A General Maturity Model and Reference Architecture for SaaS Service

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1 A General Maturity Model and Reference Architecture for SaaS Service Seungseok Kang 1, Jaeseok Myung 1, Jongheum Yeon 1, Seong-wook Ha 2, Taehyung Cho 2, Ji-man Chung 2, and Sang-goo Lee 1 1 Department of Computer Science and Engineering, Seoul National Univ., Seoul, Korea {pyxis81,jsmyung,jonghm,sglee}@europa.snu.ac.kr 2 Q.N.SOLV Corporation, Seoul, Korea {suha,thcho,comgen27}@qnsolv.com Abstract. In today s dynamic IT environment with increased global competition, enterprises must achieve greater business agility and decrease the TCO (Total Cost of Ownership) of their system for service. As the need for innovative software circulation process emerges, SaaS (Software as a Service) is introduced for integrating software service framework. But most of current ASP (Application Service Provider) Players have difficulties to migrate their systems to SaaS Platform for the lack of maturity model and process. In this paper, we have surveyed several cases of SaaS service, and we identified the common key functions of SaaS service. We contend that the practical maturity model is a key enabler for achieving migration to innovative SaaS service platform. To assist in building our SaaS maturity model, we defined two important axes of maturity model and introduced the detailed components of each phase with the reference architecture which contains the essential activities according to the common functions of SaaS service. Keywords: SaaS Service, ASP, Maturity Model, Software Business. 1 Introduction The economical, social, and technological development in the computing environment triggers big changes in the software business. The emergence of Web and its infrastructure has become an integral part of enterprise computing and continues to give both new opportunities and challenges to the software providing vendors. Intuitively, the development of IT technology and business environment gives a significant influence on software business as well as software itself. Traditional business paradigm on software is evolved due to the rapid change of IT technology, and it also brings the change of the type of service and technology. This paradigm shift in software business is categorized into four key parts of core service component such as data, system, service, and business. The emerging of SaaS is one of the results which are derived by paradigm shift. Based on the changes of software business environment, a number of current ASP players have tried to advance to new paradigm with SaaS service component. However, there are still some challenging issues due to the lack of adequate growth H. Kitagawa et al. (Eds.): DASFAA 2010, Part II, LNCS 5982, pp , Springer-Verlag Berlin Heidelberg 2010

2 338 S. Kang et al. strategy and proper guideline for adapting the characteristics of SaaS service in their current service model. In this respect, we believe that a SaaS service architecture based on a general SaaS maturity model is an enabler of a myriad of current ASP players who want to adapt the concept of SaaS service. In this paper, we survey several cases of current SaaS service, and identify the common key functions of SaaS service to build successful SaaS service from their service model. Second, we define our general SaaS maturity model and the detailed components of each phase of our model with two important axes. Finally, we propose the SaaS service architecture which contains the essential activities according to the common functions of SaaS service. 2 Related Work It s a common experience among software companies today with increasing cost pressure, high customer expectation, and global competition all placing new demands on development and delivery processes. SaaS is a software delivery model where instead of purchasing the software and implementing, users can rent the software on a monthly cost-per-user or usage basis and can scale up or down as needed [1]. There are some representative SaaS vendors including Microsoft, Google, Salesforce.com, and Amazon which provide successful service cases. They have different strategies to catch up the paradigm shift toward SaaS respectively. However, nowadays, it seems that software vendors have reached a consensus that SaaS model can be achieved in an incremental way. Several research groups have reported characteristics and maturity model for SaaS service platform. Microsoft characterizes configurability, multi-tenancy, scalability as key criteria of SaaS maturity model [2]. Forrester group also presented 6 levels of maturity model from traditional ASP to SaaS service model [3]. In addition, SaaS has been intensively studied with the academic point of view. A number of academic researchers have analyzed principal aspects of SaaS model, and also, have reported several features and advantages with both customer s and enterprise s perspectives [4-6]. Actually, SaaS is a complex business model which has many role players such as customer, developer, vendors, and so on. Therefore, some researches argued processes and interactions between them [7-8], and also, some researchers introduced lesson learned of implementing SaaS [9-11]. There also have been discussions about the maturity of SaaS model [12]. The rest of this paper is organized as follow. In section 3, we examine current SaaS service cases and identify common features of SaaS service according to the research methodology to find out key enablers for SaaS service model. In section 4, current SaaS maturity models are introduced and compared with our maturity model. A detail activities and architecture based on the maturity model is presented in section 5, and finally we draw our conclusion in section Research Methodology Our research methodology consists of three steps - Deriving SaaS Service Functions, Defining SaaS Maturity Model, and Establishing SaaS Service Architecture.

