Simulative analysis of optimal resource allocation and routing in IBCN's

SUMMARYAs the Internet evolves from a packet network supporting a single best effort service class towards an integrated infrastructure supporting several service classes}some with QoS guarantees}there is a growing interest in the introduction of admission control and in devising bandwidth sharing strategies, which meet the diverse needs of QoS-assured and elastic services. In this paper we show that the extension of the classical multi-rate loss model is possible in a way that makes it useful in the performance analysis of a future admission control based Internet that supports traffic with peak rate guarantee as well as elastic traffic. After introducing the model, it is applied for the analysis of a single link, where it sheds light on the trade-off between blocking probability and throughput. For the investigation of this trade-off, we introduce the throughput-threshold constraint, which bounds the probability that the throughput of a traffic flow drops below a predefined threshold. Finally, we use the model to determine the optimal parameter set of the popular partial overlap link allocation policy: we propose a computationally efficient algorithm that provides blocking probability-and throughput guarantees. We conclude that the model and the numerical results provide important insights in traffic engineering in the Internet.

Section: Related Workmentioning

confidence: 96%

Section: System Descriptionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

On providing blocking probability and throughput guarantees in a multi‐service environment

Fodor¹,

Rácz²,

Telek³

2002

“…The average carried traffic and CBP for each service-class and VP are measured during the control interval in the ATM switches. At the end of each control interval the simulator passes these measurements to the controller and waits for its response (2).…”

Section: Dissociation Between Core Simulation and Built-in Functionsmentioning

confidence: 99%

“…Furthermore, we believe that general purpose programming languages (GPPL), used as simulation languages, are more flexible than actual simulation languages and in most cases they can achieve faster execution times [1]. Therefore, in this paper we propose a simple and fast method for simulating the call-level operations of telecom networks and especially of ATM networks [2], by using a GPPL. For a researcher who wishes to build his/her own network simulator, the use of his/her familiar GPPL, an easy-to-implement data structure and a fast-execution simulation method are key points.…”

Section: Introductionmentioning

confidence: 99%

A batch‐type time‐true ATM‐network simulator—design for parallel processing

Logothetis

Liotopoulos

2002

SUMMARYThis paper presents a new type of network simulator for simulating the call-level operations of telecom networks and especially ATM networks. The simulator is a pure time-true type as opposed to a call-by-call type simulator. It is also characterized as a batch-type simulator. The entire simulation duration is divided into short time intervals of equal duration, t: During t; a batch processing of call origination or termination events is executed and the time-points of these events are sorted. The number of sorting executions is drastically reduced compared to a call-by-call simulator, resulting in considerable timesaving. The proposed data structures of the simulator can be implemented by a general-purpose programming language and are well fitted to parallel processing techniques for implementation on parallel computers, for further savings of execution time. We have first implemented the simulator in a sequential computer and then we have applied parallelization techniques to achieve its implementation on a parallel computer. In order to simplify the parallelization procedure, we dissociate the core simulation from the built-in call-level functions (e.g. bandwidth control or dynamic routing) of the network. The key point for a parallel implementation is to organize data by virtual paths (VPs) and distribute them among processors, which all execute the same set of instructions on this data. The performance of the proposed batch-type, time-true, ATM-network simulator is compared with that of a call-by-call simulator to reveal its superiority in terms of sequential execution time (when both simulators run on conventional computers). Finally, a measure of the accuracy of the simulation results is given.

Modelling and analysis of routing and resource allocation techniques in multi‐service networks

Fodor

Barta

Marquetant

et al. 1999

In this paper a novel call level model based on the extension of the classical Erlang multi-rate model for broadband integrated services networks is proposed. We use the model to study routing strategies in multi-service networks where service classes with/without QoS guarantees coexist. Examples for such networks include ATM and IP-based integrated networks. In ATM, the CBR and VBR service classes provide QoS guarantees, while the ABR and UBR service classes are of the best effort type. In IP, traditional TCP/IP traffic is of the best effort type, while new protocols like the RSVP or the differentiated services with central resource handling attempt to support QoS parameters. The coexistence of guaranteed and best effort traffic gives rise to new challenging problems since for a given elastic (best effort) connection the bottleneck link determines the available bandwidth and thereby puts constraints on the bandwidth at the other links along the connection's path. Since the available bandwidth fluctuates in time following the load on the links, routing and link allocation in this environment together with blocking probability calculations and fairness issues need to be studied. By means of our proposed model we are able to conduct a survey of various routing and link allocation techniques as well as to develop a modified shortest path routing algorithm which, according to the numerical examples, performs well in this environment. Figure 9. Impact of partial blocking and queueing on total call holding times of: (a) ABR1 sources and (b) ABR2 sourcesAll in all, from the numerical results we conclude that in PB-Q systems, which we have used as models for multi-rate 'per-session state aware' connection-oriented networks, there are a number of means to control blocking probabilities and thus network resource utilization and fairness. As we have seen on the numerical examples, call queueing and partial blocking, in general, decreases the blocking probabilities at the expense of increased holding times. We are currently working on the formulation of optimization criteria and an optimization model for the PB-Q system. Relationship to and comparison with related works Related worksRouting high-bandwidth traffic in a fair manner and resource allocation in multi-service networks supporting best effort (also called 'elastic') traffic are the topics of current state-of-the-art research papers.\\ Also, the issue of fairness is in the focus of both the ITU-T and the ATM Forum. Although these papers delve into important aspects of fairness 117