QoS

Open the Page

Access the QoS (quality of service) page from the Diagnostics tab (Menu → Services → QoS):

NOTE:

QoS values are automatically set when you select positions for the rotary switches.
Click Detail View to expand the list of parameters.
This page is updated every 5 seconds.

Service Status

This table shows the possible states for the Service Status:

Status	Description
Running	The service is correctly configured and running.
Disabled	The service is disabled.
Uknown	The status of the service is not known.

Diagnostic Information

QoS causes the module to add a differentiated services code point () tag to each Ethernet packet it transmits, thereby indicating the priority of that packet:

Field	Parameter	Description
Precision Time Protocol	DSCP PTP Event Priority	Point-to-point time synchronization.
Precision Time Protocol	DSCP PTP General	Point-to-point general.
EtherNet/IP Traffic	DSCP Value for I/O Data Scheduled Priority Messages	Configure the priority levels to prioritize the management of data packets.
EtherNet/IP Traffic	DSCP Value for Explicit Messages
Modbus/TCP Traffic	DSCP Value for I/O Messages	NOTE: We recommend that you use a larger timeout value for explicit messaging connections and a smaller timeout value for implicit messaging connections. The specific values that you employ depend on your application requirements.
Modbus/TCP Traffic	DSCP Value for Explicit Messages
Network Time Protocol Traffic	DSCP Value for Network Time	—

Considerations

Take measures to effectively implement QoS settings in your Ethernet network:

Use only network switches that support QoS.
Apply the same DSCP values to all network devices and switches.
Use switches that apply a consistent set of rules for handling the different DSCP values when transmitting and receiving Ethernet packets.