• KIPS Transactions on Computer and Communication Systems
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• v.9 no.3
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• pp.45-58
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• 2020

In the current trend of increasing network traffic due to the popularization of cloud service and mobile devices, WAN bandwidth is very low compared to LAN bandwidth. In a WAN environment, a WAN optimizer is needed to overcome performance problems caused by transmission protocol, packet loss, and network bandwidth limitations. In this paper, we analyze the data deduplication algorithm of WANProxy, an open source WAN optimizer, and evaluate its performance in terms of network latency and WAN bandwidth. Also, we evaluate the performance of the two-stage compression method of WANProxy and Zstandard. We propose a new method to improve the performance of WANProxy by revising its data deduplication algorithm and evaluate its performance improvement. We perform experiments using 12 data files of Silesia with a data segment size of 2048 bytes. Experimental results show that the average compression rate by WANProxy is 150.6, and the average network latency reduction rates by WANProxy are 95.2% for a 10 Mbps WAN environment and 60.7% for a 100 Mbps WAN environment, respectively. Compared with WANProxy, the two-stage compression of WANProxy and Zstandard increases the average compression rate by 33%. However, it increases the average network latency by 2.1% for a 10 Mbps WAN environment and 5.27% for a 100 Mbps WAN environment, respectively. Compared with WANProxy, our proposed method increases the average compression rate by 34.8% and reduces the average network latency by 13.8% for a 10 Mbps WAN and 12.9% for a 100 Mbps WAN, respectively. Performance analysis results of WANProxy show that its performance improvement in terms of network latency and WAN bandwidth is excellent in a 10Mbps or less WAN environment while superior in a 100 Mbps WAN environment.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.11C
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• pp.1112-1123
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• 2002

Providing a multimedia service requires efficient network bandwidth allocation scheduling. Typically, transmission of information with bursty characteristics, such as a video data stream, utilizes some type of smoothing technique that reduces the transmission rate fluctuation. While capable of a drastic reduction in the peak transmission rate, even the optimum smoothing algorithm proposed to date, however, is rather inadequate for multi-stream applications that share network bandwidth since such an algorithm has been designed and applied toward handling each independent stream. In this paper, we proposed an efficient bandwidth allocation algorithm that addresses these shortcomings. The proposed bandwidth allocation algorithm is divided into two steps, a static bandwidth allocation and a dynamic bandwidth allocation. In the former case, the peak rate reduction is achieved by maintaining the accumulated data in the user buffer at a high level, whereas the concept of real demand factor is employed to meet the needs of multi-stream bandwidth allocation in the latter case, Finally, the proposed algorithm's performance was verified with ExSpect 6.41, a Petri net simulation tool.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10a
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• pp.6-8
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• 1998

프로세서와 네트워크의 성능이 향상됨에 따라 이들을 이용한 많은 멀티미디어 응용물들이 개발되었다. 특히 인터넷의 발전은 이러한 멀티미디어 응용물들로 하여금 여러 곳에 분산되어 있는 데이터들을 쉽게 이용할 수 있도록 하였다. 멀티미디어 응용물들이 요구하는 데이터는 그 크기가 크고, 실시간 전송을 요구한다는 특성을 가진다. 따라서 이러한 데이터를 제공하는 서버는 여러 데이터를 다수의 사용자에게 일정한 전송률로 제공할 수 있어야 한다. 본 논문에서는 디스크 배열을 이용하는 주문형 비디오 서버에 있어서 디스크 탐색 시간으로 낭비되는 디스크 대역폭을 최소화하는 논리적 디스크 분할 기법과 이에 적합한 비디오 파일 배치 기업을 제시한다. 추가적으로 얻어진 디스크 대역폭들은 보다 많은 사용자 요구들을 처리하기 위해 사용되거나 비동기적인 사용자 요구들을 처리하는데 이용될 수 있는데, 이를 스트림 지원에 이용할 경우, 평균 3~11%정도의 스트림수 증가가 있음을 모의 실험을 통해 확인하였다.

• The Journal of the Korea Contents Association
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• v.8 no.1
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• pp.169-176
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• 2008

In this paper, we develop radio resource management queueing model in IEEE 802.IS networks considering both connection and packet level. In the upper level connection, we model connection admission control depending on availability of bandwidth and priority queue in each service class. In the lower level packet, we model dynamic bandwidth allocation considering threshold and availability of bandwidth in each service class simultaneously. Hierarchical model is built using an extended Petri Nets, SRN (Stochastic Reward Nets). Bandwidth utilization and normal throughput as performance index for all service classes of traffic are calculated and numerical results are obtained.

• Journal of KIISE:Information Networking
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• v.34 no.2
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• pp.100-109
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• 2007

Streaming protocol with the Available Bandwidth measurement scheme has problems that are to measure a Available Bandwidth uncorrectly and slowly. In this basis, in order to overcome limitations of the previous streaming protocols, we propose the NABO that is a New Available Bandwidth measurement scheme used by OWD(One-Way Delay). Proposed NABO(New Available Bandwidth measurement based on OWD) measures the constant transmission delay occurred by bottleneck link capacity and the variable delay. Competing traffic contribute to the variable delay. Through the measurement of the constant transmission delay and the competing traffic, a NABO can measure the Available Bandwidth correctly and fast in network. The simulation result proves that the proposed NABO has a performance that satisfies both accuracy viewpoint and measurement speed viewpoint.

