Load balancer topology design (Cisco ACE, F5 BIG-IP LTM)

Adding a load balancer to an existing network is easy. You just open the vendor’s quick start guide, connect some cables to the server segment, maybe some to the core network. Load balancer configuration includes assigning IP addresses, defining virtual servers and adding server pools. Practically you are done, all the rest you need to do is adding some static routes to some servers or tweaking some NAT setting on the load balancer.

Actually, I don’t say this is evil. Such setups can work for long times with moderate risks and operation principles may be well defined and documented. Even if it can cause problems for network redesign or firewall projects and I estimate slightly higher opex as the tricky load balancer topology most be considered at all changes, still, I can accept such a method in some cases.

However, I am a networker and I prefer creating a design that reflects general best practice of networking.