• Title/Summary/Keyword: Xcast

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Enhancement of Xcast far Supporting Few-to-Few Multicast (소수-대-소수 지원을 위한 Xcast 확장 방안)

  • 진민숙;김상하
    • Proceedings of the Korean Information Science Society Conference
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    • 2002.04a
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    • pp.208-210
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    • 2002
  • Xcast(Explicit Multicast)는 기존 멀티캐스트 방식인 ASM(Any-Source Multicast)이 상태정보를 유지해야 하는 확장성 문제를 해결하기 위해 제안되었다. 하지만 Xcast를 망에 적용하는 경우, 헤더 크기의 제한으로 인하여 일반적인 멀티캐스트 메커니즘이 아닌 작은 그룹을 위안 메커니즘으로 인식되고 있다. 그러나, 현재의 Xcast는 일-대-다 전송 방법과 데이터 통신만을 기술하고 있다. 따라서 본 논문은 소수-대-소수 멀티캐스트를 지원하기 위하여 XCast 서버를 적용하는 방안을 제안한다. Xcast 서버는 각 그룹의 정보와 함께 그룹 참가자의 정보를 유지하며 데이터 라우팅은 원래의 Xcast와 같은 방법을 적용하고 Xcast 서버와 각 참가자 사이의 제어 측면을 위한 프로토콜을 기술한다.

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Enhancement of Xcast far Supporting Few-to-Few Multicast (Few-to-Few 멀티캐스트를 위한 Xcast 확장 방안)

  • 김기일;서정현;김상하
    • Proceedings of the Korean Information Science Society Conference
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    • 2001.10c
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    • pp.367-369
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    • 2001
  • Explicit Multicast (Xcast)[1]은 기존의 Any Source Multicast (ASM)이 라우터에서 멀티캐스트 라우팅을 위하여 상태 정보를 갖아야만 한다는 문제점을 해결하기 위하여 제안된 메커니즘이다. Xcast는 이러한 상태 정보를 전송하려는 패킷의 헤더에 삽입함으로써 확장성 문제를 해결하였다. 하지만, 현재 제안되고 있는 Xcast는 데이터 측면에서의 라우팅 방법에 대한 설명만 존재할 뿐 제어 측면에 대한 언급은 존재하지 않게 된다. 이에 관련하여 Xcast+[2]가 제안되고는 있지만 Xcast+의 경우에는 단순히 일-대-소수 전송만을 지원하고 있다. 따라서. Xcast론 소수-대-소수 전송에 적용시키기 위해서는 향상된 새로운 메커니즘이 필요하다. 본 논문은 Xcast를 소수-대-소수에 적용시키기 위하여 Xcast Server틀 송신자의 Designated Router (DR)라우터에 적용하는 방법을 제안한다. Xcast 서버는 각 그룹 정보와 함께 그룹 참가자에 대한 정보를 유지함으로써 작은 그룹의 멀티캐스트를 효율적으로 지원할 수 있다. 본 메커니즘은 Xcast 서버와 각 참가자 사이의 제어 측면을 위한 프로토콜에 관한 것이며 데이터 라우팅은 원래의 Xcast와 같은 방법을 사용하게 된다.

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Trends on Xcast Technologies (Xcast 기술 동향)

  • Shin, M.G.;Kim, Y.J.
    • Electronics and Telecommunications Trends
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    • v.16 no.5 s.71
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    • pp.85-93
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    • 2001
  • 본 고에서는 최근 IETF를 중심으로 새롭게 제안되고 있는 Xcast(Explicit Multicast) 기술에 관해 소개한다. Xcast 멀티캐스트 방식은 IBM의 SGM(Small Group Multicast), Alcatel의 CLM(Connectionless Multicast), Fujitsu의 MDO6(Multiple Destination Option for IPv6) 제안을 수정, Xcast로 통합한 것으로 기존 IP 멀티캐스트 방식과는 달리, IP 패킷 내에 수신자 목록을 명시적으로 포함하여 전송함으로써 소규모 그룹 통신을 위해 적합한 새로운 멀티캐스트 통신 방식이다. 본 고에서는 Xcast 기본 프로토콜 규격을 중심으로 최근 기술동향 및 국내 Xcast-KR 연구동향 등을 소개한다.

An Enhanced Xcast Protocol for Mobile Nodes in IP Networks (IP 망에서의 이동 노드를 위한 향상된 Xcast, 프로토콜)

  • Nam Sea-Hyeon
    • Journal of Internet Computing and Services
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    • v.6 no.3
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    • pp.85-95
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    • 2005
  • Whereas the traditional multicast schemes based on Mobile IP can support a limited number of very large multicast groups, the Xcast protocol can support a very large number of small multicast groups, In the Xcast, the source node encodes the list of destinations in the Xcast header. Therefore, the maximum packet size in the network limits the number of destinations that a Xcast packet may have. In this paper, an enhanced Xcast protocol is proposed to solve the multicast group size limitation of the existing Xcast protocol in providing multicast service for mobile nodes. Moreover, the SIP (a very flexible control plane protocol) is integrated with the proposed multicast scheme to provide mobility awareness on the application layer. The simulation results verify that the proposed multicast scheme not only increases the packet delivery ratio and the data packet forwarding efficiency but also achieves low latency of packets in the network.

