• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.4C
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• pp.353-364
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• 2002

To prevent the performance degradation of TCP due to packet loss in the smooth handoff by the route optimization extension of Mobile If protocol, a buffering of packets at a base station is needed. A buffering of packets at a base station recovers the packets dropped during the handoff by forwarding the buffered packets at the old base station to the mobile user. But, when the mobile user moves to a new foreign network which is connected to a congested router, the buffered packets forwarded by the old base station are dropped and the link utilization performance degraded due to increased congestion by the forwarded packets. In this paper, when the mobile user moves to a new foreign network which is connected to a congested router, Ive propose a packet forwarding control scheme required far the old base station to improve TCP performance in mobile networks. The old base station forwards or discards the buffered packets during handoff by proposed packet forwarding control scheme based on congestion states of RED(Random Early Detection) at the congested router. Simulation results slow that link utilization performance can be improved by applying proposed packet forwarding control scheme.

• The KIPS Transactions:PartC
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• v.9C no.1
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• pp.55-64
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• 2002

A number of MPLS ATM systems have been proposed to increase the access speed of current rooters, which only support the beat-effort service. However, the MPLS ATM systems have to support the so-called differential service, which discriminates the applications according to the servile clads because they do not be satisfied the Internet users who use diverse applications. In this paper, to support this differential service a detailed forwarding procedure based on a LSP control method and an application-based marking algorithm is suggested. The LSP control method establishes several different LSPs for each FEC according to the service class and the application-based marking algorithm chooses a proper differential service depending on the application category. Also, a design scheme of forwarding engine, which can be easily implemented with a minimum modification of existing MPLS ATM systems is proposed. And, the best simulation result of high priority application category is gained when the proposed forwarding algorithm is compared with existing algorithms.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10a
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• pp.497-499
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• 1998

인터넷이 월드 와이드 웹()의 인기에 힘입어 일상 생활의 일부가 되고는 있지만 보안 요건 중의 하나인 '통신의 비밀성(Confidentiality)요건'을 만족시키지 못하고 있기 때문에 많은 네트워크 응용에서 문제가 되고 있다. 새로운 네트워크 프로토콜인 IPv6[4]에서는 프로토콜 단계에서의 암호화 서비스 제공을 통해 네트워크 통신을 보호해 줄 것으로 기대되지만 아직 표준으로 확정되지 않았으며 실제 네트워크 통신에 언제부터 사용 가능할 지 예측할 수도 없다. 이러한 상황에서, 기존의 네트워크 응용들에 대해 암호화 서비스를 제공하는 방법으로 원천코드(source code)를 변경하여 다시 컴파일 하는 수밖에 없다. 본 논문에서는 '포트 포워딩(port forwarding)'기법을 사용하여 클라이언트/서버 모델로 동작하는 기존 TCP/IP네트워크 응용들의 원천코드(source code)변경 없이 네트워크 통신을 보호할 수 있는 네트워크 통신 보호 시스템을 설계하고 구현하였다.

• Journal of information and communication convergence engineering
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• v.9 no.6
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• pp.775-779
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• 2011

As the technology of multimedia sensor networks is desired in large numbers of applications nowadays, real-time service becomes one of the most important research challenges. Even though lots of related works have been conducted to meet this requirement in several ways, the specific traffic model for real-time has not been taken yet. Thus, it causes lack of adaptability of those approaches in real deployment. To solve this problem, in this paper, we model the application via (m,k)-firm streams which have weakly hard real-time property. And then, a novel forwarding scheme based on modified DBP (Distance-Based Priority) is proposed by considering local-DBP and stream DBP together. Local-DBP can contribute to identify the detailed causes of unsatisfied quality, that is, network congestion or wireless link failure. Simulation results reveal that (m,k)-firm is a good traffic model for multimedia sensor networks and the proposed scheme can contribute to guarantee real-time requirement well.

