Voice over Internet Protocol (VoIP) is a general term for a family of transmission technologies to delivery of voice communications over IP networks such as the Internet or other packet-switched networks. VoIP systems employ session control protocols to control the set-up and tear-down of calls as well as audio codecs which encode speech allowing transmission over an IP network as digital audio...

VoIP (Voice over IP) is a service that requires synergy between the underlying network for transport and the endpoints responsible for voice processing. We evaluate the end-to-end quality and performance of several VoIP end-points. In particular, we focus on the following aspects: mouth-to-ear (M2E) delay, clock skew and behavior under packet loss. Our measurement results show that M2E delay de...

Die Arbeit beschreibt ein Konzept für ein neues Messsystem zur Beurteilung der Qualität des Videostroms beim Dienst Video Telephony in IP-Umgebungen (VToIP). Das System basiert auf dem Prinzip einer aktiven Messung und verwendet den PEVQAlgorithmus. Es ermöglicht sowohl die Bestimmung der QoS als auch der QoE. Die durchgeführten Untersuchungsreihen liefern wertvolle Hinweise für die Implementie...

Heterogeneous Networking poses many challenges in several areas. The expansion of link and MAC layers has been accompanied by contracting in the network layer as a core networks use IP packets to facilitate key service including telephony, data and multimedia. In this paper we discuss the Heterogeneous Networks, presented a reference model and scenario and applied an authentication mechanism to...

Quality of Service in Enterprise VoIP Voice-Over-IP (VoIP) allows the convergence of voice and data traffic on the enterprise packet-based data network. Migration to VoIP telephony is accelerating: organizations upgrading or changing facilities are examining VoIP-based solutions. For those implementing VoIP, success depends on guaranteeing that “Quality of Service” (QoS) is equivalent to that p...

Spam over Internet Telephony (SPIT) is a potential source of disruption in Voice over IP (VoIP) systems. The use of anti-SPIT mechanisms, such as filters and audio CAPTCHA (Completely Automated Public Turing Test to Tell Computer and Humans Apart) can prevent

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. A wide range of Internet telephony systems are currently marketed. However, most of these systems are developed using proprietary technology. Interoperability between systems from different vendors are not sup...

Over the past several years, the primary focus of investigation for speech recognition has been over the telephone or IP network. Recently more and more IP telephony has been extensively used. This paper describes the performance of a speech recognizer on noisy speech transmitted over an H.323 IP telephony network, where the minimum mean-square error log spectra amplitude (MMSE-LSA) method [1,2...

Talk given by Kevin McIntyre 1 1 ZARLINK Semiconductors 1 INTRODUCTION. Zarlink Semiconductor is a provider of TDM voice/data switching chips, with the broadest line of TDM switches in the industry establishing a leadership in timing chips for T1/E1 equipment. " Zarlink holds a strong portfolio of intellectual property, numbering about 2,100 patents and pending applications in key technologies ...

 As a IP telephony protocol, the SIP is gaining increasing popularity. There is yet POTS(Plain Old Telephone Service) line as the existing subscriber line. The Megaco/H.248 may be used for call between the POTS line and SIP. So, it is needed that method for interworking between Megaco/H.248 and SIP. In this paper, we propose the implementation of Residential Media Gateway Prototype in Interwor...