Enterprise Mobile Service Architecture

Today, enterprise systems are integrated across wired and wireless networks. Enterprise Mobile Service Computing (EMSC) is a recent development style in distributed computing, and Enterprise Mobile Service Architecture (EMSA) is a new enterprise architectural style for mobile system integration. This chapter introduces the concepts of EMSC, discusses the opportunities, and addresses mobile constraints and challenges in EMSC. The mobile constraints include aspects relating to mobile hardware, software, networking, and mobility. Many issues such as availability, performance, and security are encountered due to these constraints. To address these challenges in EMSC, the chapter proposes seven architectural views: Enterprise Mobile Service, Enterprise Mobile Service Consumer, Enterprise Mobile Service Data, Enterprise Mobile Service Process, Enterprise Mobile Service Infrastructure, Enterprise Mobile Service Management, and Enterprise Mobile Service Quality. Each is described with principles, design constraints, and emerging technologies. In order to illustrate a practical implementation of EMSA, the chapter presents a major shipping and delivery services enterprise as a case study to describe the integration of Service-driven mobile systems in the enterprise.

Coordinating Enterprise Services and Data

The critical inter-dependencies between Enterprise Services and Enterprise Data are often not given due consideration. With the advent of Cloud Computing, it is becoming increasingly important for organizations to understand the relationships between them, in order to formulate strategies to jointly manage and coordinate enterprise services and data to improve business value and reduce risk to the enterprise. Enterprise Services encompass Service-driven applications deployed on-premises in the enterprise data centers as well as in the Cloud for the “extended enterprise.” Enterprise Data Management encompasses the cross-application enterprise-level perspective of data in an information-sharing enterprise, and the critical business data that is created, maintained, enriched, and shared outside the traditional enterprise firewall. This chapter discusses and proposes best practice strategies for coordinating the enterprise SOA & EDM approaches for mutual success. Primary coordination aspects discussed include: Service & Data Governance, Master Data Management, Service-driven & EDM Architecture Roadmaps, Service Portfolio Management, Enterprise Information Architecture, and the Enterprise Data Model. It recommends a facilitative Service-driven Data Architecture Framework & Capability Maturity Model to help enterprises evaluate and optimize overall effectiveness of their coordinated Service-driven & EDM strategies.

Architectural Practices for Improving Fault Tolerance in a Service-Driven Environment

Enterprises that implement Service-driven applications face challenges relating to unprecedented scale, high availability, and fault-tolerance. There is exponential growth with respect to request volume in Service-driven systems, requiring the ability to provide multipoint access to shared services and data while preserving a single system image. Maintaining fault-tolerance in business services is a significant challenge due to their compositional nature, which instills dependencies among the services in the composition. This causes the dependability of the business services to be based on the reliability of the individual services in the composition. This chapter explores the architectural approaches such as service redundancy and design diversity, scaling, clustering, distributed data caching, in-memory data grid, and asynchronous messaging, for improving the dependability of services. It also explores the data scaling bottleneck in data centralization paradigms and illustrates how that presents significant scalability and fault-tolerance challenges in service-driven environments. Prevalent strategies to handle failure recovery such as backward and forward recovery mechanisms as well as the built-in mechanisms in WS-BPEL for exception handling and transactional compensation are discussed.

Maintaining Transactional Integrity in Long Running Workflow Services

This chapter presents a framework to provide autonomous handling of long running transactions based on dependencies which are derived from the workflow. Business Processes naturally involve long running activities and require transactional behaviour across them. This framework presents a solution for forward recovery from errors by automatic application of compensation to executing instances of workflows. The mechanism is based on propagation of failures through a recursive hierarchical structure of transaction components (nodes and execution paths). The authors discuss a transaction management system that is implemented as a reactive system controller, where system components change their states based on rules in response to triggering of events, such as activation, failure, force-fail, completion, or compensation events. One notable feature of the model is the distinction of vital and non-vital components, allowing the process designer to express the cruciality of activities in the workflow with respect to the business logic. Another novel feature is that in addition to dependencies arising from the structure of the workflow, the approach also permits the workflow designer to specify additional dependencies which will also be enforced. Thus, the authors introduce new techniques and architectures supporting enterprise integration solutions that cater to the dynamics of business needs. The approach is implemented through workflow actions executed by services and allows management of faults through a policy-driven framework.

Enterprise Integration

The purpose of this chapter is to discuss the current state and associated challenges of Enterprise Integration (EI). The chapter will explore EI’s past, present and future, examine its path towards the current practices, and contemplate its future evolution. Synergies between Service-driven and other modern architectural approaches will be investigated. Major challenges associated with EI strategy and execution will be explored in depth. This will include organizational, technology, process, methodology, and governance challenges. In addition to the current state concerns, future trends and directions will be investigated and specific challenges outlined. A major part of this chapter will be devoted to defining and discussing modern solution architectures associated with EI. This will include current architectural best practices, technology constructs employed, design patterns, governance mechanisms, and implementation considerations.