• Proceedings of the Korea Information Processing Society Conference
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• 2006.05a
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• pp.1219-1222
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• 2006

3GPP에서는 단대단 QoS 보장을 위해 정책 기반 망 관리(PBNM:Policy-based Network Management) 방식을 적용할 것을 권고하고 있다. 본 논문에서는 3GPP에서 제시하는 핵심망 구조에 정책 기반 망 관리 기법 중 DiffServ를 적용해서 현재 DSCP(Differentiated Service Code Point)는 8bit 구성되어 있으나 그 중 6bit만 사용되고 있고, 사용하지 않는 이 2bit를 사용하여 DF(Default Forwarding), EF(Expedited Forwarding), AF(Assured Forwarding)의 DSCP에 Service Class Code Point를 부여해서 DiffServ를 서비스하는 망에서 동일한 Diffserv 정책을 설정해서 효율적인 QoS 기법을 제안하고자 한다.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10e
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• pp.610-612
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• 2002

현재 인터넷은 IPv4주소 고갈로 인해 종래의 클래스(class)별 주소의 분배와 사용을 지양하고 클래스 없는 CIDR(Classless InterDomain Routing)〔1〕방식을 채택하고 있다. 본 논문에서는 라우터의 개발 및 성능에 영향을 미치는 라우팅 엔트리의 분포와 특성을 다음의 세가지 관점에서 분석하였다. 그리고 분석에 사용된 데이터는 백본용 라우터의 라우팅 테이블이다. 첫째, 현재 인터넷에서 CIDR 방식에 따른 서브넷팅(Subnetting)과 슈퍼넷팅(Supernetting)〔2〕〔3〕정도를 분석하였으며 둘째, 현재 포워딩 테이블(Forwarding Table)내의 불필요한 포워딩 엔트리(Forwarding Entry)들이 차지하는 구성비를 조사하였다. 마지막으로는 멀티홈밍(Multi-homing)이 포워딩 테이블의 크기에 미치는 영향을 분석하였다. 조사에 의하면 MAE-East와 MAE-West〔4〕와 같은 백본(Backbon) 라우터의 경우에 A클래스는 8에서 26비트까지, B클래스는 14비트에서 27비트까지 그리고 C클래스는 17비트에서32비트까지 서브넷팅과 슈퍼넷팅이 되어있다. 또한 불필요한 포워딩 엔트리는 전체 엔트리의약 1%를 차지하고 있으며, 멀티홈밍 엔트리는 약 5%를 차지하는 것으로 확인되었다.

• IE interfaces
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• v.14 no.3
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• pp.263-271
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• 2001

MPLS LER is located at the boundary of MPLS domain as an ingress or an egress router and plays a role in connecting with the existing Internet. Among the components of the MPLS LER, forwarding engine(FE) is a key device which assigns a label to an IP packet by analyzing the destination address of its header in order to enter the MPLS domain, or restructures the cells from MPLS domain into IP packet by reversely processing. In this paper, we investigate the design of FE by analyzing the traffic performance of its components and estimate the IP packet processing capacity of a FE using queueing model and simulation. It is found that the maximum IP packet processing capacity of the Forwarding Engine is about 150,000 packets/sec.

• Proceedings of the Korea Contents Association Conference
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• 2003.11a
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• pp.227-233
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• 2003

In paper, we present design and implementation of MPLS based VPN with QoS capabilities. We propose a design architecture of an edge router for MPLS based VPN with QoS capabilities in backbone network. We design functional blocks, interface specifications, detail routing and forwarding information based structure, and packet forwarding engine for the purpose of implementation of an edge router, We extend bgp-4 software for implementation differentiated service packet forwarding schemes in MPLS based VPN.

• International Journal of Internet, Broadcasting and Communication
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• v.5 no.2
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• pp.18-22
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• 2013

Mobile IPv6 (MIPv6) is a host-based protocol supporting global mobility while Proxy Mobile IPv6 (PMIPv6) is a network-based protocol supporting localized mobility. This paper makes its focus on how to reduce the longer delay and extra cost arising from the combination of authentication, authorization and accounting (AAA) and PMIPv6 further. Firstly, a novel authentication scheme (Proxy-AAA) is proposed, which supports fast handover mode and forwarding mode between different local mobility anchors (LMAs). Secondly, a cost analysis model is established based on Proxy-AAA. From the theoretical analysis, it could be noted that the cost is affected by average arrival rate and residence time.

• 한국전산유체공학회:학술대회논문집
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• 2007.10a
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• pp.77-81
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• 2007

In this paper, helicopter aerodynamics is simulated in hovering and forwarding flighst. The governing equation is the unsteady Euler equation. To consider the blade motion and moving effects, an overset grid technique is applied in this simulation. At the boundary, the Riemann invariants condition is used for inflow and outflow. To validate this method, the result is compared with Caradonna-Tung's experimental data.