services to the mobile network. Cross platform IP-telephony service creation is a challenging task. Although, the emergence of JAIN-SIP has reinforced the development and implementation of platform-independent IP-telephony services, the development of advanced cross-platform SIP (Session Initiati...

Telecommunications at home is changing rapidly. Many people have moved from the traditional PSTN phone to the mobile phone. Now for increasingly many people Voice-over-IP telephony on a PC platform is becoming the primary technology for voice communications. In this tutorial paper we give an overview of some of the current trends and try to characterize the next generation of home telephony, in...

Internet telephony was first used as a simple way to provide point-to-point voice transport between two IP hosts. However, the growing interest in providing integrated voice, data, and video services has caused its scope to be expanded. Internet telephony now encompasses a range of services. These services include not only traditional conferencing, call control, multimedia, and mobility service...

Over the last years Voice-over-IP (VoIP) is getting widespread adoption from business and residential customers.The preference towards VoIP services stems from the fact that VoIP provides many ways to communicate, with a lower cost than traditional telephony. However, VoIP in its present form may allow malicious users to exploit a number of vulnerabilities, make bulk unsolicited telephony calls...

In this paper, we evaluate available steganographic techniques for SIP (Session Initiation Protocol) that can be used for creating covert channels during signaling phase of VoIP (Voice over IP) call. Apart from characterizing existing steganographic methods we provide new insights by introducing new techniques. We also estimate amount of data that can be transferred in signalling messages for t...