• Journal of the Korean Operations Research and Management Science Society
• /
• v.33 no.2
• /
• pp.103-114
• /
• 2008

Overlay Multicast is a promising approach to overcome the implementation problem of IP multicast. Real time services like Internet broadcasting are provided by the overlay multicast technology due to the complex nature and high cost of IP multicast. To reduce frequent updates of multicast members and to support real time service without delay, we suggest a reliable overlay multicast tree based on members' sojourn probabilities. Path reliabilities from a source to member nodes are considered to maximize the reliability of an overlay multicast tree. The problem is formulated as a binary integer programming with degree and delay bounds. A tabu search heuristic is developed to solve the NP-complete problem. Outstanding results are obtained which is comparable to the optimal solution and applicable in real time.

• Journal of Communications and Networks
• /
• v.7 no.3
• /
• pp.294-306
• /
• 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.

• IE interfaces
• /
• v.11 no.1
• /
• pp.155-163
• /
• 1998

In multiparty multimedia communication, each participant not only receives information from other participants but also generates real-time data streams to distribute to others and therefore the difference between source and destination is not clear in terms of data transmission. During a teleconference session, many sub-multicast trees may be generated to exchange information to specific members within the multicast group and if those sub-multicast trees use the same fixed multicast tree, the blocking probability will be high and it is hard to provide QoS for each sub-multicast group. Also, even though there exits some shortcuts between each sub-multicast group, fixed multicast tree does not allow to use those shortcuts. Thus to overcome these problems. We propose a network resource reservation protocol and show that its effectiveness in terms of blocking probability and network resources usage.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2002.05a
• /
• pp.402-408
• /
• 2002

Multicast technology allows the transmission of data from one source node to a selected group of destination nodes. Multicast routes typically use trees, called multicast routing trees, to minimize resource usage such as cost and bandwidth by sharing links. Moreover, the quality of service (QoS) is satisfied by distributing data along a path haying no more than a given number of arcs between the root node of a session and a terminal node of it in the routing tree. Thus, a multicast routing tree for a session can be represented as a hop constrained Steiner tree. In this paper, we consider the hop-constrained multicast route packing problem with bandwidth reservation. Given a set of multicast sessions, each of which has a hop limit constraint and a required bandwidth, the problem is to determine a set of multicast routing trees in an arc-capacitated network to minimize cost. We propose an integer programming formulation of the problem and an algorithm to solve it. An efficient column generation technique to solve the linear programming relaxation is proposed, and a modified cover inequality is used to strengthen the integer programming formulation.

• Journal of Communications and Networks
• /
• v.14 no.1
• /
• pp.63-74
• /
• 2012

Multicast data communication is an efficient communication scheme, especially inmulti-hop ad hoc networks where the media access control (MAC) layer is based on one-hop broadcast from one source to multiple receivers. Compared to unicast, multicast over a wireless channel should be able to deal with varying channel conditions of multiple users and user mobility to provide good quality to all users. IEEE 802.11 does not support reliable multicast owing to its inability to exchange request-to-send/clear-to-send and acknowledgement packets with multiple recipients. Thus, several MAC layer protocols have been proposed to provide reliable multicast. However, additional overhead is introduced, as a result, which degrades the system performance. In this paper, we propose an efficient wireless multicast MAC protocol with small control overhead required for reliable multicast in multi-hop wireless ad hoc networks. We present analytical formulations of the system throughput and delay associated with the overhead.

• Proceedings of the Korean Information Science Society Conference
• /
• 2001.10c
• /
• pp.370-372
• /
• 2001