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An Implementation of Explicit Multicast with Mobile IP for Small Group Communications in Mobile Networks (이동통신환경에서의 소규모 그룹통신을 위한 XMIP 프로토콜의 구현)

  • PARK IN-SOO;PARK YONG-JIN
    • The KIPS Transactions:PartC
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    • v.12C no.2 s.98
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    • pp.267-280
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    • 2005
  • In this paper, we implement and verify XMIP integrating IETF Mobile IP and the Explicit Multicast mechanism for a great number of small group multicast communications. U a source node sends Xcast packets explicitly inserting destination nodes into the headers, each Xcast router decides routes and forwards the packets toward each destination node based on unicast routing table without the support of multicast trees. n is a straightforward and simple multicast mechanism just based on a unicast routing table without maintaining multicast states because of the inheritance from the Explicit Multicast mechanism. This research modifies and extends the functionality of IETF Mobile IP's mobility agents, such as HA/FA to HA+/FA+ respectively, considering interworking with Xcast networks. Xcast packets captured by HA+ are forwarded into X-in-X tunnel interfaces for each FA+ referred to the binding table of HA.. This X-in-X tunneling mechanism can effectively solve the traffic concentration problem of IETF Mobile IP multicast services. Finally WLAN-based testbed is built and a multi-user Instant messenger system is developed as a Xcast application for finally verify the feasibility of the implemented XMIP/Xcast protocols.

A Domain Xcast Scheme for a Dense Multicast Group (밀집 멀티캐스트 그룹을 위한 도메인 Xcast 방안)

  • Kim, Byungsoon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.29 no.6A
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    • pp.583-588
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    • 2004
  • For the Explicit Multicast (Xcast) scheme, we propose a scheme that provides dynamic group membership and supports a large, dense multicast group. To do so, we use a hierarchical joining mechanism, where a domain agent joins a group on behalf of hosts. In our scheme, a sender transmits multicast packets to a domain agent, and then the agent forwards the packets to receivers in a domain. A host can join or leave a group at my time via the domain agent. Thus, a destination field of the Xcast header has addresses of domain agents instead of hosts. Simulation results show that our scheme can reduce more the Xcast header size and cost in forwarding packets than the Xcast, especially for a large multicast group. Like traditional multicast schemes, our scheme can support large multicast group members.

The Study on the Improvement of Multicast in IPv6 (Xcast적용 및 성능향상을 위한 연구)

  • Lim, Seung-Ho;Song, Jeong-Young
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • v.9 no.2
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    • pp.146-149
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    • 2005
  • Confusion of network traffic is increased by increasing of internet user and large of network, Specially olded one and one communication caused loss of bandwidth because of redundant packet by increasing video conference and internet broadcasting. Thereupon multicast technique, method reducing loss of bandwith, for multimedia data transmission was proposed. This paper proposes method to solve overhead problem in the middle router through group management and capsuling with the Xcast technique added Disignated Router(DR). To solve the middle router not supporting IPv6, Xcast using tunneling technique in the IPv6 design and analyze the performance through a simulated examination.

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A Scalable Explicit Multicast Protocol for MANETs

  • Gossain Hrishikesh;Anand Kumar;Cordeiro Carlos;Agrawal Dharma P.
    • Journal of Communications and Networks
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    • v.7 no.3
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    • pp.294-306
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    • 2005
  • Group oriented multicast applications are becoming increasingly popular in mobile ad hoc networks (MANETs). Due to dynamic topology of MANETs, stateless multicast protocols are finding increased acceptance since they do not require maintenance of state information at intermediate nodes. Recently, several multicast schemes have been proposed which scale better' with the number of multicast sessions than traditional multicast strategies. These schemes are also known as explicit multicast (Xcast; explicit list of destinations in the packet header) or small group multicast (SGM). In this paper, we propose a new scheme for small group' multicast in MANETs named extended explicit multicast (E2M), which is implemented on top of Xcast and introduces mechanisms to make it scalable with number of group members for a given multicast session. Unlike other schemes, E2M does not make any assumptions related to network topology or node location. It is based on the novel concept of dynamic selection of Xcast forwarders (XFs) between a source and its potential destinations. The XF selection is based on group membership and the processing overhead involved in supporting the Xcast protocol at a given node. If the number of members in a given session is small, E2M behaves just like the basic Xcast scheme with no intermediate XFs. As group membership increases, nodes may dynamically decide to become an XF. This scheme, which can work with few E2M aware nodes in the network, provides transparency of stateless multicast, reduces header processing overhead, minimizes Xcast control traffic, and makes Xcast scalable with the number of group members.

Explicit Multicast Extension (Xcast+) for Efficient Multicast Packet Delivery

  • Shin, Myung-Ki;Kim, Yong-Jin;Park, Ki-Shik;Kim Sang-Ha
    • ETRI Journal
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    • v.23 no.4
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    • pp.202-204
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    • 2001
  • In this letter, we propose a new multicast scheme, named Xcast+, which is an extension of Explicit Multicast (Xcast) for an efficient delivery of multicast packets. The mechanism incorporates the host group model and a new control plane into existing Xcast, and not only does it provide the transparency of traditional multicast schemes to senders and receivers, but it also enhances the routing efficiency in networks. Since intermediate routers do not have to maintain any multicast states, it results in a more efficient and scalable mechanism to deliver multicast packets. Our simulation results show distinct performance improvements of our approach compared to Xcast, particularly as the number of receivers in a subnet increases.

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Multicast support for mobile nodes by using SIP and Xcast (SIP과 Xcast를 이용한 이동 멀티캐스트 지원 방안)

  • Nam, Seahyeon
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.41 no.8
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    • pp.27-33
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    • 2004
  • A new multicast scheme for mobile nodes is proposed to support real-time communication in a more efficient way. In the proposed multicast scheme, the Xcast (a very flexible data plane mechanism) is integrated with the SIP (a very flexible control plane protocol) to support multicast for mobile nodes. The simulation results verify that the proposed scheme reduces unnecessary network traffic and achieves low latency of packets in the network.