Quality of Service (QoS): Managing Bandwidth More Effectively

Introduction

 

Classifiers for Prioritizing Outbound Packets

 

 

N o t e O n U s i n g

ProCurve recommends that you configure a minimum number of the available

M u l t i p l e

QoS classifiers for prioritizing any given packet type. Increasing the number

C r i t e r i a

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

11 (highest) IP Type of Service (ToS) field (IP packets only)

22 Incoming source-port on the switch

33 (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 5-4to 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.

5-10