Connectivity Guide

You can obtain a snapshot of the buer statistics for the dierent buer objects, such as a snapshot of all ingress priority-groups
associated to a port, all egress unicast queues bound to a port, and so on.
You can enable BST at the global level. OS10 tracks buer utilization and provides the maximum peak statistics value over a period of time
and the current value of the monitored BST counter.
Use the buffer-statistics-tracking command in SYSTEM-QOS mode to enable BST:
OS10# configure terminal
OS10(config)# configure system-qos
OS10(config-sys-qos)# buffer-statistics-tracking
Clear the counter
You can choose to reset the peak buer utilization value and determine a new peak buer utilization value. Use the clear qos
statistics type buffer-statistics-tracking command to clear the tracked value and to refresh this counter.
BST tracks peak buer utilization over a period of time. At any given point in time, the peak buer usage from the past is displayed.
For example, if you enable BST at time T0 and use the show command to view the peak buer utilization value at time T1, the peak usage
between T0 and T1 is displayed. If you view the peak buer utilization again at time T2, the peak usage between T0 and T2 is displayed.
However, if you clear the counter using the clear qos statistics type buffer-statistics-tracking command at time
T3 and view the peak buer utilization at time T4, the peak usage between T3 and T4 is displayed.
NOTE: When BST is enabled, if you make any conguration changes that aect the priority group or priority mapping
conguration, such as removal of class map, addition of class map to policy map (nqos), and so on, be sure to clear the buer
statistics using the clear qos statistics type buffer-statistics-tracking command to view the actual peak
buer utilization for the current conguration.
Advantages of BST include:
• Detecting microburst congestions
• Monitoring buer utilization and historical trends
• Determining optimal sizes and thresholds for the ingress or egress shared buers and headroom on a given port or queue based on real-
time data
NOTE
: BST is not supported on the S4248F-ON and S5148F-ON platforms.
After you disable BST, be sure to clear the counter using the clear qos statistics type buffer-statistics-tracking
command.
QoS commands
bandwidth
Assigns a percentage of weight to the queue.
Syntax
bandwidth percent value
Parameters percent value — Enter the percentage assignment of bandwidth to the queue, from 1 to 100.
Default Not congured
Command Mode POLICY-MAP QUEUE
Usage Information If you congure this command, you cannot use the priority command for the class.
Quality of service 995