• Title/Summary/Keyword: Priority Mechanism

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Performance Analysis of ATM Switch with Priority Control Mechanisms (우선순위제어기능을 가진 ATM스위치의 성능 분석)

  • 장재신;신병철;박권철
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.18 no.8
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    • pp.1190-1200
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    • 1993
  • In this work, the performance of both delay sensitive traffics and loss sensitive traffics of the output buffered ATM switch with priority control mechanisms has been evaluated. We choose the partial buffer sharing mechanism as the loss priority control mechanism and the HOL(Head Of Line) priority control mechanism as the time priority control mechanism. We model loss sensitive traffics with Poisson process and delay sensitive traffics with MMPP. With loss priority control, it is confirmed that loss probability of loss sensitive traffice decreases when the loss priority control mechanism is chosen. With time priority control, it has also been confirmed that mean cell delay of delay sensitive traffics decreases when the HOL priority control mechanism is used. From this analysis, It has been confirmed that the requirements of QOS for both loss sensitive and delay sensitive traffics can be satisfied in the ATM switch by combining both the loss priority control mechanism and the HOL priority control mechanism.

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Dynamic and Strict Packet Dropping Mechanism for Assured Forwarding Classes (Assured Forwarding 클래스를 위한 동적 엄격 패킷 폐기 메커니즘)

  • Kim, Su-Yeon;Lee, Ho-Gyun;Kim, Cheol-Beom
    • The Transactions of the Korea Information Processing Society
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    • v.6 no.11S
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    • pp.3251-3259
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    • 1999
  • In this paper, we present a new mechanism applying more strict priority than RIO mechanism proposed as a drop precedence policy of AF classes in differentiated services. In this mechanism, applying strict priority to drop precedence policy, we get better performance on priority level. Simulation results indicate that the proposed mechanism may provide more efficient and more strict priority transmissions as compared to RIO regardless of traffic load.

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A Study on the Performance of Priority Mechanisms in ATM Multiplexer (ATM 멀티플렉서에서의 우선순위 메카니즘에 관한 연구)

  • 윤성호;박광채;이재호
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.18 no.6
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    • pp.779-792
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    • 1993
  • In a switching node or an ATM multiplexer of the ATM network, a good bandwidth utilization can be achieved by the priority control using the 1-bit(Cell Loss priority) in ATM cell header. In this paper, the mixed mechanism is proposed to make up for shortcomings of existing space priority control mechanisms and to decrease the loss probability of high priority cell and its performance is analyzed about the cell loss probability. To estimate the performance of proposed mixed mechanism, its cell loss probability is compared with those of non-priority mechanism, push-out mechanism and partial buffer sharing mechanism. The cell loss probability is analyzed using a M/D/1/N modeling and a 2-state MMPP/D/1/N modeling and also comparison between two modelings is made. To verify this result of numerical analysis, the computer simulation is performed for each mechanism using the simulation language, SIMSRIPT II.5.

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A Study on PBS Mechanism with Two-Threshold in ATM Networks (ATM망에서 두 개의 임계값을 갖는 PBS 기법에 관한 연구)

  • 정현숙;신효영;박호균;류황빈
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.19 no.1
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    • pp.56-65
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    • 1994
  • As a method to control the congestion, priority mechanism which gives two-level priority to various traffics using CLP bit in cell haeder is carried in ATM network. In this paper, we proposed PBS(partial buffer sharing) mechanism with two threshold for provide three-level priority using CLP bit and Res. bit. By performance analysis proposed mechanism, we knew that provides flexibility to satisfy requirements of various quality of service, compare to existing mechanism with two-level priority.

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The Number of ONU based Priority Scheduling Mechanism for IPTV Multicast Service (IPTV 멀티캐스트 서비스를 위한 ONU 수 기반 우선순위 스케줄링 기법)

  • Kwon, Young-Hwan;Choi, Jun-Kyun
    • The KIPS Transactions:PartC
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    • v.16C no.2
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    • pp.217-222
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    • 2009
  • This paper proposes the number of Optical Network Unit (ONU) based priority scheduling mechanism over Ethernet Passive Optical Network (EPON) to support multicast Quality of Service (QoS) for Internet Protocol Television (IPTV) service. Multicast QoS is effected by the receivers' number of a packet because multicast efficiency is determined by how many receivers are received multiple copied packets. Therefore, the proposed mechanism assigns a priority with the number of ONUs to allocate high priority to IPTV services used by many people and firstly transmits a packet with high priority. By doing so, we show that the proposed mechanism support favorite IPTV services with better and stable QoS in spite of congestion.

Performance evaluation of ATM switch with space priority control mechanism (우선순위 기능을 가진 ATM스위치의 성능분석)

  • 장재신;신병철
    • Proceedings of the Korean Institute of Communication Sciences Conference
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    • 1991.10a
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    • pp.141-144
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    • 1991
  • In this paper, we analyze the performance of ATM switch with output buffer which has a space priority control mechanism. As we assumed that the input traffic consists of loss tolerable voice and loss sensitive data, we modeled it with MMPP(Markov Modulated Poisson Process). We confirmed that the loss probability of loss sensitive traffic decreases when we use the space priority control mechanism.

