Fahad Aijaz

Enabling High Performance Mobile Web Services Provisioning

The Telecommunication (TelCo) and Information Technology (IT) domains are converging at their intersection to provide vast variety of efficiently accessible services to the consumers. Specially in mobile communication domain, a vital factor that can affect the performance of any mobile application is the resource constraint nature of mobile devices with limited processing and storage capacity. On the other hand integration of heterogeneous networks and systems bring influential research challenges. In this paper, we present a concept of REST based Mobile Web Services (MobWS) provisioning and its comparison with a similar SOAP architecture in terms of HTTP payload. The requirements of REST architecture are discussed and URL structures are defined for the interaction with synchronous and asynchronous RESTful MobWS. A resource oriented approach for optimizing HTTP payload is presented and related message structures are discussed. It is shown that the REST based MobWS provisioning when compared to SOAP, offers promising results by significantly reducing the payload.

Towards Peer-to-Peer Long-Lived Mobile Web Services

Mobile phones in todays era are not just small devices that provide the means of communication, rather, they are equipped with more processing power, storage capacity and battery performance. Now, the hand held devices are not only service consumers but are also capable of hosting and providing services to their peers. These services deployed on mobile devices bring in the idea of mobile Web services (Mob-WS) to the research community. This paper concentrates on a middleware for long- lived Mob-WS that are accessible asynchronously over the network. Since the synchronous Mob-WS are not feasible for long durational tasks, therefore a concept and architecture of controllable and monitor able asynchronous Mob-WS middleware is presented. The service interaction techniques are discussed followed by the middleware subsystem and high-level architecture and control flow. The presented middleware is a potential basis for innovative mobile applications, therefore, a proof-of- concept prototype of asynchronous Mob-WS application is developed and presented with a special focus on network optimization for wireless sensor networks (WSN).

Mobile Web Service Communication Over UDP

A Web service based middleware for mobile applications is a promising platform to accelerate the application development for mobile systems. Currently, the Web service protocol stack is using by default the simple object access protocol (SOAP) on top of HTTP. Since HTTP is using TCP, the round-trip time of a Web service call in mobile networks is high due to the connection establishment of TCP (three-way- handshake) and the congestion and error control mechanisms (slow-start phase). Some applications do not require delivery guarantees of TCP. For these applications an unreliable transport of SOAP messages over the user datagram protocol (UDP) is a natural choice. If an application needs a reliable transport of SOAP messages a lightweight ARQ mechanism on top of UDP is the better choice than using HTTP over a mobile link. The session management of HTTP is substituted by introducing Web services addressing properties within the SOAP header. This paper will present the architecture and the realization of an unreliable and reliable UDP SOAP binding for a mobile Web service based middleware, which consumes Web services (client) and provides Web Services (server). Both bindings will map two basic MEP to UDP services. The reliable binding encapsulates a selective-repeat (explicit request) ARQ protocol on top of UDP which ensures even the transmission of SOAP messages over several datagrams. Some use cases and examples motivate the work and stress the importance according to the mobile middleware. A comparison of method invocation latencies of the reliable UDP binding and the HTTP binding illustrate the performance enhancements.

Middleware for Communication and Deployment of Time Independent Mobile Web Services

With the increasing storage capacity, processing power and battery capabilities, mobile devices are now able to providing services instead of just being service consumers. This paper introduces a middleware for time independent mobile Web services (Mob-WS) that avoids the overheads of long durational synchronous communication. Details of communication architecture and interaction among the middleware components is presented and discussed. The Bluetooth binding for SOAP has been developed and briefly presented.

Asynchronous mobileweb services: Concept and architecture

Today, mobile devices are capable of providing services instead of just being service consumers. These services deployed on mobile devices are known as MobileWeb Services (Mob-WS). In this paper, a middleware for long running Mob-WS that avoids the overheads of long durational synchronous Mob-WS in introduced. A concept and architecture of such asynchronous Mob-WS middleware is presented. Moreover, the middleware subsystem, the high-level architecture and control flow are presented in detail. Since every service has application specific requirements, the service data representations that eases the service deployment process are described. In order to verify the notion, a prototype with a focus on Wireless Sensor Networks (WSN) has been developed and briefly discussed. Finally, the manuscript is concluded and future research directions are identified.

