Multicast Connections Research Articles

Algorithms for multicast connection under multi-path routing model

Given a source node and a set of destination nodes in a network, multicast routing problem is usually treated as Steiner tree problem. Unlike this well-known tree based routing model, multicast routing under multi-path model is to find a set of paths rooted at the source node such that in each path at most a fixed number of destination nodes can be designated to receive the data and every destination node must be designated in a path to receive the data. The cost of routing is the total costs of paths found. In this paper we study how to construct a multicast routing of minimal cost under multi-path model. We propose two approximation algorithms for this NP-complete problem with guaranteed performance ratios.

Point-to-group blocking in the switching networks with unicast and multicast switching

In this paper, a new approximate effective availability method of the point-to-group blocking probability calculation in switching networks carrying a mixture of different multi-rate unicast and multicast traffic streams is presented. Until recently, such methods have only been proposed for the single-services switching networks. To the best of our knowledge, methods of blocking probability calculation for multi-service switching network with multicast connection have not yet been considered. In this paper, four algorithms of setting-up multicast connections in multi-service switching networks are considered and discussed. Special attention is paid to the methods for determining the effective availability parameter in the case of multicast connections. The results of the analytical calculations are compared with the data of the digital simulations of the switching networks with unicast and multicast connections.

Multicast routing, load balancing, and wavelength assignment on tree of rings

There are two steps to establish a multicast connection in WDM networks: routing and wavelength assignment. The shortest path tree (SPT) and minimum spanning tree (MST) are the two widely used multicast routing methods. The SPT method minimizes the delay from the source to every destination along a routing tree, and the MST method is often used to minimize the network cost of the tree. Load balancing is an important objective in multicast routing, which minimizes the maximal link load in the system. The objective of wavelength assignment is to minimize the number of wavelengths used in the system. This paper analyzes the performance of the shortest path tree (SPT) and minimum spanning tree (MST) methods in the tree of ring networks, regarding the performance criteria such as the delay and network cost of the generated routing trees, load balancing, and the number of wavelengths required in the system. We prove that SPT and MST methods can not only produce routing trees with low network costs and short delays, but also have good competitive ratios for the load balancing problem (LBP) and wavelength assignment problem (WAP), respectively.

Optimal partition of QoS requirements on unicast paths and multicast trees

We investigate the problem of optimal resource allocation for end-to-end QoS requirements on unicast paths and multicast trees. Specifically, we consider a framework in which resource allocation is based on local QoS requirements at each network link, and associated with each link is a cost function that increases with the severity of the QoS requirement. Accordingly, the problem that we address is how to partition an end-to-end QoS requirement into local requirements, such that the overall cost is minimized. We establish efficient (polynomial) solutions for both unicast and multicast connections. These results provide the required foundations for the corresponding QoS routing schemes, which identify either paths or trees that lead to minimal overall cost. In addition, we show that our framework provides better tools for coping with other fundamental multicast problems, such as dynamic tree maintenance.

MCoRe: an adaptive scheme for rerouting multicast connections in mobile ATM networks

In this paper we propose multicast connection rerouting (MCoRe), a novel scheme for efficient multicasting in mobile asynchronous transfer mode (ATM) networks. We investigate and evaluate McoRe's performance in mobile ATM networks in the presence of mobile source fand/or receivers. In the past, multicasting from and to mobile hosts in mobile ATM networks has not received much attention from researchers. MCoRe is based on active network (AN) technologies, where the computation required for rerouting connections is performed at switches. Due to intra-network processing, MCoRe is efficient, requires minimal buffer requirements, has low handoff latency and high reuse, and incurs low signaling overheads. Apart from that, MCoRe preserves cell ordering, prevents cell duplication and minimizes cell loss during source or receiver migration. We show how shortest path tree adapts to source migration without incurring high signaling overheads. With MCoRe, source migration is transparent to the multicast group members and does not entail reconstruction of existing multicast tree. We also show how receiver migration is achieved and how cell ordering is preserved, when the receiver rejoins the multicast session.

Scheduling multicast traffic in input-buffered ATM switch

Performance of an input-buffered ATM switch is limited by the head-of-line (HOL) blocking problem. HOL blocking is even more pronounced in multicast switch where cells compete for multiple outputs simultaneously. Previous studies in input-buffered unicast switch have shown that HOL blocking can only be eliminated by using per-output queuing and sophisticated scheduling methods, such as the maximal weight matching (MWM) or the parallel iterative matching (PIM) methods. The MWM or PIM types of scheduling algorithm cannot be applied to multicast switch because of the high computation complexity. In this paper, we present a reservation based scheduling algorithm, which employs per-VC queuing for multicast connections and per-output queuing for unicast connections. Instead of the input ports sending a huge amount of state information to the output ports for processing, we circulate reservation vectors amongst the input ports. Each input port will then make reservation based on its local state and the availability of the output ports. The scheduling is done on a frame by frame basis. While the input ports are transmitting cells according to the schedule of the current frame, the next frame schedule is computed. Simulations reveal that our method substantially outperforms the methods that employ FIFO queuing discipline.

