Administrator Guide

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
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
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 resuming in KB
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.
Default The default size of the ingress buffer is 45 KB. The default buffer limit at which the port sends the pause
to peer and recommences the sending of packets to the peer is 10 KB. The default threshold weight of
the shared buffer space 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
Networking OS Command Line Reference Guide.
Version Description
9.8(0.0) Introduced on the S3048-ON and S4048-ON.
9.7(0.0) Introduced on the S6000-ON and Z9500.
9.3(0.0) Introduced on the S4810, S4820T, S6000, and MXL platforms.
Usage
Information
You must apply this buffer policy at the interface level for the attributes to be applicable in conjunction
with the DCB input policy.
For each QoS policy buffer, 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 set up both the administrative and peer-related PFC priorities. For example, you can
configure the intended buffer configuration for all 8 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)# qos-policy-buffer test
Dell(conf-qos-policy-buffer)#queue 0 pause no-drop buffer-size 128000
pause-threshold 103360 resume-threshold 83520
Dell(conf-qos-policy-buffer)# queue 4 pause no-drop buffer-size 128000
pause-threshold 103360 resume-threshold 83520
526 Data Center Bridging (DCB)