Pfc And Ets Configuration Examples; Using Pfc To Manage Converged Ethernet Traffic; Operations On Untagged Packets; Generation Of Pfc For A Priority For Untagged Packets - Dell S6000–ON Configuration Manual

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PFC and ETS Configuration Examples

This section contains examples of how to configure and apply DCB policies on an interface.

To use PFC for managing converged Ethernet traffic, use the following command:

dcb-map stack-unit all dcb-map-name

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 that come in with packet-dot1p 2 alone will be assigned to PG6 on ingress.

The packets that come in with packet-dot1p 2 alone will use Q1 (as per dot1p to Queue classification –

Table 2) on the egress port.

When Peer sends a PFC message for Priority 2, based on above PRIO2COS table (TABLE 2), Queue 1 is

Queue 1 starts buffering the packets with Dot1p 2. This causes PG6 buffer counter to increase on the

ingress, since P-dot1p 2 is mapped to PG6.

As the PG6 watermark threshold is reached, PFC will be generated for dot1p 2.

In order to generate PFC for a particular priority for untagged packets, and configuring PFC for that

priority, you should find the queue number associated with priority from TABLE 1 and Associate a DCB

map to forward the matched DSCP packet to that queue. PFC frames gets generated with PFC priority

associated with the queue when the queue gets congested.

Data Center Bridging (DCB)