Example: Configuring Excess Rate for PTX Series Packet Transport Routers

CLI Quick Configuration

To quickly configure this example, copy the following commands, paste them into a text file, remove any line breaks, change any details necessary to match your network configuration, and then copy and paste the commands into the CLI at the [edit] hierarchy level.

set class-of-service schedulers sched_queue_0 transmit-rate percent 20
set class-of-service schedulers sched_queue_1 transmit-rate percent 40
set class-of-service schedulers sched_queue_2 transmit-rate percent 10
set class-of-service schedulers sched_queue_3 transmit-rate percent 10

Step-by-Step Procedure

In this example, four queues are configured and each associated scheduler is assigned the indicated transmit rate. Across the four queues, the transmit rate totals to 80 percent. No excess rate is configured. Assuming that each queue has loads greater than or equal to the configured transmit rate, the remaining 20 percent of the bandwidth is distributed in proportion to the configured transmit rates (20:40:10:10):

• sched_queue_0—5% (20% of the guaranteed rate plus 5% of the remaining bandwidth is 25%)

• sched_queue_1—10% (40% of the guaranteed rate plus 10% of the remaining bandwidth is 50%)

• sched_queue_2—2.5% (10% of the guaranteed rate plus 2.5% of the remaining bandwidth is 12.5%)

• sched_queue_3—2.5% (10% of the guaranteed rate plus 2.5% of the remaining bandwidth is 12.5%)

The following example requires you to navigate various levels in the configuration hierarchy. For instructions on how to do that, see Using the CLI Editor in Configuration Mode in the Junos OS CLI User Guide.

To configure the schedulers:

1. Create the scheduler for queue 0:

   content_copy zoom_out_map

   [edit class-of-service]
   user@host# set schedulers sched_queue_0 transmit-rate percent 20
   

2. Create the scheduler for queue 1:

   content_copy zoom_out_map

   [edit class-of-service]
   user@host# set schedulers sched_queue_1 transmit-rate percent 40
   

3. Create the scheduler for queue 2:

   content_copy zoom_out_map

   [edit class-of-service]
   user@host# set schedulers sched_queue_2 transmit-rate percent 10
   

4. Create the scheduler for queue 3:

   content_copy zoom_out_map

   [edit class-of-service]
   user@host# set schedulers sched_queue_3 transmit-rate percent 10
   

Results

From configuration mode, confirm your configuration by entering the show class-of-service schedulers command. If the output does not display the intended configuration, repeat the configuration instructions in this example to correct it.

    sched_queue_0 {
        transmit-rate percent 20;
    }
    sched_queue_1 {
        transmit-rate percent 40;
    }
    sched_queue_2 {
        transmit-rate percent 10;
    }
    sched_queue_3 {
        transmit-rate percent 10;
    }

If you are done configuring the device, enter commit from configuration mode.

CLI Quick Configuration

To quickly configure this example, copy the following commands, paste them into a text file, remove any line breaks, change any details necessary to match your network configuration, and then copy and paste the commands into the CLI at the [edit] hierarchy level.

set class-of-service schedulers sched_queue_0 transmit-rate percent 25
set class-of-service schedulers sched_queue_0 excess-rate percent 25
set class-of-service schedulers sched_queue_1 transmit-rate percent 25
set class-of-service schedulers sched_queue_1 excess-rate percent 50
set class-of-service schedulers sched_queue_2 transmit-rate percent 25
set class-of-service schedulers sched_queue_3 transmit-rate percent 25

Step-by-Step Procedure

In this example, four schedulers are configured and each is assigned a transmit rate of 25 percent. Queue 0 is configured with 25 percent and queue 1 with 50 percent of the excess rate. If the offered load through queue 2 is only 10 percent, the remaining bandwidth is distributed as: queue excess rate / total excess rate * remaining bandwidth percentage. If a queue has transmit rate configured but not excess rate, the excess rate for that queue is 1. In this example, the excess rate ratio is 25:50:1:1, which yields the following distribution of the 15 percent remaining bandwidth from queue 2:

• sched_queue_0—4.93% (25 / 76 * 15%)

• sched_queue_1—9.87% (50 / 76 * 15%)

• sched_queue_3—0.197% (1 / 76 * 15%)

When the offered load on queue 2 increases to 25 percent or greater, the other queues get only their configured transmit rates.

The following example requires you to navigate various levels in the configuration hierarchy. For instructions on how to do that, see Using the CLI Editor in Configuration Mode in the Junos OS CLI User Guide.

