Study of architecture and protocols for reliable multicasting in packet switching networks

Group multicast protocols have been challenged to provide scalable solutions that meet the following requirements: (i) reliable delivery from different sources to all destinations within a multicast group; (ii) congestion control among multiple asynchronous sources. Although it is mainly a transport layer task, reliable group multicasting depends on routing architectures as well. This dissertation covers issues of both network and transport layers. Two routing architectures, tree and ring, are surveyed with a comparative study of their routing costs and impact to upper layer performances. Correspondingly, two generic transport protocol models are established for performance study. The tree-based protocol is rate-based and uses negative acknowledgment mechanisms for reliability control, while the ring-based protocol uses window-based flow control and positive acknowledgment schemes. The major performance measures observed in the study are network cost, multicast delay, throughput and efficiency. The results suggest that the tree architecture costs less at network layer than the ring, and helps to minimize latency under light network load. Meanwhile, heavy load reliable group multicasting can benefit from ring architecture, which facilitates window-based flow and congestion control. Based on the comparative study, a new two-hierarchy hybrid architecture, Rings Interconnected with Tree Architecture (RITA), is presented. Here, a multicast group is partitioned into multiple clusters with the ring as the intra-cluster architecture, and the tree as backbone architecture that implements inter-cluster multicasting. To compromise between performance measures such as delay and through put, reliability and congestion controls are accomplished at the transport layer with a hybrid use of rate and window-based protocols, which are based on either negative or positive feedback mechanisms respectively. Performances are compared with simulations against tree- and ring-based approaches. Results are encouraging because RITA achieves similar throughput performance as the ring-based protocol, but with significantly lowered delay. Finally, the multicast tree packing problem is discussed. In a network accommodating multiple concurrent multicast sessions, routing for an individual session can be optimized to minimize the competition with other sessions, rather than to minimize cost or delay. Packing lower bound and a heuristic are investigated. Simulation show that congestion can be reduced effectively with limited cost increase of routings

Issues in providing a reliable multicast facility

Issues involved in point-to-multipoint communication are presented and the literature for proposed solutions and approaches surveyed. Particular attention is focused on the ideas and implementations that align with the requirements of the environment of interest. The attributes of multicast receiver groups that might lead to useful classifications, what the functionality of a management scheme should be, and how the group management module can be implemented are examined. The services that multicasting facilities can offer are presented, followed by mechanisms within the communications protocol that implements these services. The metrics of interest when evaluating a reliable multicast facility are identified and applied to four transport layer protocols that incorporate reliable multicast

Multicast in DKS(N, k, f) Overlay Networks

Recent developments in the area of peer-to-peer computing show that structured overlay networks implementing distributed hash tables scale well and can serve as infrastructures for Internet scale applications. We are developing a family of infrastructures, DKS(N; k; f), for the construction of peer-to-peer applications. An instance of DKS(N; k; f) is an overlay network that implements a distributed hash table and which has a number of desirable properties: low cost of communication, scalability, logarithmic lookup length, fault-tolerance and strong guarantees of locating any data item that was inserted in the system. In this paper, we show how multicast is achieved in DKS(N, k, f) overlay networks. The design presented here is attractive in three main respects. First, members of a multicast group self-organize in an instance of DKS(N, k, f) in a way that allows co-existence of groups of different sizes, degree of fault-tolerance, and maintenance cost, thereby, providing flexibility. Second, each member of a group can multicast, rather than having single source multicast. Third, within a group, dissemination of a multicast message is optimal under normal system operation in the sense that there are no redundant messages despite the presence of outdated routing information

Protocols for packet switched communication and reliable multicasting in fully-dynamic multi-hop wireless networks

