The need for web services is constantly increasing, while the requirements for web services are getting more and more complicated. Thus, web server systems with ever increasing performance are constantly in need. To efficiently satiate this need, web cluster systems, which have been a topic of much research, have been suggested due to its scalability. In this paper, we design and implement a sc...

To persistently maintain client-server connections in mobile ad-hoc networks, we investigate the reliable server pooling (RSP), where servers that can provide equivalent functionality are pooled together. The RSP is meant to increase the availability and survivability of the battlefield infrastructure by allowing clients to access a pool of redundant information sources. As a result, some faile...

Local recovery approaches for reliable mw!ticmt have the potential to provide significant performance gains in terms of reduced bandwidth and delay, and higher system throughput. In this paper we ezamine two local recovery approaches — one server-based, and the other receiver–based, and compare their performance. The server-based approach makes use of specially designated hosts, called repair s...

Reliable Web service requires the ability to complete transactions that are in progress when a Web server fails. We have previously presented a client-transparent scheme, based on a standby backup and logging, for providing such fault-tolerant Web service. The scheme does not require deterministic servers and can thus properly handle dynamic content. This paper presents two performance optimiza...

Location-based services (LBS) become more feature-rich and versatile due to the explosion of mobile devices and the advances of positioning technologies. However, revealing personal private locations to potentially un-trusted LBS server and others may raise serious privacy concerns if these locations are not protected adequately. In this paper, we present a survey of existing methods dealing wi...

Hashcash was originally proposed as a mechanism to throttle systematic abuse of un-metered internet resources such as email, and anonymous remailers in May 1997. Five years on, this paper captures in one place the various applications, improvements suggested and related subsequent publications, and describes initial experience from experiments using hashcash. The hashcash CPU cost-function comp...

In reliable multicast communications, data packets are disseminated to all receivers in a multicast group. Generally, end-to-end congestion control adjusts transmission rate of the sender to the node of the lowest throughput in a multicast group. In this situation, when a multicast group includes receivers of significantly low throughput, lots of receivers suffer throughput degradation due to e...

The present investigation deals with the bulk arrival M/G/1 retrial queue with impatient customers and modified vacation policy. The incoming customers join the virtual pool of customers called orbit if they find the server being busy, on vacation or in broken down state otherwise the service of the customer at the head of the batch is started by the server. The service is provided in k</em...

The embedded web server is a combination of hardware and application software. Now a day’s these embedded web servers are widely used in industries for hazardous area data monitoring and controlling applications, like temperature, pressure, field device data can monitor and access remotely through wired or wireless communications. The wired embedded web server data accessed through Ethernet. In...

We apply some of the existing web server redundancy techniques for high service availability and scalability to the relatively new IP telephony context. The paper compares various failover and load sharing methods for registration and call routing servers based on the Session Initiation Protocol (SIP). In particular, we consider SIP server failover techniques based on the clients, DNS (Domain N...