irule with diameter result code

[root@ve1023:Active] config  b virtual bar list
virtual bar {
   snat automap
   pool foo
   destination 172.28.19.79:3868
   ip protocol 6
   rules myrule2
   profiles {
      diameter {}
      mblb {}
      tcp {}
   }
}
[root@ve1023:Active] config  b pool foo list
pool foo {
   members 200.200.200.101:3868 {}
}
[root@ve1023:Active] config  b rule myrule2 list
rule myrule2 {
   when SERVER_CONNECTED {
        TCP::collect
}

when SERVER_DATA {
        while {[TCP::payload length] > 20} {
                binary scan [TCP::payload] II a b
                set comcode [expr {$b & 0xffffff}]
                set mlen [expr {$a & 0xffffff}]
                set rflag [expr {($b >> 31)&1}]

                if {!($rflag)} {
                        switch $comcode {
                                280 -
                                282 {}
                                default {
                                        set index 20
                                        while {$index < $mlen} {
                                                binary scan [TCP::payload $mlen] @${index}II avp_code avp_len
                                                set avp_len [expr {$avp_len & 0xffffff}]
                                                set avp_len_pad [expr {(($avp_len + 3)/4)*4}]
                                                if {$avp_code == 268} {
                                                        set avp_dlen [expr {$avp_len - 8}]
                                                        binary scan [TCP::payload $mlen] @[expr {$index + 8}]I result
                                                        break
                                                }
                                                incr index $avp_len_pad
                                        }
                                }
                        }

                        switch $result {
                                2001 { log local0. "2001" }
                                default { log local0. "others" }
                        }
                }
                TCP::release $mlen
        }
        TCP::collect
}
}

[root@ve1023:Active] config  tail /var/log/ltm
Nov 30 10:52:27 local/tmm info tmm[23027]: Rule myrule2 : 2001
Nov 30 10:52:27 local/tmm info tmm[23027]: Rule myrule2 : 2001
Nov 30 10:52:28 local/tmm info tmm[23027]: Rule myrule2 : 2001
Nov 30 10:52:29 local/tmm info tmm[23027]: Rule myrule2 : 2001
Nov 30 10:52:30 local/tmm info tmm[23027]: Rule myrule2 : 2001
Nov 30 10:52:31 local/tmm info tmm[23027]: Rule myrule2 : 2001
Nov 30 10:52:32 local/tmm info tmm[23027]: Rule myrule2 : 2001
Nov 30 10:52:33 local/tmm info tmm[23027]: Rule myrule2 : 2001
Nov 30 10:52:34 local/tmm info tmm[23027]: Rule myrule2 : 2001
Nov 30 10:52:35 local/tmm info tmm[23027]: Rule myrule2 : 2001