Performance evaluation of per-hop forwarding behavior in the Diffserv Internet

In these days, IP network customers become sensitive to the QoS guarantee provided by the network. Amongst many QoS guarantee schemes, Diffserv (Differentiated Services) is the one of the most practical candidates for the next generation IP networks. Under these circumstances, the commercial network venders have already provided the Diffserv routers that support EF (Expedited Forwarding) PHB (Per Hop Behavior). However, AF (Assured Forwarding) PHB in Diffserv still has not been provided by commercial routers. Therefore, it is a realistic solution that SBR3 (Statistical Bit Rate 3) of ATM emulates AF PHB, but it is not clear whether TCP traffic over AF PHB emulated by ATM is differentiated from the best effort TCP traffic over DF (Default Forwarding) PHB. To confirm the differentiation, we have experimentally studied TCP performance through the link into which TCP connections over AF PHB and DF PHB are aggregated. This paper describes the experimental results and discusses the possibility of the TCP performance differentiation between AF PHB and DF PHB over ATM.

Performance evaluation of prioritized scheduling with buffer management for differentiated services architectures

Differentiated services (DiffServ) are a set of technologies used to enable the provisioning of class-based, differentiated quality of services. One of the essential building blocks to realize DiffServ is the use of traffic conditioning mechanisms to support the required forwarding behaviors. In this paper, a generic model for traffic conditioning is proposed. The generic traffic conditioner (GTC) can be used to provide the traffic control functionalities required in support of various defined per-hop forwarding behaviors. To demonstrate this capability, a configuration of GTC for an expedited forwarding (EF) service that guarantees low packet loss, delay and jitter bounds is presented. Per-hop delay due to traffic conditioning is briefly analyzed. The GTC is currently implemented in a Linux platform Experimental results show that the GTC can achieve minimal packet loss with bounded jitter and delay.

The differentiated services (DS) architecture provides a framework for the scalable provisioning of multiple service levels in the Internet. Its definition and initial work have concentrated mainly on per-hop behaviors (PHB) and mechanisms at each DS domain. Equally important is what happens between DS domains. Thanks to the flexibility of the architecture, it is the providers’ choice how to interconnect with peers. In principle, traditional, static peering agreements work together with DS, but they do not offer the flexibility and dynamics needed in an electronic market for network capacity. Therefore, we look at dynamic service level agreements at the interdomain level. Such agreements are established by software entities called traders. These traders follow market-based principles to decide which contracts will be beneficial. In particular, traders compare the offers made by neighbor providers and select the most interesting ones. This selection of peer services creates competition among providers and integrates route selection based on service level and destination. We describe and implement a framework for service level agreement trading. We show the basic workings and first performance results of SLA trading using specific traders and an experimentally defined PHB in a simulation environment. Keywords— Network architecture, differentiated services architecture, service level agreement, pricing, trading, interdomain QoS routing.

In this paper, a novel adaptive ant colony slot assignment (ACSA) algorithm including construct solution and pheromone update is proposed to assign OFDMA-based radio resource. The aim of ACSA is to achieve high bandwidth efficiency on the basis of specific channel conditions while guaranteeing the QoS requirements. Performance comparisons with the rate-guaranteed competitive scheduling (RCS) are presented in terms of delay, jitter, packet dropping rate, throughput and waste to highlight the better behavior of our proposed schemes.

Video streaming over the Internet is a challenging task since the Internet is a shared environment offering only best effort service. That is, it offers no quality of service and no guarantee of resources in term of (1) bandwidth, (2) transfer delay, (3) delay variation (jitter), and (4) packet losses. Then, network stability and traffic fairness become critical issues. To solve these problems some source rate control and adaptation should be introduced for UDP traffic as well, in such a way that this traffic becomes TCP-compatible “TCP-friendly”. In this article we propose an adaptive streaming framework for unicast MPEG-4 streams over TCP/IP networks. Based on Audio-Visual Content (AVOs) classification and network congestion feedback, video sources dynamically adds and drops MPEG-4 AVO to the streamed multiplex to conform to the TCP-Friendly Rate Control (TFRC) mechanism. Using a content classification model, TFRC automatically adjusts the number of AVOs to be streamed to adapt to network congestion while given much attention to the quality of the service perceived by the end-user. To achieve such a dynamic output rate and video quality adjustment, MPEG-4 AVOs are classified and multiplexed according to both application-level QoS parameters and AVOs semantic descriptors. AVOs requiring same QoS from the network are automatically classified and mapped to one of the available IP DiffServ PHB (Per Hop Behaviors). Performance evaluation shows that transmitted video gracefully adapts to network bandwidth variations while optimizing user perceived quality.

