ATP: a Datacenter Approximate Transmission Protocol

Many datacenter applications such as machine learning and streaming systems do not need the complete set of data to perform their computation. Current approximate applications in datacenters run on a reliable network layer like TCP. To improve performance, they either let sender select a subset of data and transmit them to the receiver or transmit all the data and let receiver drop some of them. These approaches are network oblivious and unnecessarily transmit more data, affecting both application runtime and network bandwidth usage. On the other hand, running approximate application on a lossy network with UDP cannot guarantee the accuracy of application computation. We propose to run approximate applications on a lossy network and to allow packet loss in a controlled manner. Specifically, we designed a new network protocol called Approximate Transmission Protocol, or ATP, for datacenter approximate applications. ATP opportunistically exploits available network bandwidth as much as possible, while performing a loss-based rate control algorithm to avoid bandwidth waste and re-transmission. It also ensures bandwidth fair sharing across flows and improves accurate applications' performance by leaving more switch buffer space to accurate flows. We evaluated ATP with both simulation and real implementation using two macro-benchmarks and two real applications, Apache Kafka and Flink. Our evaluation results show that ATP reduces application runtime by 13.9% to 74.6% compared to a TCP-based solution that drops packets at sender, and it improves accuracy by up to 94.0% compared to UDP

A simulation model for video traffic performance via ATM over TCP/IP

Although TCP has emerged as the standard in data communication, the introduction of ATM technology has raised numerous problems regarding the effectiveness of using TCP over A TM networks, especially when video traffic performance is considered. This paper presents a simulation model for transmission performance of video traffic via ATM over TCP/IP. The interactivity between TCP/IP and ATM, generation of MPEG traffic and evaluation of traffic performance are implemented in the model. The design and implementation details of the model are carefully described. The experiments conducted using the model and experimental results are briefly introduced, revealing the capability of our model in simulating network events and in evaluating potential solutions to performance issues.<br /

Study on vehicular network application and simulation

VANET is an emerging mobile ad hoc network paradigm that facilitates vehicle-to-vehicle and vehicle-to-infrastructure communication. The most important application of the VANET is for driving safety. Road condition-awareness is critical for driving safety. Existing VANET-based systems usually assume drivers detect and report safety related road conditions, which however may be untrue because, drivers may not be willing to perform these duties, or such duties may distract drivers and thus make driving even unsafe. Therefore, automatic detection without human intervention is desired. As the first contribution of this thesis work, an automatic road condition detection system has been designed based on the idea of collecting and analysing the footprints of vehicles to infer anomaly. It has also been studied how to utilize inexpensive roadside devices, such as sensors, to facilitate the information collection and analysis, especially in the absence of connectivity between vehicles. Due to the difficulty of conducting large-scale experiments on real roads, simulation plays an important role in VANET research. To make simulation close to the reality, it is desired to include detailed and realistic simulation of vehicle behaviour under various road conditions, and this is especially needed for studies targeted at driving safety. In the past, however, the simulation of vehicle behaviours are often overly simplified and implemented as a trivial extension of the network simulator. As a second contribution of this thesis work, a detailed and realistic simulator of vehicle behaviour has been developed based on the car-following and lane-changing models. As the simulation of vehicle behaviour and that of communication behaviour are different tasks, they should be implemented separately for better modularity and meanwhile they should be seamlessly integrable. As another contribution of this thesis work, the online and seamless integration of vehicle behaviour simulator and network simulator has been studied. Specifically, a set of APIs has been designed and implemented atop the vehicular behaviour simulator to facilitate its integration with network simulator. Being a concrete example, the integration of ns2 and SUMO, an open-source vehicular behaviour simulator, has been implemented, and applied to simulate an electric vehicular network

