Does LACP traffic need to fail to switch links in a trunk?

[rcsauvag]

I have creted a static trunk with lacp in a lab between 2 HP Procurve switches, my firmware is OLD. I have a few nodes connected to the switches to test something we use specifically from a vendor, this test passed perfectly. My question is about the IP Hash that lacp uses. When I sever one of the connections between the two switches, I have trunked 2, sometimes I lose one ping between nodes while it switches over to the other port in the lacp trunk. 

Is this normal for LACP? Does the redundancy portion of LACP need the one failover before it will switch links?

[16again · Accepted solution]

LACP will send its own keep-alive packets, to determine if link is still present.
After losing connectivity, it will take some time to detect neighbor not being present, before failover takes place.
Another way to detect link going down is just the layer 1 link status.

Both mechanisms will take some time to readjust, and can result  in some lost traffic. (but only for traffic that was using that specific link).   On TCP streams , retransmit will mask packet loss, on VOIP call tiny silence is introduced.

This failover isn't initiated by lost network traffic, even without traffic failover mechanism kicks in