LevelOne GTL-5280 Manual - Page 154
QoS class, DP level, Tag Class., DSCP Based, Buttons, Apply, Reset
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Parameter description: Port : The port number for which the configuration below applies. QoS class : Controls the default QoS class, i.e., the QoS class for frames not classified in any other way. There is a one to one mapping between QoS class, queue and priority. A QoS class of 0 (zero) has the lowest priority. DP level : Controls the default DP level, i.e., the DP level for frames not classified in any other way. PCP : Controls the default PCP for untagged frames. DEI : Controls the default DEI for untagged frames. Tag Class. : Shows the classification mode for tagged frames on this port. Disabled: Use default QoS class and DP level for tagged frames. Enabled: Use mapped versions of PCP and DEI for tagged frames. Click on the mode in order to configure the mode and/or mapping. DSCP Based : Click to Enable DSCP Based QoS Ingress Port Classification. Buttons: Apply - Click to Apply changes. Reset- Click to undo any changes made locally and revert to previously Saved values. NOTE: DP level : Every incoming frame is classified to a Drop Precedence Level (DP level), which is used throughout the device for providing congestion control guarantees to the frame according to what was configured for that specific DP level. PCP : PCP is an acronym for Priority Code Point. It is a 3-bit field storing the priority level for the 802.1Q frame. DEI : DEI is an acronym for Drop Eligible Indicator. It is a 1- bit field in the VLAN tag. Actual PCP is Pri column in Vlan tag packet , DEI is cfi column PCP value from 0~7 , it can be used for priority definition . DEI value is 0 or 1 , it is settable , map to DP value is 0 or 1. When ingress Qos class value is the same , then through DP level value to define the priority , DP value larger will be dropped first. ex: From Port 1 input 1G Pkts , Egress Port 7 Rate be set with 500M . Port 1 Pkts will includes two kinds packet: a. PCP & DEI = 0 0 , via configured map to Qos class & DP level = 1 , 0 b. PCP & DEI = 0 1 , via configured map to Qos class & DP level = 1 , 1 Result will find (a) Packet all past, and (b) packets all drop 146