• 전기전자학회논문지
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• 제10권2호통권19호
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• pp.123-127
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• 2006

인프라가 없는 Ad-hoc 네트워크에서 트래픽 집중은 시스템 성능에 영향을 준다 이에 트래픽을 고르게 분배하여 자원을 효율적으로 소비하는 것이 필요하다. Ad-hoc 네트워크는 경로가 설정되고 통신이 시작되면 링크의 단절이 생기지 않는 한, 경로의 재설정이 이루어지지 않는다. 본 논문에서는 부하증가에 따른 처리능력이 우수한 AODV 라우팅 프로토콜을 수정 개선하여 네트워크의 트래픽 변화에 능동적으로 부하분산을 할 수 있도록 하였다. 수정된 AODV 라우팅 프로토콜은 트래픽이 집중된 노드가 자신의 프래픽 집중을 메시지로 알리고, 이 메시지를 받은 노트들은 대체 노드가 존재하면 경로 변경 후 데이터를 전송한다 수정한 프로토콜의 동작과 성능은 ns2 시뮬레이터를 이용하여 실험 평가하였다.

• 한국통신학회논문지
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• 제22권4호
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• pp.618-636
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• 1997

DQDB(Distributed Queue Dual Bus) protocol, the IEEE 802.6 standard protocol for metropolitan area networks, does not fully take advantage of the capabilities of dual bus architecture. Although fairness in bandwidth distribution among nodes is improved when using so called the bandwidth balancing mechanism, the protocol requires a considerable amount of time to adjust to changes in the network load. Additionally, the bandwidth balancing mechanism leaves a portion of the available bandwidth unused. In a high-speed backbone network, each node may act as a bridge/ router which connects several LANs as well as hosts. However, Because the existence of high speed LANs becomes commonplace, the congestionmay occur on a node because of the limitation on access rate to the backbone network and on available buffer spaces. to release the congestion, it is desirable to install some congestion control algorithm in the node. In this paper, we propose an efficient congestion control mechanism and fair and waster-free MAC protocol for dual bus network. In this protocol, all the buffers in the network can be shared in such a way that the transmission rate of each node can be set proportional to its load. In other words, a heavily loaded node obtains a larger bandwidth to send the sements so tht the congestion can be avoided while the uncongested nodes slow down their transmission rate and store the incoming segments into thier buffers. this implies that the buffers on the network can be shared dynamically. Simulation results show that the proposed probotol significantly reduces the segment queueing delay of a heavily loaded node and segment loss rate when compared with original DQDB. And it enables an attractive high throughput in the backbone network. Because in the proposed protocol, each node does not send a requet by the segment but send a request one time in the meaning of having segments, the frequency of sending requests is very low in the proposed protocol. so the proposed protocol signigificantly reduces the segment queuing dely. and In the proposed protocol, each node uses bandwidth in proportion to its load. so In case of limitation of available buffer spaces, the proposed protocol reduces segment loss rate of a heavily loaded node. Bandwidth balancing DQDB requires the wastage of bandwidth to be fair bandwidth allocation. But the proposed DQDB MAC protocol enables fair bandwidth without wasting bandwidth by using bandwidth one after another among active nodes.

• Journal of information and communication convergence engineering
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• 제5권2호
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• pp.88-92
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• 2007

In this paper, an SS-RRA protocol that is based on Code Division Multiple Access is proposed and analyzed under the integrated voice and data traffic load. The backward logical channels consist of slotted time division frames with multiple spreading codes per slot. The protocol uses a reservation mechanism for the voice traffic, and a random access scheme for the data traffic. A discrete-time, discrete-state Markov chain is used to evaluate the performance. The numerical results show that the performance can be significantly improved by a few distinct spreading codes.

• International Journal of Control, Automation, and Systems
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• 제5권5호
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• pp.584-593
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• 2007

BACnet is a standard data communication protocol especially designed for building automation and control networks. BACnet uses the Master-Slave/Token-Passing (MS/TP) protocol as one of its field-level networks. In this study, the performance of the BACnet MS/TP protocol is evaluated using an experimental model. The network performance is investigated and evaluated in terms of token rotation time and round trip time. The experimental results show that the performance of the MS/TP network is heavily influenced by the network traffic load, the assignment of MS/TP node address and the network configuration parameter called $N_{max_info-frames}$. Based on the experimental results, simple practical designing guidelines for BACnet MS/TP network systems are also proposed.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -3
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• pp.1685-1688
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• 2002

Application Routing Load Balancing (ARLB) is a novel load balancing mode that combines QoS routing and load balancing in per application to support QoS far real-time application based on wired network. Zone Routing Protocol (ZRP) is a recent hybrid proactive/reactive routing approach in an attempt to achieve scalability of ad-hoc network. This routing approach has the potential to be efficient in the generation of control traffic than traditional routing schemes. Up to now, without proper load balancing tools, the ZRP can actually guarantee QoS for delay-sensitive applications when congestion occurred in ad-hoc network. In this paper, we propose the ARLB to improve QoS fur delay-sensitive applications based on ZRP in ad-hoc network when congestion occurred and to be forwarding mechanism fur route coupling to support QoS for real-time applications. The critical point is that the routing metric of ARLB is originally designed for wired network environment. Therefore, we study and present an appropriate metric or cost computation routing of ARLB for recently proposed ZRP over ad-hoc network environment.

