Journal of High Speed Networks - Volume 3, issue 4

Authors: Parekh, Abhay K.

Article Type: Other

DOI: 10.3233/JHS-1994-3401

Citation: Journal of High Speed Networks, vol. 3, no. 4, pp. 331-333, 1994

Authors: Bohn, Roger | Braun, Hans-Werner | Claffy, Kimberly C. | Wolff, Stephen

Article Type: Research Article

Abstract: The current architecture and implementation of the Internet assumes a vast aggregation of traffic from many sources and stochastic distribution of traffic both in space (traffic source) and time (burstiness of traffic volume). Given this general assumption, Internet components typically have little if any ability to control the volume and distribution of incoming traffic. As a result the network, particularly from the perspective of the router, is vulnerable to significant consumption of networking resources by high-volume applications, with possibly little stochastic behavior, from a few users. This often impacts the overall profile of network traffic as aggregated from many clients. …An example is the continuous flows introduced by real time applications such as packet audio, video, or rapidly changing graphics. This situation creates a time window where applications exist on a network not designed for them, but before an appropriately architected network can augment the current infrastructure and cope with the new type of workload. We propose a scheme for voluntarily setting Internet traffic priorities by end-users and applications, using the existing 3-bit Precedence field in the Internet Protocol header. Our proposal has three elements. First, network routers would queue incoming packets by IP Precedence value instead of the customary single-threaded FIFO. Second, users and their applications would voluntarily use different and appropriate precedence values in their outgoing transmissions according to some defined criteria. Third, network service providers may monitor the precedence levels of traffic entering their network, and use some mechanism such as a quota system to discourage users from setting high precedence values on all their traffic. All three elements can be implemented gradually and selectively across the Internet infrastructure, providing a smooth transition path from the present system. The experience we gain from an implementation will furthermore provide a valuable knowledge base from which to develop sound accounting and billing mechanisms and policies in the future. Show more

Keywords: Internet, Usage-Based Accounting, Precedence, Traffic Growth, Delays, Loss Behavior, Congestion Control, Bandwidth

DOI: 10.3233/JHS-1994-3402

Citation: Journal of High Speed Networks, vol. 3, no. 4, pp. 335-349, 1994

Authors: Nagarajan, Ramesh | Kurose, Jim | Towsley, Don

Article Type: Research Article

Abstract: Future high-speed networks (HSNs) are expected to support a wide variety of services such as voice and video and provide a guaranteed quality-of-service (QOS). Traditionally, the computation of user-oriented performance criteria such as the average delay has been carried out via steady state analysis of queueing theoretic models of communication networks. In this paper, we show that the steady state analysis is not entirely sufficient for QOS purposes in future high-speed networks as it yields long-run performance measures that are not appropriate for envisaged applications in HSNs. New QOS criteria for such applications are proposed and their computation detailed for …some simple queueing models. These new QOS criteria essentially capture the network performance over the short-run and are more accurate indicators of the actual user-perceived quality of, for example, audio or video. For the numerical examples presented in this paper, our focus will be primarily on the fractional packet loss and we will be interested in the probability (frequency) of occurence of high or low loss “periods.” When our interest is in maximizing the occurence of no loss periods, we show for the M/M/1/K queue that reasonably high values of traffic load may be supported and fairly good QOS (as defined in this paper) provided to applications. In this context, steady state analysis is found to be woefully inadequate. On the other hand, when we are interested in minimizing the occurence of high loss periods, we find for a packet voice multiplexer that large values of the carried load may not be supportable while providing an acceptable QOS. Show more

Keywords: Quality-of-Service, High-Speed Networks, Statistical Guarantees, Transient Analysis

DOI: 10.3233/JHS-1994-3403

Citation: Journal of High Speed Networks, vol. 3, no. 4, pp. 351-373, 1994

Authors: Yaron, Opher | Sidi, Moshe

Article Type: Research Article

Abstract: We consider virtual circuit packet switching communication networks that employ processor sharing type service disciplines and study their stability when the offered traffic to the network has exponentially bounded burstiness (EBB). The advantages of processor sharing switching techniques both in terms of service flexibility and the potential capability to guarantee certain grades of service, were emphasized in [7]. The study presented there assumes that the traffic offered to the network is flow-controlled by the leaky-bucket mechanism, and the performance of both generalized processor sharing (GPS) and packet-by-packet generalized processor sharing (PGPS) is analyzed. In this paper we employ an …exponential characterization (EBB) introduced in [11] to analyze this type of systems in a stochastic setting. We first examine the GPS and PGPS servers in isolation, and demonstrate their superiority to a general server in the stochastic environment. We then show that a network of servers, that are all either GPS or PGPS, is stable whenever the service rate of each node is larger than the total arrival rate to it. In addition, we provide exponential upper bounds to the traffic flows within the network links, and to the backlogs of each session in the various nodes on its path. Show more

