• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.3
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• pp.27-36
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• 2012

With the increase of various user's requirements, lots of interesting applications on the Internet have been emerging recently. However, Internet has many limitations for providing upcoming new services because it was only designed to provide basic connectivity between research networks and simplified forwarding functions at the first time. Internet has many problems in the aspects of routing scalability, mobility, security and QoS, so lots of researches are being actively performed in many countries to solve these problems. In this paper, we implement RED(Random Early Detection) scheduler using NetFPGA platform and local testbed to provide active queue management. Using the implemented RED scheduler, packets are dropped according to the specified drop probability, so Global Synchronization coming from simultaneous TCP segment losses in a congestion condition can be prevented. With the comparison to the Drop-Tail scheme in the basic router, we show TCP performance can be enhanced in the congestion situation using the NetFPGA-based RED scheduler.

• Journal of KIISE:Information Networking
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• v.31 no.1
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• pp.70-80
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• 2004

In order to reduce the increasing packet loss rates caused by an exponential increase in network traffic, the IETF(Internet Engineering Task Force) is considering the deployment of active queue management techniques such as RED(Random Early Detection). But, RED configuration has been a problem since its first proposal. This problem is that proposed configuration is only good for the particular traffic conditions studied, but may have detrimental effects if used in other conditions. While active queue management in routers and gateways can potentially reduce packet loss rates in the Internet, this paper has demonstrated the inherent weakness of current techniques and shows that they are unstable for tile various traffic conditions. The inherent problem with these queue management algorithms is that they all use static parameter setting. In this paper, in order to solve this problem, a new active queue management algorithm called SQM(Stabilized Queue Management) is proposed. This paper shows that it is easy to parameterize SQM algorithm to perform well under different congestion scenarios. This algorithm can effectively reduce packet loss while maintaining high link utilizations and is good for the various traffic conditions.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10c
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• pp.427-429
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• 2001

최근 라우터에서는 정체를 회피하고 전송률을 향상시키기 위한 능동적 큐 관리와 패킷 스케줄링에 대한 많은 논의가 이루어지고 있다. 본 논문은 라우터에서의 전송률 향상을 위한 Random Early Detection (RED) 알고리즘과 최근가지 변형된 RED알고리즘들의 특징을 살펴보고, RED라우터에 적용하여 실제로 종단 호스트(End-to-end)에서 전송 받는 패킷의 양을 창상하기 위한 선별적 처리 알고리즘을 제안한다.

• Journal of KIISE:Information Networking
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• v.30 no.3
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• pp.437-447
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• 2003

In order to reduce the increasing packet loss rates caused by an exponential increase in network traffic, the IETF(Internet Engineering Task Force) is considering the deployment of active queue management techniques such as RED(Random Early Detection) algorithm. However, RED algorithm simple but does not protect traffic from high-bandwidth flows, which include not only flows that fail to use end-to-end congestion control such as UDP flow, but also short round-trip time TCP flows. In this paper, in order to solve this problem, we propose a simple fairness queue management scheme, called AFQM(Approximate Fair Queue Management) algorithm, that discriminate against the flows which submit more packets/sec than is allowed by their fair share. By doing this, the scheme aims to approximate the fair queueing policy Since it is a small overhead and easy to implement, AFQM algorithm controls unresponsive or misbehaving flows with a minimum overhead.

• The Journal of the Korea Contents Association
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• v.10 no.3
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• pp.80-91
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• 2010

Due to the convergence of broadcasting and communications, IPTV services are spotlighted as the that next-generation multimedia services. IPTV services should have functionality such as unlimited channel capacity, extension of media, QoS awareness and are required increasing traffic and quality control technology to adapt the attributes of IPTV service. Consequently, flow based quality control techniques are needed. Therefore, many studies for providing Internet QoS are performed at IETF (Internet Engineering Task Force). As the buffer management mechanism among IP QoS methods, active queue management method such as RED(Random Early Detection) and modified RED algorithms have proposed. However, these algorithms have difficulties to satisfy the requirements of various Internet user QoS. Therefore, in this paper we propose the Flow based AQM(Active Queue Management) algorithm for the multimedia services that request various QoS requirements. The proposed algorithm can converge the packet loss ratio to the target packet loss ratio of required QoS requirements. And we present a performance evaluation by the simulations using the ns-2.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.6B
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• pp.605-614
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• 2009

