LB 4200v with CMP disable does not distribute evenly but 3400 does

After disable CMP, It's better but some client still sent to the same server. This is a problem.

it seems okay here.

 hardware

root@(B4200-R77-S7)(cfg-sync Standalone)(Active)(/Common)(tmos) show sys hardware | grep -A 4 Platform
Platform
  Name           BIG-IP 4200
  BIOS Revision  OBJ-0433-xx Build: 2.02.171.0 05/02/2014
  Base MAC       00:23:e9:5b:19:40

 configuration

root@(B4200-R77-S7)(cfg-sync Standalone)(Active)(/Common)(tmos) list ltm virtual bar
ltm virtual bar {
    cmp-enabled no
    destination 100.100.100.108:http
    ip-protocol tcp
    mask 255.255.255.255
    pool foo
    profiles {
        tcp { }
    }
    rules {
        qux
    }
    source 0.0.0.0/0
    source-address-translation {
        type automap
    }
    vs-index 3
}
root@(B4200-R77-S7)(cfg-sync Standalone)(Active)(/Common)(tmos) list ltm pool foo
ltm pool foo {
    members {
        200.200.200.101:http {
            address 200.200.200.101
        }
        200.200.200.102:http {
            address 200.200.200.102
        }
        200.200.200.111:http {
            address 200.200.200.111
        }
    }
}
root@(B4200-R77-S7)(cfg-sync Standalone)(Active)(/Common)(tmos) list ltm rule qux
ltm rule qux {
    when SERVER_CONNECTED {
  log local0. "tmm=[TMM::cmp_unit] client=[IP::client_addr]:[TCP::client_port] server=[IP::server_addr]:[TCP::server_port]"
}
}

 /var/log/ltm

[root@B4200-R77-S7:Active:Standalone] config  tail -f /var/log/ltm
Apr 19 21:11:02 B4200-R77-S7 info tmm[14550]: Rule /Common/qux : tmm=0 client=100.100.100.3:42423 server=200.200.200.102:80
Apr 19 21:11:02 B4200-R77-S7 info tmm[14550]: Rule /Common/qux : tmm=0 client=100.100.100.3:42424 server=200.200.200.101:80
Apr 19 21:11:02 B4200-R77-S7 info tmm[14550]: Rule /Common/qux : tmm=0 client=100.100.100.3:42425 server=200.200.200.111:80
Apr 19 21:11:02 B4200-R77-S7 info tmm[14550]: Rule /Common/qux : tmm=0 client=100.100.100.3:42426 server=200.200.200.102:80
Apr 19 21:11:02 B4200-R77-S7 info tmm[14550]: Rule /Common/qux : tmm=0 client=100.100.100.3:42427 server=200.200.200.101:80
Apr 19 21:11:02 B4200-R77-S7 info tmm[14550]: Rule /Common/qux : tmm=0 client=100.100.100.3:42428 server=200.200.200.111:80
Apr 19 21:11:02 B4200-R77-S7 info tmm[14550]: Rule /Common/qux : tmm=0 client=100.100.100.3:42429 server=200.200.200.102:80
Apr 19 21:11:02 B4200-R77-S7 info tmm[14550]: Rule /Common/qux : tmm=0 client=100.100.100.3:42430 server=200.200.200.101:80
Apr 19 21:11:02 B4200-R77-S7 info tmm[14550]: Rule /Common/qux : tmm=0 client=100.100.100.3:42431 server=200.200.200.111:80

I capture traffic and see F5 still use tmm1,tmm2 ,... to manage traffic. Why it use that even though we disable CMP?

i understand it is normal because incoming traffic may be hashed to any tmm (not only tmm0). in case not tmm0, that traffic will be internally forwarded to tmm0. if you make a log in irule, you will see tmm which executes is tmm0.

