Cisco Nexus 9000 Series Configuration Manual page 159

Configuring Priority Flow Control
Command or Action
Step 14
class type network-qos class-name
Example:
switch(config-pmap-nqos)# class type
network-qos c-nq1
switch(config-pmap-nqos-c)#
Step 15
pause buffer-size buffer-size pause-threshold
xoff-size resume-threshold xon-size pfc-cos
cos-value
Example:
switch(config-pmap-nqos-c)# pause
buffer-size 20000 pause-threshold 100
resume-threshold 1000 pfc-cos 1
Purpose
Associates a class map with the policy map, and enters the configuration
mode for the specified system class.
The associated class map must be the same type as the policy
Note
map type.
Specifies the buffer threshold settings for pause and resume.
• buffer-size buffer-size—Specifies the buffer size for ingress
traffic, in bytes. Valid values are from 10240 to 490880.
You can configure a maximum buffer size of 143680
Note
bytes.
• pause-threshold xoff-size—Specifies the buffer limit at which
the port pauses the peer, in bytes. Valid values are from 0 to
490880.
You can configure a maximum pause threshold value of
Note
58860 bytes.
• resume-threshold xon-size—Specifies the buffer limit at which
the port resumes the peer, in bytes. Valid values are from 0 to
490880.
Note You can configure a maximum resume threshold value
of 38400 bytes.
• pfc-cos cos-value—Specifies the CoS values on which to assert
PFC. Valid values are from 0 to 7.
When you configure the buffer size, ensure the following:
Note
Cisco Nexus 9000 Series NX-OS Quality of Service Configuration Guide, Release 7.x
Enabling Priority Flow Control on a Traffic Class
• The buffer size must be greater than the pause
threshold value, and the pause threshold value must
be greater than the resume threshold value.
Otherwise, the following message appears:
ERROR: buffer-size can't be less then
pause/resume-threshold
• The minimum difference between the pause
threshold value and the resume threshold value
must be 20480 bytes. Otherwise, the following
message appears:
Warning: The recommended difference between
pause and resume threshold is 20480 bytes
• The pause threshold value must be greater than the
resume threshold value. Otherwise, the following
message appears:
ERROR: pause-threshold can't be less then
resume-threshold
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