910 Priority Flow Control CommandsThe effective default behavior on an interface enabled for PFC without a no-drop priority is that no flow control (legacy or PFC) is enabled. If the userenables PFC but does not create any no-drop priorities, the interface will notbe lossless.Changing the drop and no-drop capabilities on an interface, either in flowcontrol or priority flow control, may require that all ports briefly drop link.The priority to flow control group cannot be changed while traffic is running.When 802.3 link flow control is enabled, all priorities are mapped to a singleflow control group. When 802.1Qbb is enabled, the priorities are eachmapped into their own flow control group, where lossless groups haveadditional buffer to handle the round trip delay for flow control. In order tominimize the impact, the link will only be dropped when changing between802.3 and 802.1Qbb.Commands in this ChapterThis chapter explains the following commands:priority-flow-control modeUse the priority-flow-control mode on command in Datacenter-BridgingConfiguration mode to enable Priority-Flow-Control (PFC) on an interface.To disable Priority-Flow-Control, use the no form of the command.Syntaxpriority-flow-control mode onpriority-flow-control mode offno priority-flow-control mode• on—Enable PFC on the interface.• off—Disable PFC on the interface.priority-flow-control modepriority-flow-control priorityclear priority-flow-control statisticsshow interfaces priority-flow-control
