Connecting to Multiple ECC systems via one Gateway system(Dynamic System Selection)

Question

Hi Experts,
We have multiple ECC systems and one Gateway server. We want to connect to these different ECC systems using one GW system.
I have created System Aliases for these ECC system in GW system. For a service, i added 2 system aliases.
Now we are looking for the solution where UI can provide the system alias (it wants to connect) as a parameter while calling oData Service.
Please help.
Regards,
Rohit

Answer 1

Hi Rohit,
we have a similar scenario where we have two system aliases for one service. Both aliases point to the same system, but different clients; it should not make a difference though, having different systems. The feature you are looking for is Multiple Origin Composition (MOC).
There are a couple of things you have to consider:
in the SEGW the entity to be called has to be marked as addressable
the URI of the service needs to include the tag for MOC (;mo) --> http://sapgw.domain.org:8000/sap/opu/odata/sap/ZSOME_SERVICE;mo/entityset
Without the ;mo the call will be routed to your default alias. The ;mo will route the call to both systems. Using MOC will generate an additional key property into your entities --> SAP__ORIGIN. The property is the alias. If you want to route to a specific system you have to provide the SAP__ORIGIN like providing normal key properties in your requests.
This will look like this:
<content type="application/xml">
  <m:properties xmlns:m="http://schemas.microsoft.com/ado/2007/08/dataservices/metadata" xmlns:d="http://schemas.microsoft.com/ado/2007/08/dataservices">
    <d:SAP__Origin>SOME_ALIAS</d:SAP__Origin>
    <d:Identifier>SOME_IDENTIFIER</d:Identifier>
    <d:Doublet />
  </m:properties>
</content>
The original Entity only consists of the key property "Identifier" and the property "Doublet". "SAP__ORIGN" is added via the ;mo.
Hope it helped...
Holger