Adib Habbal

Loss Detection and Recovery Techniques for TCP in Mobile Ad Hoc Network

Currently, Transmission Control Protocol (TCP) is the dominant protocol used in the Internet. It is the transport protocol that is responsible for the transmission of around 90% of the Internet traffic. TCP was originally designed for wired network where packet loss due to congestion dominates. Mobile Ad Hoc Network (MANET), one of the wireless networks, has special characteristics which cause several types of losses that are not related to congestion; leading to violate some design concepts of TCP because TCP handles any loss as a sign of congestion. In this paper, we provide an overview on MANET characteristics that cause packet loss. Afterwards, a survey on the recent solutions that propose loss detection and recovery techniques is conducted, placing special emphasis on proposals that preserve end-to-end semantic.

Context-Aware Radio Access Technology Selection in 5G Ultra Dense Networks

Ultra dense network (UDN) is the extreme densification of heterogeneous radio access technologies (RATs) that are deployed closely in a coordinated or uncoordinated manner. The densification of RATs forms an overlapping zone of signal coverage, leading user equipment (UE) to frequent signal handovers among the available RATs. Consequently, this degrades the overall system performance. The traditional approach of RAT selection is network-centric and the decision is primarily focused on the signal aspect. However, the next generation of digital wave is a paradigm shift to being user-centric. In this paper, a context-aware multi-attribute RAT (CMRAT) selection approach is proposed to eliminate unnecessary handover of UE among RATs and determine the best RAT as the next point of attachment among the available ones in the UDN. CMRAT integrates the context-aware concept with multi-attribute decision making (MADM) theory in RAT selection. CMRAT is formed with two mechanisms, including, first, a context-aware analytical hierarchy process mechanism to prioritize the criteria for obtaining the weight. Then, a context-aware technique for order preference by similarity to an ideal solution mechanism is employed to choose the best RAT amongst the available RATs. The proposed CMRAT mechanism was implemented and validated using MATLAB. The obtained simulation findings demonstrate that the proposed CMRAT approach outperforms classic MADM methods, namely TOPSIS, SAW, and GRA with respect to the number of handovers and ranking abnormality metrics. Hence, this paper paves the way to choose RAT based on context information comprising network and user preference criteria information.

Mobility Support for the Routing Protocol in Low Power and Lossy Networks

Mobility is the most issues for the majority of protocols including the RPL (IPv6 Routing Protocol for Low Power and Lossy Networks). RPL a routing protocol standardized by IETF is usually used in Internet of Things Technology. It is proposed to support communications in Low power and Lossy Networks (LLNs). However, mobility limits the use of RPL protocol in realistic study. In this paper we have classify the mobility models in two entities in order to evaluate the performances of RPL in each entity separately. So we have defines two different scenarios. We first, evaluate characteristics of RPL with a group mobility models which contain Reference Point Mobility Model (RPGM) and Nomadic Mobility Model (Nomadic) Mobility Models. Then we give another evaluation of features of RPL with the Entity mobility models which contain Random Walk Mobility Model(RWK), Random Waypoint Mobility Models (RWP) and self similar least action walk (SLAW) Mobility models. The results show that the type of mobility models has a direct influence on the protocol performances. In addition, increasing of number of nodes causes an increasing of all parameters, especially in delivered and received data. Furthermore, the group mobility models give better metrics than entity mobility models in terms of lost packets, Packet Delivery Ratio (PDR) and Throughput. Also, in each type of mobility models each model provides better metrics than others. RPG offers best number of lost packets and PDR than Nomadic model and lowest in terms of Throughput while SLAW models gives the best value in all metrics than RWK and RWP. Our simulation shows clearly that lost packets, PDR and Throughput are directly related to the type of mobility models.

Delay-Based Loss Discrimination Mechanism for Congestion Control in Wireless Ad-Hoc Network

Transmission Control Protocol (TCP) is the dominant protocol used in the Internet today. It was well designed to work over a wired network. However, TCP suffers from performance degradation in a wireless ad-hoc network. The main reason is that regular TCP misinterprets packet loss due to wireless channel error as network congestion and consequently reduces its sending rate,. In this paper, we propose a new end-to-end mechanism to support TCP discriminating congestion loss from none-congestion loss. The proposed mechanism is evaluated using simulation under different network topologies and varying PER levels; results demonstrate that the proposed scheme outperforms NewReno, in terms of throughput, by 30%.

A Model for Congestion Control of Transmission Control Protocol in Mobile Wireless Ad Hoc Networks

Transmission Control Protocol (TCP) is a fundamental protocol in the TCP/IP Protocol Suite.TCP was well designed and optimized to work over wired networks where most packet loss occurs due to network congestion. In theory, TCP should not care whether it is running over wired networks, WLANs, or Mobile Ad hoc Networks (MANETs). In practice, it does matter because most TCP deployments have been carefully designed based on the assumption that congestion is the main factor of network instability. However, MANETs have other dominating factors that cause network instability. Forgetting the impact of these factors violates some design principles of TCP congestion control and open questions for future research to address. This study aims to introduce a model that shows the impact of MANET factors on TCP congestion control. To achieve this aim, Design Research Methodology (DRM) proposed by BLESSING was used as a guide to present this model. The proposed model describes the existing situation of TCP congestion control. Furthermore, it points to the factors that are most suitable to be addressed by researchers in order to improve TCP performance. This research proposes a novel model to present the impact of MANET factors on TCP congestion control. The model is expected to serve as a benchmark for any intended improvement and enhancement of TCP congestion control over MANET.

