Sharif Digital Repository

In this paper, we consider multiple multicast sessions with intra-session network coding where rates over all links are integer multiples of a basic rate. Although having quantized rates over communication links is quite common, conventional minimum cost network coding problem cannot generally result in quantized solutions. In this research, the problem of finding minimum cost transmission for multiple multicast sessions with network coding is addressed. It is assumed that the rate of coded packet injection at every link of each session takes quantized values. First, this problem is formulated as a mixed integer linear programming problem, and then it is proved that this problem is strongly... 

For a given multicast network problem, there are different solutions. Sometimes some links of a network may be removed by failure and then we will be encountered with link failure in the network. Therefore, one of the objectives of selecting a specific network code solution among different options is to increase the robustness provided by this solution against such failure. In this paper we extend the definition of the minimal subtree graph and replace it with a new definition of minimal subgraph and use it as a basis of a faster method with lower complexity for finding a static network code resistant against all solvable link failure patterns of a network. ©2008 IEEE  

In this paper, we present a decentralized algorithm that computes minimum cost QoS flow subgraphs in network coded multicast networks. These subgraphs are minimum cost solutions that also satisfy user-specified QoS constraints, specifically handling elastic rate and delay demands. Although earlier network coding algorithms in this area have only demonstrated QoS improvements, the proposed QoS network coding is clearly different in the sense that it guarantees that given QoS constraints are met over the network  

In this paper, a new dynamic proxy solution based on overlay multicasting network for layered video streaming is presented. In our proposed approach, all clients in an Internet service provider network interested in receiving a video stream, provided by a media server in the Internet, organize themselves into an overlay tree. The root of the overlay tree acts as a proxy and receives video stream from original server and distributes it in the local overlay tree. In addition to introducing a new architecture, our main contribution in this paper is proposing a number of distributed protocols for construction and improvement of local overlay tree in video streaming applications. The experimental... 

In this paper we propose a rate-efficient peer-to-peer architecture for video multicasting over the Internet. The limited capacity of the Internet hosts and the heterogeneous property of their access links are the main challenges of the peer-to-peer video multicasting over the Internet. Although, the rate-optimized overlay tree construction is a NP-hard problem, we propose a number of distributed and efficient protocols for rate-efficient overlay tree construction. Our proposed protocols include efficient join, improvement, overlay tree refinement and an optimum rate allocation protocol. The simulation results show the efficiency of the proposed protocols in rate-efficient overlay tree... 

Named Data Networking (NDN) is a new information-centric networking architecture in which data or content is identified by a unique name and saved pieces of the content are used in the cache of routers. Certainly, routing is one of the major challenges in these networks. In NDN, to achieve the required data for users, interest messages containing the names of data are sent. Because the source and destination addresses are not included in this package, routers forward them using the names that carried in packages. This forward will continue until the interest package is served. In this paper, we propose a routing algorithm for NDN. The purpose of this protocol is to choose a path with the... 

Named data networking (NDN) is a new information-centric networking architecture in which data or content is identified by a unique name and saved pieces of the content are used in the cache of routers. Certainly, routing is one of the major challenges in these networks. In NDN, to achieve the required data for users, interest messages containing the names of data are sent. Because the source and destination addresses are not included in this package, routers forward them using the names that carried in packages. This forward will continue until the interest package is served. In this paper, we propose a routing algorithm for NDN. The purpose of this protocol is to choose a path with the... 

Exponential growth of traffic and bandwidth demands in current data center networks requires low-latency high-throughput interconnection networks, considering power consumption. By considering growth of both multicast and unicast applications, power efficient communication becomes one of the main design challenges in today's data center networks. Addressing these demands, optical networks suggest several benefits as well as circumventing most disadvantages of electrical networks. In this paper, we propose an all-optical scalable architecture, named as OMUX, for communicating intra-data centers. This architecture utilizes passive optical devices and enables optical circuit switching without... 

In this paper, we present a decentralized algorithm that computes minimum cost QoS flow subgraphs in network coded multicast networks. These subgraphs are minimum cost solutions that also satisfy user-specified QoS constraints, specifically handling elastic rate and delay demands. Although earlier network coding algorithms in this area have only demonstrated QoS improvements, the proposed QoS network coding is clearly different in the sense that it guarantees that given QoS constraints are met over the network. ©2008 IEEE  

The authors consider the problem of finding a minimum cost multicast sub-graph based on network coding, where delay values associated with each link, limited buffer-size of the intermediate nodes and link capacity variations over time are taken into account. The authors consider static multicast (where membership of the multicast group remains constant for the duration of the connection) in lossless wireline networks. For such networks, first the continuous-time (asynchronous packet transmissions) model is formulated. Subsequently, the discrete-time model for the synchronous packet transmissions scenario is derived. Then, by using an auxiliary time-expanded network, a decentralised algorithm... 