A Message Priority-based TCP Transmission Algorithm for Drone Systems (드론 시스템을 위한 메시지 우선순위 기반 TCP 통신 알고리즘)

  • Choi, Joon-Hyuck;Kim, Bo-Ram;Lee, Dong-Ik
    • The Journal of the Korea institute of electronic communication sciences
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    • v.13 no.3
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    • pp.509-516
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    • 2018
  • TCP is a well-known communication protocol which is widely used for reliable message transmissions. The urgent mechanism of TCP plays a key role to transmit messages with a high priority. If a high priority message occurs at the transmitting node, the urgent mechanism informs the receiving node about the presence of a high priority message prior to its transmission so that the receiving node can be prepared for handling this message in advance. This implies that the existing urgent mechanism of TCP does not guarantee an immediate or faster delivery of the high priority message itself. Therefore, the ability of priority-based transmission is required on TCP not only to ensure reliable transmissions of normal messages but also to offer a differentiated service according to the priority of message. This paper presents a priority-based transmission algorithm over TCP using a priority queue in a multi-threaded environment. The effectiveness of the proposed algorithm is explored using an experimental setup in which various messages with different priority levels are transmitted.

Priority-based Overlay Multicast for Distributed Interactive Application (Distributed Interactive Application을 위한 우선 순위 기반 오버레이 멀티캐스트)

  • Lee, Hyung-Ok;Nam, Ji-Seung
    • Proceedings of the Korea Information Processing Society Conference
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    • 2013.11a
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    • pp.1367-1369
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    • 2013
  • Applying Application-Level Multicast technology (ALM) to Distributed Interactive Applications (DIAs) becomes more and more popular. Especially for DIAs embedded priority that the sender forwards data to receivers due to their respective priorities. The priority-based directed minimum spanning tree (PST) algorithm was designed for these DIAs. However, the PST has no efficient priority selection and filtering mechanism. The system will consume a tremendous amount of resource for reconstructing distribution tree and becomes unstable and unscalable. In this paper, First, We propose a novel priority-based application level multicast algorithm: Predict-and-Quantize for Priority with directed minimum Spanning Tree (PQPST), which can efficiently predict efficient priorities for the receivers and quantize the predicted priorities to build the multicast distribution tree. Second, we propose Priority Discrepancy Heuristic Mechanism (PDHM), which sets different thresholds of priority discrepancy within the priority discrepancy interval to control the distribution tree construction can efficiently decrease the repeated distribution tree construction, and we get the best heuristic priority discrepancy interval by PQPST. According to the simulation results, the PQPST and PDHM can efficiently improve the performance of the PST algorithm.

Priority MAC based on Multi-parameters for IEEE 802.15.7 VLC in Non-saturation Environments

  • Huynh, Vu Van;Le, Le Nam-Tuan;Jang, Yeong-Min
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.37 no.3C
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    • pp.224-232
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    • 2012
  • Priority MAC is an important issue in every communication system when we consider differentiated service applications. In this paper, we propose a mechanism to support priority MAC based on multi-parameters for IEEE 802.15.7 visible light communication (VLC). By using three parameters such as number of backoff times (NB), backoff exponent (BE) and contention window (CW), we provide priority for multi-level differentiated service applications. We consider beacon-enabled VLC personal area network (VPAN) mode with slotted version for random access algorithm in this paper. Based on a discrete-time Markov chain, we analyze the performance of proposed mechanism under non-saturation environments. By building a Markov chain model for multi-parameters, this paper presents the throughput and transmission delay time for VLC system. Numerical results show that we can apply three parameters to control the priority for VLC MAC protocol.

The enhance driority transfer control mechanism for multimedia communication in ATM networks (ATM 망에서 멀티미디어 통신을 위한 EPT(enhanced priority transfer)제어기법)

  • 박성호;박성곤;최승권;조용환
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.23 no.9A
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    • pp.2249-2257
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    • 1998
  • In this paper, we propose the enhanced priority control algorithm that adaptively controls the cell service ratio according to the relative cell occupancy ratio of buffer. The asynchronous transfer mode (ATM) provides the means to support various multimedia services in broadband networks. To support multimedia services, various data traffics of different priorities should be controlled effectively. And also it needs congestion control functions required in the netowrk to carry out the control operation. To accomplish this in a flexible and effective manner, priority classes for the different services ar ecommonly used. The proposed enhanced priority control mechanism have two service calsses of the delay sensitive class and the loss sensitive class. The simulation results show that te proposed control mechanism improves the QoS, the charateristics of cell loss probability and mean cell delay time, by selecting propeor relativ ecell occupancy ratio of buffer and the average arrival rate.

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