Service-Driven Approaches to Software Architecture

Software Architecture has evolved from simple monolithic system designs to complex, multi-tiered, distributed, and componentized abstractions. Service-driven architectural approaches have been a major driver for enabling agile, cost-effective, flexible, and extensible software applications and integration solutions that support the business dynamics of today’s fast-paced enterprises. SOA and the SCA model have been the typical Service-driven architectural approaches used in enterprises today, to tackle the challenges of developing and implementing agile and loosely coupled software and enterprise integration solutions. Recent trends involve the use of Web APIs and RESTful architecture in the enterprise for agile service development and application integration. The goal of this chapter is to explore, discuss, and recommend methodologies for Service-driven Computing in the enterprise. Service versioning is detailed as a primary architectural approach for accommodating modifications to services during their life cycle. Service Mediation, Enterprise Service Bus, and Composition mechanisms including Enterprise Mashups are explored. The chapter also presents the business value of APIs in the enterprise and investigates the value-add to Social Media and Cloud enterprise initiatives. The typical phases of a Service-driven development life cycle are explained and service design patterns to facilitate the engineering of flexible service-based applications are described. The chapter concludes with thoughts on future opportunities and challenges in the area of Service-driven computing.

Access Control in Service Compositions

Pervasive applications are entering the mainstream, but at the present time, exhibit significant security weaknesses. Service-driven architectural approaches facilitate the development of pervasive applications, however, security with respect to access control and data privacy of pervasive applications are currently not managed comprehensively from design time through run time. This chapter presents a use case emphasizing the security challenges for pervasive applications and proposes a novel, generative architectural approach, to include security in pervasive applications at design time. This is a model-driven approach based on models pertaining to access control management that respect the temporal constraints relating to pervasive applications. The approach is implemented with a design and runtime environment and the results of the validation applied to the pervasive use case are presented.

Enabling Vendor Diversifiable Enterprise Integration

Without effective architectural oversight, enterprises risk stifling their ability to innovate, because vendor products are too tightly woven into their key business processes, which impedes the evolution of their technology environment in support of business needs. Vendors gain negotiation leverage due to monopoly on the technology that supports key enterprise processes and capabilities. The goal of this chapter is to provide practical guidance on business flexibility advantages through carefully managed vendor diversification options for enterprises that are implementing Service-driven applications and integration solutions. The approach presented in this chapter recommends adherence to four basic principles, namely, owning the ability to control delivery channels and integration, compartmentalizing concepts into fulfillment roles in the Service-driven enterprise, using a vendor agnostic enterprise service interface, and owning the key data. The dual reinforcing concepts of ownership and control underpin the vendor diversification opportunities. A reference architecture is presented that distills these principles into a conceptual model that can be applied to any enterprise. A real world transportation and logistics business enterprise integration project is used as an example to illustrate the advantages of using vendor agnostic principles in a Service-driven environment.

Governing the Service-Driven Environment

The purpose of this chapter is to discuss tools, technologies, and practices employed to govern the service lifecycle in a Service-driven environment. Aside from defining the complete service lifecycle, the discussion will concentrate on specific approaches to governing each stage in the lifecycle and best practices associated with it. SOA governance methodology will be covered in great detail. The topics discussed will include SOA Governance program structure, methodology, processes, funding, value demonstration, and adoption levers. These governance mechanisms will be aligned with each stage in the service lifecycle, and appropriate applications will be identified accordingly. Current and future state of governance tools and technologies will be explored. Some examples of existing tools will be provided to highlight and support the assertions made throughout the chapter. Connection between stages in the service lifecycle and the governance tools and technologies will be identified and best practices explored.

Mediating Message Heterogeneity in Service Compositions

Atomic Web Services (WS) may not always be sufficient for service requests. For such cases, several services may have to be assembled to create a new composite service of added functionality and value. Establishing message exchange between related but independently developed Web Services is a key challenge faced during WS composition which has hereto received inadequate attention. One of the challenges lies in resolving the differences in the schema of the messages that are input to and output from the Web Services involved. Data mediation is required to resolve these challenges. This chapter introduces a formal model for data mediation that considers the types and semantics of the message elements. Based on this model, it proposes methods for resolving different kinds of message-level heterogeneity. These methods are evaluated on synthetic and real-world pairs of Web Services, with the ultimate aim of integrating the data mediation techniques presented within WS composition tools.