LB_FAILED event

Ah, nice work! Didn't think of that, & didn't realize that was in the profile.

So first retransmission if no response is typically 3 seconds, and typcial backoff timer algorithm is to double wait time after each failed attempt. I verified for LTM @ the command line, and it looks like max syn retrans is set to 5, producing the following progression and timing out after 93 seconds:

Trying 172.24.2.200...
11:26:24.455153 172.24.2.41.55507 > 172.24.2.200.http: S ...
11:26:27.452465 172.24.2.41.55507 > 172.24.2.200.http: S ...
11:26:33.452465 172.24.2.41.55507 > 172.24.2.200.http: S ...
11:26:45.452465 172.24.2.41.55507 > 172.24.2.200.http: S ...
11:27:09.452481 172.24.2.41.55507 > 172.24.2.200.http: S ...
11:27:57.452466 172.24.2.41.55507 > 172.24.2.200.http: S ...
telnet: connect to address 172.24.2.200: Connection timed out

Looks like "Maximum Syn Retransmissions" is set to 4 in LTM's default tcp profile though, so LB_FAILED would be triggered if server didn't respond in 45 seconds:

  1st SYN:  0
  2nd SYN: +3 seconds
  3rd SYN: +6 seconds
  4th SYN: +12 seconds
  5th SYN: +24 seconds
 ======================
 LB_FAILED: 45 seconds

I will update the LB_FAILED wiki page with details to that effect.

/deb