Dept. of Commun. Network Eng., Okayama Univ., Japan
DOI: 10.1109/ICON.2005.1635456 Conference: Networks, 2005. Jointly held with the 2005 IEEE 7th Malaysia International Conference on Communication., 2005 13th IEEE International Conference on, Volume: 1
Application-level multicast (ALM) communications replicate packets on host level to deliver them from a single source to multiple clients, so that it can efficiently realize a variety of network applications using moving pictures such as video conferences, distance learning, and video-on-demands. In this paper, we propose the CT+ (compact tree plus) algorithm for finding a better ALM routing tree in terms of delay minimization between hosts. CT+ consists of a tree construction stage from the existing CT algorithm, and a newly added iterative tree improvement stage. Then, we define the extended ALM routing problem and its heuristic algorithm ExCT+, to optimize the effectiveness of the multihome network in ALM communications by selecting multihomed hosts and connections in the ALM routing tree simultaneously. For their evaluations, we construct a network simulation model named MINET (multiple-ISP network simulator), where the topology is composed of multiple ISP backbone networks with IX connections, and the network traffic is generated by following the M/M/1 queuing process. The simulation results using MINET verify the effectiveness of our algorithms.
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[Show abstract][Hide abstract]ABSTRACT: The paper addresses the issue of minimizing the number of nodes involved in routing over a multicast tree and in the maintenance of such a tree in a datagram network. It presents a scheme where the tree routing and maintenance burden is laid only upon the source node and the destination nodes associated with the multicast tree. The main concept behind this scheme is to view each multicast tree as a collection of unicast paths and to locate only the multicast source and destination nodes on the junctions of their multicast tree. The paper shows that despite this restriction, the cost of the created multicast trees is not necessarily higher than the cost of the trees created by other algorithms that do not impose the restriction and therefore require all nodes along the data path of a tree to participate in routing over the tree and in the maintenance of the tree
[Show abstract][Hide abstract]ABSTRACT: Multicast services can be provided either as a basic network service or as an application-layer service. Higher level multicast implementations often provide more sophisticated features and can provide multicast services at places where no network layer support is available. Overlay multicast networks offer an intermediate option, potentially combining the flexibility and advanced features of application layer multicast with the greater efficiency of network layer multicast. In this paper, we introduce the multicast routing problem specific to the overlay network environment and the related capacity assignment problem for overlay network planning. Our main contributions are the design of several routing algorithms that optimize the end-to-end delay and the interface bandwidth usage at the multicast service nodes within the overlay network. The interface bandwidth is typically a key resource for an overlay network provider, and needs to be carefully managed in order to maximize the number of users that can be served. Through simulations, we evaluate the performance of these algorithms under various traffic conditions and on various network topologies. The results show that our approach is cost-effective and robust under traffic variations.
Full-text · Article · Nov 2002 · IEEE Journal on Selected Areas in Communications
[Show abstract][Hide abstract]ABSTRACT: In this paper, we analyze several models of overlay multicast routing problem, and bring forward a new model based on multi-objective programming, discussing the solution of the model simultaneously. Then we employ the Prufer sequence as chromosome code and then propose a genetic algorithm to solve the model. Finally, we analyze the complexity of the algorithm.
[Show abstract][Hide abstract]ABSTRACT: All of the advantages of application-layer overlay networks arise from two fundamental properties: 1) the network nodes in an overlay network, as opposed to lower-layer network elements such as routers and switches, are end systems and have capabilities far beyond basic operations of storing and forwarding; 2) the overlay topology, residing above a densely connected Internet protocol-layer wide-area network, can be constructed and manipulated to suit one's purposes. We seek to improve end-to-end throughput significantly in application-layer multicast by taking full advantage of these unique characteristics. This objective is achieved with two novel insights. First, we depart from the conventional view that overlay nodes can only replicate and forward data. Rather, as end systems, these overlay nodes also have the full capability of encoding and decoding data at the message level using efficient linear codes. Second, we depart from traditional wisdom that the multicast topology from source to receivers needs to be a tree, and propose a novel and distributed algorithm to construct a two-redundant multicast graph (a directed acyclic graph) as the multicast topology, on which network coding is applied. We design our algorithm such that the costs of link stress and stretch are explicitly considered as constraints and minimized. We extensively evaluate our algorithm by provable analytical and experimental results, which show that the introduction of two-redundant multicast graph and network coding may indeed bring significant benefits, essentially doubling the end-to-end throughput in most cases.
Preview · Article · Feb 2004 · IEEE Journal on Selected Areas in Communications
[Show abstract][Hide abstract]ABSTRACT: Network layer multicast is know as the most efficient way to
support multicast sessions. However, for security, QoS and other
considerations, most of the real-time application protocols can be
better served by upper layer (transport or application) multicast. We
propose a scheme called M-RTP for multicast RTP sessions. The idea
behind this scheme is to set up the multicast RTP session over a set of
unicast RTP sessions, established between the various participants
(source and destinations) of the multicast session. We then address the
issue of finding a set of paths with maximum bottleneck for an M-RTP
session. We show that this problem is NP-complete, and propose several
heuristics to solve it
[Show abstract][Hide abstract]ABSTRACT: Application level multicast schemes have traditionally been evaluated with respect to the efficiency penalties incurred in migrating the multicast functionality from the network layer to the application layer. We argue that the current performance measures, and therefore design strategies, are incomplete as they do not consider transience of peers. The routers in application level multicast systems are participant clients, and not infrastructure units. As such, the assumptions on the behavior of these application routers are significantly different from the infrastructure routing units that traditional research has dealt with, especially in a peer-to-peer setting where peers are multi-use and the management is decentralized. we argue that the transience in peer behavior has implications on end-performance enabled. We outline a design philosophy that seeks to separate policy decisions in handling peer behavior from the end-application at a basic infrastructural peering layer. As a proof of concept, we have implemented a peering layer prototype, which is available for download.
Full-text · Article · Jan 2003 · ACM SIGCOMM Computer Communication Review
[Show abstract][Hide abstract]ABSTRACT: Application-level multicast is a new mechanism for enabling multicast in the Internet. Driven by the fast growth of network audio/video streams, application-level multicast has become increasingly important for its efficiency of data delivery and its ability of providing value-added services to satisfy application specific requirements. From a network design perspective, application-level multicast differs drastically from traditional IP multicast in its network cost model and routing strategies. We present these differences and formulate them as a network design problem consisting of two parts: one is bandwidth assignment in the overlay network, the other is load-balancing multicast routing with delay constraints. We use analytical methods and simulations to show that our design solution is a valid and cost-effective approach. Simulation results show that we are able to achieve network utilization within 10% of the best possible utilization while keeping the session rejection rate low.