Network Response Time Research Articles

Impact of PCS handoff response time

In a personal communications services (PCS) network, the network delay for a handoff request is limited by a timeout period. If the network fails to respond within the timeout period, the handoff call is forced terminated. We study the effect of the network response time on the performance (the call incompletion probability) of a PCS network. Our study indicates that at a small offered load, the network response time has a significant effect on the call incompletion probability. We also observe that the effect of the network response time is more significant if the mobile residence time distribution at a cell has a smaller variance.

Intelligent Neural Network Based Decision Unit for Robot Safety

This article concerns the use of a neural system in a previously unreported, but highly significant, application in robotics safety. It presents a neural network based decision unit for a real-time robot safety system. The decision unit occupies a high level position in the sensory processing hierarchy, using information from signal processing and detection at lower levels. The developed neural network accepts the following input: a map containing potential collision zones encoded as belief values into grids, the magnitude of a robot's velocity vector, and the robot's steering angle. The neural network decision is based on computation of the scalar product of two vectors, the virtual repulsive force vector generated by the obstacle and the robot's velocity vector; it produces one of the following safety decisions: move as intended, slow down, or emergency stop. The effectiveness of this approach is verified by computer simulation. The response time of the neural network measured on the state of the art personal computer is 6 msec, and the correctness of the safety decisions exceeds 90%.

Performance evaluation of a lightweight logical link control protocol in slotted ring networks

AbstractThis paper evaluates the performance of a fast select connection oriented (FS‐CO) logical link control (LLC) protocol in slotted ring networks. the FS‐CO‐LLC protocol is one of the light‐weight protocols. It employs a method of implicit connection establishment and release to reduce overhead of connection control. l'his paper analyzes the performance (throughput and average response time) of a slotted ring network in which a single slot circulates by means of Equilibrium Point Analysis. the performance in the case of plural slots is evaluated by simulation. This paper also compares the FS‐CO‐LLC protocol with connection‐oriented (CO) and connection‐less (CL) LLC protocols. Numerical results show that the performance of FS‐CO‐LLC and CL‐LLC protocols is superior to that of CO‐LLC protocol when the average message length is smaller than the buffer size. On the other hand, when the average message length is larger than the buffer size, CO‐LLC protocol has the best performance. It is also shown that the per formance of FS‐CO‐LLC protocol does not‐degrade but CL‐LLC protocol does, even if the average message length becomes larger.

The SSABLE system: automated archive, catalog, browse and distribution of satellite data in near-real time

SSABLE is a new interactive tool for the archive, browse, order, and distribution of satellite data based on X Window, high-bandwidth networks, and digital image rendering techniques. SSABLE provides for automatically constructing relational database queries to archived image datasets based on time, data, geographical location, and other selection criteria. SSABLE also provides a visual representation of the selected archived data for viewing on the user's X terminal. SSABLE is a near-real-time system-for example, data are added to SSABLE's database within 10 min after capture. SSABLE is network and machine independent, running identically on any machine that has a bit-mapped display (monochrome or greater), is running the X Window system, and is on a network directly reachable by the SSABLE system. SSABLE has been evaluated at over 100 international sites. Network response time in the United States and Canada varies between 4 and 7 s for browse image updates; reported transmission times to Europe and Australia typically are 20-25 s. >

Response time calculation for VSAT networks

This paper calculates the response time of a VSAT network. The response time consists of network access time from VSAT terminals to the hub station, query waiting and processing time, plus response queueing and transmission delay. The calculation is first done for a VSAT network which only has a central hub. The work is then extended to a distributed environment in which regional hubs are assumed. In addition to mathematical derivations, numerical examples are given to demonstrate several interesting phenomena. Computer simulations are also provided to verify the validity of the derived results.

A mean-field limit for a class of queueing networks

A model of centralized symmetric message-switched networks is considered, where the messages having a common address must be served in the central node in the order which corresponds to their epochs of arrival to the network. The limitN → ∞ is discussed, whereN is the branching number of the network graph. This procedure is inspired by an analogy with statistical mechanics (the mean-field approximation). The corresponding limit theorems are established and the limiting probability distribution for the network response time is obtained. Properties of this distribution are discussed in terms of an associated boundary problem.

Performance analysis of bridged LANs

As the requirements of LANs have evolved, an increasing number of LANs now incorporate MAC bridges. In many instances, however, the choice of bridges, and the interconnection topologies used with them, is being made based on technological grounds rather than on firm predictions of improvements in overall network response times. The paper identifies the issues that must be considered when expanding a LAN and also, through a series of simulation results, illustrates the effect on the overall network performance of various bridge parameters and interconnection topologies. The paper concludes with some guidelines to be followed for creating a bridged LAN comprising many interconnected segments.

Response-time evaluation of transaction-oriented applications in VSAT networks

The authors present modeling of an integrated terrestrial-satellite network using very small aperture terminals (VSATs), for transaction-oriented computer applications. They address the analytical and simulation modeling techniques used to study the network performance. More specifically, these models are used to obtain network response times for an integrated terrestrial-VSAT network for inquiry-response applications under various load conditions at the cluster controller units. The major result obtained through this analytical and simulation modeling suggests that communications satellite channels can be used efficiently for the interactive inquiry-response traffic at an acceptable response time, provided that the system parameters including the link transmission rates are chosen appropriately. >

Evaluating performance of high-speed multiaccess networks

An overview of high-speed multiaccess networks is presented, and their potential roles are discussed. It is shown that network response time sufficiently characterizes network performance under a number of scenarios and that more invaluable performance information, like end-to-end throughput, can be derived from these results. Examples based on the operating fundamentals of token-passing (e.g. FDDI), slotted (e.g. DQDB), and other approaches to high-speed networking are given. These approaches are compared for scenarios that require different measures of performance, and it is shown that their performance matches the needs of the environment from which they come. >

Acyclic fork-join queuing networks

In this paper the class of acyclic fork-join queuing networks that arise in various applications, including parallel processing and flexible manufacturing are studied. In such queuing networks, a fork describes the simultaneous creation of several new customers, which are sent to different queues. The corresponding join occurs when the services of all these new customers are completed. The evolution equations that govern the behavior of such networks are derived. From this, the stability conditions are obtained and upper and lower bounds on the network response times are developed. These bounds are based on various stochastic ordering principles and on the notion of association of random variables.