Designing protocols for a fully dynamic wireless packet switched networks pose unique challenges due to the constantly changing topology of the network. A set of protocols is presented that are capable of handling a fully dynamic wireless network in which switching centers and base stations are mobile as well as the end users. The protocols provide basic message delivery, network routing information updates, and support for reliable multicasting. There are four contributions of this work: (i) a hierarchical architecture for a fully dynamic wireless network, (ii) improved routing and update protocols with reduced control traffic, (iii) a method to provide reliable multicasting in a wireless environment that is near optimal in terms of the number of messages sent, and (iv) a set of load balancing algorithms that allow the network to autonomously and dynamically reconfigure the network topology to even out the load on the base stations. A detailed simulation of the protocols is developed and exercised to evaluate the performance of the protocols. For point to point delivery, the protocols successfully deliver all packets even when the rate of motion of the terminals causes more than 1/2 of them to be in a transitional state at any time. The results are similar for base station

Distributed Anonymity Based on Blockchain in Vehicular Ad Hoc Network by Block Size Calibrating

The network connectivity problem is one of the critical challenges of an anonymous server implementation in the VANET. The objective and main contribution of this paper are to assure the anonymity in VANET environments. In the proposed blockchain method, before packaging transactions into blocks, anonymity risk reduced through techniques such as k-anonymity, graph processing, dummy node, and silence period. This paper addresses the challenges of anonymous servers, such as update challenges and single point of failure, by exploiting append-only, distributed, and anonymity features. Although mounting the blockchain process with asymmetric cryptography solves the connectivity challenge, start-up delay and network overhead are severe. The significant feature of the proposed method solves this delay challenge by aggregating many transactions into a block and fixing constraint range of multicasting blocks. Also, aggregating transactions of various end-users into a block preserves the path anonymity. The asymmetric cryptography with ring public and private keys protects the identity anonymity as well as unlinkability. The robust anonymity mechanism existence and the traceability of all transactions constitute the main advantages of the proposed method. The simulation is running by the python to evaluate blockchain performance in VANET with connectivity failure and rapidly changing topology. The results indicate the stabilization of the proposed method in the VANET environment

A Survey on Wireless Sensor Network Security

Wireless sensor networks (WSNs) have recently attracted a lot of interest in the research community due their wide range of applications. Due to distributed nature of these networks and their deployment in remote areas, these networks are vulnerable to numerous security threats that can adversely affect their proper functioning. This problem is more critical if the network is deployed for some mission-critical applications such as in a tactical battlefield. Random failure of nodes is also very likely in real-life deployment scenarios. Due to resource constraints in the sensor nodes, traditional security mechanisms with large overhead of computation and communication are infeasible in WSNs. Security in sensor networks is, therefore, a particularly challenging task. This paper discusses the current state of the art in security mechanisms for WSNs. Various types of attacks are discussed and their countermeasures presented. A brief discussion on the future direction of research in WSN security is also included.Comment: 24 pages, 4 figures, 2 table

An Efficient and Reliable Data Transmission Service using Network Coding Algorithms in Peer-to-Peer Network

Network coding is a progressive enhancement in natural network routing that increases throughput and reliability for unicast, multicast, and even broadcast transmissions. P2P networks are ideal for implementing network coding algorithms for two reasons: I. A P2P network's topology isn't predetermined. As a result, designing a topology that is compatible with the network coding algorithm is much easier. II. Every peer is an end host in this network.  As a result, instead of saving and sending the message, complex network coding operations, such as encoding and decoding, are now easier to perform. The objective of this work is to use the best features of network coding algorithms and properly apply them to P2P networks to create an efficient and reliable data transmission service. The goal of the network coding algorithm is to make better use of network resources and thus increase P2P network capacity. An encoding algorithm that enables an intermediate peer to produce output messages by encoding (that is, computing a function of the data it receives. The decoder's role is to obtain enough encoded packets so that the original information can be recovered. This research work has measured an amount of hypothetical and applied consequences in which the network coding procedure or a variation of it is used to improve performance parameters such as throughput and reliability in P2P network data transmission based on network coding. The comparison of data transmission between network routing and network coding algorithms was the main focus of this paper.  According to our simulations, the new network coding systems can reach 15% to 20% upper throughput than supplementary P2P network routing systems