Multicast Communication Services Research Articles

Runtime connection-oriented guaranteed-bandwidth network-on-chip with extra multicast communication service

This paper presents a flexible runtime connection-oriented guaranteed-bandwidth Network on Chip (NoC). Comparing with a standard time-division multiplexing (TDM) method, our local ID-based method provides better flexibility to establish dynamic runtime connections. A specific pre-designed algorithm for finding a conflict-free scheduling, as commonly used in the TDM-based method, is not needed. The contention problem is solved with the hardware solution based on the locally organized message identity (ID), in which flits belonging to the same stream packet will have the same unique/local identity-tag (ID-tag) on each communication link. The ID-tags of each stream will vary locally over communication links and are updated. The updating is organized by ID-tag mapping management units. The routing is organized using runtime programmable routing reservation table. In addition, the proposed methodology supports also a deadlock-free multicast routing service.

A modular framework for the development of peer-to-peer applications and services

The development of peer-to-peer architectures and services is a cumbersome task, as it needs to handle multiple aspects at many levels (e.g., communication, coordination, topology construction and management, etc.). In order to facilitate the development process, several frameworks and component models have been proposed which allow the developer to focus on the main functionality of the service or application, without having to deal with the other aspects. In this paper, we propose a new modular framework for constructing and maintaining peer-to-peer overlays on top of which applications and services can be developed and deployed. We also consider two services, a multicast communication service and a data storage and retrieval service, and show how they can be developed using our framework.

Realization of a Scalable and Reliable Multicast Transport Protocol for Many-to-Many Sessions

In this paper, we present the Enhanced Communication Transport Protocol–Part 5 (ECTP-5), which provides scalable and reliable multicast communication service for many-to-many applications by constructing high quality recovery trees from two-layer logical trees and repairing the losses via unicast automatic repeat request–based error control. In order to realize the protocol, we developed feasible protocol architectures and building blocks including additional functions which deal with engineering details, such as membership dynamics and sender coordination. Experimental results show that ECTP-5 scales well with various session sizes and packet loss rates in terms of control overhead and recovery latency.

Reliable multicast routing in mobile networks: a neural-network approach

Mobile networks that handle multicast communication services, such as video-on-demand, news-on-demand etc., require a kind of reliable and secure point-to-point, point-to-multipoint specific group communications for sophisticated organisation of multicast communications. A reliable multicast tree is an efficient connectivity between the source node and the multicast group members through the dependable hosts. Because the mobile host changes its access point over time, multicast routes must be updated. This poses several challenges to provide an efficient multicast routing. A neural-network-based multicast routing algorithm is proposed for constructing a reliable multicast tree that connects the participants of a multicast group. The problem is tackled by dividing a mobile network into clusters of nodes based on the adjacency relation between the nodes (mobile support stations), by considering a suitable neighbourhood distance. The centre cluster, whose nodes are almost equidistant from the multicast group members, is computed to construct a shortest multicast tree that passes through the centre cluster and reliable routers among all the group members. A Kohonens self-organising-map neural network has been used for clustering. Hopfield neural networks are used to construct a multicast tree with a minimum number of links which passes through the nodes that belong to centre cluster. In addition, the tree is constructed as and when the member(s) moves. This scheme should construct a reliable multicast tree and minimise recomputation time of the multicast tree as and when the multicast route is updated when the mobile hosts change their access point due to mobility. The computational power of the proposed neural-network-based multicast routing algorithm is demonstrated through simulation. The algorithm is also tested for mobility of the participating mobile hosts. The proposed work facilitates a possible multicast routing algorithm for future high-speed mobile networks.

Copy node allocation algorithms for multicast routing in large-scale ATM networks

Multicast communication services will be one of the most promising future applications in both public B-ISDN and the Internet. Generally, multicast communication can be realized by forwarding information along tree-shaped route. In order to realize rapid multicast routing, it is suitable and realistic to restrict the number of copy nodes in calculating multicast route. However, even in this approach we need to adequately select the restricted number of copy nodes which satisfy the conditions of both priority for multicasting and geographical distribution at the same time. As for this problem, we propose two heuristic algorithms, basic version named “concurrent type” and improved version named “sequential type”, by greatly developing the concept of “elastic network algorithm”. In addition to setting all important parameters through fundamental simulation testing, performance of this tuned-up new algorithms is evaluated.

Adaptive group multicast with time-driven priority

This paper shows how to provide an adaptive real-time group multicast (many-to-many) communication service. Adaptive means that the number of nodes that transmit to the multicast group is continuously changing. In order to meet deterministic quality-of-service (QoS) requirements of a real-time group multicast, some communication resources are reserved. We show (1) how bandwidth is reserved for each multicast group and (2) how an active source can dynamically share the bandwidth allocated to this multicast group with other active group members. Quality-of-service support for a real-time multicast group is based on time-driven priority. In this scheme the time is divided into time frames of fixed duration, and all the time frames are aligned by using a common global time reference, which can be obtained from the Global Positioning System. Bandwidth is allocated to a multicast group as a whole, rather than individually to each user. The allocation is done by reserving time intervals within time frames in a periodic fashion. This type of allocation raises two problems that are studied in this paper: (1) scheduling: how time intervals are reserved to each multicast group and (2) adaptive sharing: how the active (transmitting) participants can dynamically share the time intervals that have been reserved for their multicast group. The proposed approach is based on the embedding of multiple virtual rings, one for each multicast group. By using the virtual rings, it is simple to route messages to all the participants while minimizing the bound on the buffer sizes and queueing delays. The final part of this paper introduces a scalable growth of the multicast group by adding multiple subtrees to the virtual ring.

Deadlock-free multicast wormhole routing in 2-D mesh multicomputers

Multicast communication services, in which the same message is delivered from a source node to an arbitrary number of destination nodes, are being provided in new-generation multicomputers. Broadcast is a special case of multicast in which a message is delivered to all nodes in the network. The nCUBE-2, a wormhole-routed hypercube multicomputer, provides hardware support for broadcast and a restricted form of multicast in which the destinations form a subcube. However, the broadcast routing algorithm adopted in the nCUBE-2 is not deadlock-free. In this paper, four multicast wormhole routing strategies for 2-D mesh multicomputers are proposed and studied. All of the algorithms are shown to be deadlock-free. These are the first deadlock-free multicast wormhole routing algorithms ever proposed. A simulation study has been conducted that compares the performance of these multicast algorithms under dynamic network traffic conditions in a 2-D mesh. The results indicate that a dual-path routing algorithm offers performance advantages over tree-based, multipath, and fixed-path algorithms. >

A kernel for high-performance multicast communications

A kernel is described, called the link kernel, for high-performance interprocess communication among shared-memory multiprocessors using an Ethernet. The link kernel provides asynchronous multicast communication service without protocol overhead. Links are created by listeners, and processes may be simultaneously talkers and listeners. Processes access links through a global link table. Multicast addresses are site-independent, so communication is independent of process locations in the network. Communication is asynchronous, so much of the overhead of message management is masked by parallel computation.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>