Dell Command Line Reference Guide for the S4048–ON System 9.14.2.8

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priority

Configure the priority for the PFC threshold to be allocated to the buffer space parameters.

Syntax
priority value buffer-size size pause-threshold threshold-value resume-offset threshold-value shared-threshold-weight size
Parameters
priority
Specify the priority of the queue for which the buffer space settings apply.
value
Enter a number in the range of 0 to 7 to denote the priority to be allocated to the dynamic buffer control mechanism.
buffer-size
Ingress buffer size.
size
Size of the ingress buffer in KB. Enter a number in the range of 0 to 7787. The default is 45 KB.
pause-threshold
Buffer limit for pause frames to be sent.
NOTE: In addition to the specified pause-threshold value, pause frames are sent only when the buffer usage exceeds some percentage of the shared buffer.
threshold-value
Buffer limit at which the port sends the pause to peer in KB. Enter a number in the range of 0 to 7787. The default is 10 KB.
resume-offset
Buffer offset limit for stopping the transmission of pause frames.
threshold-value
Buffer offset limit at which the port resumes the peer in KB. Enter a number in the range of 1 to 7787. The default is 10 KB.
shared-threshold-weight
Buffer shared threshold weight
size
Weightage of the priorities on the shared buffer size in the system. Enter a number in the range of 0 to 9. The default shared threshold weight is 10.
Command Modes
DCB-BUFFER-THRESHOLD mode
Command History

This guide is platform-specific. For command information about other platforms, see the relevant Dell EMC Networking OS Command Line Reference Guide.

Version
Description
9.11(2.0P0)
Default values of buffer threshold profile parameters are changed for the Z9100-ON and S6100-ON.
9.10(0.1)
Introduced on the S6010-ON and S4048T-ON.
9.10(0.0)
Introduced on the S6100.
9.8(1.0)
Introduced on the Z9100–ON.
9.8(0.0)
Introduced on the S3048-ON and S4048-ON.
9.7(0.0)
Introduced on the S6000-ON.
9.3(0.0)
Introduced on the S4810, S4820T, and S6000 platforms.
Usage Information

For each priority, you can specify the shared buffer threshold limit, the ingress buffer size, buffer limit for pausing the acceptance of packets, and the buffer offset limit for resuming the acceptance of received packets. When PFC detects congestion on a queue for a specified priority, it sends a pause frame for the 802.1p priority traffic to the transmitting device.

You can use the priority command to set up both the administrative and peer-related PFC priorities. For example, you can configure the intended buffer configuration for all eight priorities. If you configure the number of lossless queues as 4 and if the administrator-configured priorities configured within the DCB input policy is applied, then the configuration for those priorities are pre-designed. However, if the peer-provided priorities are applied, although a DCB input policy is present, the peer-provided priorities become effective for buffer configuration. This method of configuration provides an easy and flexible technique to accommodate both administratively-configured and peer-configured priorities.

Example
DellEMC(conf-dcb-buffer-thr)# priority 0 buffer-size 52 pause-threshold 16 resume-offset 10 shared-threshold-weight 7

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