인터넷에서 멀티캐스팅을 지원하기 위해 제안된 기존의 Any Source Multicast(ASM)는 실제 망에의 적용시 멀티 캐스팅 세션 관리 문제, 주소 할당 문제 등과 같은 구현상의 문제를 가지고 있다. 이러한 문제를 해결하기 위한 새로운 관점의 다양한 메커니즘들이 제안되고 있다. 현재 제안되고 있는 메커니즘은 크게 Source Specific Multicast(SSM). Small Group Multicast(SGM)이 있다. 하지만, SGM은 많은 수의 사용자들에게 지원이 어렵고 새로운 헤더가 추가되어야 하는 부담이 있으며, SSM은 <송신자 주소, 그룹 주소>의 쌍으로 멀티캐스트 세션을 식별하게 하여 기존 ASM의 주소 할당 문제를 해결하였으나 경로 상의 모든 라우터에서 <송신자 주소, 그룹 주소> 별로 멀티캐스트 세션 정보를 유지해야 하는 측면에서 확장성의 문제점이 있다. 본 논문은 멀티캐스트 지원을 위하여 인터넷의 계층적인 구조를 이용하여 SSM을 확장한 멀티캐스트 지원 방안을 제안한다. 제안된 메커니즘은 확장성 문제를 해결하기 위하여 송신자로부터 칵 도해인의 경계 라우터까지 터널링 메커니즘을 도입하고 도메인 내에서는 다양한 멀티캐스트 제공 메커니즘을 지원한다.

• Electronics and Telecommunications Trends
• /
• v.16 no.2 s.68
• /
• pp.1-9
• /
• 2001

인터넷 멀티캐스트 기술은 IETF의 중점 표준화 분야중의 하나로써, 많은 연구에도 불구하고 아직까지 널리 보급되지 못하고 있다. 이는 멀티캐스트 기술에 대한 기술적 복잡성 및 관련 서비스의 수익모델 부재에서 그 원인을 찾아볼 수 있다. 한편, 최근 국내.외적으로 선풍적인 인기를 끌고 있는 인터넷 방송 서비스의 경우, 멀티캐스트 Killer 응용서비스로써 간주할 만하며, 멀티캐스트 전송에 대한 요구사항은 성숙 단계에 있다고 볼 수 있다. 본 고에서는 Simple Multicast, Source Specific Multicast 및 Overlay Multicast 등 최근에 제안되고 있는 기술 동향에 대하여 살펴보고자 한다.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.15 no.9
• /
• pp.3138-3150
• /
• 2021

Multimedia services on the Internet are continuously increasing. Accordingly, the demand for a technology for efficiently delivering multimedia traffic is also constantly increasing. The multicast technique, that delivers the same content to several destinations, is constantly being developed. This technique delivers a content from a source to all destinations through the multicast tree. The multicast tree with low cost increases the utilization of network resources. However, the finding of the optimal multicast tree that has the minimum link costs is very difficult and its calculation complexity is the same as the complexity of the Steiner tree calculation which is NP-complete. Therefore, we need an effective way to obtain a multicast tree with low cost and less calculation time on SDN-based smart network platforms. In this paper, we propose a new multicast tree generation algorithm which produces a multicast tree using an agent trained by model-based meta reinforcement learning. Experiments verified that the proposed algorithm generated multicast trees in less time compared with existing approximation algorithms. It produced multicast trees with low cost in a dynamic network environment compared with the previous DQN-based algorithm.

• ETRI Journal
• /
• v.33 no.3
• /
• pp.355-365
• /
• 2011

IPTV broadcast channels and video content distribution are increasingly saturating network paths. New solutions based on inter-domain multicast protocols could contribute to the enhancement of multimedia content distribution over the Internet. The aim of this paper is to propose new capabilities for an existing inter-domain multicast protocol, the Protocol Independent Multicast-Sparse Mode. We describe the modified protocol and analyze its behavior using newly developed tools based on an open-source software simulator. The resulting protocol does not require topology information, which is advantageous for easier deployment. In addition, the adopted solution avoids inherent problems with inter-domain multicast routing, such as multiple paths and path asymmetries.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.36 no.7B
• /
• pp.745-759
• /
• 2011

In this paper, we propose the global handover mechanism that is able to provide the unlimited range of next-generation multimedia mobile services in an integrated environment. This mechanism consists of a multicast source based forwarding scheme and a global session management scheme. Global session management scheme provides LMA session information management, global mobility and route optimization. Multicast source based forwarding scheme delivers data between previously attached LMA and newly attached LMA without packet loss. In addition, this scheme removes the redundancy of buffered data. We present a performance evaluation and features analysis by the simulations using the ns-2. Global session management scheme has a less handover latency, propagation delay and signaling cost than the conventional methods. Multicast source based forwarding scheme can deliver buffer data without loss and it has less buffer size than conventional method.