SOA and REST

Question

Hi
I start this thread to get an insight from the Architect community who is working on the Best-Built applications to know the direction related to adhering and adopting to SOA and REST based applications.
In this guidelines book, I see SOA as the framework to expose the business functionality as Enterprise Services, even it suggests that BAPIs and RFCs are to be encapsulated in webservices as far as possible. I like the guidelines to provide the application flexibility for the business logic so that I can use irrespective of the platforms, versions and so forth. Also it helps me in orchestrating these services in A2A, B2B and in the integration scenario where multiple systems and softwares are used.
Then came the new buzzword, I understand that many developers and Architects are considering REST as the go to Architecture for the future and SOA enterprise services may be outdated.
I do believe that REST and SOA webservices are different architectural styles, REST can be used more in sin point to point simple client server and point to point applications(synchronous) and mobile scenarios, so that the SOAP payload that exists in SOA can be avoided to improve the performance and data tranfer. But how much it can be used in the A2A, B2B integration scenarios where the critical business applicartions always rely on Asynchronous communication. SAP Bnaking and Utilities are heavily developed based on SOA based Enterprise Services. At the same time within SAP some people are still under the impression SOA is dead.
I am now confused, as an Architect I would like to follow these guidelines to suggest the customers and the developers I am working with that follow the guidelines. But, there is no mention about REST in this book except in one place. It would be nice to mention in this book about guidelines of using REST and SOA.
I am really interested in hearing from you all and the document owners as well.
Regards,
Suresh

Answer 1

Hi Suresh,
you raise a very good question, which keeps the BBA team quite busy. I might not be able to give a perfect answer right now, but stay tuned for our next BBA updates. We are working on new SAP NetWeaver Gateway and a Mobile chapter. I foresee that those new chapters will also trigger some minor updates on language in the existing Process/SOA chapter.
For last weeks TechEd in Las Vegas we already published a preview of the Gateway and Mobile chapter in the pdf version of our book. My personal opinion is that SOA comes with different implementation flavors, which are optimized for different use cases. Web Services and REST are both just different means of Service Orientation. As you said, web services is a good choice for A2A, B2B integration. On the other hand other more light weight integration for mobile but also other very light weight applications are a better use case for REST.
We need to be thorough on releasing our official SAP Guidelines and need to ask for your patients. As said stay tuned for more updates on Gateway, Mobile and Process/SOA.
Best, Joerg