For years the only solutions for WAN optimisation have been hardware-based appliances. But recently WAN optimisation and application acceleration technologies have leveraged virtualisation technology to give birth to software-based virtual appliances that deliver the performance, flexibility and cost-efficiencies the agile enterprise requires.

There are a number of hardware products on the market that use virtualisation technology, but the question is: do they really bring the benefits of virtualisation or are they just building the buzz around virtualisation?

A true virtual appliance is software running on a hypervisor that can be provisioned and scaled to the available system resources of the virtual machine (VM) environment. And any virtual appliance worth its salt must be managed, controlled and deployed by the VM management tools as an integral component within the virtual environment.

Hardware WAN optimisation and application acceleration solutions typically host some virtualisation capabilities by providing a limited virtualisation session on top of the appliance's standard operating system. These appliances do not support full hypervisors, mainly because the appliance design requires complete control of the system resources (CPU, memory, storage), allocating some limited capabilities for other applications.

The hardware appliance, the virtualisation container and any application running in the virtualisation container are all disconnected from the virtualisation management system. Without the support of a full-fledged hypervisor, hardware appliances cannot take advantage of the scalability, flexibility and manageability benefits of going virtual.

Fortunately for companies looking for a truly virtualised approach, WAN optimisation and application acceleration can be delivered via software-based virtual appliances. These tools deliver the same optimisation benefits of data compression, history caching and traffic de-duplication with the added benefit of these processes being managed by, and using the tools of, the virtualisation environment.

Here are the top five reasons for "going soft" when weighing the differences among various vendors' virtualized WAN optimisation and application acceleration solutions:

1. Flexibility to run on industry standard servers and hypervisors

Software virtual appliances running on industry standard servers and VM hypervisors accelerate server consolidation initiatives, eliminating appliance sprawl and the powering, cooling and management costs for all of that extraneous hardware. Virtual appliances for application acceleration can also run alongside other applications without limitation.

2. Building on the benefits of virtualisation

A true virtual appliance can take advantage of the core benefits of a VM, including but not limited to:

  • Dynamic resource allocation and sharing: VMs allocate system resources based on changes in user load or requirements. Dynamic resource allocation and sharing can be applied to application acceleration virtual appliances, adjusting capabilities to match changing business needs.
  • Increased utilisation: Virtual appliances can also be dynamically moved or a separate instance can be started without disrupting processes. Since virtual appliances can run alongside other VM applications and share system resources with those applications, there is less underutilisation of system resources.
  • High availability: A virtual appliance leverages the high availability features of a virtual environment, working around soft or hard failures. Because virtual appliances run on existing systems, there is no requirement to purchase redundant hardware appliances to support business continuity plans.

3. Performance and scalability

The performance of virtual appliance software is equal to hardware appliances in reducing application response time and bandwidth utilization. The scalability of the virtual appliance compared with scalability of a hardware appliance is where the rubber meets the road. Virtual appliances scale to support more concurrent optimised network connections per VM with the addition of CPU, memory or storage.

The number of concurrent optimized network connections for an appliance is commonly fixed by the size of the hardware platform and/or licensing restrictions and requires overpriced or fork lift hardware upgrades as enterprises expand capabilities and services. Virtual appliances will scale as system resources are added, enabling a more cost-efficient path to supporting more users.

4. Central deployment and management

Virtual appliance software makes deployment and management of WAN optimisation and application acceleration fast and easy. Virtual appliance images can be deployed and provisioned via VM central management systems. With virtual appliances, shipping hardware appliances to multiple remote offices is a thing of the past; now it's possible to centrally manage software distribution, setup and updates.

Virtual appliances also enable the growing number of mobile workers to reap remote access performance benefits wherever they are. A virtual appliance can be deployed directly onto desktops and laptops without requiring a physical appliance to be located at a local branch office to manage client licensing or provisioning for those users.

5. Lower cost

Lowering IT total cost of ownership (TCO) in today's economic environment is the most compelling reason to go with virtual appliances for WAN optimisation and application acceleration. Virtualised application acceleration can result in as much as a 60 percent lower TCO than deploying hardware over a period of three years. Virtual appliances can offer cost savings in everything from acquisition costs to real estate and maintenance and support expenditures.

For enterprises that are looking to reduce costs and simplify IT infrastructures via virtualisation, or those that are considering deploying cloud computing environments, more cost-efficient and flexible virtual appliances for WAN optimisation and application acceleration are essential to success. The differences between hardware appliances and virtual appliances can be calculated in dollars and by how the solution fully supports virtualised infrastructures and leverages virtualisation benefits.

What the comparison ultimately comes down to is the application performance experience and the hard numbers. The proof of any comparison like this is: put a virtual appliance next to a hardware appliance and test the capabilities in your own sandbox with your most performance-challenged applications. But to really appreciate the value of deploying virtual appliances for application acceleration, perform your own TCO comparison to see how going soft can significantly bring down your hard IT costs.