Pilz PSSnet SHL 8T MRP - Manual (Page 118)

Network load control
PSSnet SHL - Basic Configuration
Pilz GmbH & Co. KG, Felix- Wankel Str. 2, 73760 Ostfildern
8.4 QoS/Priority
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8.4.2 VLAN tagging
The VLAN tag is integrated into the MAC data frame for the VLAN and Prior-
itization functions in accordance with the IEEE 802.1 Q standard. The VLAN
tag consists of 4 bytes. It is inserted between the source address field and
the type field.
For data packets with a VLAN tag, the device evaluates
X the priority information at all times, and
X the VLAN information if VLANs have been set up.
Data packets with VLAN tags containing priority information but no VLAN in-
formation (VLAN ID = 0), are known as Priority Tagged Frames.
Note: Network protocols and redundancy mechanisms use the highest traffic
class 3. Therefore, you select other traffic classes for application data.
Priority
entered Traffic class
(default setting) IEEE 802.1D traffic type
0 1 Best effort (default)
1 0 Background
2 0 Standard
3 1 Excellent effort (business critical)
4 2 Controlled load
(streaming multimedia)
5 2 Video, less than 100 milliseconds of latency and
jitter
6 3 Voice, less than 10 milliseconds of latency and jit-
ter
7 3 Network control reserved traffic
Table 8: Assignment of the priority entered in the tag to the four traffic classes