11,437 research outputs found

    Multicast source mobility support for regenerative satellite networks

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    YesSatellite communications provides an effective solution to the ever increasing demand for mobile and ubiquitous communications especially in areas where terrestrial communication infrastructure is not present. IP multicasting is a bandwidth saving technology which could become an indispensable means of group communication over satellites since it can utilise the scarce and expensive satellite resources in an efficient way. In Source-Specific Multicast (SSM) the data is sent through a multicast tree from the source to all the receivers. However, if a source is a mobile node moving from one network to another, then special mechanisms are required to make sure this multicast tree does not break. Until now, while many research efforts have been made to provide IP multicast for the mobile nodes, they are mainly focused on terrestrial networks. Unfortunately, the terrestrial mobile multicast schemes are not directly applicable in a satellite environment. This paper, proposes a new mechanism to support multicast source mobility in SSM based applications for a mesh multi-beam satellite network with receivers both within the satellite network and in the Internet. In the proposed mechanism, the SSM receivers continue to receive multicast traffic from the mobile source despite the fact that the IP address of the source keeps on changing as it changes its point of attachment from one satellite gateway (GW) to another. The proposed scheme is evaluated and the results compared with the mobile IP home subscription (MIP HS)-based approach. The results show that the proposed scheme outperforms the MIP HS-based approach in terms of signalling cost and packet delivery cost

    SDL model for Source Specific Multicast

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    Tato práce se zabývá problematikou síťové komunikace s použitím metody Source Specific Multicast. Zaměřuje se na problematiku, přihlašování, odhlašování a administrace klientů v multicastové skupině a protokolu IGMP, který má toto na starost. Dále na problematiku signalizace mezi zdrojem dat a přihlášenými klienty, kteří data odebírají. V úvodu této práce je rozebrána problematika multicastové komunikace. Následuje kapitola se zaměřením na metodu Source–Specific Multicast (SSM). Další kapitola se zaměřuje na rozbor používaných protokolů potřebných k distribuci datového vysílání pomocí SSM ve směru od zdroje vysílání ke klientům a opačně. Následující kapitola se zabývá signalizací komunikace v SSM, zvláště se zaměřuje na použití metody přeposílání paketů a metody spojování paketů ve zdroji. Kapitola také uvádí základní matematické vztahy pro výpočet odesílání signalizace a navrhuje také možná řešení a postupy pro zjednodušení komunikace a zmenšení zpoždění, které je pro signalizaci důležitou vlastností. Následně už se práce zabývá rozdíly obou používaných metod signalizace. Na znalostech získaných teoretickými poznatky je v praktické části navržena aplikace simulující komunikaci klientů a zdroje v SSM multicastu. Daná problematika je vysvětlena v MSC diagramech. Aplikace také simuluje reálné chování komunikace za použití obou signalizačních metod v závislostech na počtu klientů a použité metodě signalizace. V poslední kapitole jsou výsledky simulace za použití obou signalizačních metod zhodnoceny.This work deals with questions of IP net communication, with using metod Source-Specific Multicast. It focused on questions of registration, unregistration and administration of clients in multicast group and IGMP protocol, which is made for this communication. Work deals also about problems of signalization between source of data and clients of multicast group.In the introduction of this work questions of communications in multicast are analyse. I tis followed by the chapter focused on the specific metod of multicast – Source Specific Multicast (SSM). Next chapter is based on the protocols in SSM, which are used for distribution of data stream in source to clients direction and also in the reverse direction. The net chapter deals with signalization of communication in SSM. It specializes for reflection and summarization metods, which are used here. This chapter also shows basic matematics formules for sending signalization packets and proposes other solutions and ways for simplify communication and minimalize delay, which is for signallization very important. After that, the work deals with differences between these two metods of signalization. The aplicationis builded in practical part of work from the knowlidge of theory from previous chapters and it simulates the real communication between data source and clients situated to multicast group. This communication is explained in MSC diagrams. The aplication also simulates both used metods of signalization and real count of cients in multicast group. The results of simulation are interpreted in the last part of work.

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

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    Design, administration and analysis of SSM multicast network