Existing Internet services were almost supported by the best effort service such as the data transmission service and were allowed the transmission delay and packet loss. However, recent Internet multimedia services such as Internet phone, Internet broadcasting are required a real-time processing and high bandwidth. Therefore, many studies for providing Internet QoS are performed at IETF (Internet Engineering Task Force). As the buffer management mechanism among IP QoS methods, active queue management method such as RED (Random Early Detection) algorithm has proposed. However, RED algorithm has a limitation of usage of an average buffer length and unfairness. So, many algorithms proposed as the modified algorithm of RED. But these modified algorithms also have difficulties to satisfy the requirements of various Internet user QoS. Therefore, in this paper we propose the QoS adaptive AQM (Active Queue Management) algorithm for the multimedia services that request various QoS requirements and present a performance evaluation by the simulations using the ns-2.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.121.1-121
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• 2001

Congestion control is a critical issue in TCP networks, Recently, active queue management (AQM) was proposed for congestion control at routers. The random early detection RED algorithm is widely known in the AQM algorithms, We present an adaptive nonlinear RED (NRED) algorithm, which has nonlinear drop probability profile. The proposed algorithm enhanced the performance of the RED algorithm by the self-parameterization based on the traffic load Furthermore, the proposed algorithm can effectively adapt itself between he RED and the drop-tail queue management by adopting proper nonlinearity in the drop probability profile. Through simulation, we show the effectiveness of the proposed algorithm comparing with the drop-tail and the original RED algorithm.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.4C
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• pp.308-315
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• 2002

Guaranteed frame rate (GFR) service has been defied to provide minimum cell rate (MCR) guarantees for virtual connections (VCs) carrying Internet traffic in ATM networks and allow them to fairly share residual bandwidth. The simplest switch implementation mechanism to support the GFR service in ATM networks consists of the frame-based generic cell rate algorithm (F-GCRA) frame classifier and the early packet discard (EPD)-like buffer acceptance algorithm in a single FIFO buffer. This mechanism is simple, but has foiled to guarantee the same bandwidth as an MCR to a VC that has reserved a relatively large MCR. This paper applies the packet spacing scheme to TCP traffic to alleviate its burstness, so as to guarantee a larger MCR to a VC. In addition, the random early detection (RED) scheme is added to the buffer acceptance algorithm in order to improve fairness in use of residual bandwidth. Simulation results show that the applied two schemes improve a quality of service (QoS) in the GFR service for the TCP traffic.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.159-162
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• 2005

Random Early Detection (RED), one of the most well-known Active Queue Management (AQM), has been designed to substitute Tail Drop and is nowadays widely implemented in commercially available routers. RED algorithm provides high throughput and low delay as well as a solution of global synchronization. However RED is sensitive to parameters setting, so the performance of RED, significantly depends on the fixed parameters. To solve this problem, the Adaptive RED (ARED) algorithm is suggested by S. Floyd. But, ARED also uses fixed parameters like target-queue length; it is hard to respond to bursty traffic actively. In this paper, we proposed AQM algorithm based on the variation of current queue length in order to improve adaptability about burst traffic. We measured performance of proposed algorithm through a throughput, marking-drop rate and bias phenomenon. In experimentation, we raised a packet throughput as reduced packet drop rate, and we confirmed to reduce a bias phenomenon about bursty traffic.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10c
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• pp.409-411
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• 2001

기존의 인터넷 라우터는 Drop tail 방식으로 패킷을 관리한다. 따라서 네트워크 트래픽의 지수적인 증가로 인한 혼잡 상황으로 발생하는 패킷 손실을 해결 한 수 없다. 이 문제를 해결하기 위해 IETF (Internet Engineering Task Force)에서는 REU(Random Early Detection) 알고리즘과 같은 능동적인 큐 관리 알고리즘을 제시하였다. 하지만 RED 알고리즘은 네트워터 환경에 따른 매개 변수의 설정의 어려움을 가지고 치어 잘못 된 매개변수 설정으로 인하여 네트워크 성능이 저하되는 문제점을 가지고 있다. 본 논문에서는 기존의 RED를 개선한 ARED를 제안했다. ARED는 RED 알고리즘의 문제점을 개선하여 네트워크 특성에 맞추어 동적으로 매개변수글 조절하는 알고리즘이다. ns를 이용한 실험을 통하여 ARED의 성능을 검증하였다.