• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.3
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• pp.303-308
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• 2016

Recently, as the rapid development of network technology and the increase of services required high bandwidth such as multimedia service, the network traffic dramatically increases. This massive increase of network traffic causes some problems such as the degradation of QoS and the lack of network resources and, to solve these problems, various research to guarantee QoS have been performing. Currently, The most representative method to guarantee the QoS is the DiffServ(: Differentiated Service). The DiffServ defines the AF(: Assured Forwarding) PHB(: Per Hop Behavior) and statistically ensures the throughput over the certain level of data rate. However, the TCP congestion control method that make up the majority of the Internet traffic is not fundamentally suitable to the DiffServ that guarantees the throughput without managing the individual flow. Therefore, in this paper, we present this mismatch through the simulation as an example and propose the solution by controlling the TCP of the terminal in the network. The proposed scheme utilizes the information of the reception window size included in the ACK frame and does not require any modification of the TCP algorithms currently in use.

• The Journal of Korean Association of Computer Education
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• v.7 no.1
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• pp.37-44
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• 2004

Differentiated services network (DiffServ) aims to provide the same service to a group of connections that have similar Quality of Service requirements. One of the essential function to realize DiffServ is the traffic conditioning mechanism. The paper proposes the enhanced traffic conditioning mechanism which can assure the reserved rates of TCP and UDP flows and support fair distribution of excess bandwidth. The simulation results show that the new mechanism is rather insensitive of the effect of UDP against TCP throughput, and performs better both in terms of throughput assurance and fair distribution of excess bandwidth in case of well-provisioned and over-provisioned network environment.

• Proceedings of the Korean Information Science Society Conference
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• 2000.04a
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• pp.319-321
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• 2000

현재 인터넷이 제공하는 최선의 서비스(best-effort)를 개선하기 위해서 IETF(Internet Engineering Task Force)의 DiffServ(Differentiated Service)WG에서는 현재의 인터넷 서비스를 보다 차별화된 QoS를 제공할 수 있도록 하는 방안으로서 Differentiated Service를 제안하였다. 본 논문에서는 이러한 Differentiated Service의 개념과 구조를 살펴보고 Differentiated Service에서 트래픽 포워딩을 효율적으로 제공하기 위한 하나의 방법으로서 CBQ를 이용한 패킷 전송 기법을 제안한다. 본 논문에서 제안하고 있는 이러한 방법을 통해 서비스 측면에서 어느 정도까지의 QoS를 보장할 수 있는지를 실험적으로 보이고자 한다.

• Proceedings of the Korea Multimedia Society Conference
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• 2002.11b
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• pp.549-552
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• 2002

복잡하고 거대한 통신망을 효율적으로 구성하고 운용 관리하기 위해 ITU-T에서는 TMN 망관리 국제표준을 정하고 있다. 그러나 TCP/IP 기반의 인터넷 망에서는 TMN보다 간단하게 정의되어 있는 SNMP를 이용해 MIB를 기반으로 망 요소(network element) 제어만을 하고 있다. 인터넷 망에서 멀티미디어 데이터 교환 서비스를 수용하면서, IP 망 설계 초기에 고려하지 않았던 서비스품질(QoS)을 제공하기 위해 IntServ, DiffServ 프로토콜 등을 정의하고 있다. 이렇게 QoS를 제공하기 위한 인터넷 망은 단순한 SNMP 만으로는 관리될 수 없다. 그러나 아직까지 이에 적합한 망관리 모델이 정립되지 못한 상태인 바, 본 논문에서는 정책을 기반(policy-based)으로 하여 QoS 서비스를 위한 자원 할당을 dynamic하게 제공할 수 있도록 하는 QoS 인터넷 망관리 모델을 제안한다. 이 모델은 TMN의 관리계층 구조에 맞도록 구성되어 있다.

