what will happen to existing connections when the monitor mark one pool member offline?

When the monitor mark one pool member offline, what will happen to existing connections? Would LTM reset the connections or wait until time out?

 

LTM will reset session for particular member and handover session to other available member in pool.

 

Hi,

 

Nit picking here but it's not always the case :-) - of course most of the time it is but not if:

 

• Monitor is set to other port than used for pool member
• Pool member still responds from it's configured port

In this case - even if member will be marked down - existing TCP connection will continue (at least when OneConnect is assigned), new LB will be made after connection finishes.

 

What LTM will do depends as well on Action on Service down (Pool setting):

 

• If None then LTM will be waiting for packet from client - when received connection will be reset
• If Reject LTM will send RST to client as soon as member is reported Down
• If Drop LTM will not send RST just remove flow from session table - if client will send packet then LTM reply with RST
• If Reselect LTM will try to send incoming client packets to newly selected member (after LB, but without 3WHS on server side) - for any non transparent type of member (like HTTP server) connection will be rejected (no match to session table on backend server) - so connection close will be handed to backend server - instead handled by LTM as with Reject.

Additionally if None is selected and there are no packets from client LTM will wait until Idle Timeout is over, then:

 

• If Reset On Timeout checked (default) will send RST to client
• If Reset On Timeout not checked will do nothing except removing flow from session table. If client will send packet after that then LTM will reset connection - non existing Flow.

Piotr