Policer Overhead to Account for Rate Shaping in the Traffic Manager

Step-by-Step Procedure

To configure the logical interfaces:

1. Enable configuration of the interface

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   [edit]
   user@host# edit interfaces ge-1/3/1
   

2. Enable multiple queues for each logical interface (so that you can associate an output scheduler with each logical interface).

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   [edit interfaces ge-1/3/1]
   user@host# set per-unit scheduler
   user@host# set vlan-tagging
   

   Note:

   For Gigabit Ethernet IQ2 PICs only, use the shared-scheduler statement to enable shared schedulers and shapers on a physical interface.

3. Configure logical interface ge-1/3/1.0.

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   [edit interfaces ge-1/3/1]
   user@host# set unit 0 vlan-id 100
   user@host# set unit 0 family inet address 10.10.10.1/30
   

4. Configure logical interface ge-1/3/1.1.

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   [edit interfaces ge-1/3/1]
   user@host# set unit 1 vlan-id 101
   user@host# set unit 1 family inet address 20.20.20.1/30 arp 20.20.20.2 mac 00:00:11:22:33:44
   

Results

Confirm the configuration of the interfaces by entering the show interfaces configuration mode command. If the command output does not display the intended configuration, repeat the instructions in this procedure to correct the configuration.

[edit]
user@host# show interfaces
ge-1/3/1 {
    per-unit-scheduler;
    vlan-tagging;
    unit 0 {
        vlan-id 100;
        family inet {
            address 10.10.10.1/30;
        }
    }
    unit 1 {
        vlan-id 101;
        family inet {
            address 20.20.20.1/30 {
                arp 20.20.20.2 mac 00:00:11:22:33:44;
            }
        }
    }
}

Step-by-Step Procedure

To configure traffic rate-shaping on the logical interface that carries output traffic:

1. Enable configuration of class-of-service features.

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   [edit]
   user@host# edit class-of-service
   

2. Configure packet scheduling on logical interface ge-1/3/1.0.

   • Configure schedulers that specify the percentage of transmission capacity.

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     [edit class-of-service]
     user@host# edit schedulers
      
     [edit class-of-service schedulers]
     user@host# set be transmit-rate percent 5
     user@host# set ef transmit-rate percent 30
     user@host# set af transmit-rate percent 30
     user@host# set nc transmit-rate percent 35
     

     A percentage of zero drops all packets in the queue. When the rate-limit option is specified, the transmission rate is limited to the rate-controlled amount. In contrast with the exact option, a scheduler with the rate-limit option shares unused bandwidth above the rate-controlled amount.

   • Configure a scheduler map to associate each scheduler with a forwarding class.

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     [edit class-of-service]
     user@host# edit scheduler-maps my-map
      
     [edit class-of-service scheduler-maps my-map]
     user@host# set forwarding-class best-effort scheduler be
     user@host# set forwarding-class expedited-forwarding scheduler ef
     user@host# set forwarding-class network-control scheduler nc
     user@host# set forwarding-class assured-forwarding scheduler af
     

   • Associate the scheduler map with logical interface ge-1/3/1.0.

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     [edit class-of-service]
     user@host# edit interfaces ge-1/3/1 unit 1
      
     [edit class-of-service interfaces ge-1/3/1 unit 1]
     user@host# set scheduler-map my-map
     

3. Configure 100 Mbps of traffic rate-shaping overhead on logical interface ge-1/3/1.1.

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   [edit class-of-service interfaces ge-1/3/1 unit 1]
   user@host# set shaping-rate 100
   

   Alternatively, you can configure a shaping rate for a logical interface and oversubscribe the physical interface by including the shaping-rate statement at the [edit class-of-service traffic-control-profiles] hierarchy level. With this configuration approach, you can independently control the delay-buffer rate.

Results

Confirm the configuration of the class-of-service features (including the 100 Mbp of shaping of the egress traffic) by entering the show class-of-service configuration mode command. If the command output does not display the intended configuration, repeat the instructions in this procedure to correct the configuration.