• IE interfaces
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• v.23 no.2
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• pp.193-202
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• 2010

The quality of service(QoS) model should be presented with the optimal network design to effectively provide the multimedia data services between users and converged services with mobile or TV in the next-generation Internet. In specific, the method to provide differentiated services for each user is needed in the given Internet node to offer the previously negotiated QoS with the user. In this paper, the performance of the QoS enabling technologies in the differentiated services(DiffServ) network domain is analyzed. The QoS offering model and QoS metrics are presented to analyze the performance of the major scheduling algorithms. Under the real network topology and virtual service scenarios in the university, the NS-2 network simulation based on the discrete-event is performed. The results show that the ratio-based scheduling method is more effective rather than the bandwidth-assignment method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.2B
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• pp.144-156
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• 2003

Internet/Intranet has been continuously enhanced by new emerging IP technologies such as differentiate service(DiffServ), IPSec(IP Security) and MPLS(Multi-protocol Label Switching) traffic engineering. According to the increased demands of various real-time multimedia services, ISP(Internet Service Provider) should provide enhanced end-to-end QoS(quality of service) and security features. Therefore, Internet and Intranet need the management functionality of sophisticated traffic engineering functions. In this paper, we design and implement the performance management functionality for the guaranteed end-to-end QoS provisioning on MPLS-based VPLS(Virtual Private LAN Service). We propose VPLS OAM(Operation, Administration and Maintenance) for efficient performance management. We focus on a scheme of QoS management and measurement of QoS parameters(such as delay, jitter, loss, etc.) using VPLS OAM functions. The proposed performance management system also supports performance tuning to enhance the provided QoS by re-adjusting the bandwidth of LSPs for VPLS. We present the experimental results of performance monitoring and analysis using a network simulator.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.11B
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• pp.1191-1199
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• 2009

As the Internet service evolves from the best effort data service to a multimedia service such as a mix of voice, data and video, a need for the guarantee of the quality of service to network services became one of the hot issues for the network operators. On the other hand, the introduction of the multimedia services over the IP network requires a managed differentiated service that adopts a prioritized treatment of packets. This incurs a need for a differentiated pricing scheme for the packets that receive different level of quality of service. This work proposes an analytic framework about packet pricing scheme for these services, and investigate the effect of service differentiation to the packet price for each class. Via numerical experiment, we validate our argument and illustrate the implication of the work.

• Journal of the Korea Society of Computer and Information
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• v.6 no.4
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• pp.74-84
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• 2001

In the current Internet, InteServ model based on Resource reSerVation Protocol (RSVP), DiffServ Model based on service differentiation according to per hope behavior(PHB) and traffic engineering policy, and two-tire model of above mentioned two models which are adapted differently as the target network status for providing the end-to-end QoS Path are suggested. But, when we integrated this internet QoS into the ATM based network, differences of the connection setup procedure, name/address translation methods, and QoS provisioning mechanisms for end-to-end path setup procedures are introduced. In this paper, we propose the method of shortcut based QoS path setup procedure to solve these problems, and to guarantee the integration and scalability of Next Generation Internet(NGI) names/address in Integrated IP network into ATM based network. This network should support the engineering differentiated into the multiple service classes, which depend on established by this path is designed suitably into the target router and host step by step. In the near future, this function which provide the QoS guaranteed path based on end-to-end shortcut between the configuration devices are extended into the NGI target network.

• The Transactions of the Korea Information Processing Society
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• v.6 no.11S
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• pp.3320-3331
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• 1999

In this paper, we explore two ways to improve the bandwidth assurance performance of Assured Service(AS). It is well known that AS fails to meet the bandwidth assurance target for large-profile TCP flows competing with many small-profile flows. This flows after the back-offs induced by packet drops. Thus currently proposed solution to this problem naturally focus on modifying TCP's behavior to counter the unfairness in the TCP dynamics. Unfortunately, these proposals lack practicability in terms of the required changes in the incumbent Internet infrastructure. Admitting this difficulty, we instead look to not yet deployed Diff-Serv mechanisms for practical solutions. In particular, we investigate the role of RIO, RED with IN(in-profile) and OUT(out-profile), queue management scheme in the assurance failure for As. Specifically, we identify the inadequacy of RIO that aggravates the bandwidth assurance failure. Then we alleviates the bandwidth assurance failure problem by separately controlling the out-of-profile packet queue length. Through extensive simulations we demonstrate that RI+O extends the regime where AS consistently provides the bandwidth assurance.

• Proceedings of the IEEK Conference
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• 2002.06a
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• pp.49-52
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• 2002

QoS support for the Internet traffic becomes an important future requirement of various network devices such as routers and switches. Differentiated Services(Diffserv) is considered as an efficient feasible solution for providing different service characteristics to different classes of network users. IETF Diffserv working group has already defined a general architecture of Diffserv and is extending its detail features. Network vendors also start implementing Diffserv enabled network devices. However, the management of Diffserv is not fully standardized yet. This paper, we present methods of traffic flow control in Diffserv Networks. we have designed a Diffserv Traffic Control system.