Zoran R. Petrovic

Building the enterprise-wide storage area network

A storage area network deployment within a global communications company is presented. The new storage-centric infrastructure includes an open, modular and scalable storage network, not tied to any one server or application. A leading provider of telecommunication solutions was looking to move ahead quickly with SAN technology to achieve early and sustainable competitive advantage by leveraging its information resources.

Impact of scheduling algorithms on performances of buffered crossbar switch fabrics

In this paper, the impacts of different scheduling algorithms on buffered crossbar switch (BCS) performances are analyzed. Four BCSs are considered: combined input- and crosspoint-queued (CICQ) switch, output-queued with speed-up N (OQ-N) switch virtual ouput-queued with iterative longest input part first (VOQ) switch and virtual output-queued with longest input port first and with throughput maximization (VOQL) switch. As solutions for input buffers and crosspoint buffers scheduling procedures, longest queue first (LQF), oldest cell first (OCF) and round robin (RR) algorithms are implemented. The simulation results show that different BCSs have very close performances, irrespective which scheduling algorithm is implemented, for both uniform and bursty traffic. Also simulations indicate that CICQ switches an very close to OQ-N. Taking into account cost-effectiveness it is proved that the RR scheduling algorithm has great perspective as an easy solution for CICQ high speed switch implementation.

A Practical Solution for Delivering Voice over IP

This paper describes a practical deployment of the VoIP (Voice over Internet Protocol) in the aim of extending the portfolio of value-added services for Italian customers of a prominent European travel services organisation. This includes unified messaging, post paid and prepaid calling card services along with related validation, billing and payment systems.

A Novel Service Retrieval Scheme

This letter proposes a novel method for multimedia service retrieval. Similarity measure is used to create a user model and then to determine the correspondence between this model and the available services. Only the top-ranked services are then offered to the user, thus helping him/her easily find the service of interest.

Error rates for trellis coded PSK modulation with pilot tone in time-selective fading channel

In this paper trellis coded modulation effects for the PSK scheme with a pilot tone have been evaluated. Closed form analytical expressions for error rates in the radio channel with TCM are derived. The obtained relations are suitable for any fading characteristics as well as for all PSK and QAM modulation methods. Error rates are presented first for the standard land mobile radio channel with flat Rayleigh fading. Then, taking into account the time-selectivity of the fading process, the necessary mathematical transformations are performed leading to error rate determination for the case of TCM PSK with a pilot tone.

Evaluation of trellis coded modulation effects in time-selective fading mobile radio channel

In this paper effects of trellis coded modulation in mobile radio systems are evaluated. The specific channel with timeselective fading process is considered. The complete descriptions of such channel and an appropriate receiver is given. General model for bit error rate calculations is presented. That model enables error determination for every type of fading encountered in mobile radio systems as well as for different TCM schemes. Here we chose to analyse trellis encoding in combination with PSK, PSK with pilot tone and DPSK.

The Impact of Cyclic Prefix Length in DMT on the PLC System Design

In this paper the impact of the cyclic prefix (CP) length in discrete multi-tone (DMT) modulation on the powerline communications (PLC) system capacity is analysed. CP values that are shorter than channel impulse response introduce intersymbol and interchannel interference, that are spectrally concentrated in the case of PLC channel. We show that a tradeoff between eliminating interference and preserving spectral efficiency can be obtained, for the purpose of maximizing system capacity. Practical implication is that short CP length values can give good system performances, despite PLC channel long impulse response durations.

Performance analysis of the dual-banyan ATM switch

Dual-banyan is a buffered banyan asynchronous transfer mode (ATM) switch which encompases multiple input-queuing (bifurcated queueing) as its buffering strategy. This paper describes an analytical model for performance evaluation of the dual-banyan switch under different traffic patterns. The developed and presented model enables computation of every buffer state probability by iterative calculations. Such a model allows determination the switch normalized throughput and cell-loss probability. Two classes of traffic pattern are considered and for each of them the traffic patterns are identified. Efficiency of the given model is also verified through comparison with simulation results.

Bifurcated buffering in internal buffer banyan ATM switch

In our paper we present a bifurcated buffer banyan ATM switch concept. Bifurcated input buffering was proposed previously for switches with input buffers. We expanded it to buffer a banyan ATM switch with internal input buffers. Here, we give a detailed description of the proposed switch performance analysis, based on the algorithm described in [3]. Our proposition advantages over the simple input buffer banyan are higher throughput and lower cell loss probability. We found that buffer size b=20, for input load p<0.78, is enough for obtaining the required ATM switch performance levels no matter the switch size. It means that cheap and simple input buffering is possible in bifurcated banyan ATM switching.

Performance of the new ATM switch for B-ISDN

In this paper a new N×N space division ATM switch architecture based on banyan network is presented. This architecture is a multistage interconnection network with more than n (n=log2N) switching stages. The interconnection algorithm offers many access outputs and resolves output contention by laying buffers. The paper analyzes the switching performance and shows that this switch has lower cell loss probability vs. buffer size than other two known solutions given in (Tobagi et al., 1991; Urushidani, 1991; Hino et al., 1995).