Chapter 4. PROFINET System Operation
GFK-2571N
May 2018
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4.1.1.3
External Switch VLAN Priority Settings
The PROFINET-IO specification indicates the VLAN priorities for each type of Ethernet traffic that originates
from a PROFINET node. VLAN priorities range from 0 to 7, with 7 being the highest.
The PACSystems PROFINET Controller supports just four traffic classes, giving four levels of preference.
Incoming traffic without a VLAN priority is assigned to the lowest priority traffic class. The table below lists the
VLAN priorities, and their corresponding priorities in the PROFINET Controller:
VLAN
Priority
PROFINET Controller
Priority
Ethernet Traffic
Description
7
Highest priority
MRP
Media Redundancy
6
Second-highest priority
RT_CLASS_1
Cyclic PROFINET IO
High Priority
RTA_CLASS_1
High-Priority PROFINET Alarms
5
Third-highest priority
Low Priority
RTA_CLASS_1
Low-Priority PROFINET Alarms
4, 3, 2, 1
Lowest priority
(reserved)
(reserved)
0
IP
DCP
Device Discovery and
Configuration
If a system includes external switches, these switches must be configured to match the VLAN Priority
groupings listed above for the PROFINET Controller.
