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

Multipath routing for video delivery over bandwidth-limited networks

The delivery of quality video service often requires high bandwidth with low delay or cost in network transmission. Current routing protocols such as those used in the Internet are mainly based on the single-path approach (e.g., the shortest-path routing). This approach cannot meet the end-to-end bandwidth requirement when the video is streamed over bandwidth-limited networks. In order to overcome this limitation, we propose multipath routing, where the video takes multiple paths to reach its destination(s), thereby increasing the aggregate throughput. We consider both unicast (point-to-point) and multicast scenarios. For unicast, we present an efficient multipath heuristic (of complexity O(|V|3)), which achieves high bandwidth with low delay. Given a set of path lengths, we then present and prove a simple data scheduling algorithm as implemented at the server, which achieves the theoretical minimum end-to-end delay. For a network with unit-capacity links, the algorithm, when combined with disjoint-path routing, offers an exact and efficient solution to meet a bandwidth requirement with minimum delay. For multicast, we study the construction of multiple trees for layered video to satisfy the user bandwidth requirements. We propose two efficient heuristics on how such trees can be constructed so as to minimize the cost of their aggregation subject to a delay constraint.published_or_final_versio

Algorithms for Constructing Overlay Networks For Live Streaming

We present a polynomial time approximation algorithm for constructing an overlay multicast network for streaming live media events over the Internet. The class of overlay networks constructed by our algorithm include networks used by Akamai Technologies to deliver live media events to a global audience with high fidelity. We construct networks consisting of three stages of nodes. The nodes in the first stage are the entry points that act as sources for the live streams. Each source forwards each of its streams to one or more nodes in the second stage that are called reflectors. A reflector can split an incoming stream into multiple identical outgoing streams, which are then sent on to nodes in the third and final stage that act as sinks and are located in edge networks near end-users. As the packets in a stream travel from one stage to the next, some of them may be lost. A sink combines the packets from multiple instances of the same stream (by reordering packets and discarding duplicates) to form a single instance of the stream with minimal loss. Our primary contribution is an algorithm that constructs an overlay network that provably satisfies capacity and reliability constraints to within a constant factor of optimal, and minimizes cost to within a logarithmic factor of optimal. Further in the common case where only the transmission costs are minimized, we show that our algorithm produces a solution that has cost within a factor of 2 of optimal. We also implement our algorithm and evaluate it on realistic traces derived from Akamai's live streaming network. Our empirical results show that our algorithm can be used to efficiently construct large-scale overlay networks in practice with near-optimal cost

Mediator-assisted multi-source routing in information-centric networks

Among the new communication paradigms recently proposed, information-centric networking (ICN) is able to natively support content awareness at the network layer shifting the focus from hosts (as in traditional IP networks) to information objects. In this paper, we exploit the intrinsic content-awareness ICN features to design a novel multi-source routing mechanism. It involves a new network entity, the ICN mediator, responsible for locating and delivering the requested information objects that are chunked and stored at different locations. Our approach imposes very limited signalling overhead, especially for large chunk size (MBytes). Simulations show significant latency reduction compared to traditional routing approaches

Performance analysis of multilayer multicast MANET CRN based on steiner minimal tree algorithm

In this study, the multicast mobile ad hoc (MANET) CRN has been developed, which involves multi-hop and multilayer consideration and Steiner minimal tree (SMT) algorithm is employed as the router protocol. To enhance the network performance with regards to throughput and packet delivery rate (PDR), as channel assignment scheme, the probability of success (POS) is employed that accounts for the channel availability and the time needed for transmission when selecting the best channel from the numerous available channels for data transmission from the source to all destinations nodes effectively. Within Rayleigh fading channels under various network parameters, a comparison is done for the performance of SMT multicast (MANET) CRN with POS scheme versus maximum data rate (MDR), maximum average spectrum availability (MASA) and random channel assignment schemes. Based on the simulation results, the SMT multicast (MANET) CRN with POS scheme was seen to demonstrate the best performance versus other schemes. Also the results proved that the throughput and PDR performance are improved as the number the primary channels and the channel’s bandwidth increased while dropped as the value of packet size D increased. The network’s performance grew with rise in the value of idle probability (P_I) since the primary user’s (PU) traffic load is low when the value of P_I is high

Protocols for collaborative applications on overlay networks.