Mobile P2P Web Services using SIP

Telecommunication networks and the Internet are growing together. Peer-to-Peer (P2P) services which are originally offered by network providers, like telephony and messaging, are provided through VoIP and Instant Messaging (IM) by Internet service providers, too. The IP Multimedia Subsystem (IMS) is the answer of the telecommunication industry to this trend and aims at providing Internet P2P and multimedia services controlled by the network operators. The IMS provides mobility and session management as well as message routing, security, and billing. This article is a comprehensive version of a conference publication [1] and introduces a Mobile P2P Web Services framework which enables the creation of arbitrary P2P application on mobile devices within the IMS. The terminals are sharing and publishing a Web Service interface, which provides the capability of coupling arbitrary applications using Web Service technologies and the support of the {IMS} infrastructure. The concept, the necessary Web Service adaptations, and extension as well as the interworking of Web Services, {IMS} nodes, and protocols are described and proofed by an exemplary mobile chess game application. In addition, the performance of mobile P2P Web Services is evaluated by means of an analytical analysis.

A Rule Based Publish/Subscribe Context Dissemination Middleware

Context information is vital data coming from mobile devices to add a value for the application execution. Such applications are called context-aware or context-sensitive applications. To enable context-aware applications in a distributed environment, first the context raw data is measured from sensors. After interpreting and structuring the data, the context objects have to be disseminated all over the distributed system. This paper introduces a context dissemination middleware based on a mobile Web Service framework. It eases the development of context aware applications by providing an abstraction layer hiding complex protocols. In addition, the protocols are optimized in terms of reducing latencies and network load. Moreover, to provide observation (monitoring) service of arbitrary context information, a rule description (policy) language has been designed, developed and structured. Web services eventing has been implemented for sending event notifications. The architecture and a prototypical implementation of the context middleware is presented in detail.

Enabling resource-oriented Mobile Web Server for short-lived services

Mobile Web Services (MobWS) are a promising technology for the integration of Information Technology (IT) and Telecommunication (TelCo) domains. The advancements in mobile communication and device technology, in terms of software and hardware, have revolutionized the focus of research and industry to investigate mobile service provisioning platforms and architectures. In this paper, we present a concept and architecture of a REST-Interfaced Mobile Web Server as a service delivery platform. Here, we discuss about the interaction strategy and URL-based access techniques for short-lived synchronousMobWS. The paper focuses on in-depth explanation of software architecture and its components of server and compares the payload requirements with the state-or-the-art SOAP based MobWS. The REST architecture has significantly reduced payload demands that shows promising signs of optimized processing performance of the mobile server when compared to SOAP.

A Mobile Context Dissemination Middleware

Context information is one of the most important data coming from, mobile devices to add a value for the application execution. This paper introduces a context dissemination middleware based on a mobile Web services framework. In a P2P environment, each context source/provider offers services to other devices. A monitor service is proposed which reduces the communication amount between devices and decreases the reaction time according to context changes. Moreover, to provide monitoring service of arbitrary context information, a rule description (policy) language has been designed. The paper presents an exemplary application in the health care domain to demonstrate the use of the middleware. Additionally, the application development process is described to point out the strength of the middleware for application developers

The resource-oriented Mobile Web Server for long-lived services

The Web Servers are globally accepted as the backbone of the Internet. The researchers in the area of the enterprise computing have studied, analyzed and implemented several architectures to optimize the performance of the largescale Web Servers. However, due to the convergence of the IT and the mobile communication domains, the mobile nodes now are also been viewed as the service hosting platforms. The aim of this article is to present an optimized Mobile Web Server architecture for provisioning the Mobile Web Services (MobWS) as lengthy processes. For that reason, the asynchronous interaction strategy is derived, and later used to comprehensively discuss the server architecture, which is based on the Representational State Transfer (REST) design principles. The manuscript presents a detailed performance evaluation of the architecture and compares the results with the server based on the Simple Object Access Protocol (SOAP) standard. The results show promising performance improvements due to the reduced payload requirements of the REST server.