PIM-SM = Protocol Independent Multicast- Sparse Mode

This paper proposes a design for IP multicast routing in hybrid satellite networks. The emergence of IP multicast for Internet group communication has placed focus on communication satellites as an efficient way to extend the multicast services for groups with distributed membership in wide-area networks. This poses interesting challenges for routing. Hybrid satellite networks can have both wired and wireless links and also combine different link-layer technologies like Ethernet and ATM. No proposed IP multicast routing protocol for wired networks offers an integrated solution for such networks. This paper attempts to provide a solution by proposing a design for IP multicast routing in wide-area networks that have terrestrial Ethernet LANs interconnected by A TM-based satellite channels. The paper reviews the multicast services offered by IP and A TM, and proposes a multicast routing framework that combines PIM-SM protocol for terrestrial multicasting with the A TM MARS and VC mesh architecture for multicast routing over the satellite links. Modifications are made to the standard protocols to suit the unique needs of the network being considered. The feasibility of the proposed design is tested by performing simulations. The proposed framework is presented in detail, along with analysis and simulation results

Framework for IP Multicast in Satellite ATM Networks

This paper proposes a design for IP multicast routing in hybrid satellite networks. The emergence of IP multicast for Internet group communication has placed focus on communication satellites as an efficient way to extend IP multicast services for groups with distributed membership in wide-area networks. This poses interesting challenges for routing. Satellite networks can have both wired and wireless links and also combine different link-layer technologies like Ethernet and ATM. No proposed IP multicast routing protocol for wired networks offers an integrated solution for such networks. This paper attempts to provide a solution by proposing a design for IP multicast routing in wide-area networks that have terrestrial Ethernet LANs interconnected by ATM-based satellite channels. The paper reviews the multicast services offered by IP and ATM, and proposes a multicast routing framework that combines PIM-SM protocol for terrestrial multicasting with the ATM MARS and VC mesh architecture for multicast routing over the satellite links. Modifications are made to the standard protocols to suit the unique needs of the network being considered. The feasibility of the proposed design is tested by performing simulations. The proposed framework is presented in detail, along with analysis and simulation results

Low Cost Quality of Service Multicast Routing in High Speed Networks

Many of the services envisaged for high speed networks, such as B-ISDN/ATM, will support real-time applications with large numbers of users. Examples of these types of application range from those used by closed groups, such as private video meetings or conferences, where all participants must be known to the sender, to applications used by open groups, such as video lectures, where partcipants need not be known by the sender. These types of application will require high volumes of network resources in addition to the real-time delay constraints on data delivery. For these reasons, several multicast routing heuristics have been proposed to support both interactive and distribution multimedia services, in high speed networks. The objective of such heuristics is to minimise the multicast tree cost while maintaining a real-time bound on delay. Previous evaluation work has compared the relative average performance of some of these heuristics and concludes that they are generally efficient, although some perform better for small multicast groups and others perform better for larger groups. Firstly, we present a detailed analysis and evaluation of some of these heuristics which illustrates that in some situations their average performance is reversed; a heuristic that in general produces efficient solutions for small multicasts may sometimes produce a more efficient solution for a particular large multicast, in a specific network. Also, in a limited number of cases using Dijkstra's algorithm produces the best result. We conclude that the efficiency of a heuristic solution depends on the topology of both the network and the multicast, and that it is difficult to predict. Because of this unpredictability we propose the integration of two heuristics with Dijkstra's shortest path tree algorithm to produce a hybrid that consistently generates efficient multicast solutions for all possible multicast groups in any network. These heuristics are based on Dijkstra's algorithm which maintains acceptable time complexity for the hybrid, and they rarely produce inefficient solutions for the same network/multicast. The resulting performance attained is generally good and in the rare worst cases is that of the shortest path tree. The performance of our hybrid is supported by our evaluation results. Secondly, we examine the stability of multicast trees where multicast group membership is dynamic. We conclude that, in general, the more efficient the solution of a heuristic is, the less stable the multicast tree will be as multicast group membership changes. For this reason, while the hybrid solution we propose might be suitable for use with closed user group multicasts, which are likely to be stable, we need a different approach for open user group multicasting, where group membership may be highly volatile. We propose an extension to an existing heuristic that ensures multicast tree stability where multicast group membership is dynamic. Although this extension decreases the efficiency of the heuristics solutions, its performance is significantly better than that of the worst case, a shortest path tree. Finally, we consider how we might apply the hybrid and the extended heuristic in current and future multicast routing protocols for the Internet and for ATM Networks.

Multicast Mobility in Mobile IP Version 6 (MIPv6) : Problem Statement and Brief Survey

Publisher PD

Efficient Micro-Mobility using Intra-domain Multicast-based Mechanisms (M&M)

One of the most important metrics in the design of IP mobility protocols is the handover performance. The current Mobile IP (MIP) standard has been shown to exhibit poor handover performance. Most other work attempts to modify MIP to slightly improve its efficiency, while others propose complex techniques to replace MIP. Rather than taking these approaches, we instead propose a new architecture for providing efficient and smooth handover, while being able to co-exist and inter-operate with other technologies. Specifically, we propose an intra-domain multicast-based mobility architecture, where a visiting mobile is assigned a multicast address to use while moving within a domain. Efficient handover is achieved using standard multicast join/prune mechanisms. Two approaches are proposed and contrasted. The first introduces the concept proxy-based mobility, while the other uses algorithmic mapping to obtain the multicast address of visiting mobiles. We show that the algorithmic mapping approach has several advantages over the proxy approach, and provide mechanisms to support it. Network simulation (using NS-2) is used to evaluate our scheme and compare it to other routing-based micro-mobility schemes - CIP and HAWAII. The proactive handover results show that both M&M and CIP shows low handoff delay and packet reordering depth as compared to HAWAII. The reason for M&M's comparable performance with CIP is that both use bi-cast in proactive handover. The M&M, however, handles multiple border routers in a domain, where CIP fails. We also provide a handover algorithm leveraging the proactive path setup capability of M&M, which is expected to outperform CIP in case of reactive handover.Comment: 12 pages, 11 figure

Analysis domain model for shared virtual environments

The field of shared virtual environments, which also encompasses online games and social 3D environments, has a system landscape consisting of multiple solutions that share great functional overlap. However, there is little system interoperability between the different solutions. A shared virtual environment has an associated problem domain that is highly complex raising difficult challenges to the development process, starting with the architectural design of the underlying system. This paper has two main contributions. The first contribution is a broad domain analysis of shared virtual environments, which enables developers to have a better understanding of the whole rather than the part(s). The second contribution is a reference domain model for discussing and describing solutions - the Analysis Domain Model

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