Like so many things, corporate video over IP has been heralded as the “next big thing” for some time now. And, like so many technology breakthroughs before it, IP video is finally entering many companies through the “back door” — the employee.
With the ranks of employees filling up with younger types accustomed to frequent visits to social networking and related sites like YouTube, the casual “checking up” on personal items that has gone on since the beginning of the online age can suddenly have resource repercussions as never before.
A single click on a video hyperlink can trigger thousands of packets full of video on a one-way trip through your corporate network. And, while it is easy to understand how accessing such video sites can chew up people’s time, what does it really mean to your network?
To find out, Tolly Group engineers conducted an informal survey and analysis of several popular video sites. After connecting network analyzers, they did just what users did and “clicked” to view short videos from a number of sites. If you are short for time and want to know whether you should worry, here it is. Yes, if you are responsible for providing corporate WAN bandwidth, your video-centric colleagues will eat it up.
Our team selected relatively short, two-minute-or-so segments from YouTube, Yahoo, Google and Apple’s movie trailer site. Apple’s video was in QuickTime format while the other three were all Flash Video (FLV). The format, though, didn’t seem to make any impact on the network behaviour.
While the “appetite” of the streams varied a bit (tested across a T1, 1.544-Mbps connection), they all put a constant 1Mbps load on the network.
Once begun, the video sites machine-gunned down a stream of mostly maximum-size (c. 1500 bytes) packets taking apparently as much bandwidth as desired or that it sensed available. The video is transported as TCP packets right over the existing browser session.
So what about the other, important traffic that needs to traverse the same links? Well, unless you have a QoS appliance in place that throttles down the video or limits a given session, the other traffic just gets pushed out of the way (so to speak).
To get that video off the wire, though, you might employ caching. While a megabit a second puts a strain on your WAN/broadband connection, it is a trivial load on your campus network. A cache solution would store a copy of the file locally such that other users calling it up would have it delivered locally.
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