• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.5 no.4
• /
• pp.716-722
• /
• 2001

This paper has defined the 3G and beyond wireless networks as the one that is based on IP network architecture and proposed the congestion control scheme in the access networks. Basically the proposed method is built on the ECN(Explicit Congestion Notification) and utilizing the advantages of the wireless and I networks in broadcasting packet in their access network. Consequently it provides the efficiency in controlling the congestion that can be happened by the mobility support in the future wireless networks.

• Proceedings of the IEEK Conference
• /
• summer
• /
• pp.189-192
• /
• 2004

This paper focuses on a TCP window-based flow control mechanism with Explicit Congestion Notification (ECN). We investigate the fundamental problem of achieving a fair window control for TCP, which cooperates with ECN. This is done by using feedback congestion pricing as a means of estimating the state of bottleneck router. The problem is solved by achieving network optimal performance, which maximize the total user utilities. We then look at the simulation of such scheme.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.16 no.1
• /
• pp.129-137
• /
• 2016

Transmission Control Protocol as a transport layer protocol provides steady data transfer service. There are some serious concerns about the performance of TCP over diverse networks. The vital concern in TCP network environment is congestion which may occur due to quick transmission rates or because of large number of new connections entering the network at the same time. Size of queues in routers grows thus resulting in packet drops. Retransmission of the dropped packets, and reduced throughput can prove costly. Explicit Congestion Notification (ECN) in conjunction with Active Queue Management mechanisms (AQM) such as Random early detection (RED) is used for packet marking rather than dropping. In IP packet header ECN bits can be added as a sign of congestion thus avoiding needless packet drops. The proposed ECN and AQM mechanism can be implemented with help of ns2 simulator and the performance can be tested on different TCP variants.

• Proceedings of the KIEE Conference
• /
• 2002.11c
• /
• pp.27-30
• /
• 2002

In this paper, we propose a window-based congestion control algorithm to achieve a fair sharing of the available bandwidth in ECN capable heterogeneous TCP networks with a single bottleneck link. The proposed algorithm is based on extracting the network status from the successive binary congestion information provided by ECN. From the explicit network information, we estimate the fair window size proportional to the propagation delay. Through simulations, the effect and performance of the proposed algorithm are shown for the heterogeneous networks.

• The KIPS Transactions:PartC
• /
• v.12C no.4 s.100
• /
• pp.559-570
• /
• 2005

ECN is accurate in determining traffic congestion since it explicitly notifies the incipient congestion. Therefore, ECN method has been thoroughly studied in the field of wireless TCP. This paper introduces a formula to find the optimal threshold for ECN marking. We have implemented a Petri net model of 'TCP with ECN strategy' and performed simulations on it in order to verify the validity of the formula. We have also introduced ideas of applying the formula in practice. The primary contribution of this paper is proposing a formula to find the optimal threshold for ECN marking. However, introducing the Petri net model of 'TCP with ECN strategy' is no less valuable contribution because it can be helpfully used by the researchers in studying network protocols. We have built the Petri net model by modifying the existing Petri net model of TCP. In order to add ECN strategy to the existing model, we have mainly modified the network part. We have also modified sender part and receiver part as well.

• 제어로봇시스템학회:학술대회논문집
• /
• 2004.08a
• /
• pp.474-479
• /
• 2004

This paper describes a feedback-based congestion control algorithm to improve TCP performance over wireless network. In this paper, we adjust the packet marking probability at the router for Max-Min fair sharing of the bandwidth and full utilization of the link. Using the successive ECN (Explicit Congestion Notification), the proposed algorithm regulates the window size to avoid the congestion and sees the packet loss only due to the wireless link error. Based on the asymptotic analysis, it is shown that the proposed algorithm guarantees the QoS of the wireless TCP. The effectiveness of the proposed algorithm is demonstrated by simulations.

• Journal of KIISE:Computing Practices and Letters
• /
• v.8 no.3
• /
• pp.336-343
• /
• 2002

Nowadays, after appearance of wireless network the existent internet environment is changing into the united wire/wireless network. But the present TCP regards all of the packet losses on transmission as the packet tosses due to the congestion. When it is applied on the wireless path, it deteriorates the end-to-end TCP throughput because it regards the packet loss by handoff or bit error as the packet loss by the congestion and it reduces the congestion window. In this paper, for solving these problems we propose the method that controls the performance of TCP on the wireless link by extending ECN which is used as a congestion control mechanism on the existent wire link. This is the method that distinguished the packet loss due to the congestion from due to bit error or handoff on the wireless network, so it calls the congestion control mechanism only when there occurs the congestion in the united wire/wireless network.

• Journal of KIISE:Computing Practices and Letters
• /
• v.16 no.2
• /
• pp.227-231
• /
• 2010

The TFRC is a congestion control mechanism which supports the requirements of video streaming applications and controls its sending rate by using the information such as loss event rate and RTT (round-trip time). However, TFRC has a performance degradation in wireless networks because it performs congestion control by judging all the losses occurred in wireless network as a congestion signal. In this paper, we propose new loss discrimination mechanism which is using ECN in order to solve the performance degradation of TFRC. Through the results of simulation, we proved that the proposed mechanism can improve the performance of TFRC.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.28 no.12B
• /
• pp.1081-1090
• /
• 2003

NGI(Next Generation Internet) is characterized by QoS(Quality of Service) and high speed transmission. Recently, DiffServ and MPLS become most influential NGI architecture. To guarantee end-to-end QoS, it is essential for NGI to interwork MPLS with DiffServ. Here, MPLS WG(Working Group) in IETF(Internet Engineering Task Force) proposed the method of E-LSP(EXP inferred-PSC LSPs) and L-LSP(Label-Only-Inferred PSC LSPs), but both of them have serious problems to satisfy perfect interworking. In this paper, we proposed an extended E-LSP architecture that supports Perfect DiffServ class and experimental function in MPLS such as ECN(Explicit Congestion Notification) capability. We verify that the proposed E-LSP architecture improves QoS in NGI by using ns2 simulator.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.8 no.3
• /
• pp.762-777
• /
• 2014

With the increasing usage of cloud applications such as MapReduce and social networking, the amount of data traffic in data center networks continues to grow. Moreover, these appli-cations follow the incast traffic pattern, where a large burst of traffic sent by a number of senders, accumulates simultaneously at the shallow-buffered data center switches. This causes severe packet losses. The currently deployed TCP is custom-tailored for the wide-area Internet. This causes cloud applications to suffer long completion times towing to the packet losses, and hence, results in a poor quality of service. An Explicit Congestion Notification (ECN)-based approach is an attractive solution that conservatively adjusts to the network congestion in advance. This legacy approach, however, lacks scalability in terms of the number of flows. In this paper, we reveal the primary cause of the scalability issue through analysis, and propose a new congestion-control algorithm called FaST. FaST employs a novel, virtual congestion window to conduct fine-grained congestion control that results in improved scalability. Fur-thermore, FaST is easy to deploy since it requires only a few software modifications at the server-side. Through ns-3 simulations, we show that FaST improves the scalability of data center networks compared with the existing approaches.