Sharif Digital Repository

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... 

Network management includes a wide range of topics such as performance, security, monitoring, debugging and so on. The network monitoring plays a vital role and can cover a wide range of network management requirements. Monitoring is the only way to know the correct network performance in accordance with the network design. In order to understand what is happening on the network and how network performance over time, the network should have a reporting system. Today, the reporting is done using network monitoring tools. In traditional networks, network monitoring is done using additional hardware which imposes high costs, complexity and also additional traffic overheads to the network. But... 

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... 

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... 

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,... 

In this dissertation a special category of RF filters known as multi-path filters are introduced, chracterized and implemented. The center frequency of the multi-path filters can be tuned by changing the frequency of the clocks applied to the filter, which makes them attractive for use in multi-standard receivers. In this thesis, different types of multi-path filters are studied and by proposing different circuits, their various applications are covered. First, the concept of multi-path filters and their chracteristics are studied. Then a novel technique to analyze these filters based on Fourier analysis is proposed and then, based on this analysis, a new circuit architecture with reduced... 

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... 

Despite being widespread, traditional IP networks are complex and hard to manage.This complexity is due to tight coupling between network control and data planes. A Software-Defined Network is a network architecture in which data plane forwarding is managed by a decoupled control plane. In these networks, control logic is moved to a logically centralized external controller which builds a global network state view and uses it to allocate network resources and provide necessary abstraction to facilitate programming forwarding elements. Generally, traffic management refers to measurement and analysis of network traffic in order to improve network performance in traffic and resources levels... 

A novel internetworking paradigm, software-defined exchange (SDX), allows multiple independent administrative domains to share computing, storage, and networking resources. Although the term SDX is very recent, the concept has already been used by many distinct disciplines.We argue that the advent of Software Defined Networking (SDN) provides a unique opportunity to effectively detect and contain network security problems such as DDoS attacks. DDoS attacks can easily exhaust the controller's or the switches' computing and communication resources and hence, breakdown the network within a short time. In this thesis we extend these functionalities with an efficient, scalable and light weight... 

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... 

Internet is the largest multi-purpose, self-reliant, complex and distributed computer network across the globe. The nodes of this network are placed in every place like homes, offices, military camps, schools and all other locations by utilizing many different communication protocols, media and capacities. Furthermore, by rapid technology development, there are many newly born applications utilizing internet in new ways such as Internet of Things systems. The explosive growth of technology causing accelerated addition of new nodes to the internet, and any new single node may have several new unpatched vulnerabilities. This is a serious issue for managing this vast chaotic configuration and... 

Wireless LANs are becoming widespread in enterprises due to extensive usage of mobile devices and appearance of bring-your-own-device policies. However, mechanisms common in home WLANs are not sufficient for managing lots of access point and clients in an enterprise WLAN and WLAN controllers which are used in enterprises nowadays are limited to a fixed set of commands operated from a CLI and the source code is not changeable. Also, their effectiveness can be harvested alongside access points from the same vendor. Thus, dynamic high level programming for whole network configuration is an absolute need in this changing business environment and Software-defined Networking (SDN) will empower us... 

There is a plethora of research and implementations that intend to increase the performance and reduce implementation costs of network routers. In this work, we review previous designs and propose a new network router design that is based on software-defined networks. Our design separates the data plane and the control plane from each other and connects both parts by using OpenFlow protocol. The control plane consists of a general small computer that utilizes the Quagga software to enforce the routing protocols. The control plane translates routing decisions to OpenFlow instructions and sends them to the data plane. The data plane is based on a switch that supports the OpenFlow protocol...