Dell C1048P Port Extender Networking Configuration Guide for the C9000 Series - Page 304

• To remove a DCB map, including the PFC configuration it contains, use the no dcb map command in Interface configuration mode. • To disable PFC operation on an interface, use the no pfc mode on command in DCB-Map configuration mode. • Traffic may be interrupted when you reconfigure PFC no-drop priorities in a DCB map or re-apply the DCB map to an interface. • For PFC to be applied, the configured priority traffic must be supported by a PFC peer (as detected by DCBx). • If you apply a DCB map with PFC disabled (pfc off), you can enable link-level flow control on the interface using the flowcontrol rx on tx on command. To delete the DCB map, first disable linklevel flow control. PFC is then automatically enabled on the interface because an interface is PFCenabled by default, when DCB is enabled. • To ensure no-drop handling of lossless traffic, PFC allows you to configure lossless queues on a port (see Configuring Lossless Queues). • When you configure a DCB map with more than the maximum lossless queues configured, an error message is displayed if the PFC dot1p priorities result in more than two lossless queues. • When you apply a DCB map, an error message is displayed if link-level flow control is already enabled on an interface. You cannot enable PFC and link-level flow control at the same time on an interface. • Configure all the backplane ports of the linecards and RPM0 and RPM1 with same dcb-map configuration. dcb-map linecard 0 backplane all name dcb-map linecard all backplane all name • Dell Networking OS allows you to change the default dot1p priority-queue assignments only if the change satisfies the following requirements in DCB maps already applied to the interfaces: • All 802.1p priorities mapped to the same queue must be in the same priority group. • A maximum of four PFC-enabled, lossless queues are supported on an interface. Otherwise, the reconfiguration of a default dot1p-queue assignment is rejected. • To ensure complete no-drop service, apply the same PFC parameters on all PFC-enabled peers. ETS Configuration Notes ETS provides a way to optimize bandwidth allocation to outbound 802.1p classes of converged Ethernet traffic. Different traffic types have different service needs. Using ETS, you can create groups within an 802.1p priority class to configure different treatment for traffics with different bandwidth, latency, and best-effort needs. When you configure ETS in a DCB map: • The DCB map associates a priority group with a PFC operational mode (on or off) and an ETS scheduling and bandwidth allocation. You can apply a DCB map on multiple egress ports. • Use the ETS configuration associated with 802.1p priority traffic in a DCB map in DCBx negotiation with ETS peers. • Traffic in priority groups is assigned to strict-queue or weighted round-robin (WRR) scheduling in an ETS configuration and is managed using the ETS bandwidth-assignment algorithm. Dell Networking OS dequeues all frames of strict-priority traffic before servicing any other queues. A queue with strict-priority traffic can starve other queues in the same port. • ETS-assigned bandwidth allocation and strict-priority scheduling apply only to data queues, not to control queues. Data Center Bridging (DCB) 304