Configure

router isis 1
 is-type level-2-only
 net 49.0000.0000.0001.00
 address-family ipv4 unicast
  metric-style wide
  segment-routing mpls
 !
 interface Loopback0
  address-family ipv4 unicast
   prefix-sid index 1
  !

sampler-map FNF_SAMPLER_MAP
 random 1 out-of 4999

flow exporter-map FNF_EXPORT_MAP
 version v9
  options sampler-table timeout 60
  template timeout 60
 !
 transport udp 20013
 source Loopback0
 destination 10.1.1.1