Keywords: Communication Networks, Generalized Processor Sharing, Exponential Bounds, Stability, Packet Switching, Burstiness

DOI: 10.3233/JHS-1994-3404

Citation: Journal of High Speed Networks, vol. 3, no. 4, pp. 375-387, 1994

Authors: Zhang, Hui | Ferrari, Domenico

Article Type: Research Article

Abstract: We propose a class of non-work-conserving service disciplines, called the rate-controlled service disciplines. When coupled with suitable admission control algorithms, rate-controlled service disciplines can provide end-to-end deterministic and statistical performance guarantees on a per-connection basis in an arbitrary-topology packet-switching network. The key feature of a rate-controlled service discipline is the separation of the server into two components: a rate controller and a scheduler. This separation makes it possible to obtain end-to-end performance characteristics by applying single node analysis at each switch. It also has several other distinct advantages: it decouples the allocation of bandwidths and delay bounds, uniformly distributes the …allocation of buffer space inside the network to prevent packet loss, and allows arbitrary combinations of rate-control policies and packet scheduling policies. Rate-controlled service disciplines provide a general framework within which most of the existing non-work-conserving disciplines can be naturally expressed. One discipline in this class, called Rate-Controlled Static Priority (RCSP), is particularly suitable for providing performance guarantees in high-speed networks. It achieves simplicity of implementation as well as flexibility in the allocation of bandwidths and delay bounds to different connections. Show more

Keywords: Multimedia Networking, Performance Guarantees, Rate Control, Real-Time Communication, Scheduling Disciplines

DOI: 10.3233/JHS-1994-3405

Citation: Journal of High Speed Networks, vol. 3, no. 4, pp. 389-412, 1994

Authors: Cruz, R.L. | Liu, H.-N.

Article Type: Research Article

Abstract: We focus on a single connection in an AIM network. To study delay for this connection, we adopt a discrete time model for several queues in tandem. A service availability process at each switch along the path of the connection indicates how many packets from the connection can be served in each slot at that switch. The service availability process at a switch is influenced by the presence of cross traffic as well as the underlying scheduling policy at the switch. The quality of service is succinctly described by the network service process. In particular, the end-to-end delay can be …expressed as a simple non-recursive function of the network service process and the cell arrival process for the connection. We consider the impact on end-to-end delay of constraining the scheduling policy at each switch along the connection according to a service curve. In particular, we develop the concept of a guaranteed network service curve, which may prove to be of some value in the service definition of AIM networks. Finally, utilizing a recently proposed stochastic model for the cell arrival process for the connection, as well as for the service availability processes, we present bounds on the probability distribution of end-to-end delay. Show more

Keywords: Performance Analysis, Queueing Theory, Flow Control, QOS Guarantees, ATM

DOI: 10.3233/JHS-1994-3406

Citation: Journal of High Speed Networks, vol. 3, no. 4, pp. 413-427, 1994

Authors: Yates, David | Kurose, James | Towsley, Don | Hluchyj, Michael G.

Article Type: Research Article

Abstract: A crucial problem facing the designers and deployers of future high-speed networks is providing applications with quality of service (QOS) guarantees. For soft real-time applications, which are delay sensitive but loss tolerant, delay distribution is an important QOS measure of interest. In this paper we study (through simulation) the end-to-end delay distribution seen by individual sessions under simple first-come-first-served (FCFS) multiplexing in a network model with two significant features: (1) all traffic is connection-oriented, (2) cross traffic along routes is representative of that seen by calls in a moderately sized wide area network (i.e., less than 100 switches). We compare …these delay distributions with the worst case analytic delay bounds predicted by three different techniques for providing such bounds (two of which require a more sophisticated link-level scheduling policy). We also consider the per-hop delay distributions Seen as a session progresses “deeper” into the network and determine the sensitivity of these delay distributions to the manner in which the interfering traffic is modeled. Finally, we use our delay distribution results to examine the tradeoff between the QOS requested by a call, the manner in which the QOS guarantee is provided, and the number of calls that are admitted at the requested QOS. Show more

