F5 LTM VIP/STP Problem

OK...

 

 

 

Firstly... I'm assuming the etherchannel you're referring to in your original post is the one BETWEEN the pair of switches only. Because 3560's don't do VPC's. (You need 6500 VSS or Nexus for that kind of stuff).

 

 

Second... Your F5 interfaces are bridged? That's why your redundant interfaces are blocking... Because you have a bridging loop. So the switches HAVE to block one of them (Because you're passing through the STP or PVST packets - As you need to if you're bridging other packets).

 

Hmm.. Thinking... You're not trying to do a trunk WITHOUT signalling are you? That won't work. It never does. (Well, OK, it CAN but any failures or mis-cabling generally lead to the problems you describe. So I tend to discourage actively any attempts to do so (i.e. won't support it and tell people to fix their end - You can only support stuff you have faith in. Unless you like to make great hourly rates fixing other peoples mistakes).

 

 

TLB & SLB... Hmm... I'm not a great fan of HP's NIC teaming... Most of the options don't actually work very well in a multi-switch environment. Switches are simple beasts. They expect IP's to map to consistent MAC's. And they expect MAC's to be on ONE switchport, and not move around. The only really useful NIC teaming mode is 802.3ad (LACP). It works fine, as long as the load-balancing is set correctly. If it's not, then again, you get the problems you're describing.

 

 

In summary.

 

Could be trunking/etherchannel problem without signalling

 

Or incorrect load balancing modes and MAC addresses moving between switches.

 

Or something else... The full config and diagram would need to be provided to give much more info.