AX Load Balancing

A tree tiered architecture has been around since AX 4.0. In AX 2009 you have 3 possible AOS configurations:

1. Single AOS instance(s)
2. Load Balanced AOS instances without a dedicated load balancer
3. Load Balanced AOS instances with a dedicted load balancer

After experimenting a little bit with all of the possible configurations, I find it a little bit difficult to separate configuration 2 and 3 above. The only difference is the presence of one (or several) AOS instance(s) defined as dedicated load balancers only handling the load balancing functionality (no end user sessions) for AX clients that whish to log on to AX (handshake). So the big question is when to use a configuration with a dedicated load balancer. I can't see any reason or benefit other than limiting the need to adjust the client configurations when AOS instances move out and in of the cluster. The only benefit deploying a dedicated load balancer is that this will be the only AOS instance referenced by the clients and that this makes the client configuration more static compared to configuration 2 when every AOS instance in fact both is acting as a load balancer and handling client sessions.

And information from Microsoft states that a dedicated load balancer only is needed when you have more than 4 AOS instances in the same cluster.

All combinations in the client configurations will work (no difference wheter you only reference the dedicated load balancing instance and/or all AOS instances).

Any comments around this matter will be appreciated.