Sharif Digital Repository

Software Defined Networks provide programmability and centralized control for network’s administrator. Like other networks, security problems are important in these networks, but there is not enough research in this area. The problem being discussed here is to elevate the security level in software defined networks using centralized control and programmability of these networks. We will accomplish this purpose by using hosts and controller at the same time to prevent unwanted traffic from entering the network. By using this approach, we will be able to remove many short comings of these networks and implement security systems, like intrusion detection systems, more efficient. One of these... 

We call medium and large networksSDN, which they can managed by centralized software. In this networks instead ofmaking routing decisions byhardware, software is making decisions by using pre-defined conditions and with each packet behave differently. With the increasing development of real-time services such as voice services the importance of network monitoring system is increasing day after day. IN order to ensure quality of service, network service providers must measure network status with metrics such as delay and packet loss rate. Obtaining accurate and meaningful statistics from network status, provide abilities to service providers to measuretheir network health and estimate amount... 

Software Defined Networking (SDN) is an emerging paradigm which makes the network programmable by separating the control plane from data plane and makes both planes to work independently. There is a centralized controller and a programmable data plane in these networks architecture and forwarding data packets is realized by programming the data plane via an open interface called OpenFlow. OpenFlow is a communication protocol between control and data planes. The centralized architecture of these networks provides a global view of the underlying network to upper applications and brings numerous advantages such as routing, traffic engineering and QoS control. Despite these advantages there are... 

With growth in using the Internet and entrance of online stores and internet banks to daily people life, security has become a vital part of this new world. This causes, industrial companies started to produce security devices such as fire walls for protecting network from outside attackers and Intrusion Detection/Prevention Systems (IPS/IDS) for detection of attacks inside network. IPS/IDS causes network overload due to requiring copy of packet or flow information. With introducing Software Defined Networking (SDN) architecture, there is a hope to solve the issue with combining IPS/IDS and SDN features. Therefore, we propose two novel approaches for fast network scanning and SYN Flood... 

Controller placement affects all aspects of separating control plane from forwarding plane in SDN networks such as flow set up delay and reliability. Also it will limit Fault tolerance, and other performance evaluation measures such as propagation delay, accessibility and Convergence in WANs. These measures influence software designing with affecting controllers’ ability to respond to real-time events and push forwarding actions to forwarding elements. The placement problem consists of finding suitable places for controllers along with the number of them. Most of the works in this field try to decrease the delay between controllers to switches and between controllers themselves. Beside,... 

Widespread use of the interconnected devices has caused an increase in the number of online services and the Internet of Things applications. Some of the protocols used in networking equipment does not have the ability to manage the high volume of traffic, scalability and mobility. Existing networks with traditional protocols are rigid and the process of policy-making on network is slow. Manging the huge number of data flows is a complex and time-consuming task. To respond to such problems, in this study a Software defined architecture is proposed as an alternative to traditional network architecture. In this type of networks, administrators have overview on network controllers and network... 

In real-time systems, jobs that miss their deadline are considered worthless or ineffective. Nowadays, real-time applications (such as multimedia) that communicate through software-defined networks (SDN) are widely used and will continue to expand in the future. SDN is an emerging network architecture in which control plane is separated from data plane to manage it directly. In this research, we make changes to the controller and the switch used in such network to deliver real time packets or real-time flows (such as video) on time, as much as possible. As missed deadline packets are worthless and they waste bandwidth, dropping them is a solution. Moreover, the controller can drop flows that... 

Software Defined Networking (SDN) is an emerging paradigm which makes the network programmable by separating the control plane from data plane and makes both planes to work independently. There is a centralized controller and a programmable data plane in these networks architecture and forwarding data packets is realized by programming the data plane via an open interface called OpenFlow. OpenFlow is a communication protocol between control and data planes. The centralized architecture of these networks provides a global view of the underlying network to upper applications and brings numerous advantages such as routing, traffic engineering and QoS control. Despite these advantages there are... 

The widely used services such as search engines, websites and social networks are deployed on multiple servers for quick and reliable access. Therefore, there is need to load balancer for distributing requests. In traditional networks usually dedicated hardware load balancers are used, which are very expensive, inflexible, single point of failure and prone to congestion. To solve this problem, using software defined networks, a simple device which works based on OpenFlow protocol can turn into a powerful load balancer with installing the rules by the controller.In software defined networks, a controller is used for load balancing, which has two main problems. First, in case of a failure in... 

