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Monday, March 18, 2019
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Automation Protocol Through Ethernet
Is it possible to communicate multiple TCP IP protocols through a single port?

Suppose I have a PLC (Only 1 Ethernet Port) which support Profinet, DNP3 (TCP IP), and Modbus TCP IP.

Can I get data using these protocols simultaneously through the Ethernet port of PLC?

Yes assuming the PLC can handle the load and supports all the protocols.

Good luck,


Since these protocols have different TCP Ports assigned
1 Ethernet interface can handle all of them at the same time.

lehrig@nb5lehrig:~/Downloads> grep -i profinet /etc/services
profinet-rt 34962/tcp # PROFInet RT Unicast [Peter_Wenzel]
profinet-rt 34962/udp # PROFInet RT Unicast [Peter_Wenzel]
profinet-rtm 34963/tcp # PROFInet RT Multicast [Peter_Wenzel]
profinet-rtm 34963/udp # PROFInet RT Multicast [Peter_Wenzel]
profinet-cm 34964/tcp # PROFInet Context Manager [Peter_Wenzel]
profinet-cm 34964/udp # PROFInet Context Manager [Peter_Wenzel]
lehrig@nb5lehrig:~/Downloads> grep -i dnp /etc/services
ndnp 2883/tcp # NDNP [Khelben_Blackstaff]
ndnp 2883/udp # NDNP [Khelben_Blackstaff]
dnp-sec 19999/tcp # Distributed Network Protocol - Secure [Grant_Gilchrist]
dnp-sec 19999/udp # Distributed Network Protocol - Secure [Grant_Gilchrist]
dnp 20000/tcp # DNP [Michael_Thesing]
dnp 20000/udp # DNP [Michael_Thesing]
lehrig@nb5lehrig:~/Downloads> grep -i modbus /etc/services
mbap 502/tcp # Modbus Application Protocol (updated 2014-06-10) [] [Dennis_Dube]
mbap 502/udp # Modbus Application Protocol (updated 2014-06-10) [] [Dennis_Dube]
mbap-s 802/tcp # Modbus Application Protocol Secure [] [Dennis_Dube]
mbap-s 802/udp # Modbus Application Protocol Secure [] [Dennis_Dube]

By Steve Myres on 27 February, 2019 - 9:25 am

Don't know which PLC you have and if it can do this, but with most PLCs it would work fine. There's no fundamental Ethernet issue with it.