Specifications

Watson Ethernet
Operating Manual
Watson-Ethernet-Manual.doc
Version 3.3-01
3-14
Revision: 2010-01-20
3.2.8 Class of Service (CoS)
The Watson Ethernet plug-in supports differentiated treatment of Ethernet pack-
ets according to their class of service. The plug-in supports four different classes
named Q1 .. Q4 (Q4 is the highest priority queue, Q1 has lowest priority), classi-
fication based on layer 2 or layer 3 information and ingress as well as egress rate
limiting.
Figure 3-12: Class of Service functions
When a packet enters the Watson Ethernet plug-in its priority is be classified ei-
ther by layer 2 information (IEEE 802.1p bits in the VLAN tag) or by layer 3 in-
formation (DSCP in the IP header). The packet is then associated with one of the
priority levels.
On ingress each priority level can be individually rate limited according to the fol-
lowing rules:
 Q1 can be limited to 128 kbps, 256 kbps, 512 kbps, 1'024 kbps, 2'048 kbps,
4'096 kbps or 8'192 kbps
 Each higher priority level can be rate limited either to the same rate as the
next lower priority level or to twice as much.