Administrator 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 congurations 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).
Conguring Lossless Queues
DCB also supports the manual conguration of lossless queues on an interface when PFC mode is turned o.
Prerequisite: A DCB with PFC conguration is applied to the interface with the following conditions:
• PFC mode is o (no pfc mode on).
• No PFC priority classes are congured (no pfc priority priority-range).
The conguration of no-drop queues provides exibility for ports on which PFC is not needed but lossless trac should egress from the
interface.
Lossless trac egresses out the no-drop queues. Ingress dot1p trac from PFC-enabled interfaces is automatically mapped to the no-drop
egress queues.
1 Enter INTERFACE Conguration mode.
CONFIGURATION mode
interface type slot/port
2 Congure the port queues that will still function as no-drop queues for lossless trac.
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 congured.
NOTE
: Dell Networking OS Behavior: By default, no lossless queues are congured on a
port.
A limit of 4 lossless queues is supported on a port. If the amount of priority trac that you congure to be paused exceeds the 4 lossless
queues, an error message displays.
Any pfc-dot1p priorities congured on a given interface need not be the same across the system, until the total lossless queues congured
on all the ports does not exceed the maximum lossless queues congured 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 congurations on the interfaces involved in a particular PFC-enabled trac-ow to
obtain lossless behavior.
Conguring Enhanced Transmission Selection
ETS provides a way to optimize bandwidth allocation to outbound 802.1p classes of converged Ethernet trac.
Dierent trac types have dierent service needs. Using ETS, you can create groups within an 802.1p priority class to congure dierent
treatment for trac with dierent bandwidth, latency, and best-eort needs.
Data Center Bridging (DCB)
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