Priority-based flow control (PFC) using Differentiated Services code points (DSCP) at Layer 3 for untagged traffic

To support lossless traffic across Layer 3 connections to Layer 2 subnetworks, you can configure priority-based flow control (PFC) to operate using 6-bit DSCP values from Layer 3 headers of untagged VLAN traffic, rather than IEEE 802.1p priority values in Layer 2 VLAN-tagged packet headers. DSCP-based PFC is required to support Remote Direct Memory Access (RDMA) over converged Ethernet version 2 (RoCEv2). To enable DSCP-based PFC, map a forwarding class to a PFC priority using the pfc-priority statement, define a congestion notification profile to enable PFC on traffic specified by a 6-bit DSCP value, and set up a classifier for the DSCP value and the PFC-mapped forwarding class.