The CORA Model

Introduction

This blog is the first in a series around on the comparion between the CORA model and SAP. In this first part, after introducing SAP, the SAP SOA Reference Architecture is mapped onto the CORA model.

The history of SAP

Over the course of three decades, SAP has evolved from developing standard application software for real-time business processing to providing collaborative, inter-enterprise solutions for end-to-end business processes. It covers standard business applications and technologies as well as specific industry specific applications. SAP has focus on two main areas, Applications and Technology put together in the 'SAP Business Suite', where the applications are based on the SAP NetWeaver technology platform. SAP Netweaver is an integration and application platform, which supports the evolution of SAP Business Suite applications to a services-based architecture. The huge amount of software components of Services to choose from calls for continuous architectural thinking and consideration.

The Vision of SAP

The vision of SAP is all about speed of time-to-market and flexibility. SAP describes this as See Clearly, Think Clearly, Act Clearly: "Our vision is for companies of all sizes to see clearly, think clearly, and act clearly so that they can close the gap between strategy and execution and become best-run businesses. Best-run businesses drive clarity into their organizations by gaining insight for improved performance, efficiency for optimized operations, and flexibility to adapt quickly to changing circumstances." 

 SAP strives to evolve its tightly integrated packaged applications to ease adoption through increased modularity. This is achieved  specifically by augmenting the extensible business process platform with point solutions  that address specific industry or line of business needs. SAP intends to develop the business model to more effectively support the end-to-end requirements of customers through:

• developing their own product portfolio,
• collaborating closely with customers and partners,
• and with targeted strategic and "fill-in" acquisitions that add to the broad solution offerings.

 

Architectural views of SAP and CORA scope

The SOA Reference Architecture of SAP describes a SOA-based layered architecture.

This Reference Architecture describes a SOA-based layered technology. Service-enabled applications contain required functionality. The provisioning layer provides abstraction from the actual backend systems by providing a consistent set of services. SOA middleware supports service-enabling legacy systems handling the system-centric and cross-organizational processes. In the consumption layer services are utilized to create user interfaces and processes. The user interfaces layer offers several possibilities to implement user interaction based on available services.

Mapping the SAP SOA reference architecture onto CORA results in the following matrix.

Assessing the results

SAP is mixing Channels and Presentation technologies compared to the CORA. It mentions Portal but also Adobe Form which in itself can be accessed throughout a Portal as an electronic form. Back-end connectivity and Service Bus are two layers. In the CORA this is one layer but separated in different elements . The Enterprise SOA consumption layer contains the same elements as the Composition layer in the CORA. The difference in the naming of the layer is interesting because composite services are not only consuming but actively providing themselves too! A Data layer is not recognized as a separate layer but positioned within applications.

SOA management is a horizontal layer while in the CORA it is positioned as a vertical layer to manage SOA on more horizontal layers. Important is the absence of a Security and IT Governance. Impact for implementing SAP is that firstly security needs to be included over all layers. Secondly the governance of SAP components and integration in the whole governance cycle including run-time governance needs to assessed. 

What is the added value of CORA in the SAP field

As shown the CORA model is used as a quality instrument to assess the the SOA Reference Architecture of SAP. The following questions could be raised:

• Why are the vertical CORA layers absent?
• What are the cluster and separation criteria based upon?
• If other architecture styles than Service Oriented Architecture (i.e. N-Tier or Resource Oriented Architecture ) is used, does this reference architecture still apply?
• Etc.

For both an Enterprise Architecture and Software Architecture on Enterprise Level it is not possible to use solely the SOA Reference Architecture of SAP as a quality instrument because

• within a common IT Landscape multiple architecture styles (N-tier, Service Oriented Architecture, Resouce Orientented Architecture) co-exist instead of just one,
• the clustering is based on SAP components, which can differ from other vendors.
  

As shown in this assesment at the (SAP) project implementation level the SOA Reference Architecture can be used to create a Solution Architecture, because of its direct relation with the SAP components. However this should only be done when it is connected to the CORA, to guarantee architectural governance between the Enterprise and the project Solution Architecture.

CORA can also be used to asses the 'SAP Business Suite', regarding separation of responsibilities, decoupling, re-usability, portability and substitutability of elements, by plotting the different SAP-components onto the CORA layers and elements. This will be described in the next blog.