• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.8
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• pp.42-50
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• 2011

Recently, research activities on the future internet are being actively performed in foreign and domestic. In domestic, ETRI and 4 universities are focused on implementation of a testbed for research on the future internet named as 'FiRST(Future Internet Research for Sustainable Testbed)'. In the 'FiRST' project, 4 universities are performing a project in collaboration named as 'FiRST@PC' project that is for an implementation of the testbed using the programmable platform-based openflow switches. Currently, the research on the virtualization of the testbed is being performed that has a purpose for supporting an isolated network to individual researcher. In this paper, we implemented a traffic scheduler for providing QoS by using the programmable platform that performs a hardware-based packet processing and we are implemented a testbed using that traffic scheduler. We perform a performance evaluation of the traffic scheduler on the testbed. As a result, we show that the hardware-based NetFPGA scheduler can provide reliable and stable QoS to virtualized networks of the Future Internet Testbed.

• The KIPS Transactions:PartC
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• v.9C no.1
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• pp.123-134
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• 2002

The requirement for QoS (Quality of Service) has become an important Issue as real-time or high bandwidth services are increasing, such as Internet Telephony, Internet broadcasting, and multimedia service etc. In order to guarantee the QoS of Internet application services, several approaches are being sought including IntServ (Integrated Service) DiffServ(Differentiated Srvices), and MPLS(Multi-Protocol Label Switching). In this paper, we describe the performance analysis of QoS guarantee mechanism using the DiffServ. To analyze how the DiffServ performance was affected by diverse input traffic models and the weight value in WFQ(Weighted Fair Queueing), we simulated and performed performance evaluation under a random, bursty, and self-similar input traffic models and for diverse input parameters. leased on the results of performance analysis, it was confirmed that significant difference exist in packet delay and loss depending on the input traffic models used. However, it was revealed that QoS guarantee is possible to the EF (expedited Forwarding) class and the service separation between RF and BE (Best Effort) classes may also be achieved. Next, we discussed the performance synthesis problem. (i. e. derived the conservation laws for a DiffServ networks, and analysed the performance variation and dynamic behavior based on the resource allocation (i.e., weight value) in WFQ.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.79-82
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• 1998

This paper proposes the MAC scheme based on variable reservation slots for the guaranteed QoS of ATM services on RF and evaluates the performance. This scheme has improved the utilization of channel and success ratio of reservation by using the variable number of RES(REServation) slots according to the collisions. It is the results of performance evaluation that the CTD of CBR Service is 7.9ms with overall $load(\rho)$ 85%. And also VBR service of it is 3.5ms, ABR service of it is 9.8ms with overall load 85%.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04a
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• pp.499-501
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• 2004

현재 IPv6에서 이동 통신에 끊김 없는 서비스를 제공하기 위해 Mobile IPv6에 관한 많은 연구가 이루어지고 있다. FMIPv6는 핸드오버 절차를 간소화시켜서 빠른 속도의 핸드오버와 데이터 전송이 가능하며 SIP나 VoIP 및 무선 인터넷 동영상 서비스와 같은 경우에 많이 사용될 것으로 예상되지만 패킷 손실의 문제점을 지니고 있다. 본 논문은 FMIPv6에서 핸드오버시 발생하는 패킷 손실을 줄이기 위하여 라우터에서 사용하는 여러 패킷 관리 스케줄링 기법 중 WFQ기법을 사용한 트래픽 관리 메커니즘을 설계하고 평가하였다.

• The KIPS Transactions:PartC
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• v.12C no.5 s.101
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• pp.679-686
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• 2005

Because EPON access network shares a medium and aggregates the traffic from EPON subscribers, scheduling media access control on EPON bandwidth allocation is very important. Furthermore DBA mechanism of EPON based on TDMA is out of specification and up to implementation. This paper deals with a DBA method to guarantee the QoS of the delay sensitive traffic on the base of best-effort service and delay priority queue management. The proposed method performs virtual scheduling algorithm for the integrated traffic. It uses the same MAC messages and tries to guarantee the QoS of higher priority traffic first with a simple DBA architecture. We evaluate the algorithm for traffic delay according to polling interval and traffic load of upstream and downstream. The results show that the proposed method can guarantee the QoS of the delay sensitive traffic with priority of the service classes.

