Download score based load balancing

With download score based load balancing, GTM estimates the load on your data centers based on how long they take to respond to GTM liveness tests. This method's advantage is that you don't need to implement a load object. The disadvantage is this is a very crude measure of load, and usually highly nonlinear. As load increases, download times do not increase significantly until there is too much load. When that happens, the download times skyrocket causing erratic load balancing or load oscillations.

Download score based load balancing is an approximate mechanism, intended only to detect and mitigate against severe overloads. Set the Load imbalance factor to a fairly high value, at least 20%, to ensure that small differences in response time will not cause users to be mapped to a distant data center.