Real-time multimedia over ATM: RMOA

RMOA is a new ATM Forum standard addressing the transport of H.323 VoIP traffic over ATM-based Internet backbones. It defines a new H.323 gateway devised to carry H.323 real-time media streams by taking advantage of the quality of service features of ATM. The approach is extremely efficient in that it reduces the protocol overhead on the ATM transport     

Overview of implementing ATM based enterprise local area networkfor desktop multimedia computing

The authors discuss important implementation issues in an ATM-based enterprise network, and propose possible migration strategies for the smooth introduction of ATM into the desktop computing environment. They present the ATM traffic service classes and the associated traffic management functions. The authors cover the latest ATM forum standardization efforts on traffic management functions and LAN emulation. Finally, they discuss how to seamlessly support the existing transport control protocol (TCP)/Internet protocol (IP) in an ATM environment     

Traffic management of multimedia over ATM networks

Multimedia is characterized by bursty traffic and often stringent real-time constraints. Multimedia traffic requires quality of service guarantees. This gives rise to traffic management issues in order to obtain high network utilization and quality of service guarantee to the multimedia stream. The aim of this article is to present an overview of the traffic management issues and their possible solutions for transmission of multimedia over asynchronous transfer mode networks     

Isochronous Ethernet-an ATM bridge for multimedia networking

A bridge between ISLAN16-T and ATM networks, where all multimedia networking technical requirements can be addressed, lets multimedia applications run between users residing across local area and wide area connections. We discuss a bridging method for transmitting integrated audio, video, and data for multimedia applications spanning ISLAN16-T in the local area network and ATM in the wide area network     

Securing multimedia services over satellite ATM networks

In recent years there has been increasing interest in interconnecting satellite and ATM networks, because both share common characteristics of the ability to provide bandwidth-on-demand and flexibility of integrating voice, video and data services. There are several new satellite constellation proposals that support multimedia service and transport ATM traffic. For a successful implementation of such systems it is essential to address the security requirements of users, satellite ATM network operators and multimedia service providers. In order to minimize delay and the cost of implementing security systems for satellite ATM networks, the network operator role (in security services) can be limited to the mutual authentication with satellite users during call set-up periods. In this paper a mutual authentication protocol between the user and the satellite network is presented using digital signature and public key systems. Also, another mutual authentication protocol between the user and the service provider is presented to provide end-to-end authentication and negotiation of security options such as selecting a secret key system and the key length. Finally, a detailed hardware implementation of ATM cell payload encryption is presented using the DES/TripleDES secret key system. © 1998 John Wiley & Sons, Ltd.     

Protocol architecture for multimedia applications over ATM networks

At the data-link layer, ATM offers a number of features, such as high-bandwidth and per-session quality-of-service (QoS) guarantees, making it particularly attractive to multimedia applications. Unfortunately, many of these features are not visible to applications because of the inadequacies of existing higher-level protocol architectures. Although there is considerable effort underway to tune these protocols for ATM networks, we believe that a new ATM-specific protocol stack is essential to effectively exploit all the benefits of ATM. We describe the semantics of such a protocol stack, and discuss its advantages over traditional protocol architectures from the perspective of multimedia applications. The performance impact of the new protocol architecture is experimentally demonstrated on a video conferencing testbed built around IBM RS/6000's equipped with prototype hardware for video/audio processing, and connected via ATM links     

ATM and AAL layer issues concerning multimedia applications

This paper presents an overview of the facilities that should be provided by theAtm layer and the adaptation layer (Aal) in order to support multimedia communications. From the analysis of data flows generated by well known multimedia applications and the services that could be offered byAtm networks both in the public and the private domain, we propose solutions enabling the availability of such applications onAtm networks taking into account both economical andQos parameters.     

Prototyping an ATM adaptation layer in a multimedia terminal

This paper describes the implementation of a prototype ATM adaptation layer (AAL) within the kernels of two machines running Sun Operating System 4.1.1. The implementation is achieved by using the STREAMS paradigm and an Ethernet link between the two machines as a surrogate optical fibre link. The flexibility of the STREAMS facility for building layered protocols, and the real-time performance limitations of the STREAMS scheduling system are identified. STREAMS is shown to be no less susceptible to naïve buffer utilization than earlier paradigms. It is necessary to minimize message passing and copying of data to achieve high throughput. This study has clarified several key issues in the functional design of AALs.     

