Setup Guide

NOTE: When only few lossless queues are congured, the Shared headroom pool must be congured carefully to avoid any
ingress MMU drops due to insucient headroom buer.
Conguring Shared Head Room Buer
You can congure a shared head room pool limit, which is the threshold value for the shared head room pool size.
To congure the shared head room pool size:
Enter the following command in global conguration mode:
CONFIGURATION Mode
dcb pfc-headroom-buffer-size buffer-size
NOTE: Earlier head room implementations are derived from the buer-size and pause-threshold attributes of the dcb-
buer-threshold prole. However, with the introduction of the shared head room feature, the buer-size attribute is
now obsolete as the head room buer is now global and is shared among all lossless queues or PGs. Any value
congured for buer-size is internally replaced with value congured for the pause-threshold attribute. The peak-head
room attribute continue to be the ingress threshold limit for bursty trac. This attribute determines the maximum
buer a PG can use from the shared head room pool.
Viewing Shared Head Room Usage
You can obtain an instantaneous usage count for the shared hear room pool.
To view the head room usage count:
Enter the following show command:
EXEC-Privilege Mode
show hardware buffer headroom-pool [detail] buffer-info
NOTE
: The detail option display the current headroom pool usage in each of the Pipelines in the device.
DellEMC#show hardware buffer headroom-pool buffer-info
------Buffer Details for Stack-Unit 1 portpipe 0 ------
-----------------------------------------------------------------
Headroom-Pool Configured Buffer(KB) Used Buffer(KB)
-----------------------------------------------------------------
HP1 0 0
DellEMC#
Monitoring Buer Statistics for Tracking Purposes
Using the buer statistics tracking feature, you can monitor the peak buer usage of the head room pool over a specic period of time.
This monitoring enables you to optimize the head room pool size based on real-time network trac data.
To view the peak head room pool usage details during a specic monitoring period:
Enter the following show command:
EXEC Privilege Mode
show hardware buffer-stats-snapshot resource headroom-pool [detail]
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Data Center Bridging (DCB)