• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.3
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• pp.1373-1379
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• 2011

The SLA (Service Level Agreement) is once determined between service provider and users in B3G networks so that the network service must be provided as QoS management. Here, the network situation is changed as the time flow, and the service environment is also altered. Hence, dynamic QoS management scheme should be considered. In this paper, we propose a handover scheme for dyanamic QoS as the network situation in B3G networks. The heterogeneous networks can be used for dynamic QoS management in B3G networks.

• Journal of KIISE:Information Networking
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• v.29 no.1
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• pp.65-76
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• 2002

QoS routing is a routing technique for finding feasible path that satisfies QoS requirements required by application programs. Since QoS routing determines such paths in terms of dynamic network state, it satisfies the requirement of applications and increases the utilization of the network. The overhead is, however, generated by routers to exchange the information of the dynamic state of network. In order to reduce this protocol overhead, a timer based update mechanism is proposed in which router checks the change of the network status periodically and network state information is exchanged if the change is greater than a certain value. Using large update period makes, though, routing performance irresponsive to the parameters which determine the update of the network state of the router. In addition to this, large update period may result in inaccurate network state information at routers and cause resource reservation failure. The resource reservation failure generates additional overhead to cancel the resource reservation of the part of the path. In this paper, we propose mechanisms enhancing the existing network state update policy with respect to these two problems. Performance of the proposed schemes are evaluated through a course of simulation.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.12
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• pp.18-26
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• 2003

In this paper, we design and implement a QoS control function in the SIP-based VoIP system. As a network infrastructure for VoIP service, we select the Intserv over Diffserv architecture where the network resources are managed by a call admission control mechanism. The SIP protocol extended to support QoS signaling procedure is modulized to operate independently with the infrastructure. The performance of the QoS-enabled VoIP system is verified by experiments.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.12
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• pp.2798-2805
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• 1997

The paper studies the Quality of Service(QoS) concept in Broadband Integrated Services Digital Network (B-ISDN). Guaranteeing the QoS requirements indistributed multimedia systems and networks is fundamentally an end-to-end issus, that is, from application to application. An important issue in the QoS translation between the application-level QoS and network-level QoS is that the translation depends not only on the translation between system resources and network resources, but also on the translation between thelayered protocol and the access procedures. In this paepr, we propose a methodology for translating the AAL(ATM Adaptation Layer) QoS parameters into the ATM layer QoS parameters in end-systems. The QoS parameters in the ATM layer and AAL are defined, and we concentrate on the translation from the AAL to the ATM layer, because the AAL must be designed to be service dependent and specific. As an example, we concentrate on the constant bit rate(CBR) guaranteed real-time service using AAL1 protocol.

• Journal of KIISE:Information Networking
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• v.29 no.5
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• pp.573-582
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• 2002

We propose centralized server based QoS routing schemes, where a route server is responsible for determining QoS paths on behalf of all the routers in a routing domain. In the proposed server based schemes, the dynamic link QoS state information, which is required for a QoS path computation, is implicitly maintained at route server as it assigns or gets back QoS paths. By maintaining the network state information this way, we may not only eliminate the overhead to exchange network state update message but also achieve higher routing performance by utilizing accurate network state information in path computation. We discuss path caching techniques for reducing the amount of path computation overhead at the route server, and evaluate the performance of the proposed schemes using simulation. The simulation results show that the path caching schemes may significantly reduce the route server load. The proposed schemes are also compared to the distributed QoS routing schemes proposed in the literature. It has been shown that the proposed server based schemes not only enhance the routing performance, but they are also competitive with respect to routing overheads.

• The KIPS Transactions:PartC
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• v.8C no.5
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• pp.597-606
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• 2001

In this paper, we propose the delay sensitive traffic and a high bandwidth QoS service in order to supply real-time traffic such as VoIP, multimedia service. We use IntServ over DiffServ network to supply end-to-end QoS service in the IETF. We define the proposed QoS services which are Best, Good, Default service. We analyze the performance using NS simulator with end to end QoS service in IntServ over DiffServ network. The proposed billing system uses the Accounting, Authentication, Authorization (AAA) functions of RADIUS protocol and proposes the dynamic pricing method according to network usage state using end-to-end QoS of IntServ over DiffServ network. In order to secure billing system, we design and implement audit trail system by the IEEE POSIX.1E standard.

• Journal of Korea Multimedia Society
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• v.11 no.12
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• pp.1730-1738
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• 2008

Quality of Service (QoS) Guarantees grant ways for service providers to establish service differentiation among subscribers. On the other hand, service subscribers are also assured the level of service they paid for. In addition, the efficient level of service quality can be selected according to the subscribers' needs thus ensuring efficient use of available bandwidth. While network utility optimization techniques assure certain QoS metrics, a number of situations exist where some QoS goals are not met. The optimality of the network parameters is not mandatory to guarantee specified QoS levels. This paper proposes a joint data rate and power control scheme that guarantees service contract QoS level to a subscriber using Goal Programming. In using goal programming, this paper focuses on finding the range of feasible solutions as opposed to solving for the optimal. In addition, in case no feasible solution is found, an acceptable compromised solution is solved.

• The KIPS Transactions:PartC
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• v.15C no.6
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• pp.557-566
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• 2008

NGN(Next Generation Network) is a communication network which can make use of broadband and QoS-enabled transport technologies. One of the main service issues over NGN is a multimedia service, such as IPTV, using a multicast method. And overlay multicast technology is one of the promising solutions instead of traditional multicast technology which has a few problems, and supports flexibility and scalability for multicast services. Also, the main controversial topic in NGN and overlay multicast is QoS. In the present paper, we designed an agent in each receiver's network, and a manager which is in a source network and which manages the whole multicast network. Both of them are communicating with each other and applying resource policies to their multicast network. This mechanism enables overlay multicast to support QoS, focusing on RACF(Resource and Admission Control Functions) in NGN QoS architecture.

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.1685-1688
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• 2002

Application Routing Load Balancing (ARLB) is a novel load balancing mode that combines QoS routing and load balancing in per application to support QoS far real-time application based on wired network. Zone Routing Protocol (ZRP) is a recent hybrid proactive/reactive routing approach in an attempt to achieve scalability of ad-hoc network. This routing approach has the potential to be efficient in the generation of control traffic than traditional routing schemes. Up to now, without proper load balancing tools, the ZRP can actually guarantee QoS for delay-sensitive applications when congestion occurred in ad-hoc network. In this paper, we propose the ARLB to improve QoS fur delay-sensitive applications based on ZRP in ad-hoc network when congestion occurred and to be forwarding mechanism fur route coupling to support QoS for real-time applications. The critical point is that the routing metric of ARLB is originally designed for wired network environment. Therefore, we study and present an appropriate metric or cost computation routing of ARLB for recently proposed ZRP over ad-hoc network environment.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.6
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• pp.75-87
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• 2009

It is difficult to support QoS service in existing MAC Protocols in Wireless Mesh Network environments. while DCF can not support QoS, EDCA is operated with prioritized channel access method but can not give full performance. This thesis proposes frame management method to support QoS in Multi-Media DCF(MMDCF) MAC Protocol working in wireless mesh network. MMDCF uses ACH phase in TDMA frame to perform selection and elimination. Prioritized phases's count m and Fair Elimination phases's count n determine contention level and make string probability to only one win the contention. Forced TDMA Frame release method can support QoS requirements. MMDCF results good performance and good channel efficiency to support QoS requirements better than EDCA in multimedia stream environments.