Dell PowerSwitch S4820T 9.50.1 Configuration Guide for the S4820T System - Page 270
QoS dot1p Traffic Classification and Queue Assignment, Honor dot1p, Layer 2 class, dot1p Value in
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dcb enable 2. Set PFC buffering on the DCB stack unit. CONFIGURATION mode dcb stack-unit all pfc-buffering pfc-ports 64 pfc-queues 2 NOTE: To save the pfc buffering configuration changes, save the configuration and reboot the system. NOTE: Dell Networking OS Behavior: DCB is not supported if you enable link-level flow control on one or more interfaces. For more information, refer to Ethernet Pause Frames. QoS dot1p Traffic Classification and Queue Assignment The following section describes QoS dot1P traffic classification and assignments. DCB supports PFC, ETS, and DCBx to handle converged Ethernet traffic that is assigned to an egress queue according to the following QoS methods: Honor dot1p Layer 2 class maps You can honor dot1p priorities in ingress traffic at the port or global switch level (refer to Default dot1p to Queue Mapping) using the service-class dynamic dot1p command in INTERFACE configuration mode. You can use dot1p priorities to classify traffic in a class map and apply a service policy to an ingress port to map traffic to egress queues. NOTE: Dell Networking does not recommend mapping all ingress traffic to a single queue when using PFC and ETS. However, Dell Networking does recommend using Ingress traffic classification using the service-class dynamic dot1p command (honor dot1p) on all DCB-enabled interfaces. If you use L2 class maps to map dot1p priority traffic to egress queues, take into account the default dot1p-queue assignments in the following table and the maximum number of two lossless queues supported on a port (refer to Configuring Lossless Queues). Although Dell Networking OS allows you to change the default dot1p priority-queue assignments (refer to Setting dot1p Priorities for Incoming Traffic), DCB policies applied to an interface may become invalid if you reconfigure dot1p-queue mapping. If the configured DCB policy remains valid, the change in the dot1p-queue assignment is allowed. dot1p Value in the Egress Queue Assignment Incoming Frame 0 2 1 0 2 1 3 3 4 4 5 5 6 6 7 7 270 Data Center Bridging (DCB)
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