• Journal of the Korea Society of Computer and Information
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• v.12 no.4
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• pp.43-52
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• 2007

As the number of public Web Services increases, there will be many services with the same functionality. These services. however, will vary in their QoS properties, such as price, response time and availability, and it is very important to choose a best service while satisfying given QoS constraints. This paper brings parallel branching and response time constraint of business processes into focus and investigates several service selection plans based on multidimensional multiple choice Knapsack model. Specifically. proposed in the paper are a plan with response time constraints for each execution flow, a plan with a single constraint over the whole service types and a plan with a constraint on a particular execution path of a composite Web Services. Experiments are conducted to observe the performance of each plan with varying the number of services, the number of branches and the values of response time constraint. Experimental results show that reducing the number of candidate services using Pareto Dominance is very effective and the plan with a constraint over the whole service types is efficient in time and solution quality for small to medium size problems.

• Journal of the Korea Society of Computer and Information
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• v.10 no.6 s.38
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• pp.261-268
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• 2005

Recently, Many People have studied in Mobile Ipv6 to provide seamless service. FMIPv6 is designed to reduce the procedure of handover and will be used SIP, VoIP and Mobile Internet moving picture service. But, If mobile node moves fast, it will happen to packet loss and interruption problem in handover procedure. So, In this paper, designed and evaluated traffic control mechanism using WFQ scheduling to reduce the packet loss that occurred to handover procedure.

• ETRI Journal
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• v.28 no.1
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• pp.77-83
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• 2006

In order to improve the accuracy of cell selection in heterogeneous cellular systems, this paper proposes a fuzzy multiple-objective decision-based cell selection (FMDCS) strategy. Since heterogeneous cellular systems have different access technologies and multiple traffic classes, the strategy adopts cell type, data rate, coverage, transmission delay, and call arrival rate as evaluation indices, and uses different weight vectors according to the traffic classes of the mobile host. Then, a fuzzy multiple-objective decision algorithm is applied to select the optimal cell from all candidates. This paper also gives an instance analysis and simulation. The instance analysis shows FMDCS makes different selections for different traffic classes. Simulation results of the after-handoff quality-of-service (QoS) show the selected cell can provide MH optimal service.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.5
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• pp.965-972
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• 2005

We propose a new resource management scheme, Distributed Channel Allocation Protocol (DCAP), for multimedia Ad Hoc Wireless LANs (AWLANS). This scheme implements a Qualify-of-Service (QoS) providing distributed resource management on the Orthogonal Frequency Division Multiplexing-Code Division Multiple Access (OFDM-CDMA) channel architecture. According to the performance evaluation results for MPEG traffic sources, DCAP can be a good choice of resource management scheme for AWLANs supporting multimedia services on the Broadband Wireless Access(BWA)-type physical layer.

• The KIPS Transactions:PartC
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• v.8C no.4
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• pp.451-458
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• 2001

무단절 통신의 목표는 이동 사용자에게 단절 자유 서비스를 제공하는데 있으며, 이동 서비스의 단절은 활동적 핸드오프에 의해 발생된다. 이동 무선망에서 무단절 서비스에 대한 완전 보장을 요구하지 않으나 매우 빈번한 단절을 허용하지 않는 많은 사용자 응용들이 있다. 이 논문에서는 무단절 서비스에 대한 언어적 보장을 제공하는 퍼지 멀티캐스트 방법을 제안한다. 무단절 서비스에 대한 언어적 보장이 이동 사용자에 의해 명세되면, 제안하는 퍼지 멀티캐스트 방법은 이동 호스트의 이동 방향과 이동 속도를 예측하고, 퍼지 논리에 의해 그 이동 호스트를 위한 체이터 패텟은 모든 이웃 셀이 아닌 일부 이웃 셀에게 전송된다. 시뮬레이션 결과, 우리는 다음 사항들을 알 수 있었다. 첫째, 퍼지 멀티캐스트 방법은 정적 대역폭 사용을 상당히 감소시키고 또한 무단절 서비스에 대한 언어적 보장을 제공한다. 둘째, 무단절 서비스 확률은 이동 사용자의 언어적 QoS와 이동 호스트의 이동 방향에 의해 결정되고, 특히 이동 사용자의 언어적 QoS에 의해 많은 영향을 받는다. 그러므로 퍼지 멀티캐스트는 이동 사용자의 언어적 QoS 명세로 무단절 서비스에 대한 좋은 차등 서비스를 제공한다.