ATM performance evaluation under transparencies of a distributed system environment (DSE)

The purpose of this paper is to study quality of service (QoS) management and performance monitoring issues in B-ISDN. A QoS framework is proposed in order to satisfy the user's service quality requirements. The basic idea of this QoS framework is that the user's QoS requirement should be represented in terms of objectives set to QoS parameters which are in turn translated into asynchronous transfer mode (ATM) network performance (NP) parameters objectives; then, meeting NP parameters objectives ensures that the user's QoS requirements are fulfilled. Performance monitoring mechanisms based on operation and maintenance (OAM) cells flows in the ATM layer and estimation methods, which are both part of a QoS framework, are reviewed. We focus in particular on the definition and estimation of NP parameters in the case of non-conforming cells transmitted on an ATM connection. Finally, a QoS management scenario for the ATM layer is proposed. >

Broadband networking has evolved dramatically in the past few years. Especially the asynchronous transfer mode (ATM) has attracted attention in the area of high-speed communication, promising the integration of almost all communication profiles such as voice, video and computer-based multimedia communication. As ATM builds the transport technology of broadband integrated services digital network (B-ISDN), it is to be considered as the key technology of the data-highway initiatives aimed by the majority of industrial countries. However, the topic of network security plays an important role in any publicly accessible telecommunication infrastructure. Unfortunately, the progresses made in providing for adequate network security still lag behind the evolution of B-ISDN.In this paper we give an interim report on a project aiming to information privacy in B-ISDN infrastructures. Several approaches to B-ISDN security with emphasis on confidential user-to-user communication are discussed. We compare the different approaches to ATM encryption and propose the application of a method known as ATM cell stream interception. Therefore, we apply an encryption module to an ATM network interface card (NIC) using standardized interfaces and, thus, propose an architecture that is almost independent of the hardware.KeywordsB-ISDN securityATM securityATM cell stream encryption

Broadband Integrated Services Digital Network (BISDN) is conceived as a universal digital network providing both integrated switching and services. Typical services include data, voice, video, high-resolution image, etc. [Spea 87]. Encouraged by developments of fast packet switches [Turn 85] and ATD experiments in France [Deva 88], a packet-oriented virtual circuit transfer mode, called ATM (Asynchronous Transfer Mode), has been adopted as the universal transport vehicle of BISDN services [Minz 89]. Data from various sources are segmented into fixed-size ATM cells and statistically multiplexed to high-speed transmission lines and switches. An ATM cells consists of a 5-octet header and a 48-octet payload fields. Unlike the conventional STM (Synchronous Transfer Mode) technique which switches data according to positions in recurrent structure (frame), ATM cells are switched by labels containing routing information in the headers. Label-based switching is believed to be flexible in integrating diverse traffic types, envisioned for BISDN environments.

High speed Asynchronous Transfer Mode (ATM) wireless networks are assuming a growing interest in the personal communication area [1–6]. This paper describes the design of a wireless ATM system, which is being implemented in the ’’MEDIAN‘‘ project belonging to the European Community (EC) Advance Communications Technologies and Services (ACTS) programme. The Medium Access Control (MAC) aims at providing a simple and efficient transport for ATM cells from a Base Station (BS), interfaced with the ATM Broadband Integrated Service Digital Network (B-ISDN), to ATM Portable Stations (PSs) and vice versa. A Time Division Duplex (TDD) scheme is adopted in which uplink and downlink frame durations can be varied frame-by-frame, in order to fit the present uplink/downlink traffic mix. Moreover, in the uplink, a contention-free based technique is considered in which the slots are assigned to the calls depending on the present load of the PS uplink buffers. The proposed interworking with the ATM network is based on the concept of intercepting the ATM Signalling and Management Cells at the BS, in order to deduce from the ATM Q.2931 messages information relevant to the registration, the call set-up and the MAC procedures.

