Configuring Lossless Queues; Configure Enhanced Transmission Selection - Dell S4820T Configuration Manual

Configuring Lossless Queues

DCB also supports the manual configuration of lossless queues on an interface when PFC mode is turned
off.
Prerequisite: A DCB with PFC configuration is applied to the interface with the following conditions:
• PFC mode is off (no pfc mode on).
• No PFC priority classes are configured (no pfc priority priority-range).
The configuration of no-drop queues provides flexibility for ports on which PFC is not needed but
lossless traffic should egress from the interface.
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 range is from 0 to 3. Separate the queue values with a comma; specify a priority range with a
dash; for example, pfc no-drop queues 1,3 or pfc no-drop queues 2-3.
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 two lossless queues is supported on a port. If the amount of priority traffic that you configure to
be paused exceeds the two lossless queues, an error message displays.

Configure 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.
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Data Center Bridging (DCB)