Batcher Banyan network with cell copy preparation stages for multicast switching

This paper considers an ATM switching network in a self-routing system for line switching, and proposes a Batcher Banyan network with a cell copy preparation network. The idea of this switching network is to consider the upper layer line in a communication network with a hierarchical structure, and to note that the traffic of a multicast connection is much smaller than the traffic of a one-to-one connection. The hardware scale is greatly reduced by allowing a small amount of blocking. More precisely, the Batcher Banyan network is used as the basic structure, and a cell copy preparation network with a small amount of hardware and a simple cell transfer algorithm is connected before the Batcher Banyan network. The cells are copied in the cell copy preparation network and the Batcher network. Routing is executed in the Batcher network and the Banyan network. The amount of hardware is greatly reduced compared to the conventional configuration in which the structure is divided into the copying network and the routing network. © 2001 Scripta Technica, Electron Comm Jpn Pt 1, 84(9): 54–63, 2001

Integrated algorithms for delay bounded multicast routing and wavelength assignment in all optical networks

There are two steps to set-up a multicast connection in all optical wavelength division multiplexing (WDM) networks: routing and wavelength assignment. Multicast routing is to find a tree in the network rooted from a source node and connecting all destination nodes. Wavelength assignment is to assign a wavelength to the generated routing tree in such a way that if two trees share a common link, then they must be assigned with two different wavelengths. This paper proposes two integrated algorithms to integrate routing and wavelength assignment. The proposed algorithms have the following advantages: (1) the number of wavelengths used is small; (2) the network cost of routing trees is low; and (3) the transmission delay from the source to any multicast destination is bounded.

A note on distributed multicast routing in point-to-point networks

The distributed algorithm for a multicast connection set-up, based on the ‘cheapest insertion’ heuristic, is reviewed. The multicast routing problem is translated into a Steiner tree problem in point-to-point networks where nodes have only a limited knowledge about the network. A solution is proposed in which the time complexity and the amount of information exchanged between network nodes are proportional to the number of members of the multicast group. The Steiner tree is constructed by means of a distributed table-passing algorithm. The analysis of the algorithm presented, backed up by simulation results, confirms its superiority over the algorithm based on ‘waving technique’. Scope and purpose Multicasting is a mechanism used in communication networks that allows distribution of information from a single source to multiple destinations. The problem of finding a multicast connection for a static group of communicating entities in connection-oriented point-to-point network can be formulated in graph theory as a minimum Steiner tree problem. Due to NP-completeness of the Steiner tree problem multicast, routing algorithms are based on heuristics. The diversity of network environments and the lack of centralised information about network topology require an effective distribution of the multicast routing algorithms among the network nodes. This article presents an alternative to the distributed algorithm proposed by Rugelj and Klavzar that implements the same heuristics for the construction of a minimum cost multicast connection in point-to-point networks. The present algorithm constitutes a substantial improvement over that previously proposed with regard to running time and the amount of the information exchanged between network nodes.

DEPLOYMENT OF NATIVE IP MULTICAST ROUTING SERVICES ON THE ITALIAN ACADEMIC AND RESEARCH NETWORK

In 1993 the GARR (Italian Academic and Research Network) was connected to MBONE (worldwide IP multicast enabled network backbone). Since then, and especially in the last few years, this network has been used to test and develop new IP multicast routing protocols and applications. However it was a tunnel-based solution, not suitable for taking advantage of the new potential of IP multicast nor for use by a large community. This paper describes the work done for a migration to a native IP multicast routing deployment, highlighting the solutions adopted when dealing with the implementation problems and the complex wide area network management. The aim of this work is also to ensure a native IP multicast connection with the other Research Networks and the rest of Internet.

Batcher Banyan network with cell copy preparation stages for multicast switching

AbstractThis paper considers an ATM switching network in a self‐routing system for line switching, and proposes a Batcher Banyan network with a cell copy preparation network. The idea of this switching network is to consider the upper layer line in a communication network with a hierarchical structure, and to note that the traffic of a multicast connection is much smaller than the traffic of a one‐to‐one connection. The hardware scale is greatly reduced by allowing a small amount of blocking. More precisely, the Batcher Banyan network is used as the basic structure, and a cell copy preparation network with a small amount of hardware and a simple cell transfer algorithm is connected before the Batcher Banyan network. The cells are copied in the cell copy preparation network and the Batcher network. Routing is executed in the Batcher network and the Banyan network. The amount of hardware is greatly reduced compared to the conventional configuration in which the structure is divided into the copying network and the routing network. © 2001 Scripta Technica, Electron Comm Jpn Pt 1, 84(9): 54–63, 2001

An integrated routing and admission control mechanism for real‐time multicast connection establishment

An integrated routing and admission control mechanism for real‐time multicast connection establishment

An integrated routing and admission control mechanism for real‐time multicast connection establishment

AbstractThere are two major difficulties in real‐time multicast connection setup. One is the design of an efficient distributed routing algorithm which optimizes the network cost of routing trees under the real‐time constraints. The other is the integration of routing with admission control into one single phase of operations. This paper presents a real‐time multicast connection setup mechanism, which integrates multicast routing with real‐time admission control. The proposed mechanism performs the real‐time admission tests on a cost optimal tree (COT) and a shortest path tree (SPT) in parallel, aiming at optimizing network cost of the routing tree under real‐time constraints. It has the following important features: (1) it is fully distributed; (2) it achieves sub‐optimal network cost of routing trees; (3) it takes less time and less network messages for a connection setup. Copyright © 2001 John Wiley & Sons, Ltd.

