Users Guide

Dell Networking OS Behavior: As soon as you apply a DCB policy with PFC enabled on an interface, DCBx starts exchanging information
with PFC-enabled peers. The IEEE802.1Qbb, CEE, and CIN versions of PFC Type, Length, Value (TLV) are supported. DCBx also validates
PFC congurations that are received in TLVs from peer devices.
NOTE: You cannot enable PFC and link-level ow control at the same time on an interface.
Dell Networking OS does not support MACsec Bypass Capability (MBC).
NOTE: We recommend that you do not use the dcb-policy input, dcb-policy output, dcb-input, dcb-output, and
priority-group commands as those are removed from Release 9.6.(0.0).
Conguring Lossless Queues
DCB also supports the manual conguration of lossless queues on an interface when PFC mode is turned o.
Prerequisite: A DCB with PFC conguration is applied to the interface with the following conditions:
• PFC mode is o (no pfc mode on).
• No PFC priority classes are congured (no pfc priority priority-range).
The conguration of no-drop queues provides exibility for ports on which PFC is not needed but lossless trac should egress from the
interface.
Lossless trac egresses out the no-drop queues. Ingress dot1p trac from PFC-enabled interfaces is automatically mapped to the no-drop
egress queues.
1 Enter INTERFACE Conguration mode.
CONFIGURATION mode
interface type slot/port
2 Congure the port queues that will still function as no-drop queues for lossless trac.
INTERFACE mode
pfc no-drop queues queue-range
For 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 default: No lossless queues are congured.
NOTE
: Dell Networking OS Behavior: By default, no lossless queues are congured on a port.
A limit of 4 lossless queues is supported on a port. If the amount of priority trac that you congure to be paused exceeds the 4 lossless
queues, an error message displays.
Any pfc-dot1p priorities congured on a given interface need not be the same across the system, until the total lossless queues congured
on all the ports does not exceed the maximum lossless queues congured globally. For example, one of the Te/Fo interfaces can have pfc-
dot1p priorities as 2 and 3. Whereas, the other Te/Fo interface(s) can have its pfc-dot1p priorities as 4 and 5.
It is the user responsibility to have symmetric PFC congurations on the interfaces involved in a particular PFC-enabled trac-ow to
obtain lossless behavior.
Conguring Enhanced Transmission Selection
ETS provides a way to optimize bandwidth allocation to outbound 802.1p classes of converged Ethernet trac.
Dierent trac types have dierent service needs. Using ETS, you can create groups within an 802.1p priority class to congure dierent
treatment for trac with dierent bandwidth, latency, and best-eort needs.
Data Center Bridging (DCB)
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