• 한국자동차공학회논문집
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• 제21권1호
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• pp.128-136
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• 2013

This study presents the development of Gateway Control Module using SAE J1939 protocol for the commercial vehicles. Presently, the load rate of CAN bus is increased by the single network composition and addition of new ECUs for development of intelligent vehicles. Because the embedded system of the integrated network control function has the errors of the CAN bus caused by the increase of ECU, it is needed for development of commercial vehicles. Also, this study presents the development of smart functions that can diagnosis CAN bus errors, fault diagnosis of ECU and basic function that arbitrates CAN bus between ECUs of commercial vehicle. GCM was designed for 4channel separation about Gateway function as solution of load rate decrease and smart functions. HILS(Hardware in the loop simulation)system that can achieve simulation about CAN Messages of all systems on vehicle was applied to evaluate performance and verification of all functions and performance. The load rate on CAN bus was decreased at using functions what was delivery, block and process of GCM. Through this, it was enabled to organize systematic architecture for gateway.

• 전자공학회논문지
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• 제50권11호
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• pp.141-149
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• 2013

IoT (Internet of Things) 환경에서 IPv6 패킷 통신을 지원하기 위한 표준 기술로 IETF 6LoWPAN (IPv6 over Low power WAPN) 표준 기술이 많은 연구가 진행되고 있다. 6LoWPAN에서 패킷 전송을 위한 프로토콜로 주로 AODV (Ad-hoc Distance Vector) 라우팅 프로토콜 기술을 확장한 다양한 연구가 진행되고 있다. 특히, 제한된 자원을 가진 노드들로 구성된 6LoWPAN에서 네트워크 오류가 발생했을 때 신뢰성 있는 데이터 전송과 빠른 경로 설정 방법이 필요하다. 이를 위해, 본 논문에서는 IETF LOAD(6LoWPAN Ad Hoc On-Demand Distance Vector Routing) 을 확장한 최적 복구 경로 알고리즘인 회복력 있는 라우팅 프로토콜기법 (Resilient Routing Protocol) 을 제안한다. 좀 더 구체적으로, 최적 복구 경로 설정 알고리즘, 상세 프로토콜 신호 흐름도 및 패킷 전송의 신뢰성 검증을 위한 수학적인 모델을 제시하였다. 제안된 프로토콜 기법의 성능을 분석하기 위해 NS-3 (Network Simulation Tool) 를 통해 성능 분석하였고 성능 분석 결과 기존의 LOAD 라우팅에 비해 종단간 지연시간, 패킷 처리율, 패킷 전송율 및 제어 패킷 오버헤드 등의 성능 면에서 우수함을 증명하였다.

• 한국컴퓨터정보학회논문지
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• 제19권1호
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• pp.43-55
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• 2014

SPDY는 기존 HTTP(Hypertext Transfer Protocol)/1.1의 문제점을 보완하여 웹 속도를 향상시키기 위한 목적으로 구글에서 새롭게 제안한 프로토콜이다. 본 논문은 다양한 환경에서의 성능 측정을 실시함으로써 SPDY 프로토콜의 특징을 알아보고 기존 프로토콜과의 차이점을 비교 분석하였으며 나아가 SPDY의 Flow Control에 대해서 좀 더 자세히 살펴보았다. 측정 실험들을 통해 SPDY 프로토콜은 3G 환경에서는 성능 향상을 보이지만 고속의 무선랜 환경과 이동체 환경에서는 뚜렷한 성능 향상을 보이지 못하는 문제점이 있음을 파악하였으며 Flow Control 역시 제대로 동작하지 않고 있음을 확인하였다. 마지막으로 성능 측정 실험 결과와 이에 대한 분석을 바탕으로 하여 SPDY 프로토콜의 개선방향을 제시하였다.

• 융합보안논문지
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• 제2권2호
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• pp.1-8
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• 2002

멀티미디어 정보 전송을 위해 RTP(Real-Time Transport Protocol)을 사용하며, 멀티미디어 정보 보안을 위해서는 RPT의 페이로드를 암호화해야 한다. RPT페이로드의 암호화를 위해서 암호화/복호화로 인한 지연이 멀티미디어 정보의 실시간 제약에 미치는 영향을 최소로 하면서 네트워크의 트래픽과 부하에 적응하며 암호화 알고리즘을 변경하기 위한 방법이 필요하다. 또한 멀티미디어 서비스 진행 중 서비스 이용을 중지한 사용자는 RPT 페이로드의 암호화 키를 알고 있기 때문에 페이로드를 보호하기 위해서는 암호화 키를 변경하기 위한 방법이 필요하다. 따라서 본 논문에서는 RPT 페이로드의 암호화를 위해, 암호화 알고리즘과 암호화 키를 변경하기 위한 SCPR(Security Control Protocol for RTP)를 설계하고 구현하였다.

• 전자공학회논문지A
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• 제31A권5호
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• pp.10-17
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• 1994

Two protocols inclouding the receiver collision avoidance function are proposed for high-speed optical fiber LANs with finite users. The basic idea to avoid receiver collision is the grouping of destination nodes by the number of channels and it is accomplished in the architecture with or without one separate control channel. While the protocol with a control channel requires a tunable optical transmitter, a fixed optical transmitter and two fixed optical receiver, the other protocol requires a tunable optical transmitter and one fixed optical receiver. The performance of two receiver collision avoidance protocols is computed and analyzed under various system parameters. The numerical results show that the receiver collision avoidance protocol has better performance for a small load than the protocol without receiver collision avoidance.