874 | Quality of Servicew w w . d e l l . c o m | s u p p o r t . d e l l . c o m For example, if you configure 70% bandwidth to multicast, 80% bandwidth to one queue in unicast and 0% to all remaining unicast queues, then first, FTOS assigns 70% bandwidth to multicast, then FTOSderives the 80% bandwidth for unicast from the remaining 30% of total bandwidth.Pre-calculating Available QoS CAM SpacePre-calculating Available QoS CAM Space is supported on platforms: c e sBefore version 7.3.1 there was no way to measure the number of CAM entries a policy-map wouldconsume (the number of CAM entries that a rule uses is not predictable; 1 to 16 entries might be used perrule depending upon its complexity). Therefore, it was possible to apply to an interface a policy-map thatrequires more entries than are available. In this case, the system writes as many entries as possible, andthen generates an CAM-full error message (Message 1). The partial policy-map configuration might causeunintentional system behavior.The command test cam-usage enables you to verify that there are enough available CAM entries beforeapplying a policy-map to an interface so that you avoid exceeding the QoS CAM space and partialconfigurations. This command measures the size of the specified policy-map and compares it to theavailable CAM space in a partition for a specified port-pipe.Test the policy-map size against the CAM space for a specific port-pipe or all port-pipes using thesecommands:• test cam-usage service-policy input policy-map {linecard | stack-unit } number port-set number• test cam-usage service-policy input policy-map {linecard | stack-unit } allThe output of this command, shown in Figure 41-16, displays:• the estimated number of CAM entries the policy-map will consume• whether or not the policy-map can be applied• the number of interfaces in a port-pipe to which the policy-map can be appliedSpecifically:• Available CAM is the available number of CAM entries in the specified CAM partition for thespecified line card or stack-unit port-pipe.• Estimated CAM is the estimated number of CAM entries that the policy will consume when it isapplied to an interface.Message 1 QoS CAM Region Exceeded%EX2YD:12 %DIFFSERV-2-DSA_QOS_CAM_INSTALL_FAILED: Not enough space in L3 Cam(PolicyQos) forclass 2 (Gi 12/20) entries on portpipe 1 for linecard 12%EX2YD:12 %DIFFSERV-2-DSA_QOS_CAM_INSTALL_FAILED: Not enough space in L3 Cam(PolicyQos) for class 5 (Gi 12/22)entries on portpipe 1 for linecard 12
