Pilz PSSnet SHL 8T MRP - Manual (Page 119)

Network load control
120
8.4 QoS/Priority
PSSnet SHL - Basic Configuration
Pilz GmbH & Co. KG, Felix- Wankel Str. 2, 73760 Ostfildern
Figure 32: Ethernet data packet with tag
Figure 33: Tag format
Although VLAN prioritizing is widespread in the industry sector, it has a num-
ber of limitations:
X The additional 4-byte VLAN tag enlarges the data packets. With small
data packets, this leads to a larger bandwidth load.
t
min. 64, max. 1522 Octets
Preamble Field S
tart Frame Delimiter Field
Desti
natio
n Address Field
S
ource Address Field
Tag Field Data Field Le
ngth/T
ype Field
Data Field Pad Field Frame Check
S
eque
nce Field
42-1500 Octets 4 2 4 6 6 7 1
t
4 Octets
User Priority
, 3 Bit
Ca
no
nical Format Ide
ntifier
1 Bit
VLAN Ide
ntifier
12 Bit
Tag Protocol Ide
ntifier
2 x 8 Bit