Pilz PSSnet SHL 8T MRP - Manual (Page 117)

Network load control
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8.4 QoS/Priority
PSSnet SHL - Basic Configuration
Pilz GmbH & Co. KG, Felix- Wankel Str. 2, 73760 Ostfildern
8.4 QoS/Priority
8.4.1 Description of Prioritization
This function prevents time-critical data traffic such as language/video or
real-time data from being disrupted by less time-critical data traffic during pe-
riods of heavy traffic. By assigning high traffic classes for time-critical data
and low traffic classes for less time-critical data, you ensure optimal data flow
for time-critical data traffic.
The device supports four priority queues (traffic classes in compliance with
IEEE 802.1D). The assignment of received data packets to these classes is
performed by
X the priority of the data packet contained in the VLAN tag when the receiv-
ing port was configured to "trust dot1p".
X the QoS information (ToS/DiffServ) contained in the IP header when the
receiving port was configured to "trust ip-dscp".
X the port priority when the port was configured to "no trust".
X the port priority when receiving non-IP packets when the port was config-
ured to "trust ip-dscp".
X the port priority when receiving data packets without a VLAN tag (see on
page 71 „Configuring the ports“) and when the port was configured to
"trust dot1p".
Default setting: "trust dot1p".
The device considers the classification mechanisms in the sequence shown
above.
Data packets can contain prioritizing/QoS information:
X VLAN priority based on IEEE 802.1Q/ 802.1D (Layer 2)