Blocking of Dynamic Multicast Connections

Multicast connections have a bandwidth saving nature. This means that a multicast connection --- in taking the form of a tree with streams merging at the nodes --- requires much less capacity from the network links than a bunch of separate point-to-point connections providing the same connectivity. In this paper, we consider dynamic multicast connections that can be used to model, for example, TV or radio delivery on a telecommunications network, such as an ATM network with virtual circuits. We show how to calculate the blocking probabilities of requests to join such a tree. First, we consider the blocking probabilities occurring in a single link. The resulting model is able to capture heterogeneous capacity requirements for different multicast channels. Then we extend the results to a whole network using the reduced load approximation. The accuracy of the approximation method is studied by simulations.

Wavelength requirements and routing for multicast connections in lightpath and light-tree models of WDM networks with limited drops

The wavelength requirements of a multicast connection in WDM networks are studied. The network model is an all-optical network, in which a message can be dropped (or split) only at a limited number of destination nodes along a lightpath or a light-tree, due to the power loss of dropping optical signals. The upper and lower bounds of wavelength requirements for establishing a multicast connection in various topologies of networks are presented. The optimal routing and wavelength assignment algorithms for multicast connections to achieve the minimal number of wavelengths are also described.

Aggregating Multicast Demands on Virtual Path Trees

In ATM networks, Virtual Path Connections (VPCs) are not only a device for bundling Virtual Circuit Connections (VCCs), but they serve as an intermediate resource management layer wherein tradeoffs between cost, complexity, and efficiency are likely to be made on a slower time scale than connection holding times. In this paper we consider bundling multicast connections on VP trees. In particular, we show that the aggregation of multicast demands onto large VP trees can be an effective way to reduce capacity requirements, balance network loads, and reduce the number of VP trees required.

An integrated routing and admission control mechanism for real-time multicast connections in ATM networks

This letter presents: 1) a delay analysis model, which is specially for the admission control of real-time multicast connections in ATM networks; 2) a distributed multicast routing algorithm, which generates suboptimal routing trees under real-time constraints; and 3) a connection setup method that integrates multicast routing with admission control.

Power-efficient design of multicast wavelength-routed networks

In this paper, we introduce the power-efficient design space for multicast wavelength-routed networks. The power-efficient design space is based on the impact of power on the overall design of wavelength-routed networks. Two cross-connect architectures on this design concept are investigated. One is an existing architecture called splitter-and-delivery (SaD). The other is a new architecture called multicast-only splitter-and-delivery (MOSaD). The MOSaD architecture uses power splitters for multicast connections only, allowing unicast connections to pass without enduring unnecessary power losses. Our cross-connect design provides a strictly nonblocking service for unicast connections while eliminating unnecessary power loss of the SaD cross-connect. Experimental results demonstrate that the MOSaD architecture provides substantial savings in cost and reduction in signal power loss with minimal effects on the blocking performance of the network.

On the Internet-Mediated TV-Like Distance Learning Services

The Internet-mediated distance learning has received a lot of attention in both universities and corporations in the past few years. With the proliferation of new network and multimedia technologies, there is an increasing need for delivering TV-like video lectures. The Cisco IP/TV system has been widely used as an efficient platform in supporting TV-like lectures in MPEG-1 format. However, since it relies on Microsoft multimedia technology, IP/TV cannot be architecture-neutral. Further, in spite that a Web interface to IP/TV is provided, it lacks in application program interfaces to endorse the development of interaction applications between instructors and students. Both limitations can be relieved by appealing to the emerging Java technology. However, playing RTP/MPEG objects using JMF (Java Media Framework) is a non-trivial task. This paper presents a novel Java-based TV-like distance learning system by integrating Cisco IP/TV and Java JMF technology so that the superiority of both models can be complemented. In particular, we enhance the JMF engine to make playing RTP/MPEG media objects over the Internet possible. This system offers two learning modes, namely on-demand learning via unicast connection and scheduled learning via multicast connection. A course sample and its performance evaluation are illustrated to validate the effectiveness and efficiency of delivering TV-like courseware. Furthermore, synchronous distance learning services can be implemented at less cost.

Wide-sense non-blocking multicast ATM switching networks

Wide-sense non-blocking multirate three-stage switching networks with multicast connections are considered in this paper. New conditions for wide-sense non-blocking multicast switching networks are derived and proved. It is shown that using an algorithm proposed in papers published earlier [K.S. Chan, S. Chan, K.L. Yeung, in: Proceedings of the GLOBECOM, Phoenix, AZ, 1997, pp. 526-530; K.S. Chan, S. Chan, K.L. Yeung, Electron. Lett. 33 (1997) 462–464], it is possible to construct a non-blocking network with less switches in a middle stage.