Performance assessment of AT&T international switched voice services

This paper describes the performance assessment of AT&T international switched voice services. Call availability and call suitability performance issues are emphasized. Field study methods and tools for studying them are discussed. Performance issues addressed include network response times, voice, and voiceband data transmission quality. Two examples of field studies, one an objective study for evaluating the performance of a new service, and the other a subjective study to assess the performance of a new technology are also presented.

Ku‐Band satellite data networks using very small aperture terminals—part II: System design

AbstractIn this part of the paper on Ku‐band VSAT networks, the issue of overall system design is considered. After discussing possible system architectures, primary attention is given to the star network configuration in which customer‐premise VSATs communicate with a central hub station, co‐located with, or terrestrially connected to a host computer. The component elements of a Ku‐band star network for interactive data applications are discussed and the critical items from the point‐of‐view of performance, capacity and cost are identified. An analytical model for the network, which combines delay‐throughput characterization of the multi‐access inbound and TDM outbound channels with satellite link analysis is described. The analytical model is exercised over a range of typical system component, traffic model and performance objective scenarios to provide a set of general design guidelines. These guidelines are useful for evaluating the trade‐offs between key system elements (channel access unit, modem, VSAT antenna and satellite), VSAT traffic message length parameters and the performance objectives (average and peak network response time and availability). The results are used to address the issue of multi‐access protocol selection over a range of scenarios typical of 1.2 or 1.8m VSAT‐based interactive networks using current commercial Ku‐band satellites. The results show that interactive star networks are often limited by satellite power rather than bandwidth, so that the use of simple contention access for VSATs may not imply a significant system capacity penalty.

Response Time Problems in Communication Networks

SUMMARY Two problem areas are discussed. The first concerns the distribution of sojourn, or response times in networks which allow overtaking. Exact results for a few special cases are presented. The second problem area has to do with determining the average response times in local area networks under particular communication protocols. Models which do not lend themselves to exact solution are studied approximately.

Regenerative simulaton of response times in networks of queues, by D. L. Iglehart and G. S. Shedler, Lecture notes in control and information Sciences, Springer‐Verlag, Berlin‐Heidelberg‐New York, 204 pp. Price: $15.70

Regenerative simulaton of response times in networks of queues, by D. L. Iglehart and G. S. Shedler, Lecture notes in control and information Sciences, Springer‐Verlag, Berlin‐Heidelberg‐New York, 204 pp. Price: $15.70

Regenerative simulation of response times in networks of queues: statistical efficiency

This paper deals with the statistical efficiency of estimation methods for "passage times" in closed, multiclass networks of queues with priorities. Informally, a passage time is the time for a job to traverse a portion of the network. Such quantities are important in computer and communication system models, and in this context, quantities other than mean values are of interest. We consider here the efficiencies of the "marked job method" for passage time simulation (based on the tracking of a distinguished job) and the "decomposition method" in which observed passage times for all of the jobs enter in the construction of point and interval estimates. We show that the decomposition method is superior in that, for simulations of equal length, it produces tighter confidence intervals. We also calculate theoretical values for variance constants entering into central limit theorems used to obtain confidence intervals for mean passage times. These results provide a means of quantifying the relative efficiency of the decomposition method.

Regenerative simulation of response times in networks of queues with multiple job types

We have previously discussed the simulation of networks of queues for general characteristics of passage times of a single job type, using the regenerative method for simulation and the idea of tracking a distinguished job through the network. We consider here, from a somewhat different point ov view, passage time simulation in closed networks of queues having multiple job types. Our results provide a means of obtaining, from a single replication, point and interval estimates for passage times of the several job types. They also yield a statistically more efficient estimation procedure for passage times of a single job type.

Simulation of Response Times in Finite-Capacity Open Networks of Queues

We extend to two types of finite-capacity open networks a previously developed technique for the estimation by simulation of job response time characteristics in closed queuing network models of multiprogrammed computer systems. Particular stochastic point processes associated with a Markov renewal process generate arrivals to the networks. Such arrival patterns are useful for representation of the work load of the computer system being modeled. The regenerative method for simulation of stochastic systems and the idea of tracking a marked job in the network form the basis for the estimation technique. We also report illustrative simulation results.

Regenerative Simulation of Response Times in Networks of Queues

article Free AccessRegenerative Simulation of Response Times in Networks of Queues Authors: Donald L. Iglehart Stanford University, Stanford, California Stanford University, Stanford, CaliforniaView Profile , Gerald S. Shedler IBM Research Laboratory, San Jose, California IBM Research Laboratory, San Jose, CaliforniaView Profile Authors Info & Claims Journal of the ACMVolume 25Issue 3July 1978 pp 449–460https://doi.org/10.1145/322077.322087Published:01 July 1978Publication History 16citation406DownloadsMetricsTotal Citations16Total Downloads406Last 12 Months8Last 6 weeks1 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my AlertsNew Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteeReaderPDF