Routing

Hello,

I'm setting some QoS architecture in lab on MX-series and got a problem with the results.

I send 200Mb of udp frame from 1000 bytes on my router from an IXIA chassis and receive the traffic back on the IXIA so I can check the frame loss and rate I got after the QoS from the MX. I attached the full configuration. The card inside the MX is a DPCE 40x 1GE R.

Configuration i'm testing

[edit class-of-service schedulers EF]
brice@MX960-re0# show
transmit-rate percent 9 exact;
priority medium-low;

I'm trying to limit the rate of a specific flow but I got unbalanced between rate I configure and rate I receive.

[edit class-of-service schedulers EF]
brice@MX960-re0# set transmit-rate X exact

Rate configured (X)      Rate received

50Mbps                            12Mbps

90Mbps                            22Mbps

150Mbps                          36Mbps

I tried to modifiy buffers and drop profile but there is no change. Also tried to use percent parameter and not rate but the result is the same if i configure 5% instead of 50M on the Giga port. Any other idea? Any explanation ?

CONFIGURATION

brice@MX960-re0# show
drop-profiles {
    NC-low {
        fill-level 80 drop-probability 50;
        fill-level 95 drop-probability 100;
    }
    NC-high {
        fill-level 80 drop-probability 50;
        fill-level 95 drop-probability 100;
    }
}
interfaces {
    ge-1/0/1 {
        scheduler-map SCHEDULER-MAP;
        shaping-rate 250m;
    }
}
scheduler-maps {
    SCHEDULER-MAP {
        forwarding-class assured-forwarding scheduler AF;
        forwarding-class expedited-forwarding scheduler EF;
        forwarding-class network-control scheduler NC;
        forwarding-class best-effort scheduler BE;
    }
}
schedulers {
    NC {
        transmit-rate 50m;
        buffer-size temporal 30k;
        priority high;
        drop-profile-map loss-priority low protocol any drop-profile NC-low;
        drop-profile-map loss-priority high protocol any drop-profile NC-high;
    }
    AF {
        transmit-rate 70m;
        priority medium-high;
    }
    EF {
        transmit-rate percent 9 exact;
        priority medium-low;
    }
    BE {
        transmit-rate 150m;
        priority low;
    }
}

brice@MX960-re0# top show firewall
family inet {
    filter CLASSIFIER {
        term NC {
            from {
                port 179;
            }
            then forwarding-class network-control;
        }
        term EF {
            from {
                dscp ef;
            }
            then forwarding-class expedited-forwarding;
        }
        term AF {
            from {
                dscp af32;
            }
            then forwarding-class assured-forwarding;
        }
        term DEFAULT {
            then forwarding-class best-effort;
        }
    }
}

Thank you all for your help.

Brice

Attachment(s)

MX.conf.txt   2 KB 1 version

Hi Brice,

There is a problem in your configurations.

You have configured the "Shaping rate as 250m" and then assigning bandwidth explicitly for each schedulers for a 1 Gig interface.

When you have "shaping rate" configured Junos will expect all scheduler bandwidth to be in "percentage" ( Not a mix of percent and rate)

But if you configure explicit BW rate for schedulers, Junos will automatically calculate the percentage according to the Interface speed ( 1 Gig) in this case and apply that percentage to the Shaping rate.

Your Result for EF was

Rate configured (X)      Rate received

50Mbps                            12Mbps

90Mbps                            22Mbps

150Mbps                          36Mbps

a)  EF scheduler BW  percentage = ( 50/1000) * 100  = 5%

     5% of shaped rate 250m is = (250M/100) *5 = 12.5M

b) (90/1000)*250 = 22.5M

c) (150/1000)*250=  37.5M

When you configured 5% , it calculated that out of 250m shaped-rate and resulted 12Mbps.

In order to make this issue clear,

If you really want to shape the total usage to 250m , then use the "bandwidth percent" for each schedulers.

Otherwise, remove the shaping-rate from interface.

Regards

Moses N

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Hi Moses

Well that explains the 1/4 ratio I got.

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mosesnehru wrote:

When you have "shaping rate" configured Junos will expect all scheduler bandwidth to be in "percentage" ( Not a mix of percent and rate)

 

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Good to know cause I don't remember to see this caution but the results makes sense now. Thank you for the clarification.