Dell S6000 FTOS 9.0(2.0) Configuration Guide for the System - Page 297

QoS dot1p Traffic Classification and Queue Assignment DCB supports PFC, ETS, and DCBx to handle converged Ethernet traffic that is assigned to an egress queue according to the following quality of service (QoS) methods: • Honor dot1p: Using the service-class dynamic dot1p command, you can honor dot1p priorities in ingress traffic at the port or global switch level (Refer to Default dot1p to Queue Mapping). Honoring dot1p priorities in ingress traffic is enabled by default. • 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 (Refer to Policy-based QoS Configurations). Important: of two S5000 Note: Dell does not recommend mapping all ingress traffic to a single queue when using PFC and ETS. Ingress traffic classification using the service-class dynamic dot1p command (honor dot1p) is recommended 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 Table 15-1 and the maximum number of two lossless queues supported on a port (Refer to Configuring Lossless Queues). FTOS allows you to change the default dot1p priority-queue assignments (Refer to Set dot1p Priorities for Incoming Traffic) only if the change satisfies the following requirements in DCB-input and DCB-output policies already applied to S6000 interfaces: - All 802.1p priorities mapped to the same queue must be in the same priority group. - A maximum of two PFC-enabled, lossless queues are supported on an interface. Otherwise the reconfiguration of a default dot1p-queue assignment is rejected. Table 15-1 shows the default queue assignment for each dot1p priority value in incoming Ethernet traffic. Data Center Bridging (DCB) | 275