The wireless sensor networks (WSNs) with dynamic topology communication among the sensor nodes is vulnerable to numerous attacks. As they have limited power, there arises a conflict between the complex security scheme and the consumption of energy which are inversely proportional to each other. Hence, a trade‐off should be accomplished between the implemented scheme and energy. A novel secure and energy‐aware routing technique quantized indexive energy‐aware clustering‐based combinatorial stochastic sampled bat optimization (QIEAC‐CSSBO) is proposed which consists of clustering, optimal route path identification, and route maintenance. The clustering process and selection of cluster head (CH) with high residual energy is done using the quantized Schutz indexive Linde–Buzo–Gray algorithm (QIEAC). Optimal route identification is done using CSSBO (combinatorial stochastic sampled Prevosti’s bat optimization), and fitness of every bat is measured on combinatorial functions, namely, distance, energy, trust, and link stability among nodes. Stochastic universal sampling selection procedure is applied to select the global best optimal path for secure data transmission. Lastly, route maintenance process is performed to identify alternative route while link failure occurs among nodes. Experimental assessment is performed using various performance metrics, namely, energy consumption, packet delivery ratio, packet drop rate, throughput, and delay. The proposed method QIEAC‐CSSBO enhances the performance of packet delivery ratio by 4%, throughput by 26%, and packet drop rate by 27% and reduces energy consumption by 11%, as well as delay by 16% as compared to existing techniques.

This document defines a general use Differentiated Services (DS) [Blake] Per-Hop-Behavior (PHB) Group called Assured Forwarding (AF). The AF PHB group provides delivery of IP packets in four independently forwarded AF classes. Within each AF class, an IP packet can be assigned one of three different levels of drop precedence. A DS node does not reorder IP packets of the same microflow if they belong to the same AF class.

We define an analytical approach and a methodology to determine the set of service level agreements (SLA) that can be effectively supported by a DiffServ IP network. We consider the assured forwarding (AF) per hop behavior (PHB), and, based on the SLA probabilistic description, we derive a worst-case mathematical formulation for the overbooking probability, i.e., the probability that the traffic crossing any link of a source-destination path exceeds the link capacity. We then compare analytical results with simulation of different traffic models.

Recent studies have shown Multiple Network Interfaces (MNI) offer inexpensive solutions toward improving the reliability of communication over multiple paths, balancing load among paths, and enhancing quality of service by aggregating bandwidth. Especially, recent studies on emerging multipath transport protocols have shown that they perform concurrent multipath transport and bandwidth aggregation quite well when packet drop rates and bandwidths of the paths are not far apart. However, in shared networks these parameters for all paths cannot be expected to be close throughout the lifetime of the connection. For instance, packet drop rates and available bandwidths are known to vary dynamically in wireless links, which have been deployed extensively. However, to the best of our knowledge no study has been reported for path imbalances involving multiple parameters. In this paper we propose a software architecture that captures high level design of two concurrent multipath transport protocols. These two protocols have been implemented on the same computing and networking environments for a meaningful evaluation under path imbalances. In our network emulation laboratory, two host computers were connected through two independent network emulators. Each network emulator runs on a separate computer, and the network parameters are adjusted independently. Our extensive experimentation with these protocols show that imbalances of path parameters drastically degrade the performance under certain conditions while an imbalance may have less impact on other conditions.

The IEEE 802.11e standard adds new optional acknowledgment (ACK) schemes called block ACK and No ACK Although these two schemes offer new data transmission services, there is no description which scheme is the most efficient under the different channel environments. In this paper, we apply the three ACK schemes (including legacy 802.11 ACK scheme) to the contention-based channel; an enhanced distributed channel access (EDCA), in IEEE 802.11e and then analyze the throughput and the packet drop rate, corresponding to the different kind of ACK schemes. Link parameters such as the number of stations, physical layer (PHY) mode, bit error rate (BER) and MAC protocol data unit (MPDU) length are considered. With the numerical results, we determine the adaptive ACK scheme for the different channel environments (represented by BER) in terms of throughput and packet drop rate.

