Reference Guide

dot1p Value in
the Incoming
Frame
Egress Queue Assignment
7 7
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 support for Max Use Count mode in Buffer Statistics is introduced in Dell Networking OS 9.3(0.). 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.
The SNMP support for monitoring PFC and BST counters and statistics is introduced in Dell Networking OS 9.3(0.1). The
enhancement is made on F10-FPSTATS MIB with additional tables to display the PFC and BST counters and statistics.
The following new tables are added in F10-FPSTATS MIB in Dell Networking OS 9.3(0.1):
● fpEgrQBuffSnapshotTable
● fpIngPgBuffSnapshotTable
● fpStatsPerPgTable
● pfcPerPrioTable
fpEgrQBuffSnaps
hotTable
This table fetches the BST statistics at Egress Port with respect to the buffer used. This table displays
the Snapshot of the Buffer cells used by Unicast and Multicast Data and Control Queues.
fpIngPgBuffSnap
shotTable
This table fetches the BST statistics at the Ingress Port with respect to 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, will be displayed in this table. This table is
indexed by stack-unit index, port number and the priority group number.
fpStatsPerPgTab
le
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 is indexed by stack-unit number, port number
and priority group number.
pfcPerPrioTable 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 is indexed by the stack-unit index,
port number and priority.
DCB Maps and its Attributes
This topic contains the following sections that describe how to configure a DCB map, apply the configured DCB map to a port,
configure PFC without a DCB map, and configure lossless queues.
DCB Map: Configuration Procedure
A DCB map consists of PFC and ETS parameters. By default, PFC is not enabled on any 802.1p priority and ETS allocates equal
bandwidth to each priority. To configure user-defined PFC and ETS settings, you must create a DCB map. The following is an
overview of the steps involved in configuring DCB.
● Enter global configuration mode to create a DCB map or edit PFC and ETS settings.
● Configure the PFC setting (on or off) and the ETS bandwidth percentage allocated to traffic in each priority group, or
whether the priority group traffic should be handled with strict priority scheduling. You can enable PFC on a maximum of two
priority queues on an interface. Enabling PFC for dot1p priorities makes the corresponding port queue lossless. The sum of all
allocated bandwidth percentages in all groups in the DCB map must be 100%. Strict-priority traffic is serviced first.
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Data Center Bridging (DCB)