Load balancing is an optimizing feature you use with clustered webMethods Integration Servers. Load balancing controls how requests are distributed to the servers in the cluster. You must use a third-party load balancer to perform load balancing. A third-party load balancer can be useful if you need load balancing for multiple types of servers, for example, web servers and application servers, in addition to webMethods Integration Servers. Third-party load balancers also offer virtual IP support, but they are not "out of the box." Most third-party load balancers perform load balancing in a round-robin manner or based on network level metrics such as TCP connections and network response time.