WAN optimisation products seek to accelerate a broad range of applications accessed by distributed enterprise users via eliminating redundant transmissions, staging data in local caches, compressing and prioritizing data, and streamlining chatty protocols (e.g., CIFS)..

In practice this usually means having an appliance at each end of a WAN link (IpSec VPN, IPClear etc) that optimises (or reduces) IP traffic between client and server or server to server. These products are purchased for various purposes which often include:

• Insufficient bandwidth available to introduce more users or new bandwidth hungry software.
• Sufficient bandwidth available but QoS would enable prioritisation of certain functions/applications, such as file and print.
• Prolong the longevity of a WAN link until such time as bandwidth or applications have been altered/improved.
• A means of minimising year on year WAN costs by taking the lowest cost option and providing “virtual bandwidth” with appliances