Users Guide

Table 122. Default ingress buffers on the S4100-ON series platform
Speed 10G 25G 40G 50G 100G
Reserved buffers
for PG 7 (default)
9KB 9KB 9KB 9KB 9KB
The following lists the link-level flow control (LLFC) buffer settings for default priority group 7:
Table 123. Default setting for LLFC
Speed 10G 25G 40G 50G 100G
Default reserved buffer 9KB 9KB 18KB 18KB 36KB
Default Xon threshold 36KB 45KB 75KB 91KB 142KB
Default Xoff threshold 9KB 9KB 9KB 9KB 9KB
Default dynamic shared buffer threshold (alpha
value)
9KB 9KB 9KB 9KB 9KB
NOTE: The supported speed varies for different platforms. After the reserved buffers are used, each LLFC starts
consuming shared buffers from the lossless pool with the alpha value determining the threshold except for the S4200-ON
series platform.
The following table lists the priority flow control (PFC) buffer settings per PFC priority group:
Table 124. Default settings for PFC
Speed 10G 25G 40G 50G 100G
Default reserved buffer for S4000, S4048–ON, S6010–ON 9KB NA 9KB NA NA
Default reserved buffer for S41xx, Z9100–ON 9KB 9KB 18KB 18KB 36KB
Default Xoff threshold 36KB 45KB 75KB 91KB 142KB
Default Xon threshold 9KB 9KB 9KB 9KB 9KB
Default dynamic share buffer threshold (alpha value) 9KB 9KB 9KB 9KB 9KB
NOTE: The supported speed varies for different platforms. After the reserved buffers are used, each PFC starts consuming
shared buffers from the lossless pool with the alpha value determining the threshold.
You can override the default priority group settings when you enable LLFC or PFC.
1. Create a network-qos type class-map to match the traffic classes. For LLFC, match all the traffic classes from 0 to 7. For
PFC, match the required traffic class.
OS10(config)# class-map type network-qos example-cmap-in-buffer
OS10 (config-cmap-nqos)# match qos-group 0-7
2. Create network-qos type policy-map to define the actions for traffic classes, such as a buffer configuration and threshold.
OS10(config)# policy-map type network-qos example-pmap-in-buffer
OS10(config-pmap-network-qos)# class example-cmap-in-buffer
OS10 (config-pmap-c-nqos)# pause buffer-size 300 pause-threshold 200 resume-threshold
100
OS10 (config-pmap-c-nqos)# queue-limit thresh-mode dynamic 5
Configure egress buffer
All port queues are allocated with reserved buffers. When the reserved buffers are consumed, each queue starts using the
shared buffers from the default pool.
The following table lists the values allocated for the default egress buffers on the S4100-ON series platform. These values may
differ for different platforms and speeds. Use the show qos egress buffers command to view the default egress buffers
on your switch.
1556
Quality of service