Quality of Service (QoS): Managing Bandwidth More Effectively
Preparation for Configuring QoS
Planning and Monitoring Rule Usage
The following two CLI commands are useful for planning and monitoring rule
usage in a QoS configuration.
Managing QoS Resource Consumption
As shown in table 6-8, QoS classifiers use 1, 2, or 8 rules depending on the
classifier selected. Extensive QoS configurations can either fully subscribe
the rules available or leave an insufficient number of rules available for
configuring another QoS policy on the switch. If there are not enough rules to
support another QoS policy, you cannot configure an additional policy.
Problems with an insufficient number of rules available can occur in either of
the following QoS scenarios:
ToS Diff-Services QoS Up to 64 rules per switch, depending on how the switch is configured
1 rule per port membership in a QoS-specified VLAN. If a port belongs
to multiple, QoS-specified VLANs, then 1 rule is used for each such
1 rule for each port configured for source-port QoS.
qos resources help
Provides a quick reference on how QoS uses rule resources
for each configuration option. See table 6-8.
show qos resources
Shows the number of rules that have been used out of the total
rules available for that feature. This command is useful for
verifying rule availability as you proceed with configuring
Attempting to configure a policy when there are an insufficient number
of rules available
Attempting to add a port to a QoS-configured VLAN where the policy
already on the VLAN requires more rule resources than are available.