Protocol; Figure 3: Ethernet Frame Structure - TR-Electronic MP-Series Benutzerhandbuch

3.3 Protocol

The PROFINET protocol, optimized for process data, is transported directly in the
Ethernet frame via a special EtherType. Non-Real-Time-Frames (NRT) use the
EtherType 0x0800. PROFINET Real-Time-Frames (RT/IRT) use the EtherType
0x8892. With Real-Time-Class 1 RT-communication additionally for the data
prioritization a so-called "VLAN-Tag" is inserted into the Ethernet frame. Additionally,
this possesses a further EtherType and is using the value 0x8100.
On the basis of the EtherType the PROFINET specific data are interpreted different.
UDP/IP datagrams are also supported. This means that in the case of RT the master
and the PROFINET IO devices can be in different subnets. The communication over
routers into other subnets is therefore possible in the case of RT.
PROFINET exclusively uses standard frames in accordance with IEEE802.3.
PROFINET frames can be sent by any Ethernet controller (master). Also standard
tools (e.g. monitor) can be used.

Figure 3: Ethernet frame structure

Printed in the Federal Republic of Germany
06/06/2019 TR - EMO - BA - DGB - 0019 - 08
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