Any discussion about application delivery would not be complete unless we talk about the Application Delivery Controllers (ADCs). Citrix has a product called NetScaler, and its main functionality is application delivery. I know that we've been talking about application delivery from XenDesktop; however, there is actually an entire market just for ADCs outside of XenApp and XenDesktop. The term ADC is sort of a misnomer; that is, it doesn't actually deliver applications but rather sits in between XenDesktop and the user to optimize and secure the application delivery.

ADCs grew up as separate physical networking devices originally used for load balancing, HA, optimization, and security. ADCs are typically deployed in HA pairs to provide stateful failover in the event that one of them goes down. These days, the best option for HA is to run a pair of these devices in a HA pair for high availability and scalability. These devices can now be found as virtual appliances...