To configure the schedulers:

1. Create the scheduler for queue 0:

   content_copy zoom_out_map

   [edit class-of-service]
   user@host# set schedulers sched_queue_0 transmit-rate percent 25
   user@host# set schedulers sched_queue_0 excess-rate percent 25
   

2. Create the scheduler for queue 1:

   content_copy zoom_out_map

   [edit class-of-service]
   user@host# set schedulers sched_queue_1 transmit-rate percent 25
   user@host# set schedulers sched_queue_1 excess-rate percent 50
   

3. Create the scheduler for queue 2:

   content_copy zoom_out_map

   [edit class-of-service]
   user@host# set schedulers sched_queue_2 transmit-rate percent 25
   

4. Create the scheduler for queue 3:

   content_copy zoom_out_map

   [edit class-of-service]
   user@host# set schedulers sched_queue_3 transmit-rate percent 25
   

Results

From configuration mode, confirm your configuration by entering the show class-of-service schedulers command. If the output does not display the intended configuration, repeat the configuration instructions in this example to correct it.

    sched_queue_0 {
        transmit-rate percent 25;
        excess-rate percent 25;
    }
    sched_queue_1 {
        transmit-rate percent 25;
        excess-rate percent 50;
    }
    sched_queue_2 {
        transmit-rate percent 25;
    }
    sched_queue_3 {
        transmit-rate percent 25;
    }

If you are done configuring the device, enter commit from configuration mode.

CLI Quick Configuration

To quickly configure this example, copy the following commands, paste them into a text file, remove any line breaks, change any details necessary to match your network configuration, and then copy and paste the commands into the CLI at the [edit] hierarchy level.

set class-of-service schedulers sched_queue_0 transmit-rate percent 90
set class-of-service schedulers sched_queue_0 priority high
set class-of-service schedulers sched_queue_1 transmit-rate percent 10
set class-of-service schedulers sched_queue_1 priority low
set class-of-service schedulers sched_queue_2 excess-rate percent 10
set class-of-service schedulers sched_queue_3 excess-rate percent 30

Step-by-Step Procedure

In this example, the scheduler for queue 0 is configured to transmit up to 90 percent of traffic if there is enough offered load. When the traffic to queue 0 is less than 90 percent, excess rate is configured to distribute the remaining bandwidth in the ratio 1:1:10:30 (when the offered load on queue 1 is greater than 10 percent), which yields the following distribution of the remaining bandwidth from queue 0:

• sched_queue_1—0.0244 * x% (1 / 41 * remaining bandwidth (x)%)

• sched_queue_2—0.244 * x% (10 / 41 * remaining bandwidth (x)%)

• sched_queue_3—0.732 * x% (30 / 41 * remaining bandwidth (x)%)

The following example requires you to navigate various levels in the configuration hierarchy. For instructions on how to do that, see Using the CLI Editor in Configuration Mode in the Junos OS CLI User Guide.

To configure the schedulers:

1. Create the scheduler for queue 0:

   content_copy zoom_out_map

   [edit class-of-service]
   user@host# set schedulers sched_queue_0 transmit-rate percent 90
   user@host# set schedulers sched_queue_0 priority high
   

2. Create the scheduler for queue 1:

   content_copy zoom_out_map

   [edit class-of-service]
   user@host# set schedulers sched_queue_1 transmit-rate percent 10
   user@host# set schedulers sched_queue_1 priority low
   

3. Create the scheduler for queue 2:

   content_copy zoom_out_map

   [edit class-of-service]
   user@host# set schedulers sched_queue_2 excess-rate percent 10
   

4. Create the scheduler for queue 3:

   content_copy zoom_out_map

   [edit class-of-service]
   user@host# set schedulers sched_queue_3 excess-rate percent 30
   

Results

From configuration mode, confirm your configuration by entering the show class-of-service schedulers command. If the output does not display the intended configuration, repeat the configuration instructions in this example to correct it.

    sched_queue_0 {
        transmit-rate percent 90;
        priority high;
    }
    sched_queue_1 {
        transmit-rate percent 10;
        priority low;
    }
    sched_queue_2 {
        excess-rate percent 10;
    }
    sched_queue_3 {
        excess-rate percent 30;
    }

If you are done configuring the device, enter commit from configuration mode.

Purpose

Verify that the excess rate configuration is producing the results you expect.

Action

From operational mode, enter the show interfaces queue interface command for the physical interface to verify.

Meaning

The show command output lists the traffic by queue and forwarding class names. Verify that the Bytes field for active queues on the specified physical interface match the proportions you expect from the excess rate configuration.