• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.11
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• pp.902-910
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• 2013

The most representative research network in Korea, KREONET, has developed DynamicKL, an advance reservation based Network Service Agent (NSA) for user driven virtual circuit services. DynamicKL provides reservation, provisioning, release, termination, and inquiry web services for network resources by using an open standard network service interface (NSI), as well as web services for network resources by using a GUI interface. In addition, it has the RICE interface to support a protection management function per VC for virtual circuits and reservations. In this article, a protection management per VC for provisioned VCs and reservations is addressed in the DynamicKL framework, as a contribution to the VC protection management issue, which results in more manageable and reliable VC services compared to other advance reservation frameworks. An administrator can detect successful or unsuccessful VC protections in the event of a primary link failure and successful or unsuccessful VC retrievals after a primary link repair, by using RICE.

• Proceedings of the Korean Information Science Society Conference
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• 2000.10c
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• pp.117-119
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• 2000

UMTS(Universal Mobile Telecommunication System)의 Core Network에서는 SGSN(Serving GPRS Support Node)과 GGSN(Gateway GPRS Support Node)사이의 전송계층을 IP-Over-ATM network을 기반으로 한다. 이는 비연결형(connectionless) IP 트래픽들을 연결지향형(connectionoriented) ATM 전송계층을 통해 전송함으로 이때 효율적인 자원관리를 위해 적절한 VC(Virtual Circuit)의 접속과 해제를 수행해야 한다. 본 논문에서는 [1]에서 제안되는 GPRS(General Packer Radio Service)의 Web 트래픽 모델에 대하여 기존의 VC의 Holding-time을 결정하는 기법인 Holding Cost Pricing Model(LRU, Mean-Variance, Adaptive policy) [2]을 GGSN과 SGSN사이의 ATM 전송계층에 적용하였다. 각각의 기법들에서 VC의 이용률(utilization)과 설정율(setup rate)을 비교함으로써 Adaptive policy 기법의 성능이 다른 기법에 비해 효율적임을 알 수 있다.

• ETRI Journal
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• v.37 no.2
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• pp.369-379
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• 2015

Fault management of virtualized network environments using user-driven network provisioning systems (NPSs) is crucial for guaranteeing seamless virtual network services irrespective of physical infrastructure impairment. The network service interface (NSI) of the Open Grid Forum reflects the need for a common standard management API for the reservation and provisioning of user-driven virtual circuits (VCs) across global networks. NSI-based NPSs (that is, network service agents) can be used to compose user-driven VCs for mission-critical applications in a dynamic multi-domain. In this article, we first attempt to outline the design issues and challenges faced when attempting to provide mission-critical applications using dynamic VCs with a protection that is both user-driven and trustworthy in a dynamic multi-domain environment, to motivate work in this area of research. We also survey representative works that address inter-domain VC protection and qualitatively evaluate them and current NSI against the issues and challenges.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.11
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• pp.4720-4738
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• 2015

Proper management on user-driven virtual circuits (VCs) is essential for seamless operation of virtual networks. The Network Provisioning System (NPS) is useful software for creating user-driven VCs automatically and must take fault management into account for physical layer impairments on user-driven VCs. This paper addresses a user-driven and trusty protection management in an NPS with an open standard Network Service Interface (NSI), as a contribution to show how to implement the user-driven and trusty protection management required for user-driven VCs. In particular, it provides a RESTful web service Interface for Configuration and Event management (RICE) that enable management of a distinguished data and control plane VC status between Network Service Agents (NSAs) in the event of a node or link fault and repair in a domain. This capability represents a contribution to show how network and protection events in a domain can be monitored between NSAs (NPSs with the NSI) in multiple domains. The implemented NPS controls and manages both the primary and backup VC with disjoint path in a user-driven manner. A demonstration to verify RICE API's capability is addressed for the trusty protection in the dynamic VC network.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.6A
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• pp.1060-1066
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• 2001