In this paper, a receiver driven overlap Forward Error Correction (FEC) scheme, which offers unequal importance protection of video layers, is proposed to protect H.264/SVC video over the Internet. A mathematical model is provided to calculate video quality in terms of subjective Video Quality Metric (VQM). With the provided mathematical model, the video server prepares for receivers a lookup table, which lists all optimal combinations of video and FEC layers under various available downlink bandwidth and packet drop rates. By table lookup, a receiver can determine an optimal combination of video and FEC layers to subscribe to maximize the subjective video quality based on its available downlink bandwidth and packet drop rates.

Mobile Ad hoc networks deploy the network with the support of self-organizing and self-configuring mobile nodes. Due to the lack of centralization, the topological structure of the network fluctuates frequently. Preserving stable link communication to obtain reliable data transmission is the key challenge in the dynamic wireless network environment. This stimulates discrepancy on discovered route paths. To address this issue a novel approach called bootstrap aggregated mutual dependency ensemble clustering and learning agent based approach to eliminate stale routes in MANET (BAMDEC-LABA) is introduced. This algorithm is used to identify the stable link based on the metrics such as residual energy, receiving signal strength, less hop count and node behavior. Maximum dependency with less hop count route paths are classified by employing bootstrap aggregation method. Learning agent examines the node behavior and identifies the selfish and corruptive nodes using node cooperativeness and trust value. The occurrence of the link failure due to the malicious nodes intimated to all the nodes with the distribution of route error packet. The inconsistent route path is eliminated from the cache to preserve the link failure. The performance of the proposed approach is evaluated with different performance metrics such as routing overhead, packet delivery ratio, packet drop rate, and delay. When compared to state-of-the-art approaches, the proposed BAMDEC-LABA technique on an average minimizes the routing overhead by 26%, improves the packet delivery ratio by 18%, packet drop rate is considerably reduced by 68% and delay is found to be minimized by 27%. The proposed method outperforms when compared to state-of-the-art approaches.

Extending long-term evolution (LTE) to unlicensed bands, termed LTE-unlicensed, is gaining significant interest recently. The coexistence of LTE-unlicensed with the current users of unlicensed bands (such as Wi-Fi) and the interference among LTE-unlicensed users themselves are the two challenges for the success of this new technology. In this paper, we propose a novel distributed online algorithm for opportunistic sharing of unlicensed bands among LTE-unlicensed base stations (BSs) while guaranteeing the quality of service (QoS) of user equipment (UE). We first derive a Lyapunov optimization-based algorithm for BSs to evaluate the true value of unlicensed spectrum, guarantee a maximum delay, and minimize the packet drop rate. We then develop a distributed auction mechanism to maximize the social welfare in each auction and enable optimal spectrum reuse. We prove that BSs bid truthfully with the proposed algorithm, while UEs’ QoS requirements on delay and packet drop rate can be guaranteed with bounded optimality gaps. We also reveal an interesting tradeoff between the delay and packet drop rate. The proposed algorithm is validated with simulations.

BD-SIIT and DSTM are widely deployed IPv4/IPv6 Transition mechanism to improve the performance of the computer network in terms of Throughput, End to End Delay(EED) and Packet Drop Rate(PDR).In this journal paper we have Implemented and Compared the Performance Issues of our newly proposed Dollops Wise Curtail(DW&C)IPv4/IPv6 Migration Mechanism with BD-SIIT and DSTM in NS2. Implementation and Comparison Performance Analysis between Dollops Wise Curtail, BD-SIIT and DSTM shows that Dollops Wise Curtail IPv4/IPv6 migration algorithm performance outperforms than BD-SIIT and DSTM. Based on extensive simulations, we show that DW&C algorithm reduces the Packet Drop Rate(PDR),End to End Delay(EED) and achieves better Throughput than BD-SIIT and DSTM. In our research work observation, the performance metrics such as Throughput, EED and PLR for DW&C,BD-SIIT and DSTM are measured using TCP,UDP,FTP and CBR Traffics.