How does SAP Handle the protocols for different set of data transfer?

Hi,

It seems that SAP handles different set of data transfer through different TCP port numbers,

such as:

SAP System Dispatcher Port 32xx

SAP System Dispatcher Security Port 47xx

SAP System Gateway Central Instance Port 33xx

SAP System Gateway Security Port 48xx

SAP message server services 36xx

GUI Client and STEAM Agent 49xx

and there is no default TCP port for any type of the data transfering. How does the SAP client initiate the connection to the SAP server? Does all the above data transfering types use the same protocol? or each type of data transfering uses different protocol? Is there any standard protocol for the SAP connection negotiation?

I would truly appreciate your help!

June