The the quality of service (QoS) concept is becoming an ever more important issue in telecommunication and computer communication. The article focuses on the QoS notion and concept. The definition of QoS in the International Telecommunications Union-Telecommunications Sector (ITU-T) recommendations and the International Standards Organization (ISO) standards is analysed. Little is known about the asynchronous transfer mode (ATM) performance requirements of the broadband integrated services digital network (B-ISDN) services, especially for multimedia applications. This is because the ATM performance requirements of multimedia applications depend not only on the diverse QoS requirements from application and user, but also on the protocol stacks and scheduling in end systems. Therefore, in order to guarantee QoS to the user, it is necessary to introduce a set of QoS parameters whose properties indicate the nature and requirements of the layered protocol stack. We describe how a proposed QoS framework can be applied to B-ISDN as a specific network. The QoS aspects related to B-ISDN signaling (the control plane) and the QoS aspects related to layer and plane management (the management plane) are described. We also describe how the QoS framework resides in a protocol stack and works together with the B-ISDN network management and signaling.

A possible network architecture for a microcellular mobile telecommunication system based on packet transmission and ATM (Asynchronous Transfer Mode) switching is proposed. A full integration and internetworking with Broadband Integrated Services Digital Network are assumed. The performance of a generic nonblocking ATM switch under input traffic patterns that consider the effect of handovers is evaluated. Special attention is paid to the preservation of packet sequence integrity on a virtual channel. The generic ATM switch architecture has been analyzed under simplified network architecture assumptions by means of computer simulation.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

The number of Internet users continues to increase due to the popularity of the WWW (World Wide Web). Intranets and extranets have also become very popular as they enable the efficient use of data within companies and enhance business processing speed. IP (Internet protocol) packets are used to realize most of these computer communication services. IP belongs to the network layer in the OSI reference model, so the transfer performance of IP is influenced by the technology used in the data link layer under the network layer. One communication technology for the data link layer is ATM (asynchronous transfer mode). ATM technology was researched and recommended for B-ISDN (broadband integrated services digital network). We have been tackling an Internet/intranet/extranet backbone system that offers high speed, high throughput, small delay and low cost by IP/MAC (media access control) over ATM. However we faced the problem that ATM does not completely suit IP packet and MAC frame transfer. For example, there is the "dead cell problem" in which the loss of even one of the ATM cells forming the IP packet causes the loss of the entire packet. There is also the "cell tax problem", in which the overhead of ATM cells is much larger than those of other long distance transfer techniques. Perfect EPD (early packet discard) is impossible because there is no indication bit that means a cell includes the head or tail part of a datagram in the payload. Moreover, intelligent and effective application use is difficult because the cell header has few CLP (cell loss priority) bits. This paper describes the main problems of datagram transfer across existing ATM networks and details a new cell structure that solves these problems. Other issues relating to this remodelling of the existing cell structure are also examined.

Fuzzy-based dynamic bandwidth allocation for heterogeneous sources in ATM networks

Error detection and correction options for data services in B-ISDN (broadband integrated services digital network) are examined. B-ISDN uses the asynchronous transfer mode (ATM) technique for transporting voice, data, and video services. Currently, the ATM cell header size, functions, and adaption layer fields for data services are being standardized in CCITT. Error protection for data payloads will be provided by a per-cell CRC (cyclic redundancy check) field. Different data services may need different degrees of error protection. The authors discuss and analyze different options for error detection and correction by considering various schemes ranging from no error protection to only error detection. Based on the analysis and results presented, a per-cell CRC has been adopted in the adaptation layer for all data services. The per-cell CRC substantially improves cell misdelivery for all data services. For error-insensitive data services, single-bit correction over MID and segment-type fields improves cell loss substantially. At the same time, single-bit correction keeps cell misdelivery sufficiently low (1 in 10/sup 13/ in the worst case). >

The future Integrated Broadband Communications Network (IBCN) will provide high-speed communication capabilities that support a variety of existing and new services. The management of such a complex environment requires innovative management systems. NEMESYS is a project within the European Commission's Research and Development in Advanced Communications in Europe (RACE) program. The project goals are to demonstrate and evaluate the use of advanced information processing techniques for quality-of-service and traffic management. To reach these goals, a series of experimental prototypes are being built. This paper describes the assumptions, objectives, and approach of NEMESYS, and in particular, the design and implementation of an experiment that investigates service and traffic management techniques in a simulated asynchronous transfer mode environment. Because the project is not yet finished, some preliminary results are presented.

