Dell C1048P Port Extender Networking Configuration Guide for the C9000 Series - Page 249

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 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. Layer 2 class maps 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. For DCB to operate effectively, you can classify ingress traffic according to its dot1p priority so that it maps to different data queues. The dot1p-queue assignments used are shown in the following table. dot1p Value in Egress Queue Assignment the Incoming Frame 0 1 1 0 2 2 3 3 4 4 5 5 6 6 7 7 Dell#show qos dot1p-queue-mapping Dot1p Priority : 0 1 2 3 4 5 6 7 Queue : 1 0 2 3 4 5 6 7 SNMP Support for PFC and Buffer Statistics Tracking Buffer Statistics Tracking (BST) feature provides a mechanism to aid in Resource Monitoring and Tuning of Buffer Allocation. Max Use Count mode in Buffer Statistics is supported. Max Use Count mode provides the maximum value of the counters accumulated over a period of time. Priority Flow Control (PFC) provides a link level flow control mechanism, which is controlled independently for each frame priority. The goal of this mechanism is to ensure zero loss under congestion in DCB networks. Data Center Bridging (DCB) 249