netflow on fortigate WAN interface

netflow on fortigate WAN interface


i have enabled sflow on WAN interface of Fortigate 90D firmware 5.4.3. configuration as below:

config system interface
    edit "wan1"
        set vdom "root"
        set mode pppoe
        set allowaccess https snmp fgfm
        set vlanforward enable
        set type physical
        set sflow-sampler enable
        set sample-rate 100
        set polling-interval 30
        set sample-direction rx

config system sflow
    set collector-ip
    set collector-port 9996

i can see NFA flow count number getting more and UDP 9996 can be captured by wireshark, but there is no analyze data show in NFA v12.
please help, thank you!