3 A General Maturity Model and Reference Architecture for SaaS Service 339 Generally SaaS service consists of core functions which represent the properties of SaaS service. In this phase, we derived some common key functions of SaaS service through the survey of several cases of SaaS vendors. Moreover, we have analyzed the current maturity model for SaaS service such as Microsoft s and Forrester s model. Considering these approaches, we defined the important axis and our maturity model based on these axes according to the incremental development phase. The last step is establishing SaaS Service Architecture according to maturity model. In order to make practical methodology to build SaaS Service, we categorized the technical activities which constitute the role of each layer on the maturity levels. 3 An Analysis of SaaS Service Since definition of SaaS is shown as various meanings according to researchers, we adapted the meaning of SaaS service through the Gartner Group as follows: software that is owned, delivered and managed remotely by one or more providers. The provider delivers an application based on a single set of common code and data definitions, which are consumed in a one-to-many model by all contracted customers, at anytime on a pay-for-use basis, or as a subscription based on usage metrics. [8]. In other words, SaaS is a service-oriented framework with high deployment efficiency and supportable platform where ASP focused on architecture-oriented solutions with low deployment efficiency relatively. In this section, we discuss several cases of current large SaaS vendors which have their own characteristics of functionalities of SaaS service, and derive the essential common functions to build successful SaaS service. 3.1 Case Study: In Case of Current SaaS Service Vendors Nowadays, the marketplace of SaaS service is mostly lead by international large software vendors and traditional solution provider for enterprise. We selected four major vendors as the successful cases of current SaaS service and surveyed the characteristics based on our conceptual SaaS service characteristics. Table 1 shows a summarized result of present condition of four SaaS service vendors Amazon: Service Infrastructure Amazon provides SaaS service in terms of Amazon Web Services. It mainly focus on providing computing resources to users rather than a separated web-based application so that it gives customers various business application on their service infrastructure that is based on cloud computing paradigm. The goal of Amazon s SaaS service can be summarized by these terms: Cost-effective, Dependable, Flexible, and Comprehensive. In order to achieve the goals of Amazon Web Services, they settled various service types from business infrastructure to Web search and on-demand workforce. A distinct characteristic of Amazon Web Service is to give the opportunity to ISVs (Independent Software Provider), where the main targeted user of other vendors is end-users themselves who use the applications on the SaaS framework.

4 340 S. Kang et al Salesforce.com: Platform as a Service The SaaS service of Salesforce.com can be summarized as Force.com platform. It is a multi-tenant on-demand business platform which consists of service component and process. The biggest difference of the strategic directions of salesforce.com is to be a solution provider to enterprise with multi-tenant support platform. The whole service process of Force.com service aimed to achieving the next level of current SaaS, which is called PaaS (Platform as a Service). It means that PaaS should be able to provide the tools for developing on-demand applications easily on the Web-based infrastructure as well as using and distributing the solutions Microsoft: Software+Service The main target users of Microsoft are customers who have used Microsoft s package software such as Windows and Microsoft Office. They try to add the service strategy based on the web to existing software in comparison with the other vendors who provide their service through network by using Web browser. This strategy is called Software+Service. The strategic directions of Microsoft are categorized into four parts: Unified Experience, Server and Cloud, Tightly Coupled System, and Multiple Business Model. By adapting these strategies, Microsoft tries to get flexibility and availability on service process from building service with software to software distribution Google: Service on the Web Google provide SaaS service as the set of Google application named GoogleApps. It provides communicate and connect service through Web browser, and they are interlinked by collaboration process of Google Application such as Google Docs and Google Sites. In order to use their infrastructure and ability to search on the Web, Google tries to organize user s service via Web application development environment named Google Apps Engine. Most of Google SaaS service is supposed in the form of distributed APIs to guarantee effectiveness, flexibility, and easiness of application usage. Table 1. Summarization of SaaS Service Vendors Vendor Service Description Business Model Origin Strategy Computing Amazon Service Amazon Web Service Resource Providing Web Services Infrastructure Web service / Platform Salesforce Web-based CRM Force.com CRM as a Service Personal / Microsoft Package Software Microsoft Office Tools Office Live Software +Service Web-based Service Google Web Office Tools Google Apps Service on the Web 3.2 Common Functions of SaaS Service By surveying representative cases of current SaaS service, the common functions are established which could be used for building standardized SaaS platform. We classified each function into technical and business functions as follows.

