Quality of Service (QoS): Managing Bandwidth More Effectively
QoS Operating Notes and Restrictions
■ Maximum QoS Configuration Entries: The switches covered in this
guide accept the maximum outbound priority and/or DSCP policy config-
uration entries of 128 rules per QoS feature.
Attempting to exceed the above limits generates the following message
in the CLI:
Unable to add this QoS rule. Maximum number (entry-#) already
reached.
■ All Switches—Not Supported: Use of an inbound 802.1p packet priority
as a classifier for remapping a packet’s outbound priority to different
802.1p priority. For example, where inbound packets carry an 802.1p
priority of 1, QoS cannot be configured use this priority as a classifier for
changing the outbound priority to 0.
■ Not Supported: TCP/UDP QoS is not supported on fragmented packets.
QoS is done by explicit hardware matching on packet information; in
fragmented TCP/UDP packets the application port number is missing. As
a result the behavior of fragmented packets is unpredictable.
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