Hi NageswaraRao,
SAP AIF is an ABAP Add-On and it works independently of SAP PI/PO. In AIF you can use interface protocols like IDoc, BAPI, RFC, Proxy, Enterprise/Web Service without SAP PI/PO as middleware.
Of course you can use AIF also in combination with non SAP solutions as long as the used protocols are supported by AIF.
Here you will find more information about RFC in AIF:
tRFC and qRFC - SAP Application Interface Framework - SAP Library
Best regards,
Ionut