5 A General Maturity Model and Reference Architecture for SaaS Service 341 Table 2. The Common Functions of SaaS Service Technical Function Shared Database and Service Multi-tenant Predefined Database Extension Support Distributed Database Schema User Interface Workflow and Business Rule Configuration Customizable Data Model Metadata Set Scalability Standard Support Integration Security Scaling The Application Scaling The Data Standard Business Data Model Business Standard Platform Standard Development API Set Mash-up API Web Service Service Connector Multi-Platform Support Authentication Authorization Security Proof Tailored Security Policy Market Scalability Development Communication Business Function Open Marketplace Application Selling Business Model SLA Adaptation and Support Service Billing Policy Guaranteed Performance Monitoring Tools for Availability and Performance Development Toolkit Providing Application Release Process Integrated Development Platform Supporting Community for Users Partnership Policy Technical Functions It means a set of functions which are related to technical issues of SaaS service such as database management, configurable user interface and business workflow, and integration technology. We expand the concept of the feature in their maturity level with Standard Support, Integration, and Security based on the features of Microsoft s maturity model such as Multi-Tenant Support, Configuration, and Scalability Business Functions Business function is another important issue because software vendors should provide proper business model to customers and guarantee the continuity of business activity on their service platform with performance. We divide the business functions into four categories such as Market, Scalability, Development, and Communication area. Each category also contains list of detailed functions, which can support availability of core business competency. 4 SaaS Maturity Model The strategic positioning of current SaaS services are promoted in different ways according to platform openness to partnership and their original service type such as packaged software or Web-based service. Nevertheless, current maturity models have not been able to present concrete procedures due to ambiguous definition of maturity levels. In this section, we introduce two maturity models from Microsoft and Forrester research group as examples of current maturity model for SaaS service.

6 342 S. Kang et al. Microsoft s maturity model is a sort of incremental development model through integration between functional features of SaaS. There are four level of maturity level such as Ad hoc/custom, Configurable, Multi-Tenant, and Scalable. Ad hoc level represents traditional ASP model with customizing to each individual users. At configurable level, users do not need to modify the application in the code level where multi-tenant architecture and tenant load balancer support the adaptation of various customers requirements. Despite of the well-defined incremental structure, it is still ambiguous to measure ASP vendors availability due to the lack of detailed concepts. Forrester s model is similar to Microsoft s maturity model, but it contains six degrees of incremental development. At level 0 and 1, it can be mapped into current ASP players who handle their business manually with single or similar application to multi clients. At level 2 and 3, it can be called SaaS service because most of the vendors provide configured solutions with multi-tenant environment via packaged or Web-based distributed application. Level 5 and 6 contains custom extensions and dynamic composition so that service provider can compose user-specific applications with custom extensions in a multi-tenant environment. However, it also does not suggest the detailed incremental process of evaluation. 4.1 The Axis of Maturity Model We decide the axis of maturity model as the core criteria for measuring the degrees of evaluation; service component axis and maturity level axis. We defined the service component as the core features of structuring software business, where each component corresponds to higher or lower layers of components. Moreover, we categorized our maturity levels which stand for the current situation of availability for ensuring SaaS service into four levels. In general, each level represents the fundamental foundation which is needed to evolve to next level in the model. Fig. 1 shows the summary of our service component and maturity level axis. Fig. 1. The two axes of maturity model: Service Component and Maturity Level 4.2 Maturity Model Combining with two axes we discussed above, we build a general SaaS maturity model in Fig. 2 as a set of keywords that represent the core requirements. In detail, the components on the maturity model have technical activities which consist of the

