With Riverbed Virtual Steelhead appliances, WAN optimization extends to deployments where physical hardware may not be conveniently suited. Military deployments, for example, typically use ruggedized, custom hardware on which running a virtual machine is more convenient. Space-limited scenarios, such as mobile news vans or construction trailers, may also require a form factor that is free from the physical limitations of hardware appliances.The Virtual Steelhead appliance can be managed by industry standard virtualization tools to fit seamlessly into fully virtualized data center environments where interoperability with existing management infrastructure is a must-have. While targeted specifically for the above-mentioned scenarios, Virtual Steelhead appliances can also be deployed as a cluster in order to scale to data center environments.Data transfer bottlenecks and unpredictability on the Wide Area Network (WAN) can hurt application performance. In addition, the time required to migrate large volumes of data to and from data centers can be a serious concern to business continuity. These limitations can also negatively impact worker productivity, constrain disaster recovery capabilities, and reduce the effectiveness of IT consolidation and virtualization strategies.