RFC and SOAP

[Former Member]

Hello,

I am writing on my master thesis about integration of ariba -> SAP R/3

I found a lot of information about the middleware SAP Netweaver PI to connect both systems.

I always find the words SOAP and RPC Call/Request. I searched a lot in google but don't understand the difference between both.

The only thing that I can find is that SAP R/3 comunicates with SAP Netweaver PI via RPC Call/Requests and SAP Netweaver PI comunicates with Ariba via SOAP.

But why? What is the difference? Could someone explain the difference? Please use simple explanation because I am not an IT-expert.

Thanks a lot!!

Best regards!

[Former Member]

Hi Stefan,

1) There are a couple of modes to speak with SAP and PI possibly at play. With traditional SAP servers they use IDOC communications which travels over the RFC channels. This model of connection goes back a long way regardless of Ariba. With newer products like SRM (shopping cart program from SAP) they use proxy which are HTTP communication (SOAP layer maybe not necessary). Ariba doesn't care much about how SAP communicates with PI.

2)  RFC terminology gets used a lot, sometimes with different implied meanings (protocol vs port vs programing API)

3) Ariba's systems are not (presumably) based on SAP. They are open web interfaces to integrate with SAP or whatever platform a trading partner wishes to use (cXML standard). For PI, Ariba has developed their own custom implementation of a SOAP adapter. We've used it for several years now and they keep improving it with each revision. We hope it gets even better now that SAP acquired them.

SOAP and RFC are widely used words in SAP. Any way from Classical SAP Technology perspective, you can look at below link..

SAP Library - Components of SAP Communication Technology

SOAP allows any XML elements to be sent through, XML-RPC is limited to a predefined number of parameters and is limited in what types they can be.

Have a look at below ans from Rich Freedman, detailed very well in short.

What are the differences between RPC, RMI and SOAP?

For SOAP, on SCN itself you will find many more blogs on SOAP.

Good luck on your thesis, and please remember to reward the people here who took time to help you along the way!

Thanks,

Seshu.

[Former Member]

Hi Stefan,

1) There are a couple of modes to speak with SAP and PI possibly at play. With traditional SAP servers they use IDOC communications which travels over the RFC channels. This model of connection goes back a long way regardless of Ariba. With newer products like SRM (shopping cart program from SAP) they use proxy which are HTTP communication (SOAP layer maybe not necessary). Ariba doesn't care much about how SAP communicates with PI.

2) ?? RFC terminology gets used a lot, sometimes with different implied meanings (protocol vs port vs programing API)

3) Ariba's systems are not (presumably) based on SAP. They are open web interfaces to integrate with SAP or whatever platform a trading partner wishes to use (cXML standard). For PI, Ariba has developed their own custom implementation of a SOAP adapter. We've used it for several years now and they keep improving it with each revision. We hope it gets even better now that SAP acquired them.

Good luck on your thesis, and please remember to reward the people here who took time to help you along the way!

[smavachee]

Hi Stefan,

You heading is slightly confusing, its indicating the RFC and SOAP whereas in details you are asking about RPC and SOAP.

SOAP and RFC are widely used words in SAP. Any way from Classical SAP Technology perspective, you can look at below link..

SAP Library - Components of SAP Communication Technology

SOAP allows any XML elements to be sent through, XML-RPC is limited to a predefined number of parameters and is limited in what types they can be.

Have a look at below ans from Rich Freedman, detailed very well in short.

What are the differences between RPC, RMI and SOAP?  

For SOAP, on SCN itself you will find many more blogs on SOAP.

Regards,

Sunil

[Former Member]

Ok thanks for the quick help!

Unfortunately I still don't know why they use RFC/RPC to connect SAP R/3 with SAP PI and why they use SOAP to connect SAP PI with Ariba? (Like shown in the attached picture of my first message)

Probably this was explained in your link but for me as a non-IT-Expert it's hard to understand.

Maybe there is an easy and short answer?

Thanks a lot!!!

[smavachee]

Hi Stefan,

SAP PI system connect to R/3 systems via RFC Adapter (RFC Adapter converts the incoming RFC calls to XML and XML messages to outgoing RFC calls),

SAP PI understand only XML..

Other way around SAP PI system connect to ARIBA via SOAP Adapter (SOAP Adapter converts incoming SOAP messages into XML and XML messages to outgoing SOAP messages).

SAP >> << (RFC Adapter) >> SAP PI << (SOAP Adapter) >> << ARIBA

Hope it helps.!

Regards,

[Former Member]

Hi Sunil,

yes it is getting clearer...:-)

1.

But why do they not use SOAP between R/3 and PI? Because R/3 can only send RFC?

2.

Is it correct that RFC is the RPC from SAP? So usually ERP systems use RPC calls between ERP system and the connecting tool?

3.

Why do they not use RFC/RPC for comunication between PI and ARIBA?

I think if you can answer those three question it is completely clear! But you already helped me a lot!

Best regards!

Stefan