Reference Guide

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 theprioritycommand 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
Dell(conf-dcb-buffer-thr)#priority 0 buffer-size 52 pause-
threshold 16 resume-offset 10 shared-threshold-weight 7
qos-policy-buffer
Create a QoS policy buffer and enter the configuration mode to configure the no-drop queues, ingress
buffer size, buffer limit for pausing, and buffer offset limit for resuming. This utility is supported on the
S4820T
Syntax
qos-policy-buffer queue queue-num pause no-drop queue buffer-
size size pause-threshold threshold-value resume-offset
threshold-value shared-threshold-weight size
Parameters
policy-name Name of the QoS policy buffer that is applied to an interface
for this setting to be effective in conjunction with the DCB
input policy. 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. This method
of configuration enables different peer-provided and
administrative priorities to be set up because the intended
queue is directly configured instead of determining the
priority to queue mapping for local and remote parameters.
queue 0 to
queue 7
Specify the queue number to which the QoS policy buffer
parameters apply
pause Pause frames to be sent at the specified buffer limit levels
and pause packet settings
no-drop The packets for this queue must not be dropped
value Enter a number in the range of 0 to 7 to denote the priority
to be allocated to the dynamic buffer control mechanism
Data Center Bridging (DCB)
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