The disk input/output performance with virtual private servers is known to be suboptimal at best. This is largely due to the fact that virtualisation leads to the usage of shared resources and in particular shared disk access. In this research we look at the possibility of improving disk reading performance by using the read-balancing option of DRBD v8.4.1. We conducted tests in three environme...

This month’s column examines and evaluates various programming techniques for developing distributed applications. Our previous column outlined the requirements for a representative distributed application in the financial services domain. This application enables investment brokers to query the price of a stock, as well as to buy shares of stock. As shown in Figure 1, the quote service that ma...

The paper presents the results of a performance analysis of mobile agents in a distributed network environment. Analytical models are developed and used to compare the performance of carrying out a simple management function with Mobile Agents (MA) or SNMP (Simple NetworkManagement Protocol). We examine how delay is affected by the size of the management domain and how each method behaves in bo...

In this paper, we compare the performance of several Webmail servers and a bare PC Webmail server running without an operating system. The conventional Webmail servers used in the study are Icewarp, MailTraq and Hexamail running on Windows, and Atmail and Afterlogic running on Linux. Server performance is compared with respect to the typical email transactions (login, compose, and read), CPU ut...

This paper advocates the use of local area networks which use 48 byte ATM cells. Hosts connected to the network are tted with ATM interfaces and run a new protocol stack, up to the network level, which avoids multiplexing and eeciently handles the out-of-band signalling used by ATM. The private network may be of WAN, MAN or LAN dimensions and contain several diierent network technologies, provi...

This document is a survey of Performance Enhancing Proxies (PEPs) often employed to improve degraded TCP performance caused by characteristics of specific link environments, for example, in satellite, wireless WAN, and wireless LAN environments. Different types of Performance Enhancing Proxies are described as well as the mechanisms used to improve performance. Emphasis is put on proxies operat...

Communication systems consist of many softand hardware components with a wide range of parameters which affect mainly the providd quality of service. One of the main challenges for configuration and structuring such a heterogeneous system is to guarantee the specified quality of service with a minimum of costs. In this paper, we introduce a simulation based approach which helps the designer to ...

Recent studies of high-resolution traffic measurement discovered the self-similarity in both LAN and WAN traffic. In this paper, we introduce a two-degree of freedom rate based flow controller, which includes a robust H∞ control block and an LMMSE based capacity predictor. The former part can guarantee the robust stability against time-varying time delay uncertainties and the latter improves th...

The VoIP networks as alternative method to traditional PSTN system has been implemented in a wide variety of structures with multiple protocols, codecs, software and hardware–based distributions. The use of cryptographic techniques let the users to have a secure communication, but the calculate throughput as well as the QoS parameters are affected according to the used algorithm. This paper ana...

Shi-Chuan TANG, Yong-Kang DIAO, Kong-Ying LIN, Chao LI, Xiao XU, Lei LIANG, Qing-Jing CHEN, Xian-Ming WANG, Fu-Bao LIU, Wei-Min GU, Ya-Hao ZHOU, Ying-Jian Hong-Zhi Ming-Da Lan-Qing YAO, Timothy M. PAWLIK, Feng SHEN, Wan Yee LAU, Tian YANG*, Yong-Yi ZENG. Ann Hepatobiliary Pancreat Surg 2023;27:S166. https://doi.org/10.14701/ahbps.2023S1.LV-PP-1-1