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.     

Overview of measurement-based connection admission control methods in ATM networks

An overview is given of previously-proposed measurement-based connection admission control (CAC) methods. First we address requirements for CAC methods, and then provide a taxonomy for CAC methods. Measurement-based CAC methods are discussed in detail, classified according to the taxonomy, and compared against each other with respect to the requirements. We conclude that measurement-based CAC methods based on effective bandwidth and bufferless models are promising because they do not require complex hardware and are less dependent on assumptions regarding traffic than methods in which the effect of buffer is considered.     

Scalable flow control for multicast ABR services in ATM networks

We propose a flow-control scheme for multicast ABR services in ATM networks. At the heart of the proposed scheme is an optimal second-order rate control algorithm, called the α-control, designed to deal with the variation in RM-cell round-trip time (RTT) resulting from dynamic drift of the bottleneck in a multicast tree. Applying two-dimensional rate control, the proposed scheme makes the rate process converge to the available bandwidth of the connection's most congested link sensed by the traffic source. It also confines the buffer occupancy to a target regime bounded by a finite buffer capacity as the system enters the equilibrium state. It works well irrespective of the topology of the multicast tree. Using the fluid analysis, we model the proposed scheme and analyze the system dynamics for multicast ABR traffic. We study the convergence properties and derive the optimal-control conditions for the α-control. The analytical results show that the scheme is stable and efficient in the sense that both the source rate and bottleneck queue length rapidly converge to a small neighborhood of the designated operating point. We present simulation results which verify the analytical observations. The simulation experiments also demonstrate the superiority of the proposed scheme to the other schemes in dealing with RM-cell RTT and link-bandwidth variations, achieving fairness in both buffer and bandwidth occupancies, and enhancing average throughput     

Explicit rate flow control for ABR services in ATM networks

We propose a novel explicit rate flow control algorithm intended for available-bit-rate (ABR) service on an ATM network subject to loss and fairness constraints. The goal is to guarantee low cell loss in order to avoid throughput collapse due to retransmission by higher level protocols. The mechanism draws on measuring the current queue length and bandwidth availability, as well as tracking the current number of active sessions contending for capacity, to adjust an explicit bound on the source transmission rates. We identify the factors that affect queue overflows and propose simple design rules aimed at achieving transmission with controlled loss in a dynamic environment. We also discuss how conservative design rules might be relaxed by accounting for statistical multiplexing in bandwidth sharing among bursty ABR sources and variable-bit-rate (VBR) sources     

Adaptive connection admission control for differentiated services access networks

In our earlier work, we have proposed some modifications for the bandwidth broker framework. With our modifications, it is possible to use measurement-based admission control in addition to the more traditional parameter-based admission control. Moreover, we have presented a new flexible admission control scheme that has proven to be very efficient in terms of bottleneck link utilization. Two problems, however, have arisen: the use of scheduling weights in admission control and bursty connection arrivals. In this paper, we present that the former one can be dealt with the use of adaptive scheduling weights, while the latter one can be fought with adaptive reservation limits. The proposed new algorithms are validated through simulations and their performance is compared against the nonadaptive basic scheme.     

Effective bandwidth approach to connection admission control formultimedia traffic in ATM networks

The authors propose an effective bandwidth approach to connection admission control in ATM networks. The aggregate arrival traffic is accurately modelled by a two-state Markov modulated Poisson process (MMPP) via the matching of four important statistics. If the buffer is large, admission control can be achieved by computing the effective bandwidth of the two-state MMPP. Simulation tests show that approach is simple and results in higher utilisation compared with conventional methods     

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     

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。     

A connection admission control scheme based on game theoretical model in ATM networks

In this paper, the main schemes of connection admission control (CAC) in ATM networks are briefly discussed especially the principle of dynamic bandwidth allocation. Then the fair share of the bandwidth among different traffic sources is analyzed based on cooperative game model. A CAC scheme is proposed using the genetic algorithm (GA) to optimize the bandwidth-delay-product formed utilization function that ensures the fair share and accuracy of accepting/rejecting the incoming calls. Simulation results show that the proposed scheme ensures fairness of the shared bandwidth to different traffic sources.     

Efficient call admission control for heterogeneous services inwireless mobile ATM networks

An efficient call admission control scheme for handling heterogeneous services in wireless ATM networks is proposed. Quality-of-service provisioning of jitter bounds for constant bit rate traffic and delay bounds for variable bit rate traffic is used in the CAC scheme to guarantee predefined QoS levels for all traffic classes. To reduce the forced handoff call dropping rate, the CAC scheme gives handoff calls a higher priority than new calls by reserving an appropriate amount of resources for potential handoff calls. Resource reservation in the CAC scheme makes use of user mobility information to ensure efficient resource utilization. Simulation results show that the proposed CAC scheme can achieve both low handoff call dropping rate and high resource utilization     

