Sharif Digital Repository

Internet video networks have already attracted millions of Internet users, and Internet video is one of the fast growing Internet services. The peer-to-peer (P2P) network is an efficient solution to supporting large scale video streaming on the Internet. P2P networks can deliver live multimedia content to millions of users with low cost at any time, and at anywhere they want. In this thesis, we investigate solutions to enhancing the performance of the unstructured mesh-based. Locality awareness or network proximity is one of the essential characteristics of P2P networks. In live P2P video streaming we face to some challenges like bandwidth heterogeneity of peers, and peer churn. In the P2P... 

In the recent years, cloud data center issues have been the center of attention. Also for them topologies with multi paths between end hosts are offered. For use of multi path traffic engineering is essential. Researches show congestion occurred in the cloud data center networks, because the mean of link utilization is down. This means, some of links are congested while there are some other with much available bandwidth. Currently, the most common method is Equal Cost Multipath (ECMP) algorithm for routing flows in the data center network. ECMP decides on routing without any attention to network congestion condition. There, may be two big flows placed in the one path and it causes creation... 

Streaming video over the Internet has become popular in recent years. There are also popular solutions for data delivery, but these approaches are very inflexible and unpleasant because no appropriate error recovery technique isprovided in the application level of these systems for multimedia contents. In the past few years numerous error resilience Peer-to-Peer (P2P) systems have been introduced but still there is no fully dynamic error recovery technique. In this thesisthe researcher proposed a frame-based hybrid FEC-ARQ (Forward Error Correction – Automatic Repeat request) error recovery in Variable Bit Rate (VBR) video streams based on the network situation in a way that before... 

Recent advances in WSN have led to next generation of it for multimedia transmission which is WMSN. WMSN has several applications like environmental monitoring, advance health care delivery and etc. However, providing QoS requirements of transmitting video data like delay, bandwidth and packet loss with minimum distortion at perceived video quality over WMSN with resource constraints is a challenging problem. Using multipath routing protocol for video communication can increase bandwidth and decrease delay over WMSN. Moreover, all video packets have not the same effect on video distortion. We propose a scheduling mechanism which classifies packets according to their types and contents and... 

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... 

"Programmable networks" are to facilitate and evolve the computer networks. Specifically, Network Defined Software (SDN) is an advanced and innovative solution in the new computer network in which the hardwares are completely independent of the control and decision regarding data transfer. Based on this logic, network management becomes much simpler and enables innovation and new solutions for different parts of the network. In SDN, the program or network intelligence is logically present in software-based controllers (on the control panel) and can be changed and programmed, and network devices are converted into network packet sending hardware (on the data page) through an interface, Such... 

IP multicasting, content distribution networks (CDN) and recently P2P streaming systems are the main scalable methods that have been researched. IP multicasting has not been activated in service provider networks due to some fundamental deployment problems and CDNs require the deployment of a large number of servers throughout the Internet. Pure P2P architecture is a more challenging approach for constant quality and continuous video streaming due to the churn nature and limited resource of the Internet peers. Therefore, we design a hybrid architecture for large-scale video streaming applications that combine an infrastructure of CDNs with the P2P network. Unlike previous work, in... 

Tool Condition Monitoring (TCM) is a vital demand of advanced manufacturing in order to develop automated unmanned production. Tool condition has an essential influence on machined surface quality and dimension of manufactured parts. Continuing machining operation with a worn or damaged tool will result in damages to workpiece and even the machine tool itself. This problem becomes more important in supplementary machining processes like drilling in which the workpiece is usually at the final stages of production and any damage to workpiece at this stage is irreparable and results in high production losses. In this thesis, sound and vibrations signals are analyzed for drill wear detection.... 

Nowadays, deployment of peer-to-peer video streaming systems over wireless mesh networks has attained increasing popularity among a large number of users around the world. In this thesis, we present an efficient peer-to-peer live video streaming architecture over multi-hop wireless mesh networks. In our proposed architecture, we take the physical topology of the network into account and based on a distributed locality-aware neighbor selection algorithm in the overlay construction phase, we generate an efficient mesh-based overlay on top of wireless mesh networks. In locality-aware neighbor selection algorithm, instead of choosing randomly, peers find their best neighbors based on their... 

To make Wireless Multimedia Sensor Networks (WMSNs) more practical, researchers have tried to meet its challenges in the last decade. Some factors of WMSNs, such as low bandwidth and channel errors, cause a decrease in the video quality that is declared as distortion. On the other hand, one important requirement in the context of multimedia streaming is its quality. In this thesis, we first introduce and use an adaptive cross-layer error control in the link layer, and then we implement a new cross-layer source rate control Mechanism for efficient and reliable real-time multimedia streaming in wireless sensor networks. Our main objective is to minimize distortion. Some of the used cross-layer... 

