Configuring Scheduler Actions

You use scheduler actions along with QoS conditions and traffic-shape actions to configure transmission scheduling and rate control. Schedulers define the priority, bandwidth, delay buffer size, rate control status, and random early detection (RED) drop profiles to be applied to a particular class of traffic. You can create scheduler actions in JUNOS scheduler policy rules.

The type of action that you can create depends on the type of policy rule. See Policy Information Model.

Use the following configuration statements to configure scheduler actions:

policies group name list name rule name scheduler-action name {
buffer-size buffer-size ;
buffer-size-unit buffer-size-unit ;
priority priority ;
transmit-rate transmit-rate ;
transmit-rate-unit transmit-rate-unit ;
exact exact ;
description description ;
}

To configure a scheduler action:

  1. From configuration mode, enter the scheduler action configuration. For example, in this procedure, sa is the name of the scheduler action.
      user@host# edit policies group junos list qos rule pr scheduler-action sa
  2. (Optional) Configure the queue transmission buffer size.
      [edit policies group junos list qos rule pr scheduler-action sa]
      user@host# set buffer-size buffer-size
  3. (Optional) Configure the type of value that you entered for buffer size.
      [edit policies group junos list qos rule pr scheduler-action sa]
      user@host# set buffer-size-unit buffer-size-unit
  4. (Optional) Configure the packet-scheduling priority. The priority determines the order in which an output interface transmits traffic from the queues.
      [edit policies group junos list qos rule pr scheduler-action sa]
      user@host# set priority priority
  5. (Optional) Configure the transmit rate.
      [edit policies group junos list qos rule pr scheduler-action sa]
      user@host# set transmit-rate transmit-rate
  6. (Optional) Configure the type of value entered for transmit rate.
      [edit policies group junos list qos rule pr scheduler-action sa]
      user@host# set transmit-rate-unit transmit-rate-unit
  7. (Optional) Specify whether or not to enforce the exact transmission rate. Under sustained congestion, a rate-controlled queue that goes into negative credit fills up and eventually drops packets.
      [edit policies group junos list qos rule pr scheduler-action sa]
      user@host# set exact exact
  8. (Optional) Enter a description for the scheduler action.
      [edit policies group junos list qos rule pr scheduler-action sa]
      user@host# set description description
  9. (Optional) Verify the scheduler action configuration. 
    [edit policies group junos list qos rule pr scheduler-action sa]
user@host# show 
buffer-size 85;
buffer-size-unit buffer_size_percentage;
priority low;
transmit-rate 10485760;
transmit-rate-unit rate_in_bps;
description "Scheduler action for logical interface scheduling";