Siemens PLC>PLC

Hi All

Have a query regarding the how to communicate over Ethernet between to via three mediums.

First of all I need to communicate between PLCs on a network via PLC (CPU319-3) to PLC (CPU 319-3). What I want to do is set a DB in each PLC and read from each PLC. Which block(s)could I use for this?

Secondly I need to communicate between PLCs on a network via CP Module(Ethernet) to CP Module(Ethernet). Again What I want to do is set a DB in each PLC and read from each PLC. Which block(s)could I use for this?

Thirdly I need to communicate between PLCs on a network via CP Module(Ethernet) to PLC (CPU 319-3). Again What I want to do is set a DB in one PLC and read from the other PLC. Which block(s)could I use for this?

Any advice, examples etc. etc. appreciated as am struggling to identify the required blocks.

You might find something useful in this compendium:

http://support.automation.siemens.com/WW/view/en/20982954

Kalle