 trace

[root@B4200-R77-S7:Active:Standalone] config  tcpdump -nni 0.0 -s0 port 80
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on 0.0, link-type EN10MB (Ethernet), capture size 65535 bytes
21:07:56.325777 IP 100.100.100.3.42422 > 100.100.100.108.80: S 4123496108:4123496108(0) win 5840  in slot1/tmm1 lis=
21:07:56.325949 IP 100.100.100.108.80 > 100.100.100.3.42422: S 2128954956:2128954956(0) ack 4123496109 win 4380  out slot1/tmm0 lis=/Common/bar
21:07:56.326325 IP 100.100.100.3.42422 > 100.100.100.108.80: . ack 1 win 5840  in slot1/tmm1 lis=/Common/bar
21:07:56.326540 IP 100.100.100.3.42422 > 100.100.100.108.80: P 1:91(90) ack 1 win 5840  in slot1/tmm1 lis=/Common/bar
21:07:56.326600 IP 200.200.200.107.42422 > 200.200.200.111.80: S 71915054:71915054(0) win 4380  out slot1/tmm0 lis=/Common/bar
21:07:56.326611 IP 100.100.100.108.80 > 100.100.100.3.42422: . ack 91 win 4470  out slot1/tmm0 lis=/Common/bar
21:07:56.328318 IP 200.200.200.111.80 > 200.200.200.107.42422: S 3326085761:3326085761(0) ack 71915055 win 5792  in slot1/tmm0 lis=/Common/bar
21:07:56.328338 IP 200.200.200.107.42422 > 200.200.200.111.80: . ack 1 win 4380  out slot1/tmm0 lis=/Common/bar
21:07:56.328447 IP 200.200.200.107.42422 > 200.200.200.111.80: P 1:91(90) ack 1 win 4380  out slot1/tmm0 lis=/Common/bar
21:07:56.328753 IP 200.200.200.111.80 > 200.200.200.107.42422: . ack 91 win 5792  in slot1/tmm0 lis=/Common/bar
21:07:56.329993 IP 200.200.200.111.80 > 200.200.200.107.42422: P 1:338(337) ack 91 win 5792  in slot1/tmm0 lis=/Common/bar
21:07:56.330012 IP 100.100.100.108.80 > 100.100.100.3.42422: P 1:338(337) ack 91 win 4470  out slot1/tmm0 lis=/Common/bar
21:07:56.330019 IP 200.200.200.107.42422 > 200.200.200.111.80: . ack 338 win 4717  out slot1/tmm0 lis=/Common/bar
21:07:56.330115 IP 200.200.200.111.80 > 200.200.200.107.42422: F 338:338(0) ack 91 win 5792  in slot1/tmm0 lis=/Common/bar
21:07:56.330126 IP 200.200.200.107.42422 > 200.200.200.111.80: . ack 339 win 4717  out slot1/tmm0 lis=/Common/bar
21:07:56.330131 IP 100.100.100.108.80 > 100.100.100.3.42422: F 338:338(0) ack 91 win 4470  out slot1/tmm0 lis=/Common/bar
21:07:56.330348 IP 100.100.100.3.42422 > 100.100.100.108.80: . ack 338 win 6432  in slot1/tmm1 lis=/Common/bar
21:07:56.330437 IP 100.100.100.3.42422 > 100.100.100.108.80: F 91:91(0) ack 339 win 6432  in slot1/tmm1 lis=/Common/bar
21:07:56.330468 IP 100.100.100.108.80 > 100.100.100.3.42422: . ack 92 win 4470  out slot1/tmm0 lis=/Common/bar
21:07:56.330486 IP 200.200.200.107.42422 > 200.200.200.111.80: F 91:91(0) ack 339 win 4717  out slot1/tmm0 lis=/Common/bar
21:07:56.330806 IP 200.200.200.111.80 > 200.200.200.107.42422: . ack 92 win 5792  in slot1/tmm0 lis=/Common/bar

 /var/log/ltm

[root@B4200-R77-S7:Active:Standalone] config  tail -f /var/log/ltm
Apr 19 21:07:56 B4200-R77-S7 info tmm[14550]: Rule /Common/qux : tmm=0 client=100.100.100.3:42422 server=200.200.200.111:80