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The Internet has now become such an important infrastructure that is capable of sending information within a very short time and easy to access. It is considered as public networks that provide affordable WAN services to most customers. Applications such as video conferencing, file transfer protocol and VoIP are the example of typical network applications supported by the Internet Protocol. Various...
Voice over Internet Protocol (VOIP) is a technology that transports voice data packets across packet-switched networks using the Internet Protocol (IP). Losing packets in the network is inevitable, and losing voice packets degrades audio quality. The Sender-Based loss-recovery techniques can be used to mitigate the undesired effects of packet loss in VOIP system. In this Paper we introduce a newly...
One of the most interesting applications of single — sided Quality of Experience (QoE) metrics is their use in improving the quality of the service, as perceived by the user. This can be done either at the application level — by for example changing the encoding in use, or the level of error correction applied — or at the network level, for instance by choosing a different DiffServ marking strategy,...
This design mainly aims at the small and medium-sized enterprise. On its existing internal integration local area network, it realizes the special-purpose IP telephone network in the enterprise, and it also realizes the main purpose that is the “zero” long-distance phone bill trans-regional enterprise. Because of VoIP is the technology of analog voice signal digitized and making the real-time transmission...
Nowadays the use of Internet protocol (IP) has transformed the delivery of content and services over networks. The perspective of low costs communications determined a very fast development of Voice over Internet Protocol (VoIP) technologies. Along with voice, VoIP communications channels can transport video streams also. This type of VoIP communications, also known as videoconferencing, demands a...
Integration of different network services into a converged infrastructure is one of the most intensive challenges in the converged network application development area. Huge differences exist regarding several characteristics of data, voice and video content traffics. While data traffic requires error free services, real time applications like interactive video transfer and VoIP distress of the high...
The next generation technology of Voice over Internet Protocol (VoIP) allows voice to be delivered over the Internet Protocol based networks. The integration of VoIP and Wireless Local Area Network (WLAN) has become popular. However, WLAN architecture was primarily designed to carry data and not for real-time applications, such as VoIP. Hence, there is a need to enhance the quality of VoIP transmission...
This paper proposes a solution for throughput and stringent delay problems of VoIP in Ad-Hoc mode of IEEE 802.11 WLAN standards. This paper analyses the behaviour different codecs and schemes of WLAN running on VoIP traffic and draws a conclusion on the performance of network based on the criteria of different QOS parameters. Later the suitability of different routing protocols like AODV, DSR, OLSR...
DCCP is proposed to replace UDP for its ability of congestion control while maintaining its promptness by ignoring lost packets as UDP does. The network would suffer less congestion. However, whether the applications that switch from UDP to DCCP can maintain their needed performance or not is a big question. This paper investigates this problem by evaluating DCCP based VoIP vs. a variety of TCPs using...
We propose new authentication protocols that support fast hand-off for real-time applications such as voice over IP and audio/video conferencing in wireless mesh networks (WMNs). A client and a mesh access point (MAP) mutually authenticate each other using one-hop communications. The central authentication server is not involved during the handover process. Fast authentication for roaming from one...
This work presents a study of a SIP-based IP telephony system in terms of Quality of Service (QoS) and admission probability. The system is designed for an enterprise with offices in different countries. A software IP PBX maintains the dial plan, and SIP proxies are used in order to implement Call Admission Control (CAC) and to allow the sharing of the gateways' lines. The system is implemented in...
Earliest Deadline First (EDF) is a delay-optimal scheduling algorithm which is commonly used in real-time applications such as Voice over IP (VoIP) and Video on Demand (VoD) in wired and wireless networks. EDF calculates the deadline of a packet as follows: the latency parameter provided by the subscriber during admission control is added to the arrival time of the packet to form the packet deadline...
This paper introduces the concept of a virtually dedicated resource allocation (VDRA) scheme that significantly reduces signaling overhead for accommodating low/medium data traffic, including real-time VoIP traffic. The basic concept of the VDRA scheme is to allocate the virtually dedicated resource to each user and to use the resource only when there are data to be transmitted. The performance of...
Today, communications technology is one of the most essential roles for our life. People had used many ways of transmissions such as internet, mobile phone and so on. Moreover, VoIP (Voice over Internet Protocol) is also a communications technology. In this paper, we focus on VoIP which transmits voice over packet switched networks such as LANs (Local Area Networks) or WANs (Wide Area Networks). Adding...
Designing a heterogeneous network including systems providing different QoS, such as the emerging WiMAX, is a difficult task. The integration of a WiMAX access system with Differentiated Services (DiffServ) enhances the overall performance of the network. This paper investigates the interworking between WiMAX and DiffServ networks, by measuring one-way delay, jitter and packet drop rate of VoIP traffic...
Voice over Internet Protocol (VoIP) is a technology that transports voice data packets across packet switched networks using the Internet Protocol (IP). The key research is to develop a new method for QoS determination and dynamic control of the network that is applicable to VoIP industry. The paper investigates the effects of packet loss, delay and jitter on speech quality for VoIP. It extends the...
Stringent QoS maintenance in a wireless environment for VoIP communication is a major challenge. VoIP inherently generates constant bit rate traffic and is highly sensitive to network delay. However, unpredictable network congestion makes a VoIP session so degraded that its QoS goes below a tolerable limit. Accordingly, a suitable solution is needed to adapt varying network conditions satisfying minimum...
Multi-channel multi-radio wireless networks improve network performance by enabling more simultaneous transmissions. Among multi-channel multi-radio protocols, the hybrid multi-channel approach has been shown to be efficient in providing higher system throughput. Voice over internet protocol (VoIP) service is expected to be widely supported in wireless networks, though its capacity has not been studied...
“Internet' is desired services platform at home. The PSTN telephone is replacing to the VoIP (Voice over IP) telephone. Call cost of the VoIP telephone is inexpensive. But, it is not quickly wide-spread device. There are various reasons. One of reasons is a phone voice quality. The VoIP phone is using network. Network has many obstacles (Jitter, Drop, Delay, and etc.). They are reasons of bad voice...
In this paper, we propose QoS-aware AQM(Active Queue Management) method considering video quality level that service users request in DiffServ network environment. QoS provision is essential in order to provide multimedia services because real-time multimedia services such as IPTV and VoIP are sensitive to delay and packet loss. However, existing AQM methods can't guarantee QoS for a multimedia service...
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