Since the contribution bandwidth of each CDN (Content Delivery Network) node and also each peer are limited, optimal allocation of their bandwidth to their partners is an interesting issue. In this work, an efficient resource allocation algorithm in a hybrid CDN-P2P (Content Delivery Network- peer to peer) video streaming network has been designed and each peer will receive the video chunks with the bit rate according to the number of nodes that the peer supports. We have added this algorithm to Coolstreaming because it does not have a resource allocation mechanism. In Coolstreaming each peer when requests chunks from its neighbors, the neighbors will send the peer the requested chunks with... 

Complex networks science have become the major method in the modeling of topological features of networks and graphs. Although file sharing Peer-to-Peer systems can be modeled by networks with un-weighted nodes and links, using these networks for Peer-to-Peer streaming systems have not led to a suitable model.In this research, we aim to model Peer-to-Peer streaming networks with weighted nodes and weighted links so that present the performance of nodes and the amount of streaming that is transmitted between nodes respectively. Due to lack of information about upload bandwidth distribution in networks we assume this distribution as uniform. Because of dynamics of network, this distribution... 

Peer-to-peer streaming has developed as a popular application in today’s Internetinfrastructure. In a typical peer-to-peer live streaming system, publishers provide the streaming content and the interested peers receive and deliver data in a distributed manner and also apeer structure is created by forming an overlay inside the network. In reality, peers are strategic and there is no motivation to contribute any of their upload bandwidth toward other peers. To address this issue, we proposed a simple arcade algorithm that makes an arcade based mechanism for peers to facilitate adjacent peers with more bandwidth to achieve a higher bandwidth themselves.Commensurate with our algorithm, if... 

According to increase of multimedia applications such as video surveillance and environment monitoring in Wireless Multimedia Sensor Networks (WMSN), energy conservation and prolonging network lifetime become increasingly important. Therefore, energy conservation and maximization of system lifetime are commonly recognized as a key challenge in the design and implementation of WMSNs. In these networks, nodes sense the area with high degree of correlation due to the overlapping Field Of Views (FoVs) and causes wasting network energy. We present “overlapped region detection clustering” as a new clustering method to reduce redundant video streams and overcome waste of the energy. We apply scene... 

attacks have become such a serious problem that according to the recent security firms’ reports, more than five thousands attacks are launched per day, whichcould lead to lots of damage and loss of online businesses. When a P2P system has millions of concurrently active peers, there is the risk that an attacker misuses these clients, or diverts their generated traffic to launch DDoS attack.As we will see, since BitTorrent has gained more popularity among other P2P protocols,and ithas the most number of concurrent active users,it may lead to destructivedamagesif exploited by attackers for lunching DDoS attack. Thus, we have focused on DDoS detection over this protocol.In this study, first,we... 

In recent years peer-to-peer video streaming systems have become the major alternative for traditional client-server models, and several P2P streaming applications have attracted a large number of users on the Internet. In a mesh based P2P streaming architecture a video stream is portioned into video blocks and each peer pulls these video blocks from its neighbors. Since the uplink bandwidth of each peer is its main constraint in transmission video blocks, efficient block scheduling can play an important role in improving the perceived video quality by peers. Moreover, the granularity of video blocks can have a significant impact on the performance of the system. In this thesis, we propose... 

Hybrid CDN-P2P architecture has been introduced to combine scalability advantage of P2P and reliability of CDN networks. Although it has been proved that CDN-P2P is more efficient than other architectures for live video streaming, there is still the question, “How is it possible to be more efficient in providing higher service quality?” Quality degradation in P2P and Hybrid CDN-P2P is mainly connected to the lack of exploiting role of peers’ heterogeneity in the system. Most of currently deployed live video streaming systems don’t adapt to bandwidth of the peers and just send one version of video to all users. To tackle this issue, many researches combine P2P solution with scalable video... 

Nowadays peer-to-peer networks are more popular than the client server model. Distributed manner of peers cooperation can decrease the heavy overhead of the server and all peers act both as clients and servers. Peer-to-peer networks have two famous structures called tree and mesh. Tree overlay has some challenges such as resiliency problems caused by peer churns and the leaf nodes that cannot use their upload bandwidth. Mesh overlay has does not have such problems, but it has a high delivery latency and overhead caused by pull mechanism. Using a hybrid mesh/tree overlay offers a push-pull approach and leads to using the advantages of both overlays simultaneously. Also in peer-to-peer...