• Journal of Broadcast Engineering
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• v.23 no.6
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• pp.813-823
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• 2018

UHD content is characterized by higher bandwidth requirements to provide seamless playback. The existing HTTP adaptive streaming scheme periodically requests video segment of lower quality than the available bandwidth in the steady state. In the steady state, the On-Off pattern is repeated due to the difference of the available bandwidth and the encoding rate of the content. And the repeated Off interval is causing the problem that can not efficiently use the available bandwidth. In the wireless environment where the delay and loss rate are higher with large bandwidth fluctuations, this problem is exacerbated because the available bandwidth is estimated inaccurately. Therefore, in this paper, we propose a segment scheduling scheme for efficient bandwidth utilization of UHD contents streaming in wireless environment. Proposed scheme is a group segment that simultaneously reqeusts multiple segments in one request message in order to reduce frequency of OFF interval. Through simulation, Our scheme improves bandwidth utilization.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.9A
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• pp.1563-1573
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• 2001

본 논문에서는 무선 ATM 망에서 멀티 서비스 클래스를 지원하기 위하여 핸드오프로 인한 이동 특성과 호 수준의 QoS를 고려한 동적 무선 자원 관리 기법을 제안하였다. 제안한 기법은 무선 자원을 우선적으로 핸드오프 호에게 할당하고 새로운 호에게도 서비스 확률에 의하여 동적으로 자원을 할당하도록 한다. 서비스 확률은 전체 무선 대역폭, 임계값, 사용중인 무선 대역폭, 이동 특성, 그리고 서비스 클래스별 조정값을 이용하여 동적으로 결정된다. 또한 제안한 기법의 성능을 평가하기 위해 수학적 분석을 실시하였고 핸드오프 호의 강제 종료 확률, 새로운 호의 블록킹 확률, 자원 이용률 관점에서 기존의 기법과 비교하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.11a
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• pp.948-951
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• 2010

네트워크 기술의 발전과 하드웨어의 발전으로 인해 많은 네트워크 응용 서비스 기술이 등장하고 있다. 이 중에서도 IPTV 와 같은 멀티미디어 스트리밍 기술은 그 수요에 의해 기하급수적으로 증가하고 있는 실정이다. 만족할만한 IPTV 서비스를 제공해 주기 위해서는 안정적인 네트워크 자원의 확보가 필수적이다. 이에 본 논문에서는 IPTV 서비스를 위한 네트워크 자원 확보를 위해 기존의 AVB 기술을 기반으로 하여 안정적인 QoS 를 보장하는 방법을 제안한다. IPTV 서비스에 해당하는 각 트래픽에 대한 대역폭 예약 방법과, 대역폭 예약 실패 상황에 대해 처리할 수 있는 개선된 MSRP를 이용하여 IPTV 서비스의 QoS 를 보장하고자 한다. 본 논문의 성능 평가를 위해 OPNET 을 이용하여 기존 방법들에 대한 시간동기의 정확성, 트래픽의 단대단지연, 네트워크 자원 활용률을 측정하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.10A
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• pp.1554-1559
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• 2000

On ATM networks, MPEG video stream is transferred using CBR or VBR services. But because the MPEG video traffic varies greatly from time to time, it is very difficult to transfer the MPEG steam efficiently without loss of transmission bandwidth. Until now, the study on the traffic analysis and control on a single MPEG video stream has been done by many researchers, but the traffic analysis and control on a multiplexed traffic of multiple MPEG video streams has not been studied by any researcher. This paper proposes a multiplexing method to reduce the PCR and traffic variance of a multiplexed traffic of multiple MPEG video streams. By reducing the PCR of the multiplexed traffic, the multiplexed VBR traffic can be transferred efficiently with less loss of transmission bandwidth.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.5
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• pp.943-950
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• 2005

Recently, many of researches on stream transmission for satisfying each of different real-time transmission condition of the multimedia data that demands various service quality through high-speed networks have been studied actively. In this paper, we design a scheme that discriminately reserves the network resources for the transmission of each multimedia application and propose a bandwidth allocation scheme for improving the utilization ratio of free resources. And we also propose a pipelining scheme for providing flexible real-time transmission. The proposed schemes can be used to support a real-time transmission by applying feedback transmission control method based on receiving buffer for guaranteeing the synchronization conditions requested by the multimedia data. Moreover, we propose a transmission control scheme that can take the amount of network resources down to the minimum amount within the range of permissible error-range under the guarantee with no quality degradation simultaneously when the bottleneck is caused by the network congestion. Finally, we propose a dynamic bandwidth smoothing scheme that can smooth the maximum bandwidth to the demand of each video steam for giving continuous transmission to the delay sensitive video steam between senders and receivers.