• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2006.07a
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• pp.744-744
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• 2006

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.07a
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• pp.173-173
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• 2004

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.07a
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• pp.163-163
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• 2004

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.07a
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• pp.246-246
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• 2004

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.07a
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• pp.135-135
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• 2004

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.7B
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• pp.613-627
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• 2004

In this paper, we propose an Aggregate Fairness Maker (ARM) required for an Edge router to improve fairness of throughput among the flows of Assured Service in DiffServ with different round trip time (RTT) and we propose a user flow Three Color Marker (uf-TCM) as a flow marker that marks packets from the flow as green, yellow, or red. A yellow packet is the packet that consumes loss token in uf-TCM as well as that is demoted green packet in AM due to disobey the aggregate traffic profile. The proposed AFH promotes yellow packet to green packet or demotes green packet to yellow packet through the fair method without per-flow management, and it improves the feirness of throughput among the flows as well as link utilization. A yellow packet and a red packet have the same drop precedence at Core Router in our scheme. So we can use the RIO buffer management scheme. We evaluated the performance of our proposed AFM and the REDP Marker that was proposed to improve fairness without per-flow management. Simulation results show that, compared with the REDP marker, proposed AFM can improve performance of throughput fairness among the flows with different RTT and link utilization under the over-provisioning, exact-provisioning, and under-provisioning network environments at Multiple DiffServ domains as well as at Single DiffServ domain.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.6B
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• pp.588-603
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• 2003

In this paper, we propose an Aggregate Three Color Marker without per flow management which is required for an Edge router to improve End-to-End QoS of Assured Service in DiffServ. Proposed Aggregate Three Color Marker is used with the Adaptive RIO-DC scheme to achieve the minimum rate guarantee without per flow management. Assuming that the admission control for Assured Service has been performed, proposed Aggregate Three Color Marker measures incoming In-profile traffic rate at the output link of an edge router using a token-bucket with a token rate equal to the sum of contracted rates of admitted flows passing the edge router. If there are token losses from the token bucket, out-of-profile packets are promoted to Yellow packets within the aggregate traffic profile. And yellow packets are demoted to out-of-profile packets at the input link to an Edge router fer the purpose of fairness maintenance. In-profile packets and Yellow packets are processed identically at the RIO-DC buffer management scheme in our proposed method. Simulation results show that through using proposed Aggregate Three Color Marker with the Adaptive RIO-DC scheme, the minimum rate guarantee for Assured Service can be achieved without per flow management at multiple DiffServ domains.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.4B
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• pp.344-348
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• 2006

This paper proposes a QoS policy for cellular networks which support the policy based network management scheme. The policy exploits the existing underlying DiffServ mechanism and the priority-based packet scheduler in order to provide the packets with different handling priority depending on their belonging traffic classes. The simulation results reveals the effectiveness of the proposed policy under the network congestion; it shows that the goodput of the real-time traffic is not affected at all in spite of the surge of the non real-time traffic.

• Journal of Communications and Networks
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• v.10 no.3
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• pp.351-361
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• 2008

This paper presents a delay-margin based traffic engineering (TE) approach to provide end-to-end quality of service (QoS) in multi-protocol label switching (MPLS) networks using differentiated services (DiffServ) at the link level. The TE, including delay, class, and route assignments, is formulated as a nonlinear optimization problem reflecting the inter-class and inter-link dependency introduced by DiffServ and end-to-end QoS requirements. Three algorithms are used to provide a solution to the problem: The first two, centralized offline route configuration and link-class delay assignment, operate in the convex areas of the feasible region to consecutively reduce the objective function using a per-link per-class decomposition of the objective function gradient. The third one is a heuristic that promotes/demotes connections at different links in order to deal with concave areas that may be produced by a trunk route usage of more than one class on a given link. Approximations of the three algorithms suitable for on-line distributed TE operation are also derived. Simulation is used to show that proposed approach can increase the number of users while maintaining end-to-end QoS requirements.

• Proceedings of the IEEK Conference
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• summer
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• pp.143-146
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• 2004

Differentiated services (DiffServ) has been widely accepted as the service model to adopt for providing quality-of­service (QoS) over the next-generation IP networks. There is a growing need to support QoS in mobile ad hoc networks. Supporting DiffServ in mobile ad hoc networks, however, is very difficult because of the dynamic nature of mobile ad hoc networks, which causes network congestion. The network congestion induces long transfer packet delay and low throughput which make it very difficult to support QoS in mobile ad hoc networks. We propose DiffServ module to support differentiated service in mobile ad hoc networks through congestion control. Our DiffServ module uses the periodical rate control for real time traffic and also uses the best effort bandwidth concession when network congestion occurs. Network congestion is detected by measuring the packet transfer delay or bandwidth threshold of real time traffic. We evaluate our mechanism via a simulation study. Simulation results show our mechanism may offer a low and stable delay and a stable throughput for real time traffic in mobile ad hoc networks.