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Connecting 2 Backend Systems, Part One: RFC Connections



Originally NWBC was designed to enable users to consume many different UI technologies from just one ABAP backend system. However, in practice, several customers are using NWBC to connect 2 or more back end systems. So I wanted to create some help for those contemplating this step. In this blog series, I’ll be describing how you set this up.

Please note: Implementing this is *not* trivial. The decision, as to whether you should embark on this is very project-specific. Factors influencing the decision include:
• Size and complexity of landscape: How many systems? What sort of systems: non-ABAP, non-on Premise systems increase complexity and maintenance costs. For integration of Java, Success Factors, Ariba, Cloud, and Mobile scenarios, Portal is generally a better option.
• Number of Users
• Skill set: Does the customer or partner have lots of experience with multiple backend connections, eg with transactions SM59, SMT1, SSO2 etc, plus the necessary role configuration in PFCG?

Also, this blog is about making it work; making it secure is beyond the scope.
In short, if you do not feel confident embarking on this, then you probably shouldn't. For more information on the considerations involved in using NWBC to connect two ABAP back ends, see SAP Note 1795171 .

The blog series is in three parts:

You can then include the CRM connection in a role, simply by following the SAP Library documentation.
The connections we'll be setting up look roughly like this:
It's probably a good idea to make a sketch of your systems before you start. People get confused more often than one might think.
OK, now to start:

Setting up the RFC Connection: ABAP

Start in the calling system – ie M10 (ERP) in this example.
  1. In NWBC (or SAP GUI), open RFC Destination: Display/Maintain (SM59).
  2. Create a new ABAP connection (type 3).
  3. Enter the settings you need:
On the Technical Settings tab:
    • Target Host, System No. : Get these from the System Selector
    • IP Address: By default the IP Address field may be blank. Just switch to Hostname and back, and the IP Address appears (derived from the target host you just entered).
On the Logon & Security tab:
5. Finally, save your changes.

Testing the ABAP RFC connection

  1. Choose Test Connection, from the toolbar at the top.. You should see something like this:
  2. Now choose Remote Logon . A new instance of NWBC should open, showing the system no. M20 (the CRM system):
If the tests don’t work, don’t go to the next step till they do ;-). Troubleshooting is beyond the scope of this tutorial, but there is more help at the end of the blog.

Setting up the RFC Connection: HTTP

Since the CRM application is Web UI-based, we also need to set up an HTTP connection. The HTTP connection should have the same name as the ABAP connection, just with a _HTTP suffix attached.
  1. Again, create a connection, this time HTTP Connection to ABAP System (Type H), and make the following settings:
On the Technical Settings tab:
    • Target Host, Service No. (= Port No.) : Get these from the System Selector
On the Logon & Security tab:

Testing the Connection: HTTP

1. If you simply choose Connection Test, you should get an HTTP Response 404 – the client found the server, but not a service. This is not surprising, since we haven’t specified a service.
So, in the path prefix, let’s specify a simple ping service.
/sap/bc/ping?sap-client=800 .
(You can check the correct path for this service in your system in transaction SICF - in the CRM system).
Note: The system won’t like this, and the text will turn red, and you will get an error message. Just press Return – the text will turn black and the test will run ok !
You should now get an HTTP Response 200:
2. If everything is working, delete the ping service, then save your changes.
CAUTION: You must delete the ping service before you save your changes. Otherwise, the system will prepend the ping to the path, and won’t be able to call the CRM service.
OK, you're now ready for Part Two: Setting Up a Trusted System Relationship.
For more information, eg troubleshooting your connections, the following may help: