Classifiers For Prioritizing Outbound Packets; 5300Xl Packet Classifiers And Evaluation Order - HP ProCurve 5300xl Series Management Manual

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Classifiers for Prioritizing Outbound Packets

The classifiers used in the 3400cl/6400cl switches are a subset of the classifiers
used in the 5300xl switches. Also, the 3400cl/6400cl switches search for
classifier matches in the opposite order of that used in the 5300xl switches.
HP 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.

5300xl Packet Classifiers and Evaluation Order

The 5300xl switches provide seven QoS classifiers (packet criteria) you can
use to configure QoS priority.
Table 8-4. 5300xl Classifier Search Order and Precedence
Search Precedence QoS Classifier Type
Order
1 1 (highest) UDP/TCP Application Type (port)
2 2 Device Priority (destination or source IP address)
3 3 IP Type of Service (ToS) field (IP packets only)
4 4 Protocol Priority (IP, IPX, ARP, DEC LAT, AppleTalk, SNA, and NetBeui)
5 5 VLAN Priority
6 6 Incoming source-port on the switch
7 7 (lowest) Incoming 802.1p Priority (present in tagged VLAN environments)
Where multiple classifier types are configured, a 5300xl switch uses the
highest-to-lowest search order shown in table 8-4 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 a 5300xl switch, if the switch is configured with multiple classi­
fiers 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.) For example, if QoS assigns high priority to packets belonging to
VLAN 100, but normal priority to all IP protocol packets, since protocol
priority (4) has precedence over VLAN priority (5), IP protocol packets on
VLAN 100 will be set to normal priority.
Quality of Service (QoS): Managing Bandwidth More Effectively
Introduction
8-9