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     

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     

Neuro-fuzzy control in ATM networks

The aynchronous transfer mode (ATM) has been deemed the transfer technique of choice in an integrated environment supporting multimedia services. The authors present an extensive review of fuzzy-logic-based and artificial-neural-network-based traffic control mechanisms that have been proposed in the field of asynchronous transfer mode networking. Following a qualitative review of the models used, system architectures suggested and results obtained, future trends and directions are briefly discussed     

Supporting mobile multimedia in integrated services networks

Owing to widespread user mobility, limited radio resources, and changing network characteristics, supporting multimedia communications in a mobile internetworking environment is a challenging problem. In this paper, we present an adaptive reserved service framework for use in integrated services networks to support mobile connections carrying multimedia traffic. Integrated in the framework are an anticipatory handoff control mechanism which enables fast handoff, and an adaptive link partitioning scheme which enhances handoff success. Besides, bandwidth reservations in the wireline network are dynamically adjusted based on resource availability in the wireless networks. An accompanying reservation protocol not only facilitates distributed control of mobile connections but also provides network feedback to mobile hosts.An earlier version of this paper appeared in the First International Conference on Mobile Computing and Networking, 1995.     

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.     

Fuzzy connection admission control for ATM networks based onpossibility distribution of cell loss ratio

This paper proposes a connection admission control (CAC) method for asynchronous transfer mode (ATM) networks based on the possibility distribution of cell loss ratio (CLR). The possibility distribution is estimated in a fuzzy inference scheme by using observed data of the CLR. This method makes possible secure CAC, thereby guaranteeing the allowed CLR. First, a fuzzy inference method is proposed, based on a weighted average of fuzzy sets, in order to estimate the possibility distribution of the CLR. In contrast to conventional methods, the proposed inference method can avoid estimating excessively large values of the CLR. Second, the learning algorithm is considered for tuning fuzzy rules for inference. In this, energy functions are derived so as to efficiently achieve higher multiplexing gain by applying them to CAC. Because the upper bound of the CLR can easily be obtained from the possibility distribution by using this algorithm, CAC can be performed guaranteeing the allowed CLR. The simulation studies show that the proposed method can well extract the upper bound of the CLR from the observed data. The proposed method also makes possible self-compensation in real time for the case where the estimated CLR is smaller than the observed CLR. It preserves the guarantee of the CLR as much as possible in operation of ATM switches. Third, a CAC method which uses the fuzzy inference mentioned above is proposed. In the area with no observed CLR data, fuzzy rules are automatically generated from the fuzzy rules already tuned by the learning algorithm with the existing observed CLR data. Such areas exist because of the absence of experience in connections. This method can guarantee the allowed CLR in the CAC and attains a high multiplex gain as is possible. The simulation studies show its feasibility. Finally, this paper concludes with some brief discussions     

Congestion control for multimedia services

The problem of congestion control in high-speed networks for multimedia traffic, such as voice and video, is considered. It is shown that the performance requirements of high-speed networks involve delay, delay-jitter, and packet loss. A framing congestion control strategy based on a packet admission policy at the edges of the network and on a service discipline called stop-and-go queuing at the switching nodes is described. This strategy provides bounded end-to-end delay and a small and controllable delay-jitter. The strategy is applicable to packet switching networks in general, including fixed cell length asynchronous transfer mode (ATM), as well as networks with variable-size packets     

IP-based access networks for broadband multimedia services

The increasing demands of new services and applications are pushing for drastic changes in the design of access networks for residential and SOHO users. Future access networks will provide full service integration, resource sharing at the packet level, and QoS support. It is expected that using IP as the base technology, the ideal plug-and-play scenario, where the management actions of the access network operator are kept to a minimum, will be achieved easily. In this article we start by giving a historical perspective of the evolution of access networks. We then describe an IP-based architecture targeted for integrated support of broadband multimedia services, designed to be low-cost and easily manageable. We illustrate the different phases of a multimedia Internet access session, when using SIP for session initiation, COPS and DIAMETER for QoS policy management, and AAA and RSVP for resource reservation.     

Analysis of Internet services in IP over ATM networks

This article presents a trace-driven analysis of IP over ATM services from an ATM-centric standpoint. We provide a characterization of TCP flows as VBR streams with burstiness (MBS) and throughput (SCR). On the other hand, a macroscopic analysis comprising percentage of flows and bytes per service, TCP average transaction duration, and bytes transferred both ways is also presented. The ATM link under analysis concentrates traffic from a large population of 1500 hosts from the Public University of Navarra campus network, that produce 1,700,000 TCP connections approximately in the measurement period of one week. The results obtained from such a wealth of data indicate that the sustained throughput of Web connections does not grow beyond 80 kb/s with 70 percent probability in the data transfer phase (i.e., in the established state), and we observe a strong influence of the connection establishment phase on the user-perceived throughput. On the other hand, the burstiness of individual TCP connections is rather small; namely, TCP connections do not produce bursts according to the geometric law given by slow start and commonly assumed in previously published studies