Bean_Counter Sometimes IT folks are tasked with coming up with the justification for purchasing technology. It's not an enjoyable task, and considering the incredible difficulty in trying to pin dollar values on soft factors like increased productivity and an improved user experience the chore can be quite painful.

Technology that's become commoditized generally doesn't require ROI justification; when is the last time you were asked what the return on investment would be for a switch? Or a router? Or a server? If you've been in IT long enough the answer might be, "Oh, about 20 years or so ago."

Even though load balancers are nearing commodity status, the application delivery controller is not despite the fact that the core of an ADC is load balancing. And in less than favorable economic times, the requirement to justify every purchase becomes, well, a requirement rather than a "it'd be nice to have this before you open the box, Ed."

     Where's F5?


Unfortunately, even when the experts talk about how valuable an investment an application delivery controller might be right now, they rarely put numbers around it. And numbers, unfortunately, are what are necessary to justify the investment to the people who write the checks.

So let's look at a few ROI equations based on benefits of an application delivery controller that can help you justify your investment in an application delivery controller today.

Almost all application delivery controllers are capable of centralizing and therefore offloading SSL processing from servers. Offloading SSL from servers generally results in a 30% increase in capacity on web and application servers. So if your servers were capable of handling 3000 transactions per second before offloading, they would each be capable of handling around 3900. If you had 10 servers, that means you were capable of processing 30000 and now you are capable of processing 39000. That's a savings of 2 servers.
ROI equation: ((Cost to license, power, manage, and cool X servers - cost of ADC)/Cost of ADC)*100
Most application delivery controllers are also capable of performing application acceleration and optimizations as well. Whether it's through caching, compression, protocol optimization, or connection management, these features reduce the overhead on servers and make them more efficient. Case studies show that these optimizations often result in a 30-50% reduction in necessary servers as well as a reduction in bandwidth usage.

ROI equation: ((Cost to license, power, manage, and cool 50% of servers - cost of ADC)/Cost of ADC)*100

ROI equation: ((Bandwidth costs realized - cost of ADC)/Cost of ADC)*100


Most application delivery controllers are capable of providing basic layer 2-4 security and many offer additional security options at layer 4-7, such as protocol security and web application firewalls. These features mitigate the risk of unscheduled downtime due to several types of DoS (Denial of Service) attacks as well as the risk of a web application breach resulting in the public disclosure of customer information.

The valuation of customer information is difficult, as is the resulting affect on your organization's reputation. Valuation of downtime is much easier, as a business usually understands the effect on revenue that downtime can have.

Research last year (2007) indicated an average of 2.2% of a large organization's revenue went into a security black hole.

start_quote_rb Network downtime caused by security attacks is costing large enterprises more than $30 million a year, according to a recent study by Infonetics Research.

According to the study, "The Costs of Network Security Attacks: North America 2007," large organizations are losing an average of 2.2% of their annual revenue because of security attacks.end_quote_rb

                 -- "Network downtime from security attacks proves costly"


ROI equation: ((2.2% of annual revenue - cost of ADC)/Cost of ADC)*100

What's really awesome is that all three ROI models can - and are often - leveraged at the same time. A single application delivery controller can justify its cost through mitigating risk, reducing bandwidth costs, and increasing capacity of servers simultaneously.

That's the benefit of investing in an application delivery controller rather than just a load balancer. Not only do you get more bang for your buck, you get those bucks back more quickly.


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