RFC vs IDOC - Functions

Hi,

Can any one tell what is the usage of RFC in BI?

<b>With my knowledge,</b>

RFC : It is just a physical communication channel. It allows to transfer data among source to destination BI.

IDOC : The data records collects in IDOC format while data transfer.

Please correct me if any thing is wrong and share your valuable views?

Is it true that RFC also sends/contains data records itself ? I think records are collected in the form of Idoc and then transfer to BI.

How to check outbound Idocs and Inbound Idocs?.

Cheers,

Sri.