Planning a QoS Configuration
QoS uses resources in a way that requires attention to rule usage when
planning a QoS configuration. Otherwise, there is an increased possibility of
oversubscribing resources, which means that at some point the switch would
not support further QoS configuration.
Prioritizing and Monitoring QoS Configuration Options
Plan and implement your QoS configuration in descending order of feature
importance. This helps to ensure that the most important features are
configured first. Also, if insufficient rule resources become a problem, this
approach can help you recognize how to distribute the desired feature
implementations across multiple switches to achieve your objectives. For
example, a given type of traffic may be of higher importance than other traffic
types you want to expedite by using QoS. In this case you should plan and
configure your QoS resource usage first for the most important traffic type
before configuring QoS resource usage for other traffic types. If insufficient
resources remain for all of the QoS implementation you want, try spreading
this implementation across multiple switches.
QoS Resource Usage and Monitoring
Each of the five types of QoS features has a maximum number of rules that
can be configured for that type.
The following table shows the maximum number of rules available for each
type and how many resources are used each time you configure a rule. You
can use a maximum of five QoS resources, after which you will not be able to
configure more rules.
You can also configure rules for trunks, and the rule will apply to all the ports
in that trunk. If you add a port that has a rule configured for it to a trunk with
a configured rule or rules, the port "drops" its rule and follows the rules for
Table 6-8. Rule Maximums and QoS Resources Required
TCP/UDP Layer 4
Quality of Service (QoS): Managing Bandwidth More Effectively
Required per Type
Preparation for Configuring QoS