Networks-on-Chip (NoCs for short) are known as the most scalable and reliable on-chip communication architectures for multi-core SoCs with tens to hundreds IP cores. Proper mapping the IP cores on NoC tiles (or assigning threads to cores in chip multiprocessors) can reduce end-to-end delay and energy consumption. While almost all previous works on mapping consider higher priority for the application's flows with higher required bandwidth, a mapping strategy, presented in this paper, is introduced that considers multicast communication flows in addition to the normal unicast flows. To this end, multicast and unicast traffic flows are first characterized in terms of some new metrics which are... 

Several unicast and multicast routing protocols have been presented for MPSoCs. Multicast protocols in NoCs are used for cache coherency in distributed shared memory systems, replication, barrier synchronization, or clock synchronization. Unicast routing algorithms are not suitable for multicast, as they increase traffic, congestion and deadlock probability. Famous multicast schemes such as tree-based and path-based schemes have been proposed originally for multicomputers and recently adapted to NoCs. In this paper, we propose a switch tree-based multicast scheme, called STBA. This method supports tree construction with a minimum number of routers. Our evaluation results reveal that, for... 

Different attacks on routing protocols in ad hoc networks occur that one of the most dangerous types is called wormhole attack. This attack happens with the assistance of at least two or more malicious nodes. In this attack nodes create a private tunnel which if a packet comes to one of them, it will be guided to other pair of these malicious nodes by this tunnel and that node broadcasts it into network. This action provides a short connection in the network that is controlled by these malicious nodes. Hence they control all Packets that come to them and threaten the security of data within packets or delete them. Totally, what a wormhole does is an incorrect understanding of network... 

Different attacks on routing protocols in ad hoc networks occur that one of the most dangerous types is called wormhole attack. This attack happens with the assistance of at least two or more malicious nodes. In this attack nodes create a private tunnel which if a packet comes to one of them, it will be guided to other pair of these malicious nodes by this tunnel and that node broadcasts it into network. This action provides a short connection in the network that is controlled by these malicious nodes. Hence they control all Packets that come to them and threaten the security of data within packets or delete them. Totally, what a wormhole does is an incorrect understanding of network... 

In this paper, we formulate an integer linear programming (ILP) to perform multicast routing and spectrum assignment (MRSA) in elastic optical networks, which serves jointly a set of multicast requests. In this formulation, all physical layer restrictions including modulation level assignment, maximum number of multicast capable nodes (MCNs), and maximum splitting degree (MSD) of MCNs, are considered. In addition, we modify the proposed joint ILP to serve multicast requests one-by-one, which is referred to as a separate ILP. Furthermore, we present three heuristic algorithms for MRSA, namely distance-based MRSA (DMRSA), congestion-based MRSA (CMRSA), and mixed CMRSA/DMRSA, which are... 

We consider joint optimization of data routing and resource allocation in multicast multihop wireless networks where interference between links is taken into account. The use of network coding in such scenarios leads to a nonconvex optimization problem. By applying the probability collectives (PCs) technique the original problem is turned into a new problem which is convex over probability distributions. The resulting problem is then further decomposed into a data routing subproblem at network layer and a power allocation subproblem at physical layer in order to achieve a cross-layer distributed solution for the whole range of SINR values. The proposed approach is also extended to minimum... 

In this paper, we propose a new approach to find a static solution for a multicast network problem. Our work relates the existence of a static network code to minimal subtree graphs of a given network. For a given multicast network there are different solutions. Sometimes some links of a network may be removed and then we will be encountered with link failure in the network. Therefore, to choose a specific satisfactory network code solution among different options, we must see how much the network code adds the network robustness against link failures. In this paper we extend the definition of the minimal subtree graph and replace it with a new definition of minimal subgraph and show that... 

Overlay multicast has gained much attention in recent years as an alternative method to network layer multicast, especially for mobile ad hoc networks (MANETs). In this paper, we propose a new overlay multicast protocol to achieve simplicity of deployment, rapid adaptation of overlay structure when nodes move, and reduced delay. In our algorithm, to join or leave a multicast group, it is only sufficient for a member node to inform its first upstream member node. This updates the tree structure more rapidly when nodes move. In addition, join and leave delays are reduced and this makes the protocol suitable for multimedia multicasting in MANETs. Simulation results compared to that of ODMRP and... 

An ad hoc network is a multi-hop wireless network formed by a collection of mobile nodes without the intervention of fixed infrastructure. Reliable Multicast plays a significant role in many applications of Mobile Ad Hoc Networks (MANETs). In recent years, a number of protocols have been proposed to deliver multicast packets reliably. In this paper we intend to propose a reliable multicast algorithm with local recovery approach, because importance of on-demand routing protocol we use this method in our algorithm. By using this algorithm nodes can join to multicast group in minimum time and data delivery will be increase. This method achieves fast recovery when route breakage happens, so... 

Device-to-device (D2D) communication improves spectrum efficiency (SE) and increases system capacity. Heterogeneous networks comprise macrocell and several small cells, such as picocells and femtocells, where femtocells are more efficient. In cooperative communications, one or several additional nodes help to send data from source to destination to improve the quality of service (QoS). Network coding (NC) in cooperative networks can extend data rate and coverage area of D2D communication. The purpose of this article is to minimize power consumption of transmitting nodes during network-coded cooperative D2D transmission to reduce the interference on co-channel transmissions. In this study, we...