UDP multiple pool irule not working for Anycast VS

Hi All,

I have setup a UDP anycast on LTM with source any to Anycast IP and for udp port 514-518 and each pool will have 3 servers. I have configure irule as below but the problem is, the traffic is not sending/distributing on all 3 real servers equally as lb method round robin.

when CLIENT_ACCEPTED {

switch [UDP::local_port] {

514 { 
  pool pool1_514
}
515 { 
  pool pool2_515
}
516 { 
  pool pool3_516
}
517 { 
  pool pool4_517
}
518 { 
  pool pool5_518
}
default {
  drop
}

} }