To Next Page

To Previous Page

Quality of Service (QoS): Managing Bandwidth More Effectively

Introduction

3400cl/6400cl Packet Classifiers and Evaluation Order

The 3400cl/6400cl switches provide six QoS classifiers (packet criteria) you

can use to configure QoS priority.

Table 8-5. 3400cl/6400cl Classifier Search Order and Precedence

Search Order Precedence QoS Classifier

6 (lowest)

Incoming 802.1p Priority (present in tagged VLAN environments)

Incoming source-port on the switch

VLAN Priority

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

Device Priority (destination or source IP address)

1 (highest)

UDP/TCP Application Type (port)

A 3400cl or 6400cl switch uses the lowest-to-highest search order shown in

table

8-5 to identify the highest-precedence classifier to apply to any given

packet. (Note that this is the opposite of the order used in the 5300xl switches.)

If there is only one configured classifier that matches a given packet, then the

switch applies the QoS policy specified in that classifier. If multiple configured

classifiers match a given packet, the switch applies each one in turn to the

packet and concludes with the QoS policy for the highest-precedence classi-

fier. Note that if the highest precedence classifier is configured to apply a

DSCP policy, then both the DSCP in the packet and the 802.1p priority applied

to the packet can be changed. However, if the highest precedence classifier is

configured to apply an 802.1p priority rule, only the 802.1p priority in the final

QoS match for the packet is changed.

Note On the 3400cl/6400cl switches, intermixing lower-precedence classifiers con-

figured with DSCP policies and higher-precedence classifiers configured with

802.1p priority rules is not recommended, as this can result in a packet with

an 802.1p priority assigned by one classifier and a DSCP policy by another

classifier. This is because the search order would allow a lower precedence

classifier configured with a DSCP policy to change both the DSCP and the

802.1p setting in a packet, and then would allow a subsequent, higher prece-

dence classifier configured with an 802.1p priority rule to change only the

802.1p setting. To avoid this problem, a DSCP policy option should be applied

only on the highest-precedence classifier in use on the switch or applied to

all QoS classifiers in use on the switch.

8-10

HP ProCurve 5300xl Series User Manual

Other manuals for HP ProCurve 5300xl Series