Nokia Network Voyager for IPSO 4.0 Reference Guide 457NoteA rule treats traffic as if it were configured for "skip," if the traffic matches a rule whoseaction has been set to "prioritize" or "shape" and no Aggregation Class is configured.6. Click Apply.7. Click Save to make your changes permanent.Configuring Queue ClassesQueue classes are used to instantiate a framework, or template, for output queue schedulers. LikeAccess Control Lists (ACLs) they are created and configured and then associated with aninterface.There are a maximum of 8 priority-level queues for a queue class. You can configure the size (inpackets) of each queue level as well as the queue specifier. The queue specifier is a tag assignedby the classifier and is used as a key to look up the proper queue level. Three queue levels arepre-defined: the Internetwork Control (IC), Expedited Forwarding (EF), and Best Effort (BE)queues. You can assign the remaining queues any name and QueueSpec you want. The tablebelow shows the values that correspond to these queue values:When you configure an ACL rule to use the priority action, you must configure an aggregationclass. This aggregation class functions as a policer, that is, non-conforming traffic will bedropped. You should configure the aggregation classes so that the aggregate of the NC and EFflows consumes no more than 50% of the output link bandwidth. This action prevents lower-priority traffic from being starved. See RFC 2598 for more information. The other policersshould also be configured to prevent the lower-priority queue from being starved.Internetwork control traffic, such as routing messages and keepalives, should be configured touse the internetwork control queue so that it receives precedence over regular IP traffic. Notethat locally originated internetwork control traffic is automatically sent through this queue. SeeRFC 791 for more information about Internetwork Control traffic.A queue class can be configured to maximize device throughput or to minimize prioritizedtraffic latency. The QoS functionality is not achieved without a cost. The choice of QoS withminimal latency is the most costly in terms of forwarding performance, but it allows the leastamount of head-of-line blocking for high priority traffic.Name of Queue Level Priority IETF DiffServ Codepoint Queue Specifier ValueInternetwork Control 0 0xc0 7Expedited Forwarding 1 0xb8 6Best Effort 7 0 0
