Editor’s Note: This week, we announced the availability of the NetEqualizer YouTube caching feature we first introduced in October. Over the past month, interest and inquiries have been high, so we’ve created the following Q&A to address many of the common questions we’ve received.
This may seem like a silly question, but why is caching advantageous?
The bottleneck most networks deal with is that they have a limited pipe leading out to the larger public Internet cloud. When a user visits a website or accesses content online, data must be transferred to and from the user through this limited pipe, which is usually meant for only average loads (increasing its size can be quite expensive). During busy times, when multiple users are accessing material from the Internet at once, the pipe can become clogged and service slowed. However, if an ISP can keep a cached copy of certain bandwidth-intensive content, such as a popular video, on a server in their local office, this bottleneck can be avoided. The pipe remains open and unclogged and customers are assured their video will always play faster and more smoothly than if they had to go out and re-fetch a copy from the YouTube server on the Internet.
What is the ROI benefit of caching YouTube? How much bandwidth can a provider conserve?
At the time of this writing, we are still in the early stages of our data collection on this subject. What we do know is that YouTube can account for up to 15 percent of Internet traffic. We expect to be able to cache at least the most popular 300 YouTube videos with this initial release and perhaps more when we release the mass-storage version of our caching server in the future. Considering this, realistic estimates put the savings in terms of bandwidth overhead somewhere between 5 and 15 percent. But this is only the instant benefits in terms bandwidth savings. The long-term customer-satisfaction benefit is that many more YouTube videos will play without interruption on a crowded network (busy hour) than before. Therefore, ROI shouldn’t be measured in bandwidth savings alone.
Why is it just the YouTube caching feature? Why not cache everything?
There are a couple of good reasons not to cache everything.
First, there are quite a few Web pages that are dynamically generated or change quite often, and a caching mechanism relies on content being relatively static. This allows it to grab content from the Internet and store it locally for future use without the content changing. As mentioned, when users/clients visit the specific Web pages that have been stored, they are directed to the locally saved content rather than over the Internet and to the original website. Therefore, caching obviously wouldn’t be possible for pages that are constantly changing. Caching dynamic content can cause all kinds of issues — especially with merchant and secure sites where each page is custom-generated for the client.
Second, a caching server can realistically only store a subset of data that it accesses. Yes, data storage is getting less expensive every year, but a local store is finite in size and will eventually fill up. So, when making a decision on what to cache and what not to cache, YouTube, being both popular and bandwidth intensive, was the logical choice.
Will the NetEqualizer ever cache content beyond YouTube? Such as other videos?
At this time, the NetEqualizer is caching files that traverse port 80 and correspond to video files from 30 seconds to 10 minutes. It is possible that some other port 80 file will fall into this category, but the bulk of it will be YouTube.
Is there anything else about YouTube that makes it a good candidate to cache?
Yes, YouTube content meets the level of stability discussed above that’s needed for effective caching. Once posted, most YouTube videos are not edited or changed. Hence, the copy in the local cache will stay current and be good indefinitely.
When I download large distributions, the download utility often gives me a choice of mirrored sites around the world. Is this the same as caching?
By definition this is also caching, but the difference is that there is a manual step to choosing one of these distribution sites. Some of the large-content open source distributions have been delivered this way for many years. The caching feature on the NetEqualizer is what is called “transparent,” meaning users do not have to do anything to get a cached copy.
If users are getting a file from cache without their knowledge, could this be construed as a violation of net neutrality?
We addressed the tenets of net neutrality in another article and to our knowledge caching has not been controversial in any way.
What about copyright violations? Is it legal to store someone’s content on an intermediate server?
This is a very complex question and anything is possible, but with respect to intent and the NetEqualizer caching mechanism, the Internet provider is only caching what is already freely available. There is no masking or redirection of the actual YouTube administrative wrappings that a user sees (this would be where advertising and promotions appear). Hence, there is no loss of potential of revenue for YouTube. In fact, it would be considered more of a benefit for them as it helps more people use their service where connections might otherwise be too slow.
Final Editor’s Note: While we’re confident this Q&A will answer many of the questions that arise about the NetEqualizer YouTube caching feature, please don’t hesitate to contact us with further inquiries. We can be reached at 1-888-287-2492 or firstname.lastname@example.org.