CAN Bus Messages: A Comprehensive Guide

Hello, my name is Martin Römer. Thank you for the invitation.

I want to implement the CAN bus in my company. I've read a lot about it, and I think I have a good fundamental understanding of it.
However, at one point, I clearly have a persistent problem.
Here's the translation:

'I understand that in the CANopen protocol, TPDOs and RPDOs occupy specific address ranges. For example, TPDO1 has the address 0x180 + Node-ID. In telegram examples, I've also seen addresses like 0x181 + the rest, or 0x281 + the rest for a TPDO2. The receiving controllers then use these TPDO addresses in their filter banks. However, I don't understand what the corresponding RPDO addresses are needed for. I haven't found them in any telegrams.'
Can anyone help me untie this knot?
Thank you in advance.