Classifiers For Prioritizing Outbound Packets; Packet Classifiers And Evaluation Order - HP ProCurve Switch 6120G/XG Management Manual

Quality of Service (QoS): Managing Bandwidth More Effectively
Introduction
N o t e O n U s i n g
M u l t i p l e
C r i t e r i a
5-10

Classifiers for Prioritizing Outbound Packets

ProCurve recommends that you configure a minimum number of the available
QoS classifiers for prioritizing any given packet type. Increasing the number
of active classifier options for a packet type increases the complexity of the
possible outcomes and consumes switch resources.

Packet Classifiers and Evaluation Order

The switches covered in this guide provide the following QoS classifiers
(packet criteria) you can use to configure QoS priority.
Table 5-4. Classifier Search Order and Precedence
Search Precedence QoS Classifier Type
Order
1 1 (highest)
IP Type of Service (ToS) field (IP packets only)
2 2 Incoming source-port on the switch
3 3 (lowest) Incoming 802.1p Priority (present in tagged VLAN environments)
Where multiple classifier types are configured, a switch uses the highest-to-
lowest search order shown in table 5-4 to identify the highest-precedence
classifier to apply to any given packet. When a match between a packet and a
classifier is found, the switch applies the QoS policy configured for that
classifier and the packet is handled accordingly.
Note that on the switches covered in this guide, if the switch is configured
with multiple classifiers that address the same packet, the switch uses only
the QoS configuration for the QoS classifier that has the highest precedence.
In this case, the QoS configuration for another, lower-precedence classifier
that may apply is ignored.