基于神经网络的ATM网络多媒体流拥塞控制

提出了一种在用户-网络接口（UNI）处利用神经网络方法实现ATM网络多媒体流拥塞控制的新方法。在该方法中，控制器输出为信源编码率及其对应的用户百分比，即根据信源编码率及对应的用户百分比调整进入复用缓冲器多媒体流速率，从而克服了以往拥塞控制方法中仅仅调整编码率带来的对所有信源进行整体调整的缺陷，使摔制系统在信元丢失率最小情况下保证了多媒体流的质量，从而有效地利用了网络资源。本文还给出了两种实现方式，方式1中，神经网络输出层变量包括编码率及对应用户百分比，由连续编码率量化成离散值；方式2中，神经网络输出层变量只有连续的编码率，然后通过一定的换算公式计算出离散的编码率和对应的用户数。这两种实现方式中，方式1较为直观，但比方式2复杂。对话音流、视频流的仿真表明方法的有效性。     

Wireless ATM: An enabling technology for multimedia personal communication

An ATM-based wireless network capable of supporting integrated voice, video and data services with Quality-of-Service (QoS) control is proposed as a key element of the future distributed multimedia computing scenario. A specific architecture for wireless ATM is described, and design issues are briefly discussed for each major functional layer of the network. The system approach is based on the incorporation of wireless channel specific medium access, data link and wireless control layers into a mobility-enhanced ATM protocol stack. Selected software emulation results are given for applicable Medium access Control (MAC) and Data Link Control (DLC) protocols. The paper concludes with a brief view of related ongoing prototyping activities aimed at demonstrating a seamless wired plus wireless multimedia networking environment.Presented in part at: Wireless Communications Seminar, Hong Kong IEEE/City U., Jan. 5, 1995, and 2nd Intl. Workshop on Mobile Multi-Media Communications, Bristol, UK, April 11–13, 1995.     

Design of a power-spectrum-based ATM connection admissioncontroller for multimedia communications

This paper proposes a power-spectrum-based connection admission controller design in asynchronous transfer mode (ATM) switches for multimedia communications. The controller contains a power-spectrum-indexed table for managing multimedia call requests, where traffic characteristics of call requests are described by the power spectrum. The power-spectrum can be obtained from the claimed traffic parameters of peak rate, mean rate, and peak rate duration; the power-spectrum has been shown to have a dominant effect on system performance. The results show that the proposed power-spectrum-based connection admission control method achieves higher system utilization and lower call-blocking probability than the equivalent-capacity allocation method     

Project EXODUS: Experimental mobile multimedia deployment in ATM networks

This paper reports on European Commission sponsored research within the EXODUS project. The project carries out research in the context of the evolution towards UMTS and performs personal and terminal multimedia mobility experiments using fixed and wide-band radio access in an international ATM network. After introducing the EXODUS platform and services, the paper presents an IN-based functional model which is suitable for support of mobile multimedia services in ATM networks. Interworking and mobility management issues are discussed, and information flows for call handling are presented. The paper includes a presentation of the mobility management and enhanced INAP protocols which have been developed by the EXODUS project. This revised version was published online in July 2006 with corrections to the Cover Date.     

A multiple access scheme for multimedia traffic in wireless ATM

This paper proposes a multiple access scheme for the forthcoming wireless ATM (Asynchronous Transfer Mode) system. Such ATM compatible wireless systems are motivated by the rapidly increasing demand for wireless extensions to broadband networks, which are expected to support mixed broadband services including Constant Bit Rate (CBR), Variable Bit Rate (VBR), and Available Bit Rate (ABR) traffic. Since these different traffics have very different performance requirements, the multiple access scheme design is very challenging. In this paper, we propose a multiple access scheme called Dynamic Time Division Multiple Access with Piggybacked Reservation (DTDMA/PR), attempting to achieve higher statistical multiplexing efficiency in the mixed VBR/CBR/ABR traffic scenario. The basic idea is to exploit two levels of reservation. The first level deals with the isochronous nature of CBR and VBR traffic and the bursty nature of ABR traffic by using the ALOHA reservation procedure. The second level exploits the piggybacked reservation approach to cope with the dynamic feature of VBR traffic in order to increase the multiplexing efficiency. An analytical model is also developed in this paper and verified by simulation. Numerical examples are given to gain some insight into the protocol itself.     

与多媒体信源模型弱相关的ATM复接器监管方案

本文提出一种与信源模型弱相关的复接器监管方案－－采用模糊漏桶控制方法改变令牌产生速率,对多媒体信源接入实施动态带宽分配。用ＭＭＢＰ模型及其合成讨论了该方案的可能性给出了模糊控制方案和规则,计算机仿真表明,在多个不同速率不同特性的语音、图像、数据信源接入时延该方法能很好地满足低时延低丢失的要求,提高带宽利用率,傅诉异步和编者复用特性被有效、充分地利用。     

