Siemens SIMATIC S7-1500R/H Manual page 24

PROFINET interface X1 with 2-port switch (X1 P1 R and X1 P2 R)
The assignment corresponds to the Ethernet standard for a RJ45 connector.
● When autonegotiation is deactivated, the RJ45 socket is allocated as a switch (MDI-X).
● When autonegotiation is activated, autocrossing is in effect and the RJ45 socket is
allocated either as data terminal equipment (MDI) or a switch (MDI-X).
Figure 3-2
PROFINET interface X2 with 1 port (X2 P1)
The assignment corresponds to the Ethernet standard for a RJ45 connector.
Autocrossing is always active on X2. This means the RJ45 socket is allocated either as data
terminal equipment (MDI) or a switch (MDI-X).
Reference
You can find additional information on the topic of "Connecting the CPU" and on the topic
"Accessories/spare parts" in the system manual for Redundant System S7-1500R/H
(https://support.industry.siemens.com/cs/ww/en/view/109754833).
CPU 1515R-2 PN (6ES7515-2RM00-0AB0)
Manual, 10/2018, A5E42009914-AA
Interface assignments
Connecting
3.1 Terminal assignment
23