Administrator Guide

Lossless traffic egresses out the no-drop queues. Ingress dot1p traffic from PFC-enabled interfaces is automatically mapped to
the no-drop egress queues.
1. Enter INTERFACE Configuration mode.
CONFIGURATION mode
interface type slot/port
2. Configure the port queues that will still function as no-drop queues for lossless traffic.
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 configured.
NOTE: Dell Networking OS Behavior: By default, no lossless queues are configured on a port.
A limit of 4 lossless queues is supported on a port. If the amount of priority traffic that you configure to be paused exceeds the
4 lossless queues, an error message displays.
Any pfc-dot1p priorities configured on a given interface need not be the same across the system, until the total lossless queues
configured on all the ports does not exceed the maximum lossless queues configured 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 configurations on the interfaces involved in a particular PFC-enabled traffic-
flow to obtain lossless behavior.
Configuring Enhanced Transmission Selection
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 traffic with different bandwidth, latency, and best-effort needs.
For example, storage traffic is sensitive to frame loss; interprocess communication (IPC) traffic is latency-sensitive. ETS allows
different traffic types to coexist without interruption in the same converged link by:
● Allocating a guaranteed share of bandwidth to each priority group.
● Allowing each group to exceed its minimum guaranteed bandwidth if another group is not fully using its allotted bandwidth.
Creating an ETS Priority Group
An ETS priority group specifies the range of 802.1p priority traffic to which a QoS output policy with ETS settings is applied on
an egress interface.
1. Configure a DCB Map.
CONFIGURATION mode
dcb-map dcb-map-name
The dcb-map-name variable can have a maximum of 32 characters.
2. Create an ETS priority group.
CONFIGURATION mode
priority-group group-num {bandwidth bandwidth | strict-priority} [[committed | peak]
bandwidth [burst-size] [peak | committed] bandwidth [burst-size]] pfc off
The range for priority group is from 0 to 7.
Set the bandwidth in percentage. The percentage range is from 1 to 100% in units of 1%.
Committed and peak bandwidth is in megabits per second. The range is from 0 to 40000.
Committed and peak burst size is in kilobytes. Default is 50. The range is from 0 to 10000.
3. Repeat Step 2 to configure all remaining dot1p priorities in an ETS priority group.
4. Specify the dot1p priority-to-priority group mapping for each priority.
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Data Center Bridging (DCB)