[edit]
user@host# show class-of-service
interfaces {
    ge-1/3/1 {
        unit 1 {
            scheduler-map my-map;
            shaping-rate 100m;
        }
    }
}
scheduler-maps {
    my-map {
        forwarding-class best-effort scheduler be;
        forwarding-class expedited-forwarding scheduler ef;
        forwarding-class network-control scheduler nc;
        forwarding-class assured-forwarding scheduler af;
    }
}
schedulers {
    be {
        transmit-rate percent 5;
    }
    ef {
        transmit-rate percent 30;
    }
    af {
        transmit-rate percent 30;
    }
    nc {
        transmit-rate percent 35;
    }
}

Step-by-Step Procedure

To configure policer overhead on the PIC or MPC that hosts the rate-shaped logical interface:

1. Enable configuration of the supported PIC or MPC.

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   [edit]
   user@host# set chassis fpc 1 pic 3
   

2. Configure 100 bytes of policer overhead on the supported PIC or MPC.

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   [edit chassis fpc 1 pic 3]
   user@host# set ingress-policer-overhead 100
   user@host# set egress-policer-overhead 100
   

   Note:

   These values are added to the length of the final Ethernet frame when determining ingress and egress policer actions for all physical interfaces on the PIC or MPC.

   You can specify policer overhead with values from 0 through 255 bytes.

Results

Confirm the configuration of the policer overhead on the physical interface to account for rate-shaping by entering the show chassis configuration mode command. If the command output does not display the intended configuration, repeat the instructions in this procedure to correct the configuration.

[edit]
user@host# show chassis
chassis {
    fpc 1 {
        pic 3 {
            egress-policer-overhead 100;
            ingress-policer-overhead 100;
        }
    }
}

Step-by-Step Procedure

To apply a policer to the logical interface that carries input traffic:

1. Configure the logical interface (aggregate) policer.

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   [edit]
   user@host# edit firewall policer 500Kbps
    
   [edit firewall policer 500Kbps]
   user@host# set logical-interface-policer
   user@host# set if-exceeding bandwidth-limit 500k
   user@host# set if-exceeding burst-size-limit 625k
   user@host# set then discard
   

2. Apply the policer to Layer 3 input on the IPv4 logical interface.

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   [edit]
   user@host# set interfaces ge-1/3/1 unit 0 family inet policer input 500Kbps
   

   Note:

   The 100 Mbps policer overhead is added to the length of the final Ethernet frame when determining ingress and egress policer actions,

Results

Confirm the configuration of the policer with rate-shaping overhead by entering the show firewall and show interfaces configuration mode commands. If the command output does not display the intended configuration, repeat the instructions in this procedure to correct the configuration.

[edit]
user@host# show firewall
policer 500Kbps {
    logical-interface-policer;
    if-exceeding {
        bandwidth-limit 500k;
        burst-size-limit 625k;
    }
    then discard;
}

[edit]
user@host# show interfaces
ge-1/3/1 {
    per-unit-scheduler;
    vlan-tagging;
    unit 0 {
        vlan-id 100;
        layer2-policer {
            input-policer 500Kbps;
        }
        family inet {
            address 10.10.10.1/30;
        }
    }
    unit 0 {
        vlan-id 101;
        family inet {
            address 20.20.20.1/30 {
                arp 20.20.20.2 mac 00:00:11:22:33:44;
            }
        }
    }
}

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

Purpose

Verify the traffic flow through the logical interface and that the policer is evaluated when packets are received on the logical interface.

Action

Use the show interfaces operational mode command for logical interface ge-1/3/1.0, and include the detail or extensive option. The command output section for Traffic statistics lists the number of bytes and packets received and transmitted on the logical interface, and the Protocol inet section contains a Policer field that would list the policer 500Kbps as an input or output policer as follows:

• Input: 500Kbps-ge-1/3/1.0-log_int-i

• Output: 500Kbps-ge-1/3/1.0-log_int-o

The log_int-i suffix denotes a logical interface policer applied to input traffic, while the log_int-o suffix denotes a logical interface policer applied to output traffic. In this example, the logical interface policer is applied to Input traffic only.

Purpose

Verify the number of packets evaluated by the policer.

Action

Use the show policer operational mode command and optionally specify the name of the policer. The command output displays the number of packets evaluated by each configured policer (or the specified policer), in each direction. For the policer 500Kbps, the input and output policer names are displayed as follows:

• 500Kbps-ge-1/3/1.0-log_int-i

• 500Kbps-ge-1/3/1.0-log_int-o

The log_int-i suffix denotes a logical interface policer applied to input traffic, while the log_int-o suffix denotes a logical interface policer applied to output traffic. In this example, the logical interface policer is applied to input traffic only.