WATMnet: a prototype wireless ATM system for multimedia personalcommunication

A prototype microcellular wireless asynchronous transfer mode network (WATMnet) capable of providing integrated multimedia communication services to mobile terminals is described in this paper. The experimental system's hardware consists of laptop computers (NEC Versa-M) with WATMnet interface cards, multiple VME/i960 processor-based WATMnet base stations, and a mobility-enhanced local-area ATM switch. The prototype wireless network interface cards operate at peak bit-rates up to 8 Mb/s, using low-power 2.4 GHz industrial, scientific, and medical (ISM)-band modems. Wireless network protocols at the portable terminal and base station interfaces support available bit rate (ABR), variable bit rate (VBR), and constant bit rate (CBR) transport services compatible with ATM using a dynamic time-division multiple-access/time-division duplex (TDMA/TDD) MAC protocol for channel sharing and data link control (DLC) protocol for error recovery. A custom wireless control protocol is also implemented between the portable and base units for support of radio link related functions such as user registration and handoff. All network entities including the portable, base and switch use a mobility-enhanced version of ATM (“Q.2931+”) signaling for switched virtual circuit (SVC) connection control functions, including handoff. In the first stage of the prototype, the application-level API is TCP/UP over ATM ABR service class using AAL5. Early experiments with the WATMnet prototype have been conducted to validate major protocol and software aspects, including DLC, wireless control, and mobility signaling for handoff, Selected network-based multimedia/video applications requiring moderate bit-rates (~0.5-1 Mb/s) in the ABR mode have been successfully demonstrated on the laptop PC     

Probabilistic burstiness-curve-based connection control forreal-time multimedia services in ATM networks

In this paper we present a method to establish real-time connections with guaranteed quality of service (QOS), based on a per-session probabilistic burstiness curve (PBC). Under two distinctive service disciplines, role proportional processor sharing and fixed rate processor sharing, we derive useful probabilistic bounds on per-session end-to-end loss which is caused by either buffer overflow in the path or excessive delay to the destination. One remarkable feature of the bounding solutions is that they are solely determined by the PBC of each session itself, independent of the network environment and other connections. To improve network resource utilization, our method is extended to allow statistical sharing of buffer resources. The admission control scheme presented in this paper has a great flexibility in connection management since bandwidth and buffer allocations can be adaptively adjusted among incoming and existing sessions according to present network resource availability. We also present a novel method to compute the PBC of multimedia traffic based on the measurement of two important statistics (rate histogram and power spectrum). Our study of MPEG/JPEG video sequences reveals the fundamental interrelationship among the PBC, the traffic statistics, and the QOS guarantee, and also provides many engineering aspects of the PBC approach to real-time multimedia services in ATM networks     

The flexibility of ATM: supporting future multimedia and mobilecommunications

ATM is no longer considered a vision for the more distant future, but as a technology that will be deployed worldwide within the very near future, in both the private and public sectors. ATM will progressively support fixed and mobile communications in several steps, beginning with data communications and possibly leading to general purpose ATM switches for narrow- and broadband, and wireless and personal communication in the longer term, including the necessary mobility management     

基于ATM的宽带多媒体通信卫星系统运维管理技术研究

随着卫星网络以及通信系统的逐渐研发,宽带多媒体通信卫星系统在通信领域中备受关注.宽带多媒体通信卫星系统能够实现全球无缝隙覆盖的网络互连,在通信系统研发中发挥着重要的作用.基于宽带多媒体通信卫星系统运行维护管理是保障通信卫星系统稳定运行的基础.在本文中对基于ATM的宽带多媒体通信卫星系统运维管理技术进行研究.     

Comparative analysis of wireless ATM channel access protocols supporting multimedia traffic

Extension of multimedia services and applications offered by ATM networks to wireless and mobile users has captured a lot of recent research attention. Research prototyping of wireless ATM networks is currently underway at many leading research and academic institutions. Various architectures have been proposed depending on the intended application domain. Successful implementation of wireless connectivity to ATM services is significantly dependent on the medium access control (MAC) protocol, which has to provide support for multimedia traffic and for qualityofservice (QoS) guarantees. The objective of this paper is to investigate the comparative performance of a set of access protocols, proposed earlier in the literature, with more realistic source traffic models. Data traffic is modeled with selfsimilar (fractal) behavior. Voice traffic is modeled by a slow speech activity detector (SAD). Video traffic is modeled as a H.261 video teleconference, where the number of ATM cells per video frame is described by a gamma distribution and a firstorder discrete autoregressive process model. A comparison of the protocols based on simulation data is presented. The goal of the paper is to identify appropriate techniques for effectively and efficiently supporting multimedia traffic and QoS. Simulation results show that boundaries between different types of services are necessary for multimedia traffic. Reservation for certain traffic type especially video can significantly improve its quality. Reducing the number of collisions is an important issue for wireless networks since contentions lead not only to potentially high delay but also result in high power consumption.