Cisco 3845 Software Guide - Page 537

Chapter 27 Configuring QoS Configuring QoS Switch(config-pmap)# exit Switch(config)# interface gigabitethernet0/1 Switch(config-if)# service-policy output out-policy-parent Switch(config-if)# exit Configuring Class-Based Priority Queuing You can use the priority policy-map class configuration command to ensure that a particular class of traffic is given preferential treatment. Strict priority queuing provides low-latency service to the class. • When priority is configured in an output policy map without the police command, you can only configure the other queues for sharing by using the bandwidth remaining percent policy-map command to allocate excess bandwidth. • You cannot configure priority and bandwidth for the same class. • You can apply priority at the class level and to the VLAN level. • You can associate the priority command with a single class at the class level and a single class at the VLAN level. Beginning in privileged EXEC mode, follow these steps to configure a strict priority queue: Step 1 Step 2 Command configure terminal class-map class-map-name Step 3 policy-map policy-map-name Step 4 class class-map-name Step 5 priority Step 6 exit Step 7 class class-map-name Step 8 bandwidth remaining percent value Step 9 Step 10 Step 11 end show policy-map copy running-config startup-config Purpose Enter global configuration mode. Create classes for three egress queues. Enter match conditions classification for each class. Create a policy map by entering the policy map name, and enter policy-map configuration mode. Enter the name of the priority class (created by using the class-map global configuration command), and enter policy-map class configuration mode for the priority class. Set the strict scheduling priority for this class. Note Only one unique class map in an attached policy map can be associated with a priority command. You cannot configure priority along with any other queuing action (bandwidth or shape average). Exit policy-map class configuration mode for the priority class. Enter the name of a nonpriority class, and enter policy-map class configuration mode for that class. Set output bandwidth limits for the policy-map class as a percentage of the remaining bandwidth. The range is 0 to 100 percent. Return to privileged EXEC mode. Verify your entries. (Optional) Save your entries in the configuration file. After you have created an output policy map, you attach it to an egress port or EFP. See the "Attaching a Service Policy to an Interface or EFP" section on page 27-56. Use the no form of the appropriate command to delete an existing policy map or class map or to cancel strict priority queuing for the priority class or the bandwidth setting for the other classes. OL-23400-01 Cisco ME 3800X and 3600X Switch Software Configuration Guide 27-49