Users Guide

continue to be the ingress threshold limit for bursty traffic. This attribute determines the maximum buffer 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 Buffer Statistics for Tracking Purposes
Using the buffer statistics tracking feature, you can monitor the peak buffer usage of the head room pool over a specific period
of time. This monitoring enables you to optimize the head room pool size based on real-time network traffic data.
To view the peak head room pool usage details during a specific monitoring period:
Enter the following show command:
EXEC Privilege Mode
show hardware buffer-stats-snapshot resource headroom-pool [detail]
NOTE: The detail option display the peak headroom pool usage in each of the Pipelines in the device.
DellEMC#show hardware buffer-stats-snapshot resource headroom-pool
---------------------------------------
HP# PEAK USE COUNT(CELLS)
---------------------------------------
0 0
1 0
2 0
3 0
DellEMC#
Behavior of Tagged Packets
The below is example for enabling PFC for priority 2 for tagged packets. Priority (Packet Dot1p) 2 will be mapped to PG6 on
PRIO2PG setting. All other Priorities for which PFC is not enabled are mapped to default PG – PG7.
Classification rules on ingress (Ingress FP CAM region) matches incoming packet-dot1p and assigns an internal priority (to
select queue as per Table 1 and Table 2).
The internal Priority assigned for the packet by Ingress FP is used by the memory management unit (MMU) to assign the packet
to right queue by indexing the internal-priority to queue map table (TABLE 1) in hardware.
PRIO2COS setting for honoring the PFC protocol packets from the Peer switches is as per above Packet-Dot1p->queue table
(Table 2).
The packets come in with packet-dot1p 2 alone are assign to PG6 on ingress.
The packets come in with packet-dot1p 2 alone use Q1Q2 (as per dot1p to Queue classification – Table 2) on the egress port.
Data Center Bridging (DCB)
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