Since the asynchronous transfer mode (ATM) has been strongly promoted as the transport structure for broadband integrated services digital networks, a variety of ATM switching architectures have been proposed. The knockout switch, which is one of the well known ATM switches, has a single-stage architecture and adopts an output buffering method. It has excellent traffic performance (cell loss probability, maximum throughput and delay, etc.), but needs many switch elements and buffers. The authors propose an ATM switch, called a knockout switch with input buffers. The proposed switch has almost the same traffic performance as the existing knockout switch but needs fewer switch elements and buffers than the existing knockout switch. The authors analyse the traffic performance and complexity (i.e. the number of switch elements and buffers required) of the proposed architecture by discrete-time Markov chain models and compare them with those of the existing knockout switch. It is found that the proposed architecture could reduce the need for over 40% of the switch elements and over 30% of the buffers while satisfying the given loss requirements.

One of the fundamental challenges facing broadband information transport is to determine congestion control strategies to support multiple classes of traffic in the future asynchronous transfer mode (ATM)-based broadband integrated services digital networks (B-ISDN). To accomplish this in a flexible and a cost-effective manner, priority classes for the different services are commonly used. The authors study priority queueing schemes implemented in a statistical multiplexer with shared and separate buffers, whose input consists of superposition of voice and data traffic. A performance comparison is given for two buffer access schemes: the common nested threshold cell discarding (NTCD) with single shared buffer and NTCD with multiple buffers (NTCD-MB). The arrival process to the multiplexer is approximated using a Markov modulated Poisson process (MMPP). It is shown that when implementing the NTCD-MB priority scheme, the parameters of the switching node can be adjusted in such away that the service quality is guaranteed for different classes of traffic. The improved performance as a result of implementing such scheme is investigated via simulations. >

The evolution of public telecommunication networks toward broadband integrated services digital networks (B-ISDNs) is presented. The asynchronous transfer mode (ATM), which supports B-ISDNs, and the B-ISDN protocol reference model are discussed. It is shown that the service offered by the ATM layer in the B-ISDN protocol reference model is equivalent to the service offered by the OSI physical layer. It is also shown that the service offered by the ATM adaptation layer (AAL) type 3/4 is similar to an OSI data link service. The emergence of the metropolitan area network (MAN) standard as an intermediate support for broadband services and the similarities between the DQDB MAC and the AAL type 3/4 in its connectionless mode are discussed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

The Asynchronous Transfer Mode (ATM) technique has been accepted as a basis for future B-ISDN networks. In ATM networks, all information is packetized and transfered in small packets of fixed length, called cells. The packetized information transfer, without flow control between the user and the network and the use of statistical multiplexing, results in a need of a Policing Mechanism (PM) to control the traffic parameters of each virtual connection in order to guarantee the required Quality of Service (QoS). Policing of the peak cell rate is generally not complex. The control of the mean cell rate is more difficult, but is intended to improve the link utilization when it has to handle bursty traffic sources. Conventional PMs, such as the Leaky Bucket Mechanism (LBM) and the Window Mechanisms (WMs), are not well suited to the bursty nature of sources supported by ATM networks, therefore intelligent PMs are needed. In this paper, we propose a Fuzzy Policing Mechanism (FPM) to police the mean cell rate of the still picture source. We consider the case when the peak cell rate of the still picture source is not controlled separately by other PMs. The performance evaluation via simulations shows that the FPM efficiently controls the mean cell rate of the still picture source. The FPM has better responsiveness and selectivity characteristics than the LBM.

Due to the connection-oriented nature of the asynchronous transfer mode (ATM), one of the challenges in mobile wireless ATM (WATM) systems is the management of terminal handovers. When ATM connections are reestablished to follow terminals moving between areas covered by distinct base stations, seamless handover protocols are necessary to guarantee that ATM cells are delivered to terminals in the correct order, with cell loss rate and delay that satisfy the contracted quality of service (QoS). A promising approach to meet QoS requirements is based on the use of handover buffers at the (destination) base station, where transmitted cells are stored while the connection is being reestablished. Up to date, only simulation and experimental results are available to determine the performance of such protocols and buffering schemes. This paper presents the first attempt to develop an analytical modeling approach to estimate the performance of handover protocols making use of handover buffers at the base station. By incorporating several approximations, the proposed models allow designers to simultaneously take into account numerous system parameters, including handover buffer size, sustainable and peak cell rates of the ATM connection, terminal offered load, and time needed to reestablish the ATM connection. Analytical performance predictions are shown to closely match results of detailed simulation experiments, thus demonstrating the suitability of the proposed modeling framework for the selection of the most adequate solution to handle handover and provide the QoS required by end users.