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Traffic Profile (traffic + profile)

Distribution by Scientific Domains

Engineering	100%

Selected Abstracts

GSn: A new service type for integrated services on the internet,

EUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 1 2001
Enrico Gregori
Network services with deterministic guarantees are based on a worst,case description of user,generated traffic. When designing a policing and scheduling algorithm for guaranteed services on the Internet, accuracy of description of the traffic profile has to be traded with simplicity of implementation. The result of this trade off is often expressed as the number of token buckets required by the service along with the choice of their parameters. The GS type of service proposed by the IETF uses two token buckets both for characterizing the traffic and for policing it. The choice of using only two token buckets is primarily driven by policing costs. In this paper we propose a method that allows the number of token buckets used for characterizing the traffic to be greater than what is actually needed to police it. This means we can obtain an accurate profile of the traffic while keeping policing simple. The method consists of computing a profile of the traffic which involves a number of token buckets of the order of ten, and then doing the policing using only the first token bucket, plus another one which is chosen depending on the delay requirements of the receivers. This paper shows that with this simple enhancement we obtain a guaranteed service whose performance closely approaches the theoretical limits of services with deterministic guarantees. [source]

Smoothing and transporting video in QoS IP networks

INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 7 2006
Khaled Shuaib
Abstract Real-time traffic such as voice and video, when transported over the Internet, demand stringent quality of service (QoS) requirements. The current Internet as of today is still used as a best effort environment with no quality guarantees. An IP-based Internet that supports different QoS requirements for different applications has been evolving for the past few years. Video streams are bursty in nature due to the instant variability of the video content being encoded. To help mitigate the transport of bursty video streams with minimal loss of information, rate-adaptive shapers (RASs) are usually being used to reduce the burstiness and therefore help preserve the desired quality. When transporting video over a QoS IP network, each stream is classified under a specific traffic profile to which it must conform, to avoid packet loss and picture quality degradation. In this paper we study, evaluate and propose RASs for the transport of video over a QoS IP network. We utilize the encoding video parameters for choosing the appropriate configuration needed to support the real-time transport of Variable Bit Rate (VBR) encoded video streams. The performance evaluation of the different RASs is based on the transport of MPEG-4 video streams encoded as VBR. The performance is studied based on looking at the effect of various parameters associated with the RASs on the effectiveness of smoothing out the burstiness of video and minimizing the probability of packet loss. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Performance evaluation of TCP-based applications over DVB-RCS DAMA schemes

INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS AND NETWORKING, Issue 3 2009
M. Luglio
Abstract Transmission Control Protocol (TCP) performance over Digital Video Broadcasting,Return Channel via Satellite (DVB-RCS) standard is greatly affected by the total delay, which is mainly due to two components, propagation delay and access delay. Both are significant because they are dependent on the long propagation path of the satellite link. The former is intrinsic and due to radio wave propagation over the satellite channel for both TCP packets and acknowledgements. It is regulated by the control loop that governs TCP. The latter is due to the control loop that governs the demand assignment multiple access (DAMA) signalling exchange between satellite terminals and the network control center, necessary to manage return link resources. DAMA is adopted in DVB-RCS standard to achieve flexible and efficient use of the shared resources. Therefore, performance of TCP over DVB-RCS may degrade due to the exploitation of two nested control loops also depending on both the selected DAMA algorithm and the traffic profile. This paper analyses the impact of basic DAMA implementation on TCP-based applications over a DVB-RCS link for a large set of study cases. To provide a detailed overview of TCP performance in DVB-RCS environment, the analysis includes both theoretical approach and simulation campaign. Copyright © 2009 John Wiley & Sons, Ltd. [source]

GSE: A flexible, yet efficient, encapsulation for IP over DVB-S2 continuous generic streams

INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS AND NETWORKING, Issue 3 2008
Juan Cantillo
Abstract The second-generation specification for Digital Video Broadcast over Satellite, DVB-S2, defines an improved and adaptive physical layer. A new framing structure at the link layer, known as the generic stream (GS), is introduced offering an alternative to the well-known MPEG transport stream (TS). This paper presents the requirements for and the design of an encapsulation protocol to transport IPv4 and IPv6 datagrams and other network protocol packets directly over DVB-S2 using this GS profile. The resulting generic stream encapsulation (GSE) is a novel method that provides flexible encapsulation with support for fragmentation. A flexible extension header format allows GSE to carry additional header information, suitable for enhanced features, such as link layer encryption and IP header compression. The paper assesses GSE performance by simulation using realistic traffic profiles and attenuation fading. This demonstrates considerable improvement in efficiency compared with the MPE/MPEG-2 TS, especially when used with adaptive coding and modulation (ACM). Although designed for DVB-S2 systems, the new encapsulation is suitable for other second-generation physical layer standards. Copyright © 2008 John Wiley & Sons, Ltd. [source]