Communication with SNC

Hi all,

I very new to SNC, but I would like to know why the communication to and from SNC is based on XML and there is no possiblity to send and receive for example IDOCs from SNC (for example to ERP systems)?

So the final question is why do I need a PI to send and receive messages from/to SAP SNC?

Is there a technical view of the internals of the SAP SNC?

Thanks and regards,

Uwe