7 A General Maturity Model and Reference Architecture for SaaS Service 343 structure of service component. The following sections describe the concrete figures which are mainly discussed as essential component of our SaaS maturity model Ad Hoc Level Ad hoc level is similar to current Ad hoc system with simple ASP business model. In this level, most of ASP players are concentrating on dedicated database and schema in data layer and schema without respect to content sharing and multi-tenant environment. System layer also consist of Ad hoc multi instances which use different applications by users. The service layer has separated system integration on Web interface mainly, where the detailed functions of the services are materialized by various requirements of customers. Finally, the business process such as SLA on Ad hoc level mostly depends on the simple contraction that reflects the necessity of separated users without any concrete policies. Many service providers have failed to find the proper ways to build SaaS service model and still have stayed in this level Standardization Level Standardization level aims to provide shared service with the discrete instances of user s application and configurability. We define other features of data and business layer as sharing contents and standardized service policy. In this phase, customers use shared and publicized database with dedicated data schema. System layer support configurable single instance and single tenant so that users build their service model within predefined instance that is given by service provider. With respect to customize applications, service layer also has configurable options in service software. In addition, the standardized methods are needed in the last business level of our maturity model. Despite of the conspicuous features which show the typical characteristics of SaaS service, it still does not support multi-tenant environment, one of the most important issues of SaaS platform Integration Level The third level of our model is integration. It contains the entire feature of former two levels while it focuses on actualizing multi-tenant environment. In other words, database schema is shared as well as database itself in the data layer in order to accommodate multi tenant simultaneously. In the system layer, multi tenant supporting platform is provided with single instance. It means that user s systems should use predefined common instance with simple configurable options where the various user functions are achieved by service combination such as Web service and mash-up. Lastly, business layer focuses on realizing measurable SLA adaptation with standardized scheme. In general, most of current SaaS vendors concentrate their ability to build multi tenant service process with service connection as the key factors of successful SaaS service we described above Virtualization Level We believe that the ideal approach to reach real SaaS service is virtualization. For achieving virtualization on the data layer, entire database and its schema should be constructed upon distributed computing power such as cloud computing. It aims

8 344 S. Kang et al. to realize optimized multi-tenant environment through well-defined set of metadata. In the system layer, the system space is transformed into virtual concept with load-balancing system. With the measurement of a quantity of service used, service providers can allocate the computing power dynamically to the users systems on the virtual space. Similar to integration level, a set of function is given by interlinked service combination whereas business process covers the requirements of users instead of customization in code levels. It is generally considered that the service architecture on full-soa can achieve the goals of service layer on virtualization level. Finally, business layer on this level is represented by optimized SLA adaptation. Service provider can use flexible and dynamic methods for measuring the amount of service used so that they ensure the optimization of SLA policy to their customers. In conclusion, virtualization level mainly focuses on maximization of practical use of resources via service modulation and encapsulation. Fig. 2. General SaaS Maturity Model 5 SaaS Service Architecture Considering the gap between the ideal figure of SaaS service and general business model of ASP players, referenceable SaaS service architecture is able to help service providers decide the service model and its development process in practical ways. We will present our SaaS service architecture roughly in terms of general service process and the major activities of SaaS service. 5.1 Major Activities of Maturity Model Assuming the role of SaaS maturity model, the abstract definition of each level is converted into technical activities with hierarchical structure which constitute the structure of service architecture. As the same ways, second level activities can be described with lower level activities. Table 3 summarizes a part of the major activities on our maturity model.