MiniCPS: A toolkit for security research on CPS Networks

In recent years, tremendous effort has been spent to modernizing communication infrastructure in Cyber-Physical Systems (CPS) such as Industrial Control Systems (ICS) and related Supervisory Control and Data Acquisition (SCADA) systems. While a great amount of research has been conducted on network security of office and home networks, recently the security of CPS and related systems has gained a lot of attention. Unfortunately, real-world CPS are often not open to security researchers, and as a result very few reference systems and topologies are available. In this work, we present MiniCPS, a CPS simulation toolbox intended to alleviate this problem. The goal of MiniCPS is to create an extensible, reproducible research environment targeted to communications and physical-layer interactions in CPS. MiniCPS builds on Mininet to provide lightweight real-time network emulation, and extends Mininet with tools to simulate typical CPS components such as programmable logic controllers, which use industrial protocols (Ethernet/IP, Modbus/TCP). In addition, MiniCPS defines a simple API to enable physical-layer interaction simulation. In this work, we demonstrate applications of MiniCPS in two example scenarios, and show how MiniCPS can be used to develop attacks and defenses that are directly applicable to real systems.Comment: 8 pages, 6 figures, 1 code listin

Self-management of lambda-connections in optical networks

This paper presents a new idea for the management of lambda-connections in optical networks. The idea consists of making multi-service optical switches responsible for automatically detecting IP flows at the packet-level, creating lambda-connections for them, and moving them to the optical-level. In addition to that, they are also in charge of tearing down the connections when no longer needed. This new idea is the result of 1 year of research work at the University of Twente (UT) and it is aimed at resulting in a Ph.D. thesis by the end of 4 years of Ph.D. research

Simulation and Evaluation of Wired and Wireless Networks with NS2, NS3 and OMNET++

Communication systems are emerging rapidly with the revolutionary growth in terms of networking protocols, wired and wireless technologies, user applications and other IEEE standards. Numbers of industrial as well as academic organizations around the globe are bringing in light new innovations and ideas in the field of communication systems. These innovations and ideas require intense evaluation at initial phases of development with the use of real systems in place. Usually the real systems are expensive and not affordable for the evaluation. In this case, network simulators provide a complete cost-effective testbed for the simulation and evaluation of the underlined innovations and ideas. In past, numerous studies were conducted for the performance evaluation of network simulators based on CPU and memory utilization. However, performance evaluation based on other metrics such as congestion window, throughput, delay, packet delivery ratio and packet loss ratio was not conducted intensively. In this thesis, network simulators such as NS2, NS3 and OMNET++ will be evaluated and compared for wired and wireless networks based on congestion window, throughput, delay, packet delivery and packet loss ratio. In the theoretical part, information will be provided about the wired and wireless networks and mathematical interpretation of various components used for these networks. Furthermore, technical details about the network simulators will be presented including architectural design, programming languages and platform libraries. Advantages and disadvantages of these network simulators will also be highlighted. In the last part, the details about the experiments and analysis conducted for wired and wireless networks will be provided. At the end, findings will be concluded and future prospects of the study will be advised.fi=Opinnäytetyö kokotekstinä PDF-muodossa.|en=Thesis fulltext in PDF format.|sv=Lärdomsprov tillgängligt som fulltext i PDF-format

Simulation of Structured Streams Transport Protocol using Network Simulator 2

There has been a lot of efforts from researchers lately to deploy alternativetransports protocols and mechanisms on providing better packet ordering anddelivery semantics. The current development of Internet and Streamingtechnologies suggests that there is a clear need for such alternatives to TCPTransport Protocols. Structured Streams Transport protocol(SSTP) is a newtransport abstraction introduced lately on ACM and it is based on a differentapproach compared to other alternative transports. Main objective of SSTP is toenhance the TCP's byte stream abstraction to permit high level applications to usecontinuous byte streams in larger numbers easily and more efficiently. SST is stillin an early experimental stage and the aim of this study is to develop a new modulefor this Protocol so it can be simulated and tested on the mostly used scientificnetwork simulator in NS2. By implementing the module in NS2, we can simulatemany aspects of this protocol and fine-tune it before we implement it on high levelapplications