Administrator Guide

Using PFC and ETS to Manage Converged Ethernet Traffic in
a Switch Stack
The following example shows how to apply the DCB PFC input policy (ipc_san_lan) and ETS output policy
(ets) on all FN IOM switches in a switch stack.
This example references the PFC and ETS Configuration Examples section.
Example of Applying DCB PFC Input Policy and ETS Output Policy in a Switch Stack
dcb-map stack-unit all stack-ports all <dcb-map-name>
Interworking of DCB Map With DCB Buffer Threshold
Settings
The dcb-input and dcb-output configuration commands are deprecated. You must use the dcp-map
command to create a DCB map to configure priority flow control (PFC) and enhanced transmission selection
(ETS) on Ethernet ports that support converged Ethernet traffic.
Configure the dcb-buffer-threshold command and its related parameters only on ports with either auto
configuration or dcb-map configuration. This command is not supported on existing front-panel interfaces or
stack ports that are configured with the dcb-input or dcb-output commands. Similarly, if the dcb-buffer-
threshold configuration is present on a stack port or any interface, the dcb-input or dcb-ouput policies
cannot be applied on those interfaces.
Example: When the dcb-buffer-threshold policy is applied on interfaces or stack ports with the dcb-input or
dcb-output policies, the following error message is displayed:
%Error: dcb-buffer-threshold not supported on interfaces with deprecated commands
Example: When the dcb-input or dcb-output policy is configured on interfaces or stack ports with the dcb-
buffer threshold policy, the following error message is displayed:
%Error: Deprecated command is not supported on interfaces with dcb-buffer-threshold
configured
You must not modify the service-class dot1p mappings when any buffer-threshold-policy is configured on
the system.
Dell(conf)#service-class dot1p-mapping dot1p0 3
% Error: PFC buffer-threshold policies conflict with dot1p mappings. Please remove
all dcb-buffer-threshold policies to change mappings.
The show dcb command has been enhanced to display the following additional buffer-related information:
Dell(conf)#do show dcb
dcb Status : Enabled
PFC Queue Count : 2 --Indicate the PFC queue configured.
Total buffer (lossy + lossless)(in KB): 7787--Total buffer space for lossy and
lossless queues
PFC total buffer (in KB): 6526 --Indicates the total buffer (configured or
default)
PFC shared buffer (in KB): 832--Indicates the shared buffer (Configured or
default)
FC Flex IO Modules 1088