Contention avoidance mechanism for TCP in mobile ad hoc network

Transmission Control Protocol (TCP) is the de-facto standard protocol that is responsible for the transmission of around 90% of the Internet traffic. TCP was originally designed for wired network where buffer overflow induced packet loss dominates. However, this type of packet loss is rare in ad hoc network and packet drop due to link-layer contention dominates. Ignoring this special characteristic leads to poor performance of TCP. In this paper, we provide an overview on spatial contention and discuss the impact of contention on TCP performance. Afterwards, a survey on the recent proposals that aim to alleviate the effects of spatial contention on TCP is conducted, placing special emphasis on techniques that preserve end-to-end semantic. Finally, we propose our contention avoidance mechanism that adapts the sending rate and enhances TCP performance. The proposed mechanism was verified and validated be comparing our result to output obtained from real test bed. Finally, it is expected that TCP with our contention avoidance mechanism will gain a significant improvement.

Trust Management for Public Key Infrastructures: Implementing the X.509 Trust Broker

A Public Key Infrastructure (PKI) is considered one of the most important techniques used to propagate trust in authentication over the Internet. This technology is based on a trust model defined by the original X.509 (1988) standard and is composed of three entities: the certification authority (CA), the certificate holder (or subject), and the Relying Party (RP). The CA plays the role of a trusted third party between the certificate holder and the RP. In many use cases, this trust model has worked successfully. However, we argue that the application of this model on the Internet implies that web users need to depend on almost anyone in the world in order to use PKI technology. Thus, we believe that the current TLS system is not fit for purpose and must be revisited as a whole. In response, the latest draft edition of X.509 has proposed a new trust model by adding new entity called the Trust Broker (TB). In this paper, we present an implementation approach that a Trust Broker could follow in order to give RPs trust information about a CA by assessing the quality of its issued certificates. This is related to the quality of the CA’s policies and procedures and its commitment to them. Finally, we present our Trust Broker implementation that demonstrates how RPs can make informed decisions about certificate holders in the context of the global web, without requiring large processing resources themselves.

Assessing Experimental Private Cloud Using Web of System Performance Model

Cloudcomputinghasattracted theattentionofeducational and research institutionsasaway to supportmoderntrendsinteachingandlearning.Thisarticledescribestheperformanceassessment ofaprivatecloudwithinauniversityenvironmentusingtheWebofSystemPerformance(WOSP) model.Asurveywascarriedout tomeasure therespondents’attitude towards theuseofprivate cloudinwhichstudentsandexpertsserveassample.Testingwasconductedbydesigningavirtual labconsistingofanumberofvirtualmachinesoperatedbyaselectedsample.Theresultsshowed that theusageofcloudcomputinginuniversityhasgoodperceivedsystemperformancejudging fromhowitfaresintheconstituentpartsoftheWOSPmodel.Furthermore,thestudyrevealedthat usabilityandflexibilityoutperformedcriterionlikesecurity.Moreover,severalnon-functionalcriteria outperformedfunctionality.Inshort,theknowledgeandresultspresentedfromassessingaprivate cloudusingWOSPmodelcouldbebeneficialforusers,designersandmanagersofprivateclouds especiallyinuniversities. KEyWoRdS Cloud Computing, Educational Technology, OpenStack, WOSP Model

HLLR: Highest Lifetime Least Request policy for high performance Pending Interest Table

Pending Interest Table (PIT) in Named Data Networking (NDN) architecture is complex in the forwarding operation in both upload of Interest packets and download of Data packets. PIT is considered useful for so many reasons in the centric-networking. These among other operations include: reducing bandwidth usage, communicating with no prior knowledge of publishers and subscribers, loop and packet loss detection and best security. However, despite the numerous advantages of PIT, hardware challenges, including PIT are still crucial in respect to NDN management for better memory efficiency. Due to the high access frequency to the PIT, it is essential to understand its functionality, and the effect it has on PIT performance, especially since PIT overflows. In our quest for designing a replacement policy as close to optimal as possible, we proposed a new replacement policy in PIT. This paper presents a new replacement policy named Highest Lifetime Least Request (HLLR). HLLR is designed to replace entries in the PIT which has the minimum number of incoming faces with maximum Lifetime. We have tested the policy using ndnSIM simulator and evaluated the results with some existing PIT replacement policies, i.e. Persistent (default), Least Recently Used (LRU) and Random. HLLR policy, design and evaluation are presented in this paper, aimed at obtaining better performance in case delay time, minimum Interest retransmission and Interest drop. The significance of this study is thus, it presents a conceptual model in order to tackle the issue of Interest replaces delay, which will be very much useful for managing the PIT when it is full.

A popularity based caching strategy for the future Internet

Information-Centric Networking (ICN) is an attractive network model receiving increasing consideration by the research community because of its inspiring features. To better manage the Internet usage move from host-centric communication to receiver-driven content retrieval, revolutionary ICN architectures have been proposed. A distinguished characteristic of these innovative architectures is to provide ubiquitous and transparent in-network caching to enhance network resource utilization and accelerate content dissemination. With the exponential increase of Internet traffic, the issue of content storage is a growing concern in ICN. In this paper, we present a caching strategy that considerably increases cache hit rate and reduces stretch ratio, which are the most important metrics in the evaluation of ICN caching. Through extensive simulations, it is shown that our proposed work is a favorable and realistic contribution for the standardization exercise of data caching for achieving accurate and valid network performance in the future Internet.