• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.11a
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• pp.452-452
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• 2004

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.5B
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• pp.253-263
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• 2005

This paper proposed a mobile multicast technique to satisfy end-to-end QoS for various user requirements in mobile network environment. In order to provide seamless mobility, fast handoff technique was applied. By using L2 mobile trigger, it was possible to minimize remarkable amount of packet loss by delay occurred during handoff. To provide efficient multicast, concept of hierarchy was introduced to Xcast++, which results in a creation of HXcast++. HXcast++ optimized transfer path of multicast and reduced expensive multicast maintenance costs caused by frequent handoff. Suggestion of GMA (Group Management Agent) mechanism allows joining to group immediately without waiting IGMP Membership query during handoff. GMA mechanism will minimize the delay for group registration process and the resource usage due to delay of withdrawal process. And also use of buffering & forwarding technique minimized packet loss during generation of multicast tree. IntServ/RSVP was used to provide End-to-End QoS in local domain and DiffServ was used in global domain. To minimize reestablishment of RSVP session delay, extended HXcast++ control messages ware designed to require PATH message. HXcast++ proposed in this thesis is defined as multicast technique to provide end-to-end QoS and also to satisfy various user requirements in mobile network environment.

• Information and Communications Magazine
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• v.25 no.8
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• pp.20-31
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• 2008

본고에서는 IPTV 서비스를 효율적으로 제공하기 위해 IPTV 서비스 제공사업자들에게 필수적으로 요구되는 멀티캐스트 전송기술 현황과 ITU-T에서 추진되고 있는 관련 국제표준화 추진 동향에 대해 소개한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.6
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• pp.1256-1264
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• 2011

MBS (Multicast Broadcast Service) is defined in WiBro networks for implementing multicast-based services. However, most of the WiBro networks currently used in Korea do not have the MBS functionality and it causes some difficulty in implementing multicast-based services. This paper evaluates the performance of VoIP-based group communication services when implementing using the following two cases: unicast-based and multicast-based group communication systems. The performance evaluation is done using QualNet for each case in terms of the amount of network resource for the service, the delay and delay jitter of packets, and the difference of the delay of members in a group. The simulation result shows that the number of groups and members in a group in a WiBro network is limited because the amount of network resource for the service is increased according to the number of members in a group, and so, the MBS service is required in a WiBro network for a fully-fledged service of VoIP-based group communications. The simulation result also shows that, when a packet bundling is used, the number of groups and members in a group that can be supported in a WiBro network can be increased due to the decrease of the amount of network resource for the service.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.7 s.337
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• pp.7-18
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• 2005

Geomulticast is a specialized location-dependent multicasting technique, where messages are multicast to some specific user groups within a specifc zone. In this paper, we propose architectures and protocols for supporting geomulticast services in a cost effective way and with high message delivery accuracy in the challenging environment of mobile ad-hoc networks. Furthermore, we define and formulate a framework in order to evaluate the performance of the design alternatives used for the support of geomulticast services in mobile ad-hoc networks. Based on this framework, we evaluate the performance of the proposed architectures and protocols and we obtain some insight about the impact of the various design and operational parameters on the overall system performance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.9B
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• pp.1342-1349
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• 2010

Full-mesh IPSec tunnels, which constitute a black network, are required so that the dynamically changing PT (Plain Text) networks can be reachable across the black network in military environments. In the secure and mobile black networks, dynamically re-configuring IPSec tunnels and security policy database (SPD) is very difficult to manage. In this paper, for the purpose of solving mobility and security issues in military networks, we suggest the relating main technologies in association with DMIDP (Dynamic Multicast-based IPSec Discovery Protocol) based on existing IPSec ESP (Encapsulating Security Payload) tunnels and IPSec key managements. We investigate the main parameters of the proposed DMIDP techniques and their operational schemes which have effects on mobility and analyze operational effectivemess of the DMIDP with proposed parameters.

• ETRI Journal
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• v.36 no.5
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• pp.819-828
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• 2014

To solve the increasing popularity of video streaming services over the Internet, recent research activities have addressed the locality of content delivery from a network edge by introducing a storage module into a router. To employ in-network caching and persistent request routing, this paper introduces a hybrid content delivery network (CDN) system combining novel content routers in an underlay together with a traditional CDN server in an overlay. This system first selects the most suitable delivery scheme (that is, multicast or broadcast) for the content in question and then allocates an appropriate number of channels based on a consideration of the content's popularity. The proposed scheme aims to minimize traffic volume and achieve optimal delivery cost, since the most popular content is delivered through broadcast channels and the least popular through multicast channels. The performance of the adaptive scheme is clearly evaluated and compared against both the multicast and broadcast schemes in terms of the optimal in-network caching size and number of unicast channels in a content router to observe the significant impact of our proposed scheme.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.8B
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• pp.539-546
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• 2007

For better performance and to avoid member service annoyance that results due to joining-clients' waiting durations and time-outs when there are more than one client wanting to join concurrently for Personal Broadcasting System service, there is a need for improving concurrent member joining mechanism. For a more efficient and better performing, this paper apply Overlay Multicast based mini-Overlay Broadcasting Control Protocol(mOBCP) Algorithm on Personal Broadcasting System. mOBCP proposed is performance-effective mechanism, since it considers the case of how fast will children, concurrently, find and join new parents when paths to existing parents are in Failure. The performance comparison, in terms of tree construction time variation and Latency are done through simulations and the results conclude in favour of the Proposed mOBCP.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.12
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• pp.1323-1326
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• 2014

In this letter, we compare the performance of two concatenated coding structures in slow FH/SS systems for multimedia/multicast transmission on shipboard. Two outer code symbols are transmitted during a hop. The first structure consists of one inner codeword per one outer code symbol, while the second structure consists of one inner codeword per two outer code symbols. We analyze the overall block error probability in asymptotic region and show that the performance of the second scheme is superior to the first one.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.11
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• pp.2862-2868
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• 1996

A sueueing model is developed and analyzed to evaluate the performance of a local and a remote destination of one multicast connection subject to a simple two-level(binary) feedback-based adaptive rate control scheme. The reate control scheme is a simple extension of the one for point-to-point case. Individual cell loss probabilities at the local and remote destinations are obtained to study the fairness of the adaptive rate control scheme. Numerical results show that this simple adaptive rate control scheme, which is fair when it is applied to a multicast connection consisting of destinations with equal propagation delays, bears bias against remote destination.