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    V diplomové práci na téma Návrh, správa a analýza SSM multicastové sítě, jsou zmapovány a podrobněji rozebrány technologie šíření paketů. Zvláštní pozornost je věnována multicastovým technologiím. V práci jsou rozebrány principy multicastu, včetně popisu adresného schématu, protokolů pro šíření multicastu, registraci v mutlicastových skupinách a jeho výhod a nevýhod. Dále je podrobně rozebrána technologie Source specific multicast (SSM), která vychází z multicastu. Je popsán způsob fungování této technologie, implementace v síťových zařízeních i na straně klienta, její výhody a nevýhody. Dále jsou popsány tzv. distribuční stromy, které se využívají při distribuování multicastu přes IP sítě, mezi něž patří i síť internet. Na základě znalostí technologie mulitcast, byla vybudována síť na šíření multimediálních dat s podporou technologie multicast a SSM. Síť je postavena na zařízeních firmy Cisco systems, konkrétně se jedná o tyto zařízení: Cisco Content Engine 566, Cisco IP/TV broadcast server a router 1812. Multimediální sít poskytuje mnoho služeb, včetně živého vysílání televizních a video programů. Na této síti, využívající multicastového šíření paketů, byla provedena analýza provozu pomocí protokolových analyzátorů Wireshark a Finisar. S jejich pomocí mohlo být provedeno srovnání efektivity přenosu multimediálních dat technologiemi unicast, multicast a SSM.My thesis deals with the Multicast transfer in IP networks and it describes distribution technology of packets with special focus on Multicast technology. The thesis is devoted to the principles of Multicast including the description of scheme, protocol Multicast distribution, registration in the Multicast groups and finally the advantages and disadvantages of the Multicast transfer. Further in the thesis is described in details the Source Specific Multicast technology (SSM) that comes from multicast. There is a description how this technology Works and its implementation in the network equipment including the user side. This part of the thesis also deals with so called Distribution Trees that are used as multicast distribution via the IP networks like for example Internet. Based on the knowledge of the Multicast was created the network to spread the multimedia data with support of Multicast and SSM. The network is designed based on the Cisco system equipment as is: Cisco Content Engine 566, Cisco IP/TV broadcast server and router 1812. This multimedia network provides many services including the live TV broadcast and video channels. In this network using the multicast distribution of packets was done an analysis by protocol analyzer unit WIreshark and Finisar. This protocol analyzer unit allows us to compare the efficiency of multimedia data transfer between the Unicast, Multicast and SSM.

    MENU: multicast emulation using netlets and unicast

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    High-end networking applications such as Internet TV and software distribution have generated a demand for multicast protocols as an integral part of the network. This will allow such applications to support data dissemination to large groups of users in a scalable and reliable manner. Existing IP multicast protocols lack these features and also require state storage in the core of the network which is costly to implement. In this paper, we present a new multicast protocol referred to as MENU. It realises a scalable and a reliable multicast protocol model by pushing the tree building complexity to the edges of the network, thereby eliminating processing and state storage in the core of the network. The MENU protocol builds multicast support in the network using mobile agent based active network services, Netlets, and unicast addresses. The multicast delivery tree in MENU is a two level hierarchical structure where users are partitioned into client communities based on geographical proximity. Each client community in the network is treated as a single virtual destination for traffic from the server. Netlet based services referred to as hot spot delegates (HSDs) are deployed by servers at "hot spots" close to each client community. They function as virtual traffic destinations for the traffic from the server and also act as virtual source nodes for all users in the community. The source node feeds data to these distributed HSDs which in turn forward data to all downstream users through a locally constructed traffic delivery tree. It is shown through simulations that the resulting system provides an efficient means to incrementally build a source customisable secured multicast protocol which is both scalable and reliable. Furthermore, results show that MENU employs minimal processing and reduced state information in networks when compared to existing IP multicast protocols

    Roaming Real-Time Applications - Mobility Services in IPv6 Networks

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    Emerging mobility standards within the next generation Internet Protocol, IPv6, promise to continuously operate devices roaming between IP networks. Associated with the paradigm of ubiquitous computing and communication, network technology is on the spot to deliver voice and videoconferencing as a standard internet solution. However, current roaming procedures are too slow, to remain seamless for real-time applications. Multicast mobility still waits for a convincing design. This paper investigates the temporal behaviour of mobile IPv6 with dedicated focus on topological impacts. Extending the hierarchical mobile IPv6 approach we suggest protocol improvements for a continuous handover, which may serve bidirectional multicast communication, as well. Along this line a multicast mobility concept is introduced as a service for clients and sources, as they are of dedicated importance in multipoint conferencing applications. The mechanisms introduced do not rely on assumptions of any specific multicast routing protocol in use.Comment: 15 pages, 5 figure

    Real-time multicast algorithms for P2P networks

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    Nowadays, many applications use multicast transmissions, such as online games, videoconference programs, or sharing applications in a P2P network. However, multicast transmission is a problem that has still not been satisfactorily solved. In this work we show a family of algorithms capable to solve this problem, concretely focused on the real-time transmissions, in which a node called root or source sends information to a specific group of nodes. These algorithms take advantage of the transmission delay of a message between one node and another in order to send it towards another node. In order to study the behaviour of these new real-time transmission algorithms we have worked with two virtual networks that models the IP network, to which we have added a number of users, from 10 to 1000. These users form the multicast group. Later, we have obtained the overlay network. This network is defined in the application layer, and the user nodes form it. Finally, the multicast algorithms have been applied on those networks and results have been analysed to extract the conclusions for our original purposes

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

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    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

    Multicast traffic aggregation in MPLS-based VPN networks

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    This article gives an overview of the current practical approaches under study for a scalable implementation of multicast in layer 2 and 3 VPNs over an IP-MPLS multiservice network. These proposals are based on a well-known technique: the aggregation of traffic into shared trees to manage the forwarding state vs. bandwidth saving trade-off. This sort of traffic engineering mechanism requires methods to estimate the resources needed to set up a multicast shared tree for a set of VPNs. The methodology proposed in this article consists of studying the effect of aggregation obtained by random shared tree allocation on a reference model of a representative network scenario.Publicad
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