Third, we address the limitations of traditional multicasting models. Towards this, we propose a model where a source node has different switching time for each child node and the message arrival time at each child depends on the order in which the source chooses to send the messages. This model captures the heterogeneous nature of communication links and node hardware on the overlay network. Given a multicast tree with link delays and generalized switching delay vectors at each non-leaf node, we provide an algorithm which schedules the message delivery at each non-leaf node in order to minimize the delay of the multicast tree.First, we consider the floor control problem wherein the participating users coordinate among themselves to gain exclusive access to the communication channel. To solve the floor control problem, we present an implementation and evaluation of distributed Medium Access Control (MAC) protocols on overlay networks. As an initial step in the implementation of these MAC protocols, we propose an algorithm to construct an efficient communication channel among the participating users in the overlay network. We also show that our implementation scheme (one of the first among decentralized floor control protocols) preserves the causal ordering of messages.Our research is focused on the development of algorithms for the construction of overlay networks that meet the demands of the distributed applications. In addition, we have provided network protocols that can be executed on these overlay networks for a chosen set of collaborative applications: floor control and multicasting. Our contribution in this research is four fold.Fourth, we address the problem of finding an arbitrary application designer specific overlay network on the Internet. This problem is equivalent to the problem of subgraph homeomorphism and it is NP-Complete. We have designed a polynomial-time algorithm to determine if a delay constrained multicasting tree (call it a guest) can be homeomorphically embedded in a general network (call it a host). A delay constrained multicasting tree is a tree wherein the link weights correspond to the maximum allowable delay between the end nodes of the link and in addition, the link of the guest should be mapped to a shortest path in the host. Such embeddings will allow distributed application to be executed in such a way that application specific quality-of-service demands can be met. (Abstract shortened by UMI.)Second, we address the problem of designing multicasting sub-network for collaborative applications using which messages are required to arrive at the destinations within a specified delay bound and all the destinations must receive the message from a source at 'approximately' the same time. The problem of finding a multicasting sub-network with delay and delay-variation bound has been proved to be NP-Complete in the literature and several heuristics have been proposed

Mesh based and Hybrid Multicast routing protocols for MANETs: Current State of the art

This paper discusses various multicast routing protocols which are proposed in the recent past each having its own unique characteristic, with a motive of providing a complete understanding of these multicast routing protocols and present the scope of future research in this field. Further, the paper specifically discusses the current development in the development of mesh based and hybrid multicasting routing protocols. The study of this paper addresses the solution of most difficult task in Multicast routing protocols for MANETs under host mobility which causes multi-hop routing which is even more severe with bandwidth limitations. The Multicast routing plays a substantial part in MANETs

Proactive detection of DDOS attacks in Publish-Subscribe networks

Information centric networking (ICN) using architectures such as Publish-Subscribe Internet Routing Paradigm (PSIRP) or Publish-Subscribe Internet Technology (PURSUIT) has been proposed as an important candidate for the Internet of the future. ICN is an emerging research area that proposes a transformation of the current host centric Internet architecture into an architecture where information items are of primary importance. This change allows network functions such as routing and locating to be optimized based on the information items themselves. The Bloom filter based content delivery is a source routing scheme that is used in the PSIRP/PURSUIT architectures. Although this mechanism solves many issues of today’s Internet such as the growth of the routing table and the scalability problems, it is vulnerable to distributed denial-of-service (DDoS) attacks. In this paper, we present a new content delivery scheme that has the advantages of Bloom filter based approach while at the same time being able to prevent DDoS attacks on the forwarding mechanism. Our security analysis suggests that with the proposed approach, the forwarding plane is able to resist attacks such as DDoS with very high probabilit

A Distance-Heuristic Tree Building Approach in Application Layer Multicast

In the application layer multicast (ALM), clustering nearby nodes can effectively improve the multicast performance. However, it is difficult for the ALM solution to quickly and accurately position the newcomer, because group members have no direct knowledge of underlying network topology. Additionally, ALM delivery trees with different performances are built when group members join the group in different join sequences. To alleviate the above problems, this paper proposes a distance-heuristic tree building protocol (called DHTB). DHTB uses our proposed distance-constrained cluster model and close-member-first-receive (CF) rule. In the model, most nearby nodes are grouped into some distance-constrained clusters, with little cluster organization and maintenance overhead. The CF rule arranges or rearranges the locations of group members according to related distances, and effectively positions the newcomer with the help of on-demand landmarks. Both the distance-constrained cluster model and CF rule are distance-heuristic. Therefore DHTB can alleviate the join sequence problem, and build the ALM tree with desirable performance