Reference Guide

You can configure the size of the PFC buffer for all switches in a stack or all port pipes on a specified
stack unit by entering the following commands on the master switch.
• Configure the PFC buffer for all switches in the stack.
CONFIGURATION mode
[no] dcb stack-unit all pfc-buffering pfc-port {1-64} pfc-queues {1-2}
By default, the PFC buffer is enabled on all ports on the stack unit.
• Configure the PFC buffer for all port pipes in a specified stack unit by specifying the port-pipe
number, number of PFC-enabled ports, and number of configured lossless queues.
CONFIGURATION mode
[no] dcb stack-unit stack-unit-id [port-set port-set-id] pfc-buffering pfc-
ports {1-64} pfc-queues {1-2}
Valid stack-unit IDs are 0 to 5.
The only valid port-set ID (port-pipe number) is 0.
Dell Networking OS Behavior: If you configure PFC on a 40GbE port, count the 40GbE port as four PFC-
enabled ports in the pfc-port number you enter in the command syntax.
To achieve lossless PFC operation, the PFC port count and queue number used for the reserved buffer
size that is created must be greater than or equal to the buffer size required for PFC-enabled ports and
lossless queues on the switch.
For the PFC buffer configuration to take effect, you must reload the stack or a specified stack unit (use
the reload command at EXEC Privilege level).
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.
To configure ETS and apply an ETS output policy to an interface, you must:
1. Create a Quality of Service (QoS) output policy with ETS scheduling and bandwidth allocation
settings.
2. Create a priority group of 802.1p traffic classes.
3. Configure a DCB output policy in which you associate a priority group with a QoS DCB output
policy.
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Data Center Bridging (DCB)