Network Load Balancing

Stateless applications such as web servers can have fault-tolerance support by establishing Network Load Balancing across multiple identical instances of the application. Network Load Balancing (NLB) technology distributes the inbound traffic headed for the application across multiple machines running the same application, which allows for one server to fail and the remaining servers to pick up the load. Windows Server has a software implementation of NLB built in.

A hardware NLB solution can distribute requests based on a variety of load-distribution algorithms. It can also monitor various nodes in the server farm and ensure that they are operating properly before sending requests to them.
This option requires that at least one additional VM be added for each application
using NLB.