Keywords: Packet-Switched Networks, Real-Time Communication, Quality of Service, Performance Guarantees, End-to-End Delay, Cross Traffic

DOI: 10.3233/JHS-1994-3407

Citation: Journal of High Speed Networks, vol. 3, no. 4, pp. 429-457, 1994

Authors: Huang, Chun-Chong | Leon-Garcia, Alberto

Article Type: Research Article

Abstract: The need to carry various real-time and non-real-time applications involving diverse traffic arrival pattern and a wide range of QoS requirements in ATM-based BISDN has spurred research activity on queueing control in ATM switches. Frame-oriented queueing policies have drawn much attention recently, which alleviates the high-speed processing requirement of the slot-oriented policies. In this paper, we propose a frame-oriented queueing control policy based on Golden-Ratio hashed slot assignment for real-time and non-real-time traffic in the output queue of ATM switches. The buffer is shared by the two types of traffic. The proposed policy updates the transmission schedule at every frame …according to the buffer state instead of the arrival traffic pattern. The enqueueing priority assignment will also be updated at every frame or slot according to the transmission schedule of the current frame and the buffer state at the current frame or slot. Under the proposed policy, the minimum aggregate time-cumulative cell loss (subject to the system parameters) can always be guaranteed for any arrival traffic pattern. The system parameters need to be changed only when the traffic load and profile change (due to setup and tear-down of connections). To exploit the potential of the proposed policy, the performance of the theoretically optimal discipline R* is used to benchmark the performance of the proposed policy under a wide variety of cases. Show more

Keywords: ATM Switching, Discrete-Time Single-Server Queue, Frame-Oriented Queueing Control, Throughput, Golden-Ratio Multiplicative Hashing, Real-Time and Non-Real-Time Applications

DOI: 10.3233/JHS-1994-3408

Citation: Journal of High Speed Networks, vol. 3, no. 4, pp. 459-489, 1994

Authors: Choudhury, Abhijit K. | Hahne, Ellen L.

Article Type: Research Article

Abstract: We study an ATM switch architecture in which the queues for all the switch output ports share space flexibly in a common buffer. Using a computer simulation of this switch under bursty traffic, we investigate various ways to manage space priorities in the shared memory. Our findings support one particular strategy which we call “Selective Pushout.” In this scheme, an arriving cell that finds the shared memory full overwrites a cell with priority less than or equal to itself from the longest output queue in the buffer (even if the arriving cell will be joining a different output queue). We …simulated Selective Pushout as well as several simpler pushout and threshold schemes under a variety of load conditions. For each load pattern we studied, the Selective Pushout scheme performed at least as well and usually much better than its competitors. Selective Pushout offered a low overall cell loss rate, with very low losses for the high priority cells. Show more

Keywords: Asynchronous Transfer Mode (ATM), Broadband ISDN (B-ISDN), Hierarchical Shared Memory Switch, Bursty Traffic, Space Priorities, Loss Priorities, Thresholds, Pushout, Selective Pushout

DOI: 10.3233/JHS-1994-3409

Citation: Journal of High Speed Networks, vol. 3, no. 4, pp. 491-512, 1994

Authors: Verma, Dinesh C. | Gopal, P. M.

Article Type: Research Article

Abstract: With the deployment of broadband integrated services networks, multipoint applications are likely to be developed on digital networks. Many, if not all, of these applications will benefit from network support for quality of service requirements, which can be readily provided if the network supports reserved bandwidth multipoint communication channels. In this paper, we discuss the different kinds of applications that may require support for bandwidth reservation, and discuss how a multipoint communication channel can be found for multi point applications. For several applications, finding a multipoint communication channel is a NP-hard problem, and we will present heuristics to solve it …under different circumstances. We study these heuristics by means of simulations and attempt to provide theoretical bounds on their performance. Show more

Keywords: Multipoint, Communication, Path-Selection

DOI: 10.3233/JHS-1994-3410

Citation: Journal of High Speed Networks, vol. 3, no. 4, pp. 513-533, 1994