IPTV is one of the developing technologies in recent years. This technology is used to broadcast TV programs over IP protocol stack. Video quality improvement is the most important advantage of this technology. Users can watch programs anytime they want in opposition to the traditional TV channels in which programs cast at certain times. One of the challenges in IPTV is high latency for channel switching. This latency is caused by different sources, including network delay. The delay between sending the channel switch request and receiving the first packet of the new channel is called network delay. In this thesis a new approach is proposed to decrease network delay. The proposed approach... 

Content-based routing, as provided by publisher/subscriber systems,has evolved as a key paradigm for interactions between loosely coupled application components (content publishers and subscribers). Content-based routing aims to increase the efficiency of forwarding by utilizing the diversity of information exchanged between application components. Using content-based forwarding rules (also called content filters) installed on content-based routers (also termed brokers), bandwidth-efficiency is increased by only forwarding content to the subset of subscribers who are actually interested in the published content. Many middle-ware implementations for content-based publish/subscribe have been... 

Internet of Things (IoT) is a concept which implies billions of smart objects being connected to the Internet and realizing the smart city. These smart objects generate massive amounts of data and send it to the cloud for process. In reality, sending all the data to the cloud isnn not performant and consumes a lot of energy, therefore fog computing which is a newer concept presented in recent years can be a solution to this problem. By moving the computations to the edge of the network and end devices, fog computing has reduced the cloud approach challenges and is more flexible and scalable. On the other side, software defined networking, with it’s most significant feature which is... 

Software defined networks are developed to provide programmability and a centralized view in networks by decoupling control plane from data plane. Software defined networks are now well received,and these networks are evolving every day. This is while more attention has been paid to widen the application of these networks and eliminating the shortcomings in their performance. On the other hand, in very large networks, the issue of efficiency and processing speed is of great importance. However, performance in these networks is not satisfactory, especially in single controller based SDN due to the complex processing of packets in a unique controller. Security needs are also of great... 

SDN-based cloud is created by new thechnologies. This infrastructure is more programmable, manageable and configurable. However SDN-based cloud is vulnerable to the DDoS attacks. A lot of researches has been accomplished to prevent these kind of attacks. Solutions that proposed in these papers are based on machine learning, statistical analysis of traffic or combination of these approaches. In this research an efficient method has been introduced, for detecting DDOS attack in SDN-based cloud environment. Detection system is based on extreme learning machine (ELM). ELMs has been pruned with genetic algorithm (GAP-ELM). Detection of attack in the proposed system, has been accomplished with... 

Software-Defined Networking is a new approach in networking which provides a great opportunity to improve network management. Network policy decisions and reachability policies are one of the main concerns of the network administrators. These policies are traditionally configured in different network devices. The configurations are manually implemented using ACLs in routers, firewalls, VLANs, etc. Network engineers configure every single device on the network with its vendor-specific low level language. As a result, access control policies of the network lie in the configuration files of the network devices or even only in the minds of the network engineers. Moreover, access control policies... 

consumption is an economical and environmental concern in nowadays world. Data centers (DC) are an important and energy power hunger part of modern life infrastructure. Many researches have shown that by considering special properties of DCs (e.g. redundancy) the energy consumption can be reduced. However new advances in hardware and software technologies have made DCs equipment more power proportional, i.e. they consume power proportional to their load. Unfortunately this new feature and many previous works do not have synergy. Also the performance of the DCs is so important that no DC owner is willing to trade it for lower power bills. Therefore algorithms that don’t consider the... 

With a growing concern on the considerable energy consumed by data centers, research efforts are targeting toward green data centers with higher energy efficiency. Networks are essential to today’s highly instrumented and connected society. Currently responsible for a fraction of the energy the IT sector consumes, networks rely on equipments that often use a constant amount of power regardless of their utilization; a worsening scenario as traffic is expected to increase by a factor of three in the next few years. Datacenter networks, for instance, employ devices that consume several kilowatts of power even when idle. This work aims to improve the energy efficiency of datacenter networks by... 

With the introduction of SDN and OpenFlow as novel approaches for better network management and virtualization, it is now easier to perform QoS measurement anywhere, anytime, and anyplace through the use of self-directed, self-tuning mechanisms that continuously monitor and measure network performance and react swiftly to problems. Using programmable interfaces to OpenFlow controllers, software-defined measurement solutions provide consistent traffic measurement of flow parameters, such as bandwidth, packet loss, and latency to support the diversity requirements of next generation network applications and services. The flexibility of software-defined measurement gives the network operator...