A new proposal for assuring services in internet

In this paper we present a new mechanism to provide an assured service in terms of target rate and fair excess bandwidth, like the Internet Assured Service. Research in Internet Assured Service faced up both questions in separate ways proposing different traffic conditioners to work with the RIO buffer management, and proposing different modifications to this buffer management, among others. In this work, we suggest using a buffer management scheme different from RIO that also treats in-of-profile and out-of-profile packets differently but avoiding interference between them. This scheme is used together with the Counters Based traffic conditioner because of its high accuracy in guaranteeing target rates. We evaluate and compare by simulation the performance of our proposal using TCP RENO sources. One important issue to be considered is that the proposal is a feasible alternative to the standard architecture for Differentiated Services in Internet.This work was supported by the Spanish Research Council under grant TIC2000-1734- C03-03

Counters-based modified traffic conditioner

Traffic conditioners play a key role in implementing the Assured Service in the framework of the DiffServ approach. Many research papers have focused on finding the best traffic conditioner able to assure contracted target rates and to fairly distribute the excess bandwidth among competing sources. Nevertheless, none of the proposals presented so far accomplishes simultaneously both features. We propose a traffic conditioner for the Internet Assured Service called Counters-Based Modified (CBM) that strictly guarantees target rates and performs a fair share of the excess bandwidth among TCP Reno sources. The ability of strictly providing the inbound bandwidth is inherited from its predecessor the Counters-Based algorithm, and the fairness in the outbound bandwidth distribution is met by probabilistically dropping OUT packets in the traffic conditioner. To determine the dropping probability of an OUT packet, the amount of excess bandwidth and the average RTT of all connections in the traffic conditioner have to be known. Although this fact implies using some sort of signaling, it results more feasible than other proposed intelligent traffic conditioners. The CBM traffic conditioner is evaluated under different conditions by simulation using TCP Reno sources. Simulation results presented in this paper lead us to suggest it as a feasible election for the traffic conditioner device implementation in DiffServ.This work was supported by the Spanish Research Council under grant FAR-IP TIC2000-1734-C03-03

Performance evaluation of profiler mechanisms for the internet assured service

As Internet is rapidly growing and receiving traffic from multimedia applications that are sensitive to available bandwidth and delay experienced in the network, there is a strong need for quality of service (QoS) support. The Integrated and Differentiated Service models are two approaches for adding QoS to Internet. The Assured Service is an end-to-end service based on the Differentiated Service architecture. In this paper, we study and compare the performance of three profiler mechanisms to provide the guaranties of an Internet Assured Service. Two of them, TSW and Leaky Bucket are the most commonly used, and the third is a new Counter Based profiler, which is proposed in this paper. The study is done by simulation employing TCP RENO sources.This work was partly supported by the Spanish Research Council under grant TIC2000-1734-C03-03

Proportional bandwidth distribution in IP networks implementing the assured forwarding PHB

Recent demands for new applications are giving rise to an increasing need of Quality of Service (QoS). Nowadays, most IP-based networks tend to use the DiffServ architecture to provide end-to-end QoS. Traffic conditioners are a key element in the deployment of DiffServ. In this paper, we introduce a new approach for traffic conditioning based on feedback signaling among boundary nodes and traffic conditioners. This new approach is intended to provide a poportional distribution of excess bandwidth to endusers. We evaluate through extensive simulations the performance of our proposal in terms of final throughput, considering contracted target rates and distribution of spare bandwidth. Results show a high level of fairness in the excess bandwidth allocation among TCP sources under different network conditions

End-to-end TCP performance of the couple CBM traffic conditioner and RIO buffer management in a three node topology

Despite the abundant literature written about the AF PHB, no solution has been found to efficiently face up its two goals, assuring a minimum rate to the users and offering a fair distribution of the excess bandwidth if available. The Counters Based Modified (CBM) traffic conditioner, presented in a previous work, is able to achieve these objectives in single-node topologies. This paper raises issues with providing bandwidth assurance and spare bandwidth distribution for TCP flows in more complex topologies than usual. Simulation results explore the effect of target rates, round trip times, and efficiency of CBM when up to three network nodes implement service differentiation, including in some cases the coexistence of assured service and best-effort traffics.This work was supported by the Spanish Research Council under projects TEC2004-05622-C04-02/TCM and TIC2001-3339-C02-02

Scalable Multiple Description Coding and Distributed Video Streaming over 3G Mobile Networks

In this thesis, a novel Scalable Multiple Description Coding (SMDC) framework is proposed. To address the bandwidth fluctuation, packet loss and heterogeneity problems in the wireless networks and further enhance the error resilience tools in Moving Pictures Experts Group 4 (MPEG-4), the joint design of layered coding (LC) and multiple description coding (MDC) is explored. It leverages a proposed distributed multimedia delivery mobile network (D-MDMN) to provide path diversity to combat streaming video outage due to handoff in Universal Mobile Telecommunications System (UMTS). The corresponding intra-RAN (Radio Access Network) handoff and inter-RAN handoff procedures in D-MDMN are studied in details, which employ the principle of video stream re-establishing to replace the principle of data forwarding in UMTS. Furthermore, a new IP (Internet Protocol) Differentiated Services (DiffServ) video marking algorithm is proposed to support the unequal error protection (UEP) of LC components of SMDC. Performance evaluation is carried through simulation using OPNET Modeler 9. 0. Simulation results show that the proposed handoff procedures in D-MDMN have better performance in terms of handoff latency, end-to-end delay and handoff scalability than that in UMTS. Performance evaluation of our proposed IP DiffServ video marking algorithm is also undertaken, which shows that it is more suitable for video streaming in IP mobile networks compared with the previously proposed DiffServ video marking algorithm (DVMA)

Safety and Reliability - Safe Societies in a Changing World

The contributions cover a wide range of methodologies and application areas for safety and reliability that contribute to safe societies in a changing world. These methodologies and applications include: - foundations of risk and reliability assessment and management - mathematical methods in reliability and safety - risk assessment - risk management - system reliability - uncertainty analysis - digitalization and big data - prognostics and system health management - occupational safety - accident and incident modeling - maintenance modeling and applications - simulation for safety and reliability analysis - dynamic risk and barrier management - organizational factors and safety culture - human factors and human reliability - resilience engineering - structural reliability - natural hazards - security - economic analysis in risk managemen