Description:
The IE CPs that support extended PROFINET diagnostics and thus also the LLDP (Link Layer Discovery Protocol) have their own MAC address for each physical interface and for the IE CP itself.

Fig. 01

Entry ID 23678970 gives an overview of the modules that support extended PROFINET diagnostics.

LLDP is a Layer 2 protocol and is used for topology discovery in PROFINET IO systems. It provides the option of communicating data between neighboring devices (e.g. device name, port, MAC address). For this, there must be unique identification of the interfaces connected with each other. The MAC address of the connected port is used for unique identification.

Example: CP443-1 (6GK7443-1EX20-0XE0)
The CP443-1EX20 with two RJ45 interfaces have the following MAC addresses:
 

Interface	MAC address
IE CP (factory setting): You will find the MAC address on the module.	00-0E-8C-B9-63-1B
Port 1	00-0E-8C-B9-63-1C
Port 2	00-0E-8C-B9-63-1D

You cannot set the MAC addresses for Port 1 and Port 2. However, if a switch is to be connected to Port 1 or Port 2 of the CP443-1EX20 that only permits one MAC address, then you disable the "LLDP" function of the CP443-1EX20.
If you do not disable the "LLDP" function at Port 1 and Port 2 of the CP443-1, the switch discovers the MAC address of the connected port and the MAC address of the IE CP as factory set.

You disable the "LLDP" function in the hardware configuration in the Properties dialog of Port 1 and of Port 2. For this, you switch to the "Options" tab in the Properties dialog of Port 1 or Port 2 respectively. Enable the new function "End of topology discovery".

Fig. 02