FastNetMon and Juniper Junos integration

Documentation to integrate FastNetMon with inline jFlow / IPFIX using Juniper MX Series routers.

In this example, we use rate=500. It works well for amount of traffic from 100 Mbits/s. But you can increase to rate=1000, depending on your traffic.

FastNetMon can learn sampling rate automatically and you do not need to configure it.

Our topology is two MX routers, named r1 and r2. From each router connected directly to FastNetMon server.

FastNetMon server has 2 interfaces: 10.50.1.2/30 – connected to r1 10.50.1.6/30 – connected to r2 c R1 has 1 transit connected to ge-1/0/0.0 R2 has 1 transit connected to ge-1/0/0.0

Setting sampling on transit interfaces. Run that on those interfaces on each router.

set interfaces ge-1/0/0.0 family inet sampling input

Check interfaces configuration:

r1# show interfaces ge-1/0/4  
unit 0 {
    description netflow-collector;
    family inet {
        address 10.50.1.1/30;
    }
}



r1# show interfaces ge-1/0/4 | display set 
set interfaces ge-1/0/4 unit 0 description netflow-collector
set interfaces ge-1/0/4 unit 0 family inet address 10.50.1.1/30

r2# show interfaces ge-1/0/4  
unit 0 {
    description netflow-collector;
    family inet {
        address 10.50.1.5/30;
    }
}
r2# show interfaces ge-1/0/4 | display set 
set interfaces ge-1/0/4 unit 0 description netflow-collector
set interfaces ge-1/0/4 unit 0 family inet address 10.50.1.5/30

Now add templates configuration on r1 and r2. Take care of flow-active-timeout and flow-inactive-timeout it should be less than average_calculation_time.

You could set new average_calculation_time using configuration option in fastnetmon.conf in FastNetMon Community.

For FastNetMon Advanced you could use command line interface to configure it:

sudo fcli set main average_calculation_time 30
sudo fcli commit

Full configuration:

set services flow-monitoring version-ipfix template ipv4 flow-active-timeout 30
set services flow-monitoring version-ipfix template ipv4 flow-inactive-timeout 30
set services flow-monitoring version-ipfix template ipv4 template-refresh-rate packets 1000
set services flow-monitoring version-ipfix template ipv4 template-refresh-rate seconds 30
set services flow-monitoring version-ipfix template ipv4 option-refresh-rate packets 1000
set services flow-monitoring version-ipfix template ipv4 option-refresh-rate seconds 30
set services flow-monitoring version-ipfix template ipv4 ipv4-template
set chassis tfeb slot 0 sampling-instance ipfix


flow-monitoring {
    version-ipfix {
        template ipv4 {
            flow-active-timeout 30;
            flow-inactive-timeout 30;
            template-refresh-rate {
                packets 1000;
                seconds 10;
            }
            option-refresh-rate {
                packets 1000;
                seconds 10;
            }
            ipv4-template;
        }
    }
}

slot 0 {
    sampling-instance ipfix;
}

Now setup ipfix exports:

r1# show forwarding-options 
sampling {
    instance {
        ipfix {
            input {
                rate 500;
            }
            family inet {
                output {
                    flow-server 10.50.1.2 {
                        port 2055;
                        version-ipfix {
                            template {
                                ipv4;
                            }
                        }
                    }
                    inline-jflow {
                        source-address 10.50.1.1;
                    }
                }
            }
        }
    }
}

r1# show forwarding-options | display set 
set forwarding-options sampling instance ipfix input rate 500
set forwarding-options sampling instance ipfix family inet output flow-server 10.50.1.2 port 2055
set forwarding-options sampling instance ipfix family inet output flow-server 10.50.1.2 version-ipfix template ipv4
set forwarding-options sampling instance ipfix family inet output inline-jflow source-address 10.50.1.1


r2# show forwarding-options 
sampling {
    instance {
        ipfix {
            input {
                rate 500;
            }
            family inet {
                output {
                    flow-server 10.50.1.6 {
                        port 2055;
                        version-ipfix {
                            template {
                                ipv4;
                            }
                        }
                    }
                    inline-jflow {
                        source-address 10.50.1.5;
                    }
                }
            }
        }
    }
}

r2# show forwarding-options | display set 
set forwarding-options sampling instance ipfix input rate 500
set forwarding-options sampling instance ipfix family inet output flow-server 10.50.1.6 port 2055
set forwarding-options sampling instance ipfix family inet output flow-server 10.50.1.6 version-ipfix template ipv4
set forwarding-options sampling instance ipfix family inet output inline-jflow source-address 10.50.1.5

If you see significant traffic calculation inaccuracy and you run MX 204 we recommend enabling option flex-flow-sizing as it well known to fix such issues.

If you still have inaccurate traffic with Juniper MX, please check our detailed guide about fine tuning for flow tables.