Evaluating Peer-to-Peer Solutions for Your Online Business
The effectiveness of P2P depends on the objectives of the content owner. For some, the overall effectiveness is measured in terms of "offload," meaning the percentage of object traffic that is delivered by the peers and in effect "offloaded" from the CDN and origin network. Offload dictates the cost savings or quality improvements now possible for the underlying business and should be in the 70-80% range for download and 50%+ range for progressive download models.
How to Evaluate P2P Solutions
In order to create the best experience for content owners and users, there are many things to consider when comparing P2P solutions. As solutions vary in effectiveness and capability, the following questions will help you assess if a given solution is right for you:
Scale Questions:
— Does the solution scale? What are the tested limits of scale?
— Has the technology bee validated in the field?
— How many clients have been distributed?
— Where (geographically) are the clients deployed?
Usability Questions:
— How does the client manage the shared resources of the end user machine and network?
— What is the size and performance of the client application?
— What different use cases does it support?
— Will the solution operate with personal firewalls and traverse NAT?
CDN Integration Questions:
— What origin server infrastructure or CDNs does the solution work with?
— What is the underlying scale of that infrastructure?
— What are the available analytics and reporting options?
Scale Questions
One of the key performance metrics of a peer-based solution is scale. Scale is often measured by the number of concurrent peers that can be supported and is typically considered in aggregate for the entire solution and concurrently for any given object.
You don’t want to be the first to test a new technology through each consecutive scaling barrier. Ask about any existing deployments and the number of concurrent users supported in each.
Another key metric for any solution is client distribution, which is the number of clients already installed and in use. Large client distributions are a good measure of the underlying technology, but in addition to the absolute number (and active number), it’s important to consider the geographic distribution of those clients as well. As with traditional CDNs, the geographic reach of a solution is a function of infrastructure, in this case, clients. And because network environments vary greatly in different parts of the world, knowing that a technology has proven effective from a global perspective ensures your users will have a good experience, no matter where they happen to be located.
Usability Questions
A usable client application must be well integrated into the comprehensive end user experience. This means the application is polite to other running applications, is polite to other users on the shared network, and doesn’t interfere with the content owners’ branded experience. A useable client is small in footprint and memory use. A useable client does not impede other applications on the network or machine. A useable client does not present a heavy interface that disrupts the brand of the content owner. As a CDN typically operates invisibly in the background, content owners should expect peer-based systems to behave the same way.
To reach the broadest market, P2P technology will need to be integrated into hardware devices or software applications. Again, the usability of a client will dictate how realistic that opportunity is. If you ever want your content to reach the television, the client technology you select must be of a small size and "embeddable" into hardware.