레이어2 스위칭과 레이어3 라우팅의 통합 모델로써 MPLS(Multi-Protocol Label Switching) 환경에서 ATM LSR(Label-Switching Routers)은 백본망에서의 고속 전송이 가능하여 현재의 라우터 구조로써 제안되어지고 있다. MPLS가 코어 라이터로써 적용이 될 경우 확장성을 위해 label merging이라는 기술이 필요하다. VC(Virtual Circuit) merging은 ATM LSR에서 많은 IP 라우터를 하나의 라벨로 매핑을 시키며 수천 개의 목적지에 전송할 수 있는 확장성 있는 매핑 기술이다. VC merging은 같은 목적지인 다른 패킷들 간의 셀들의 섞임을 방지하기 위해 재 조합 버퍼가 요구된다. 재 조합 버퍼 사용시 일시적인 체증 현상이 발생하며 Non-VC merging과 비교시 많은 셀 손실과 많은 버퍼를 요구하게 된다. 본 논문에서는 RED(Random Early Detection) 알고리즘을 적용하여 VC merging이 필요한 버퍼의 요구량과 셀 손실을 줄였다.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.1193-1194
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• 2008

In this paper, we propose application training kit using parallel port circuit of standard architecture in computer system. The proposed training kit is verified through the design of hardware board and a virtual driving test using GUI method in VC++ under window XP operating system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.6B
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• pp.1113-1122
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• 1999

In this paper, we propose MSS(Multicast Synchronization Server) and QCS(QoS Conversion Server) models that can support IP multicast and QoS(Quality of Service) over the ATM network more efficiently. In the MSS model, it is possible to establish shortcut VCs(Virtual Circuits) among all hosts in the ATM network and to transfer multicast data at high speed. Also the MSS model is more scalable, because the number of inter-cluster VCs needed in the MSS model is less than that of EARTH. In the QCS model, ATM switch is modified to support one QoS service and best effort service through the one point-to-multipoint VC at the same time so required network resources are reduced, and dedicated server is used for QoS conversion to accept heterogeneous receivers more efficiently. In this Paper, the proposed MSS model and QCS model have solved both efficiency problem and scalability problem. It is proved through the comparison of the VCs required in each model.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.648-652
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• 2003

In the GPRS(General Packet Radio Service) network, the transport layer between SGSN(Serving GPRS Support Node) and GGSN (Gateway GPRS Support Node) is based on IP-Over ATM Network. which means that the connectionless IP traffic is transmitted through connection oriented ATM transport layer. Efficient resource management is needed to perform connection and disconnection of the pertinent VC because of the connectionless IP traffic being passed through ATM transport layer In this paper, Internet Web service traffic model in the GPRS network is applied to the various VC holding Cost Pricing Model. each method is compared through analyzing each VC utilization and setup rate.

• The KIPS Transactions:PartC
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• v.10C no.1
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• pp.45-50
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• 2003

Guaranteed Frame Rate (GFR) service category is one of the most recent ATM service categories. The GFR specification was recently finalized by the ATM Forum and is expected to become an important service category which can efficiently support TCP/IP traffic in ATM network. In GFR switch implementation, it is important to guarantee MCR (minimum cell rate) and improve fairness. In this paper, we propose a new scheduling algorithm for the GFR service. Proposed algorithm provides priority to VC (virtual circuit)s and high Priority given to a VC which has fewer untagged cells in buffer. High priority VCs are serviced before low priority VCs. Proposed algorithm can guarantee MCR and improve fair sharing of the remaining bandwidth between GFR VCs. From computer simulation results, we demonstrate the proposed scheduling algorithm provide much better performance in TCP goodput and fairness than previous schemes.

• Journal of the Korean Institute of Telematics and Electronics
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• v.22 no.6
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• pp.114-123
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• 1985

This is the second part of the four-part paper describing the development of a packet-switched computer network named the cORNET In this paper, following the first par paper that describes the concepts of the KORNET and the development of the network management center (NMC), wc present the design of the KORNET and the development of the network node processor (NNP) The initial configuration of the KORNET consists of three NNP's and one NMC. We have developed each NNP as a microprocessor-based (Mc68000) multiprocessor system, and implemented the NMC using a super-mini computer (Mv/8000) For the KORNET we use the virtual circuit (VC) method as the packet service strategy and the distributed adaptive routing algorithm to adapt efficiently the variation of node and link status. Also, we use a dynamic buffer management algorithm for efficient storage management. Thc hardware of the NNP system has been designed with emphasis on modularity so that it may be expanded esily . Also, the software of the NNP system has been developed according to the CCITT recommendations X.25, X.3, X.28 and X.29.