interface type slot/port[/subport]2 Configure the port queues that will still function as no-drop queues for lossless traffic.INTERFACE modepfc no-drop queues queue-rangeFor the dot1p-queue assignments, refer to the dot1p Priority-Queue Assignment table.The maximum number of lossless queues globally supported on the switch is two.The range is from 0 to 3. Separate the queue values with a comma; specify a priority range with a dash; for example, pfc no-dropqueues 1,3 or pfc no-drop queues 2-3.The default: No lossless queues are configured.NOTE: Dell Networking OS Behavior: By default, no lossless queues are configured on aport.A limit of two lossless queues is supported on a port. If the amount of priority traffic that you configure to be paused exceeds the twolossless queues, an error message displays.Configuring PFC in a DCB MapA switch supports the use of a DCB map in which you configure priority-based flow control (PFC) setting. To configure PFC parameters,you must apply a DCB map on an interface.PFC Configuration NotesPFC provides flow control based on the 802.1p priorities in a converged Ethernet traffic that is received on an interface and is enabled bydefault when you enable DCB. As an enhancement to the existing Ethernet pause functionality, PFC stops traffic transmission for specifiedpriorities (CoS values) without impacting other priority classes. Different traffic types are assigned to different priority classes.When traffic congestion occurs, PFC sends a pause frame to a peer device with the CoS priority values of the traffic that needs to bestopped. DCBx provides the link-level exchange of PFC parameters between peer devices. PFC allows network administrators to createzero-loss links for SAN traffic that requires no-drop service, while at the same time retaining packet-drop congestion management for LANtraffic.On a switch, PFC is enabled by default on Ethernet ports (pfc mode on command). You can configure PFC parameters using a DCBmap or the pfc priority command in Interface configuration mode. For more information, see Configuring Priority-Based Flow Control.As soon as you apply a DCB map with PFC enabled on an interface, DCBx starts exchanging information with a peer. The IEEE802.1Qbb,CEE and CIN versions of PFC TLV are supported. DCBx also validates PFC configurations that are received in TLVs from peer devices. Byapplying a DCB map with PFC enabled, you enable PFC operations on ingress port traffic. To achieve complete lossless handling of traffic,configure PFC priorities on all DCB egress ports.When you apply or remove a DCB input policy from an interface, one or two CRC errors are expected to be noticed on the ingress ports foreach removal or attachment of the policy. This behavior occurs because the port is brought down when PFC is configured. When a DCBinput policy with PFC profile is configured or unconfigured on an interface or a range of interfaces not receiving any traffic, interfaces withPFC settings that receive appropriate PFC-enabled traffic (unicast, mixed-frame-size traffic) display incremental values in the CRC anddiscards counters. (These ingress interfaces receiving pfc-enabled traffic have an egress interface that has a compatible PFCconfiguration).NOTE: DCB maps are supported only on physical Ethernet interfaces.• To remove a DCB map, including the PFC configuration it contains, use the no dcb map command in Interface configuration mode.260 Data Center Bridging (DCB)
