Setup Guide

!
class-map match-any dscp-pfc-2
match ip dscp 20-25,30-35
2. Associate above class-maps to Queues Queue assignment as below.
DellEMC(conf)#do show qos dot1p-queue-mapping
Dot1p Priority : 0 1 2 3 4 5 6 7
Queue : 1 0 2 3 4 5 6 7
3. Dot1p->Queue Mapping Configuration is retained at the default value.
4. Interface Configurations on server connected ports.
a. Enable DCB globally.
DellEMC(conf)#dcb enable
b. Apply PFC Priority configuration. Configure priorities on which PFC is enabled.
DellEMC(conf-if-te-1/1/1)#pfc priority 1,2
SNMP Support for PFC and Buffer Statistics
Tracking
Buffer Statistics Tracking (BST) feature provides a mechanism to aid in Resource Monitoring and Tuning of Buffer Allocation. The Max
Use Count mode provides the maximum value of the counters accumulated over a period of time.
Priority Flow Control (PFC) provides a link level flow control mechanism, which is controlled independently for each frame priority. The
goal of this mechanism is to ensure zero loss under congestion in DCB networks.
Dell EMC Networking OS provides SNMP support for monitoring PFC and BST counters, and statistics. The enhancement is made on
DELL-NETWORKING-FPSTATS-MIB with additional tables to display the PFC and BST counters and statistics.
The following tables are available in DELL-NETWORKING-FPSTATS-MIB:
• dellNetFpEgrQBuffSnapshotTable
• dellNetFpIngPgBuffSnapshotTable
• dellNetFpStatsPerPgTable
• dellNetPfcPerPrioTable
dellNetFpEgrQBuf
fSnapshotTable
This table fetches the BST statistics at Egress Port for the buffer used. This table displays the Snapshot of the
Buffer cells used by Unicast and Multicast Data and Control Queues.
dellNetFpIngPgBu
ffSnapshotTable
This table fetches the BST statistics at the Ingress Port for the Shared Cells, and the Headroom cells used per
Priority Group. The snapshot of the Ingress Shared cells used and the Ingress Headroom cells used per Priority
Group, when PFC is enabled, display in this table. This table lists the stack-unit index, port number and the priority
group number.
dellNetFpStatsPer
PgTable
This table fetches the Allocated Min cells, Shared cells, and Headroom cells per Priority Group, the mode in which
the buffer cells are allocated — Static or Dynamic and the Used Min Cells, Shared cells and Headroom cells per
Priority Group. The table fetches a value of 0 if the mode of allocation is Static and a value of 1 if the mode of
allocation is Dynamic. This table lists thestack-unit number, port number and priority group number.
dellNetPfcPerPrio
Table
This table fetches the number of PFC frames transmitted (PFC Requests) and the number of PFC frames
received (PFC Indications) per priority on a per port basis. This table lists the stack-unit index, port number and
priority.
Performing PFC Using DSCP Bits Instead of
802.1p Bits
Priority based Flow Control (PFC) is currently supported on Dell EMC Networking OS for tagged packets based on the packet Dot1p. In
certain data center deployments, VLAN configuration is avoided on the servers and all packets from the servers are untagged. These
packets will carry IP header and can be differentiated based on the DSCP fields they carry on the server facing switch ports. Requirement
is to classify these untagged packets from the server based on their DSCP and provide PFC treatment.
Data Center Bridging (DCB)
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