9 A General Maturity Model and Reference Architecture for SaaS Service 345 Table 3. A Part of Major Activities on SaaS Maturity Model Virtualization Integration Standardization Virtualization Integration Standardization Data Metadata Management Data Structure Optimization Data Structure Management Data Model Management Database Performance Management Database Security Management Service Service Optimization On-Demand based Business Process Standard Service Distribution Service Reuse Measurement Software Quality Management User Requirement Management System System Provisioning Resource Optimization Resource Management Resource Measurement System Composition Management Business SLA KPI Optimization SLA KPI Measurement Standard SLA template production 5.2 Reference Architecture Based on the service activities described above, we design SaaS service architecture and its service process. Our service architecture is a middleware between service users and service vendors, where the SaaS service platform in the architecture consist of three parts such as data, system, and service. Each part of service platform guarantees the core competencies of SaaS service. Fig. 3 describes a big picture of SaaS service architecture with the flow of business process. Fig. 3. SaaS service architecture 6 Conclusion and Future Work This paper reviewed the SaaS service model and offered a practical SaaS maturity model and the service architecture with core functionalities of SaaS service. From our analysis described in previous sections, we concluded that the challenging issues of migrating current ASP service to SaaS can be solved incrementally by adapting the concept of our maturity model with two important axes. Our maturity model only considers 2-dimension axes such as service component and maturity level. We believe that expanding the maturity model with n-dimension axes according to the organizations or characteristics of enterprise can contribute for designing future SaaS platform. In addition, we also aim at implementing real SaaS service platform with our maturity model and architecture with service process.

10 346 S. Kang et al. It is essential for enterprises to provide a strong and steady vision of SaaS service. However, existing approaches are still too general to design the detailed business process. We believe that the maturity model should give a concrete way of constructing a strategy to build practical SaaS service. Based on this research, we will begin organizing the nature of SaaS service and refining our maturity model with core competencies and more detailed requirements considering the current situation of industry as a whole. We also expect that our research will contribute to spread the concept of SaaS service within the service architecture as well as unique strategies within some practical semantic technology in the near future. Acknowledgments. This research was supported by the MKE(The Ministry of Knowledge Economy), Korea, under the ITRC(Information Technology Research Center) support program supervised by the NIPA(National IT Industry Promotion Agency). (grant number NIPA-2009-C ). References 1. Upadhyay, S.: Software as a Service (SaaS). Oracle (2008) 2. Chong, F., Carraro, G.: Architecture Strategies for Catching the Long Tail, MSDN Library. Microsoft Corporation (2006) 3. Ried, S., Rymer, J.R., Iqbal, R.: Forrester s SaaS Maturity Model. Forrester Research (2008) 4. Ma, D.: The Business Model of Software-As-A-Service. In: IEEE International Conference on Services Computing (SCC 2007), pp (2007) 5. Waters, B.: Software as a service: A look at the customer benefits. Journal of Digital Asset Management 1(1), (2005) 6. Xin, M., Levina, N.: Software-as-a-Service Model: Elaborating Client-Side Adoption Factors. In: 29th International Conference on Information Systems, Paris, France (2008) 7. Sääksjärvi, M., et al.: Evaluating the Software as a Service Business Model: From CPU Time-Sharing to Online Innovation Sharing. In: IADIS International Conference e-society, Qawra, Malta, pp (2005) 8. Choudhary, V.: Software as a Service: Implications for Investment in Software Development. In: 40th Annual Hawaii International Conference on System Sciences, HICSS 2007 (2007) 9. Greschler, D., Mangan, T.: Networking lessons in delivering Software as a Service - part I. International Journal of Network Management 12(5), (2007) 10. Guo, C.J., et al.: A Framework for Native Multi-Tenancy Application Development and Management. In: 9th IEEE International Conference on E-Commerce Technology and (CEC 2007), Tokyo, Japan (2007) 11. Chou, D.C., et al.: Analysis of a new information systems outsourcing practice: softwareas-a-service business model. International Journal of Information Systems and Change Management 2(4), (2007) 12. Goth, G.: Software-as-a-Service: The Spark That Will Change Software Engineering? IEEE Distributed Systems Online 9(7), Art.No o7003 (2008)